content: /*
   * Copyright (c) 2011 Kevin Sawicki <kevinsawicki@gmail.com>
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to
   * deal in the Software without restriction, including without limitation the
   * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
   * sell copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
   * IN THE SOFTWARE.
   */
  package com.github.kevinsawicki.http;
  
  import static java.net.HttpURLConnection.HTTP_BAD_REQUEST;
  import static java.net.HttpURLConnection.HTTP_CREATED;
  import static java.net.HttpURLConnection.HTTP_INTERNAL_ERROR;
  import static java.net.HttpURLConnection.HTTP_NOT_FOUND;
  import static java.net.HttpURLConnection.HTTP_NOT_MODIFIED;
  import static java.net.HttpURLConnection.HTTP_OK;
  import static java.net.Proxy.Type.HTTP;
  
  import java.io.BufferedInputStream;
  import java.io.BufferedOutputStream;
  import java.io.BufferedReader;
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.Closeable;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.FileOutputStream;
  import java.io.Flushable;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.InputStreamReader;
  import java.io.OutputStream;
  import java.io.OutputStreamWriter;
  import java.io.PrintStream;
  import java.io.Reader;
  import java.io.UnsupportedEncodingException;
  import java.io.Writer;
  import java.net.HttpURLConnection;
  import java.net.InetSocketAddress;
  import java.net.MalformedURLException;
  import java.net.Proxy;
  import java.net.URI;
  import java.net.URISyntaxException;
  import java.net.URL;
  import java.net.URLEncoder;
  import java.nio.ByteBuffer;
  import java.nio.CharBuffer;
  import java.nio.charset.Charset;
  import java.nio.charset.CharsetEncoder;
  import java.security.AccessController;
  import java.security.GeneralSecurityException;
  import java.security.PrivilegedAction;
  import java.security.SecureRandom;
  import java.security.cert.X509Certificate;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.concurrent.Callable;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.concurrent.atomic.AtomicReference;
  import java.util.zip.GZIPInputStream;
  
  import javax.net.ssl.HostnameVerifier;
  import javax.net.ssl.HttpsURLConnection;
  import javax.net.ssl.SSLContext;
  import javax.net.ssl.SSLSession;
  import javax.net.ssl.SSLSocketFactory;
  import javax.net.ssl.TrustManager;
  import javax.net.ssl.X509TrustManager;
  
  /**
   * A fluid interface for making HTTP requests using an underlying
   * {@link HttpURLConnection} (or sub-class).
   * <p>
   * Each instance supports making a single request and cannot be reused for
   * further requests.
   */
  public class HttpRequest {
  
    /**
     * 'UTF-8' charset name
     */
    public static final String CHARSET_UTF8 = "UTF-8";
  
    /**
     * 'application/x-www-form-urlencoded' content type header value
     */
    public static final String CONTENT_TYPE_FORM = "application/x-www-form-urlencoded";
  
    /**
     * 'application/json' content type header value
     */
    public static final String CONTENT_TYPE_JSON = "application/json";
  
    /**
     * 'gzip' encoding header value
     */
    public static final String ENCODING_GZIP = "gzip";
  
    /**
     * 'Accept' header name
     */
    public static final String HEADER_ACCEPT = "Accept";
  
    /**
     * 'Accept-Charset' header name
     */
    public static final String HEADER_ACCEPT_CHARSET = "Accept-Charset";
  
    /**
     * 'Accept-Encoding' header name
     */
    public static final String HEADER_ACCEPT_ENCODING = "Accept-Encoding";
  
    /**
     * 'Authorization' header name
     */
    public static final String HEADER_AUTHORIZATION = "Authorization";
  
    /**
     * 'Cache-Control' header name
     */
    public static final String HEADER_CACHE_CONTROL = "Cache-Control";
  
    /**
     * 'Content-Encoding' header name
     */
    public static final String HEADER_CONTENT_ENCODING = "Content-Encoding";
  
    /**
     * 'Content-Length' header name
     */
    public static final String HEADER_CONTENT_LENGTH = "Content-Length";
  
    /**
     * 'Content-Type' header name
     */
    public static final String HEADER_CONTENT_TYPE = "Content-Type";
  
    /**
     * 'Date' header name
     */
    public static final String HEADER_DATE = "Date";
  
    /**
     * 'ETag' header name
     */
    public static final String HEADER_ETAG = "ETag";
  
    /**
     * 'Expires' header name
     */
    public static final String HEADER_EXPIRES = "Expires";
  
    /**
     * 'If-None-Match' header name
     */
    public static final String HEADER_IF_NONE_MATCH = "If-None-Match";
  
    /**
     * 'Last-Modified' header name
     */
    public static final String HEADER_LAST_MODIFIED = "Last-Modified";
  
    /**
     * 'Location' header name
     */
    public static final String HEADER_LOCATION = "Location";
  
    /**
     * 'Proxy-Authorization' header name
     */
    public static final String HEADER_PROXY_AUTHORIZATION = "Proxy-Authorization";
  
    /**
     * 'Referer' header name
     */
    public static final String HEADER_REFERER = "Referer";
  
    /**
     * 'Server' header name
     */
    public static final String HEADER_SERVER = "Server";
  
    /**
     * 'User-Agent' header name
     */
    public static final String HEADER_USER_AGENT = "User-Agent";
  
    /**
     * 'DELETE' request method
     */
    public static final String METHOD_DELETE = "DELETE";
  
    /**
     * 'GET' request method
     */
    public static final String METHOD_GET = "GET";
  
    /**
     * 'HEAD' request method
     */
    public static final String METHOD_HEAD = "HEAD";
  
    /**
     * 'OPTIONS' options method
     */
    public static final String METHOD_OPTIONS = "OPTIONS";
  
    /**
     * 'POST' request method
     */
    public static final String METHOD_POST = "POST";
  
    /**
     * 'PUT' request method
     */
    public static final String METHOD_PUT = "PUT";
  
    /**
     * 'TRACE' request method
     */
    public static final String METHOD_TRACE = "TRACE";
  
    /**
     * 'charset' header value parameter
     */
    public static final String PARAM_CHARSET = "charset";
  
    private static final String BOUNDARY = "00content0boundary00";
  
    private static final String CONTENT_TYPE_MULTIPART = "multipart/form-data; boundary="
        + BOUNDARY;
  
    private static final String CRLF = "\r\n";
  
    private static final String[] EMPTY_STRINGS = new String[0];
  
    private static SSLSocketFactory TRUSTED_FACTORY;
  
    private static HostnameVerifier TRUSTED_VERIFIER;
  
    private static String getValidCharset(final String charset) {
      if (charset != null && charset.length() > 0)
        return charset;
      else
        return CHARSET_UTF8;
    }
  
    private static SSLSocketFactory getTrustedFactory()
        throws HttpRequestException {
      if (TRUSTED_FACTORY == null) {
        final TrustManager[] trustAllCerts = new TrustManager[] { new X509TrustManager() {
  
          public X509Certificate[] getAcceptedIssuers() {
            return new X509Certificate[0];
          }
  
          public void checkClientTrusted(X509Certificate[] chain, String authType) {
            // Intentionally left blank
          }
  
          public void checkServerTrusted(X509Certificate[] chain, String authType) {
            // Intentionally left blank
          }
        } };
        try {
          SSLContext context = SSLContext.getInstance("TLS");
          context.init(null, trustAllCerts, new SecureRandom());
          TRUSTED_FACTORY = context.getSocketFactory();
        } catch (GeneralSecurityException e) {
          IOException ioException = new IOException(
              "Security exception configuring SSL context");
          ioException.initCause(e);
          throw new HttpRequestException(ioException);
        }
      }
  
      return TRUSTED_FACTORY;
    }
  
    private static HostnameVerifier getTrustedVerifier() {
      if (TRUSTED_VERIFIER == null)
        TRUSTED_VERIFIER = new HostnameVerifier() {
  
          public boolean verify(String hostname, SSLSession session) {
            return true;
          }
        };
  
      return TRUSTED_VERIFIER;
    }
  
    private static StringBuilder addPathSeparator(final String baseUrl,
        final StringBuilder result) {
      // Add trailing slash if the base URL doesn't have any path segments.
      //
      // The following test is checking for the last slash not being part of
      // the protocol to host separator: '://'.
      if (baseUrl.indexOf(':') + 2 == baseUrl.lastIndexOf('/'))
        result.append('/');
      return result;
    }
  
    private static StringBuilder addParamPrefix(final String baseUrl,
        final StringBuilder result) {
      // Add '?' if missing and add '&' if params already exist in base url
      final int queryStart = baseUrl.indexOf('?');
      final int lastChar = result.length() - 1;
      if (queryStart == -1)
        result.append('?');
      else if (queryStart < lastChar && baseUrl.charAt(lastChar) != '&')
        result.append('&');
      return result;
    }
  
    /**
     * Creates {@link HttpURLConnection HTTP connections} for
     * {@link URL urls}.
     */
    public interface ConnectionFactory {
      /**
       * Open an {@link HttpURLConnection} for the specified {@link URL}.
       *
       * @throws IOException
       */
      HttpURLConnection create(URL url) throws IOException;
  
      /**
       * Open an {@link HttpURLConnection} for the specified {@link URL}
       * and {@link Proxy}.
       *
       * @throws IOException
       */
      HttpURLConnection create(URL url, Proxy proxy) throws IOException;
  
      /**
       * A {@link ConnectionFactory} which uses the built-in
       * {@link URL#openConnection()}
       */
      ConnectionFactory DEFAULT = new ConnectionFactory() {
        public HttpURLConnection create(URL url) throws IOException {
          return (HttpURLConnection) url.openConnection();
        }
  
        public HttpURLConnection create(URL url, Proxy proxy) throws IOException {
          return (HttpURLConnection) url.openConnection(proxy);
        }
      };
    }
  
    private static ConnectionFactory CONNECTION_FACTORY = ConnectionFactory.DEFAULT;
  
    /**
     * Specify the {@link ConnectionFactory} used to create new requests.
     */
    public static void setConnectionFactory(final ConnectionFactory connectionFactory) {
      if (connectionFactory == null)
        CONNECTION_FACTORY = ConnectionFactory.DEFAULT;
      else
        CONNECTION_FACTORY = connectionFactory;
    }
  
    /**
     * <p>
     * Encodes and decodes to and from Base64 notation.
     * </p>
     * <p>
     * I am placing this code in the Public Domain. Do with it as you will. This
     * software comes with no guarantees or warranties but with plenty of
     * well-wishing instead! Please visit <a
     * href="http://iharder.net/base64">http://iharder.net/base64</a> periodically
     * to check for updates or to contribute improvements.
     * </p>
     *
     * @author Robert Harder
     * @author rob@iharder.net
     * @version 2.3.7
     */
    public static class Base64 {
  
      /** The equals sign (=) as a byte. */
      private final static byte EQUALS_SIGN = (byte) '=';
  
      /** Preferred encoding. */
      private final static String PREFERRED_ENCODING = "US-ASCII";
  
      /** The 64 valid Base64 values. */
      private final static byte[] _STANDARD_ALPHABET = { (byte) 'A', (byte) 'B',
          (byte) 'C', (byte) 'D', (byte) 'E', (byte) 'F', (byte) 'G', (byte) 'H',
          (byte) 'I', (byte) 'J', (byte) 'K', (byte) 'L', (byte) 'M', (byte) 'N',
          (byte) 'O', (byte) 'P', (byte) 'Q', (byte) 'R', (byte) 'S', (byte) 'T',
          (byte) 'U', (byte) 'V', (byte) 'W', (byte) 'X', (byte) 'Y', (byte) 'Z',
          (byte) 'a', (byte) 'b', (byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f',
          (byte) 'g', (byte) 'h', (byte) 'i', (byte) 'j', (byte) 'k', (byte) 'l',
          (byte) 'm', (byte) 'n', (byte) 'o', (byte) 'p', (byte) 'q', (byte) 'r',
          (byte) 's', (byte) 't', (byte) 'u', (byte) 'v', (byte) 'w', (byte) 'x',
          (byte) 'y', (byte) 'z', (byte) '0', (byte) '1', (byte) '2', (byte) '3',
          (byte) '4', (byte) '5', (byte) '6', (byte) '7', (byte) '8', (byte) '9',
          (byte) '+', (byte) '/' };
  
      /** Defeats instantiation. */
      private Base64() {
      }
  
      /**
       * <p>
       * Encodes up to three bytes of the array <var>source</var> and writes the
       * resulting four Base64 bytes to <var>destination</var>. The source and
       * destination arrays can be manipulated anywhere along their length by
       * specifying <var>srcOffset</var> and <var>destOffset</var>. This method
       * does not check to make sure your arrays are large enough to accomodate
       * <var>srcOffset</var> + 3 for the <var>source</var> array or
       * <var>destOffset</var> + 4 for the <var>destination</var> array. The
       * actual number of significant bytes in your array is given by
       * <var>numSigBytes</var>.
       * </p>
       * <p>
       * This is the lowest level of the encoding methods with all possible
       * parameters.
       * </p>
       *
       * @param source
       *          the array to convert
       * @param srcOffset
       *          the index where conversion begins
       * @param numSigBytes
       *          the number of significant bytes in your array
       * @param destination
       *          the array to hold the conversion
       * @param destOffset
       *          the index where output will be put
       * @return the <var>destination</var> array
       * @since 1.3
       */
      private static byte[] encode3to4(byte[] source, int srcOffset,
          int numSigBytes, byte[] destination, int destOffset) {
  
        byte[] ALPHABET = _STANDARD_ALPHABET;
  
        int inBuff = (numSigBytes > 0 ? ((source[srcOffset] << 24) >>> 8) : 0)
            | (numSigBytes > 1 ? ((source[srcOffset + 1] << 24) >>> 16) : 0)
            | (numSigBytes > 2 ? ((source[srcOffset + 2] << 24) >>> 24) : 0);
  
        switch (numSigBytes) {
        case 3:
          destination[destOffset] = ALPHABET[(inBuff >>> 18)];
          destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
          destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
          destination[destOffset + 3] = ALPHABET[(inBuff) & 0x3f];
          return destination;
  
        case 2:
          destination[destOffset] = ALPHABET[(inBuff >>> 18)];
          destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
          destination[destOffset + 2] = ALPHABET[(inBuff >>> 6) & 0x3f];
          destination[destOffset + 3] = EQUALS_SIGN;
          return destination;
  
        case 1:
          destination[destOffset] = ALPHABET[(inBuff >>> 18)];
          destination[destOffset + 1] = ALPHABET[(inBuff >>> 12) & 0x3f];
          destination[destOffset + 2] = EQUALS_SIGN;
          destination[destOffset + 3] = EQUALS_SIGN;
          return destination;
  
        default:
          return destination;
        }
      }
  
      /**
       * Encode string as a byte array in Base64 annotation.
       *
       * @param string
       * @return The Base64-encoded data as a string
       */
      public static String encode(String string) {
        byte[] bytes;
        try {
          bytes = string.getBytes(PREFERRED_ENCODING);
        } catch (UnsupportedEncodingException e) {
          bytes = string.getBytes();
        }
        return encodeBytes(bytes);
      }
  
      /**
       * Encodes a byte array into Base64 notation.
       *
       * @param source
       *          The data to convert
       * @return The Base64-encoded data as a String
       * @throws NullPointerException
       *           if source array is null
       * @throws IllegalArgumentException
       *           if source array, offset, or length are invalid
       * @since 2.0
       */
      public static String encodeBytes(byte[] source) {
        return encodeBytes(source, 0, source.length);
      }
  
      /**
       * Encodes a byte array into Base64 notation.
       *
       * @param source
       *          The data to convert
       * @param off
       *          Offset in array where conversion should begin
       * @param len
       *          Length of data to convert
       * @return The Base64-encoded data as a String
       * @throws NullPointerException
       *           if source array is null
       * @throws IllegalArgumentException
       *           if source array, offset, or length are invalid
       * @since 2.0
       */
      public static String encodeBytes(byte[] source, int off, int len) {
        byte[] encoded = encodeBytesToBytes(source, off, len);
        try {
          return new String(encoded, PREFERRED_ENCODING);
        } catch (UnsupportedEncodingException uue) {
          return new String(encoded);
        }
      }
  
      /**
       * Similar to {@link #encodeBytes(byte[], int, int)} but returns a byte
       * array instead of instantiating a String. This is more efficient if you're
       * working with I/O streams and have large data sets to encode.
       *
       *
       * @param source
       *          The data to convert
       * @param off
       *          Offset in array where conversion should begin
       * @param len
       *          Length of data to convert
       * @return The Base64-encoded data as a String if there is an error
       * @throws NullPointerException
       *           if source array is null
       * @throws IllegalArgumentException
       *           if source array, offset, or length are invalid
       * @since 2.3.1
       */
      public static byte[] encodeBytesToBytes(byte[] source, int off, int len) {
  
        if (source == null)
          throw new NullPointerException("Cannot serialize a null array.");
  
        if (off < 0)
          throw new IllegalArgumentException("Cannot have negative offset: "
              + off);
  
        if (len < 0)
          throw new IllegalArgumentException("Cannot have length offset: " + len);
  
        if (off + len > source.length)
          throw new IllegalArgumentException(
              String
                  .format(
                      "Cannot have offset of %d and length of %d with array of length %d",
                      off, len, source.length));
  
        // Bytes needed for actual encoding
        int encLen = (len / 3) * 4 + (len % 3 > 0 ? 4 : 0);
  
        byte[] outBuff = new byte[encLen];
  
        int d = 0;
        int e = 0;
        int len2 = len - 2;
        for (; d < len2; d += 3, e += 4)
          encode3to4(source, d + off, 3, outBuff, e);
  
        if (d < len) {
          encode3to4(source, d + off, len - d, outBuff, e);
          e += 4;
        }
  
        if (e <= outBuff.length - 1) {
          byte[] finalOut = new byte[e];
          System.arraycopy(outBuff, 0, finalOut, 0, e);
          return finalOut;
        } else
          return outBuff;
      }
    }
  
    /**
     * HTTP request exception whose cause is always an {@link IOException}
     */
    public static class HttpRequestException extends RuntimeException {
  
      private static final long serialVersionUID = -1170466989781746231L;
  
      /**
       * Create a new HttpRequestException with the given cause
       *
       * @param cause
       */
      public HttpRequestException(final IOException cause) {
        super(cause);
      }
  
      /**
       * Get {@link IOException} that triggered this request exception
       *
       * @return {@link IOException} cause
       */
      @Override
      public IOException getCause() {
        return (IOException) super.getCause();
      }
    }
  
    /**
     * Operation that handles executing a callback once complete and handling
     * nested exceptions
     *
     * @param <V>
     */
    protected static abstract class Operation<V> implements Callable<V> {
  
      /**
       * Run operation
       *
       * @return result
       * @throws HttpRequestException
       * @throws IOException
       */
      protected abstract V run() throws HttpRequestException, IOException;
  
      /**
       * Operation complete callback
       *
       * @throws IOException
       */
      protected abstract void done() throws IOException;
  
      public V call() throws HttpRequestException {
        boolean thrown = false;
        try {
          return run();
        } catch (HttpRequestException e) {
          thrown = true;
          throw e;
        } catch (IOException e) {
          thrown = true;
          throw new HttpRequestException(e);
        } finally {
          try {
            done();
          } catch (IOException e) {
            if (!thrown)
              throw new HttpRequestException(e);
          }
        }
      }
    }
  
    /**
     * Class that ensures a {@link Closeable} gets closed with proper exception
     * handling.
     *
     * @param <V>
     */
    protected static abstract class CloseOperation<V> extends Operation<V> {
  
      private final Closeable closeable;
  
      private final boolean ignoreCloseExceptions;
  
      /**
       * Create closer for operation
       *
       * @param closeable
       * @param ignoreCloseExceptions
       */
      protected CloseOperation(final Closeable closeable,
          final boolean ignoreCloseExceptions) {
        this.closeable = closeable;
        this.ignoreCloseExceptions = ignoreCloseExceptions;
      }
  
      @Override
      protected void done() throws IOException {
        if (closeable instanceof Flushable)
          ((Flushable) closeable).flush();
        if (ignoreCloseExceptions)
          try {
            closeable.close();
          } catch (IOException e) {
            // Ignored
          }
        else
          closeable.close();
      }
    }
  
    /**
     * Class that and ensures a {@link Flushable} gets flushed with proper
     * exception handling.
     *
     * @param <V>
     */
    protected static abstract class FlushOperation<V> extends Operation<V> {
  
      private final Flushable flushable;
  
      /**
       * Create flush operation
       *
       * @param flushable
       */
      protected FlushOperation(final Flushable flushable) {
        this.flushable = flushable;
      }
  
      @Override
      protected void done() throws IOException {
        flushable.flush();
      }
    }
  
    /**
     * Request output stream
     */
    public static class RequestOutputStream extends BufferedOutputStream {
  
      private final CharsetEncoder encoder;
  
      /**
       * Create request output stream
       *
       * @param stream
       * @param charset
       * @param bufferSize
       */
      public RequestOutputStream(final OutputStream stream, final String charset,
          final int bufferSize) {
        super(stream, bufferSize);
  
        encoder = Charset.forName(getValidCharset(charset)).newEncoder();
      }
  
      /**
       * Write string to stream
       *
       * @param value
       * @return this stream
       * @throws IOException
       */
      public RequestOutputStream write(final String value) throws IOException {
        final ByteBuffer bytes = encoder.encode(CharBuffer.wrap(value));
  
        super.write(bytes.array(), 0, bytes.limit());
  
        return this;
      }
    }
  
    /**
     * Encode the given URL as an ASCII {@link String}
     * <p>
     * This method ensures the path and query segments of the URL are properly
     * encoded such as ' ' characters being encoded to '%20' or any UTF-8
     * characters that are non-ASCII. No encoding of URLs is done by default by
     * the {@link HttpRequest} constructors and so if URL encoding is needed this
     * method should be called before calling the {@link HttpRequest} constructor.
     *
     * @param url
     * @return encoded URL
     * @throws HttpRequestException
     */
    public static String encode(final CharSequence url)
        throws HttpRequestException {
      URL parsed;
      try {
        parsed = new URL(url.toString());
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
  
      String host = parsed.getHost();
      int port = parsed.getPort();
      if (port != -1)
        host = host + ':' + Integer.toString(port);
  
      try {
        String encoded = new URI(parsed.getProtocol(), host, parsed.getPath(),
            parsed.getQuery(), null).toASCIIString();
        int paramsStart = encoded.indexOf('?');
        if (paramsStart > 0 && paramsStart + 1 < encoded.length())
          encoded = encoded.substring(0, paramsStart + 1)
                    + encoded.substring(paramsStart + 1).replace("+", "%2B");
        return encoded;
      } catch (URISyntaxException e) {
        IOException io = new IOException("Parsing URI failed");
        io.initCause(e);
        throw new HttpRequestException(io);
      }
    }
  
    /**
     * Append given map as query parameters to the base URL
     * <p>
     * Each map entry's key will be a parameter name and the value's
     * {@link Object#toString()} will be the parameter value.
     *
     * @param url
     * @param params
     * @return URL with appended query params
     */
    public static String append(final CharSequence url, final Map<?, ?> params) {
      final String baseUrl = url.toString();
      if (params == null || params.isEmpty())
        return baseUrl;
  
      final StringBuilder result = new StringBuilder(baseUrl);
  
      addPathSeparator(baseUrl, result);
      addParamPrefix(baseUrl, result);
  
      Entry<?, ?> entry;
      Object value;
      Iterator<?> iterator = params.entrySet().iterator();
      entry = (Entry<?, ?>) iterator.next();
      result.append(entry.getKey().toString());
      result.append('=');
      value = entry.getValue();
      if (value != null)
        result.append(value);
  
      while (iterator.hasNext()) {
        result.append('&');
        entry = (Entry<?, ?>) iterator.next();
        result.append(entry.getKey().toString());
        result.append('=');
        value = entry.getValue();
        if (value != null)
          result.append(value);
      }
  
      return result.toString();
    }
  
    /**
     * Append given name/value pairs as query parameters to the base URL
     * <p>
     * The params argument is interpreted as a sequence of name/value pairs so the
     * given number of params must be divisible by 2.
     *
     * @param url
     * @param params
     *          name/value pairs
     * @return URL with appended query params
     */
    public static String append(final CharSequence url, final Object... params) {
      final String baseUrl = url.toString();
      if (params == null || params.length == 0)
        return baseUrl;
  
      if (params.length % 2 != 0)
        throw new IllegalArgumentException(
            "Must specify an even number of parameter names/values");
  
      final StringBuilder result = new StringBuilder(baseUrl);
  
      addPathSeparator(baseUrl, result);
      addParamPrefix(baseUrl, result);
  
      Object value;
      result.append(params[0]);
      result.append('=');
      value = params[1];
      if (value != null)
        result.append(value);
  
      for (int i = 2; i < params.length; i += 2) {
        result.append('&');
        result.append(params[i]);
        result.append('=');
        value = params[i + 1];
        if (value != null)
          result.append(value);
      }
  
      return result.toString();
    }
  
    /**
     * Start a 'GET' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest get(final CharSequence url)
        throws HttpRequestException {
      return new HttpRequest(url, METHOD_GET);
    }
  
    /**
     * Start a 'GET' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest get(final URL url) throws HttpRequestException {
      return new HttpRequest(url, METHOD_GET);
    }
  
    /**
     * Start a 'GET' request to the given URL along with the query params
     *
     * @param baseUrl
     * @param params
     *          The query parameters to include as part of the baseUrl
     * @param encode
     *          true to encode the full URL
     *
     * @see #append(CharSequence, Map)
     * @see #encode(CharSequence)
     *
     * @return request
     */
    public static HttpRequest get(final CharSequence baseUrl,
        final Map<?, ?> params, final boolean encode) {
      String url = append(baseUrl, params);
      return get(encode ? encode(url) : url);
    }
  
    /**
     * Start a 'GET' request to the given URL along with the query params
     *
     * @param baseUrl
     * @param encode
     *          true to encode the full URL
     * @param params
     *          the name/value query parameter pairs to include as part of the
     *          baseUrl
     *
     * @see #append(CharSequence, String...)
     * @see #encode(CharSequence)
     *
     * @return request
     */
    public static HttpRequest get(final CharSequence baseUrl,
        final boolean encode, final Object... params) {
      String url = append(baseUrl, params);
      return get(encode ? encode(url) : url);
    }
  
    /**
     * Start a 'POST' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest post(final CharSequence url)
        throws HttpRequestException {
      return new HttpRequest(url, METHOD_POST);
    }
  
    /**
     * Start a 'POST' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest post(final URL url) throws HttpRequestException {
      return new HttpRequest(url, METHOD_POST);
    }
  
    /**
     * Start a 'POST' request to the given URL along with the query params
     *
     * @param baseUrl
     * @param params
     *          the query parameters to include as part of the baseUrl
     * @param encode
     *          true to encode the full URL
     *
     * @see #append(CharSequence, Map)
     * @see #encode(CharSequence)
     *
     * @return request
     */
    public static HttpRequest post(final CharSequence baseUrl,
        final Map<?, ?> params, final boolean encode) {
      String url = append(baseUrl, params);
      return post(encode ? encode(url) : url);
    }
  
    /**
     * Start a 'POST' request to the given URL along with the query params
     *
     * @param baseUrl
     * @param encode
     *          true to encode the full URL
     * @param params
     *          the name/value query parameter pairs to include as part of the
     *          baseUrl
     *
     * @see #append(CharSequence, String...)
     * @see #encode(CharSequence)
     *
     * @return request
     */
    public static HttpRequest post(final CharSequence baseUrl,
        final boolean encode, final Object... params) {
      String url = append(baseUrl, params);
      return post(encode ? encode(url) : url);
    }
  
    /**
     * Start a 'PUT' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest put(final CharSequence url)
        throws HttpRequestException {
      return new HttpRequest(url, METHOD_PUT);
    }
  
    /**
     * Start a 'PUT' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest put(final URL url) throws HttpRequestException {
      return new HttpRequest(url, METHOD_PUT);
    }
  
    /**
     * Start a 'PUT' request to the given URL along with the query params
     *
     * @param baseUrl
     * @param params
     *          the query parameters to include as part of the baseUrl
     * @param encode
     *          true to encode the full URL
     *
     * @see #append(CharSequence, Map)
     * @see #encode(CharSequence)
     *
     * @return request
     */
    public static HttpRequest put(final CharSequence baseUrl,
        final Map<?, ?> params, final boolean encode) {
      String url = append(baseUrl, params);
      return put(encode ? encode(url) : url);
    }
  
    /**
     * Start a 'PUT' request to the given URL along with the query params
     *
     * @param baseUrl
     * @param encode
     *          true to encode the full URL
     * @param params
     *          the name/value query parameter pairs to include as part of the
     *          baseUrl
     *
     * @see #append(CharSequence, String...)
     * @see #encode(CharSequence)
     *
     * @return request
     */
    public static HttpRequest put(final CharSequence baseUrl,
        final boolean encode, final Object... params) {
      String url = append(baseUrl, params);
      return put(encode ? encode(url) : url);
    }
  
    /**
     * Start a 'DELETE' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest delete(final CharSequence url)
        throws HttpRequestException {
      return new HttpRequest(url, METHOD_DELETE);
    }
  
    /**
     * Start a 'DELETE' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest delete(final URL url) throws HttpRequestException {
      return new HttpRequest(url, METHOD_DELETE);
    }
  
    /**
     * Start a 'DELETE' request to the given URL along with the query params
     *
     * @param baseUrl
     * @param params
     *          The query parameters to include as part of the baseUrl
     * @param encode
     *          true to encode the full URL
     *
     * @see #append(CharSequence, Map)
     * @see #encode(CharSequence)
     *
     * @return request
     */
    public static HttpRequest delete(final CharSequence baseUrl,
        final Map<?, ?> params, final boolean encode) {
      String url = append(baseUrl, params);
      return delete(encode ? encode(url) : url);
    }
  
    /**
     * Start a 'DELETE' request to the given URL along with the query params
     *
     * @param baseUrl
     * @param encode
     *          true to encode the full URL
     * @param params
     *          the name/value query parameter pairs to include as part of the
     *          baseUrl
     *
     * @see #append(CharSequence, String...)
     * @see #encode(CharSequence)
     *
     * @return request
     */
    public static HttpRequest delete(final CharSequence baseUrl,
        final boolean encode, final Object... params) {
      String url = append(baseUrl, params);
      return delete(encode ? encode(url) : url);
    }
  
    /**
     * Start a 'HEAD' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest head(final CharSequence url)
        throws HttpRequestException {
      return new HttpRequest(url, METHOD_HEAD);
    }
  
    /**
     * Start a 'HEAD' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest head(final URL url) throws HttpRequestException {
      return new HttpRequest(url, METHOD_HEAD);
    }
  
    /**
     * Start a 'HEAD' request to the given URL along with the query params
     *
     * @param baseUrl
     * @param params
     *          The query parameters to include as part of the baseUrl
     * @param encode
     *          true to encode the full URL
     *
     * @see #append(CharSequence, Map)
     * @see #encode(CharSequence)
     *
     * @return request
     */
    public static HttpRequest head(final CharSequence baseUrl,
        final Map<?, ?> params, final boolean encode) {
      String url = append(baseUrl, params);
      return head(encode ? encode(url) : url);
    }
  
    /**
     * Start a 'GET' request to the given URL along with the query params
     *
     * @param baseUrl
     * @param encode
     *          true to encode the full URL
     * @param params
     *          the name/value query parameter pairs to include as part of the
     *          baseUrl
     *
     * @see #append(CharSequence, String...)
     * @see #encode(CharSequence)
     *
     * @return request
     */
    public static HttpRequest head(final CharSequence baseUrl,
        final boolean encode, final Object... params) {
      String url = append(baseUrl, params);
      return head(encode ? encode(url) : url);
    }
  
    /**
     * Start an 'OPTIONS' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest options(final CharSequence url)
        throws HttpRequestException {
      return new HttpRequest(url, METHOD_OPTIONS);
    }
  
    /**
     * Start an 'OPTIONS' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest options(final URL url) throws HttpRequestException {
      return new HttpRequest(url, METHOD_OPTIONS);
    }
  
    /**
     * Start a 'TRACE' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest trace(final CharSequence url)
        throws HttpRequestException {
      return new HttpRequest(url, METHOD_TRACE);
    }
  
    /**
     * Start a 'TRACE' request to the given URL
     *
     * @param url
     * @return request
     * @throws HttpRequestException
     */
    public static HttpRequest trace(final URL url) throws HttpRequestException {
      return new HttpRequest(url, METHOD_TRACE);
    }
  
    /**
     * Set the 'http.keepAlive' property to the given value.
     * <p>
     * This setting will apply to all requests.
     *
     * @param keepAlive
     */
    public static void keepAlive(final boolean keepAlive) {
      setProperty("http.keepAlive", Boolean.toString(keepAlive));
    }
  
    /**
     * Set the 'http.maxConnections' property to the given value.
     * <p>
     * This setting will apply to all requests.
     *
     * @param maxConnections
     */
    public static void maxConnections(final int maxConnections) {
      setProperty("http.maxConnections", Integer.toString(maxConnections));
    }
  
    /**
     * Set the 'http.proxyHost' & 'https.proxyHost' properties to the given host
     * value.
     * <p>
     * This setting will apply to all requests.
     *
     * @param host
     */
    public static void proxyHost(final String host) {
      setProperty("http.proxyHost", host);
      setProperty("https.proxyHost", host);
    }
  
    /**
     * Set the 'http.proxyPort' & 'https.proxyPort' properties to the given port
     * number.
     * <p>
     * This setting will apply to all requests.
     *
     * @param port
     */
    public static void proxyPort(final int port) {
      final String portValue = Integer.toString(port);
      setProperty("http.proxyPort", portValue);
      setProperty("https.proxyPort", portValue);
    }
  
    /**
     * Set the 'http.nonProxyHosts' property to the given host values.
     * <p>
     * Hosts will be separated by a '|' character.
     * <p>
     * This setting will apply to all requests.
     *
     * @param hosts
     */
    public static void nonProxyHosts(final String... hosts) {
      if (hosts != null && hosts.length > 0) {
        StringBuilder separated = new StringBuilder();
        int last = hosts.length - 1;
        for (int i = 0; i < last; i++)
          separated.append(hosts[i]).append('|');
        separated.append(hosts[last]);
        setProperty("http.nonProxyHosts", separated.toString());
      } else
        setProperty("http.nonProxyHosts", null);
    }
  
    /**
     * Set property to given value.
     * <p>
     * Specifying a null value will cause the property to be cleared
     *
     * @param name
     * @param value
     * @return previous value
     */
    private static String setProperty(final String name, final String value) {
      final PrivilegedAction<String> action;
      if (value != null)
        action = new PrivilegedAction<String>() {
  
          public String run() {
            return System.setProperty(name, value);
          }
        };
      else
        action = new PrivilegedAction<String>() {
  
          public String run() {
            return System.clearProperty(name);
          }
        };
      return AccessController.doPrivileged(action);
    }
  
    private HttpURLConnection connection = null;
  
    private final URL url;
  
    private final String requestMethod;
  
    private RequestOutputStream output;
  
    private boolean multipart;
  
    private boolean form;
  
    private boolean ignoreCloseExceptions = true;
  
    private boolean uncompress = false;
  
    private int bufferSize = 8192;
  
    private String httpProxyHost;
  
    private int httpProxyPort;
  
    /**
     * Create HTTP connection wrapper
     *
     * @param url Remote resource URL.
     * @param method HTTP request method (e.g., "GET", "POST").
     * @throws HttpRequestException
     */
    public HttpRequest(final CharSequence url, final String method)
        throws HttpRequestException {
      try {
        this.url = new URL(url.toString());
      } catch (MalformedURLException e) {
        throw new HttpRequestException(e);
      }
      this.requestMethod = method;
    }
  
    /**
     * Create HTTP connection wrapper
     *
     * @param url Remote resource URL.
     * @param method HTTP request method (e.g., "GET", "POST").
     * @throws HttpRequestException
     */
    public HttpRequest(final URL url, final String method)
        throws HttpRequestException {
      this.url = url;
      this.requestMethod = method;
    }
  
    private Proxy createProxy() {
      return new Proxy(HTTP, new InetSocketAddress(httpProxyHost, httpProxyPort));
    }
  
    private HttpURLConnection createConnection() {
      try {
        final HttpURLConnection connection;
        if (httpProxyHost != null)
          connection = CONNECTION_FACTORY.create(url, createProxy());
        else
          connection = CONNECTION_FACTORY.create(url);
        connection.setRequestMethod(requestMethod);
        return connection;
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
    }
  
    @Override
    public String toString() {
      return method() + ' ' + url();
    }
  
    /**
     * Get underlying connection
     *
     * @return connection
     */
    public HttpURLConnection getConnection() {
      if (connection == null)
        connection = createConnection();
      return connection;
    }
  
    /**
     * Set whether or not to ignore exceptions that occur from calling
     * {@link Closeable#close()}
     * <p>
     * The default value of this setting is <code>true</code>
     *
     * @param ignore
     * @return this request
     */
    public HttpRequest ignoreCloseExceptions(final boolean ignore) {
      ignoreCloseExceptions = ignore;
      return this;
    }
  
    /**
     * Get whether or not exceptions thrown by {@link Closeable#close()} are
     * ignored
     *
     * @return true if ignoring, false if throwing
     */
    public boolean ignoreCloseExceptions() {
      return ignoreCloseExceptions;
    }
  
    /**
     * Get the status code of the response
     *
     * @return the response code
     * @throws HttpRequestException
     */
    public int code() throws HttpRequestException {
      try {
        closeOutput();
        return getConnection().getResponseCode();
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
    }
  
    /**
     * Set the value of the given {@link AtomicInteger} to the status code of the
     * response
     *
     * @param output
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest code(final AtomicInteger output)
        throws HttpRequestException {
      output.set(code());
      return this;
    }
  
    /**
     * Is the response code a 200 OK?
     *
     * @return true if 200, false otherwise
     * @throws HttpRequestException
     */
    public boolean ok() throws HttpRequestException {
      return HTTP_OK == code();
    }
  
    /**
     * Is the response code a 201 Created?
     *
     * @return true if 201, false otherwise
     * @throws HttpRequestException
     */
    public boolean created() throws HttpRequestException {
      return HTTP_CREATED == code();
    }
  
    /**
     * Is the response code a 500 Internal Server Error?
     *
     * @return true if 500, false otherwise
     * @throws HttpRequestException
     */
    public boolean serverError() throws HttpRequestException {
      return HTTP_INTERNAL_ERROR == code();
    }
  
    /**
     * Is the response code a 400 Bad Request?
     *
     * @return true if 400, false otherwise
     * @throws HttpRequestException
     */
    public boolean badRequest() throws HttpRequestException {
      return HTTP_BAD_REQUEST == code();
    }
  
    /**
     * Is the response code a 404 Not Found?
     *
     * @return true if 404, false otherwise
     * @throws HttpRequestException
     */
    public boolean notFound() throws HttpRequestException {
      return HTTP_NOT_FOUND == code();
    }
  
    /**
     * Is the response code a 304 Not Modified?
     *
     * @return true if 304, false otherwise
     * @throws HttpRequestException
     */
    public boolean notModified() throws HttpRequestException {
      return HTTP_NOT_MODIFIED == code();
    }
  
    /**
     * Get status message of the response
     *
     * @return message
     * @throws HttpRequestException
     */
    public String message() throws HttpRequestException {
      try {
        closeOutput();
        return getConnection().getResponseMessage();
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
    }
  
    /**
     * Disconnect the connection
     *
     * @return this request
     */
    public HttpRequest disconnect() {
      getConnection().disconnect();
      return this;
    }
  
    /**
     * Set chunked streaming mode to the given size
     *
     * @param size
     * @return this request
     */
    public HttpRequest chunk(final int size) {
      getConnection().setChunkedStreamingMode(size);
      return this;
    }
  
    /**
     * Set the size used when buffering and copying between streams
     * <p>
     * This size is also used for send and receive buffers created for both char
     * and byte arrays
     * <p>
     * The default buffer size is 8,192 bytes
     *
     * @param size
     * @return this request
     */
    public HttpRequest bufferSize(final int size) {
      if (size < 1)
        throw new IllegalArgumentException("Size must be greater than zero");
      bufferSize = size;
      return this;
    }
  
    /**
     * Get the configured buffer size
     * <p>
     * The default buffer size is 8,192 bytes
     *
     * @return buffer size
     */
    public int bufferSize() {
      return bufferSize;
    }
  
    /**
     * Set whether or not the response body should be automatically uncompressed
     * when read from.
     * <p>
     * This will only affect requests that have the 'Content-Encoding' response
     * header set to 'gzip'.
     * <p>
     * This causes all receive methods to use a {@link GZIPInputStream} when
     * applicable so that higher level streams and readers can read the data
     * uncompressed.
     * <p>
     * Setting this option does not cause any request headers to be set
     * automatically so {@link #acceptGzipEncoding()} should be used in
     * conjunction with this setting to tell the server to gzip the response.
     *
     * @param uncompress
     * @return this request
     */
    public HttpRequest uncompress(final boolean uncompress) {
      this.uncompress = uncompress;
      return this;
    }
  
    /**
     * Create byte array output stream
     *
     * @return stream
     */
    protected ByteArrayOutputStream byteStream() {
      final int size = contentLength();
      if (size > 0)
        return new ByteArrayOutputStream(size);
      else
        return new ByteArrayOutputStream();
    }
  
    /**
     * Get response as {@link String} in given character set
     * <p>
     * This will fall back to using the UTF-8 character set if the given charset
     * is null
     *
     * @param charset
     * @return string
     * @throws HttpRequestException
     */
    public String body(final String charset) throws HttpRequestException {
      final ByteArrayOutputStream output = byteStream();
      try {
        copy(buffer(), output);
        return output.toString(getValidCharset(charset));
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
    }
  
    /**
     * Get response as {@link String} using character set returned from
     * {@link #charset()}
     *
     * @return string
     * @throws HttpRequestException
     */
    public String body() throws HttpRequestException {
      return body(charset());
    }
  
    /**
     * Get the response body as a {@link String} and set it as the value of the
     * given reference.
     *
     * @param output
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest body(final AtomicReference<String> output) throws HttpRequestException {
      output.set(body());
      return this;
    }
  
    /**
     * Get the response body as a {@link String} and set it as the value of the
     * given reference.
     *
     * @param output
     * @param charset
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest body(final AtomicReference<String> output, final String charset) throws HttpRequestException {
      output.set(body(charset));
      return this;
    }
  
  
    /**
     * Is the response body empty?
     *
     * @return true if the Content-Length response header is 0, false otherwise
     * @throws HttpRequestException
     */
    public boolean isBodyEmpty() throws HttpRequestException {
      return contentLength() == 0;
    }
  
    /**
     * Get response as byte array
     *
     * @return byte array
     * @throws HttpRequestException
     */
    public byte[] bytes() throws HttpRequestException {
      final ByteArrayOutputStream output = byteStream();
      try {
        copy(buffer(), output);
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
      return output.toByteArray();
    }
  
    /**
     * Get response in a buffered stream
     *
     * @see #bufferSize(int)
     * @return stream
     * @throws HttpRequestException
     */
    public BufferedInputStream buffer() throws HttpRequestException {
      return new BufferedInputStream(stream(), bufferSize);
    }
  
    /**
     * Get stream to response body
     *
     * @return stream
     * @throws HttpRequestException
     */
    public InputStream stream() throws HttpRequestException {
      InputStream stream;
      if (code() < HTTP_BAD_REQUEST)
        try {
          stream = getConnection().getInputStream();
        } catch (IOException e) {
          throw new HttpRequestException(e);
        }
      else {
        stream = getConnection().getErrorStream();
        if (stream == null)
          try {
            stream = getConnection().getInputStream();
          } catch (IOException e) {
            if (contentLength() > 0)
              throw new HttpRequestException(e);
            else
              stream = new ByteArrayInputStream(new byte[0]);
          }
      }
  
      if (!uncompress || !ENCODING_GZIP.equals(contentEncoding()))
        return stream;
      else
        try {
          return new GZIPInputStream(stream);
        } catch (IOException e) {
          throw new HttpRequestException(e);
        }
    }
  
    /**
     * Get reader to response body using given character set.
     * <p>
     * This will fall back to using the UTF-8 character set if the given charset
     * is null
     *
     * @param charset
     * @return reader
     * @throws HttpRequestException
     */
    public InputStreamReader reader(final String charset)
        throws HttpRequestException {
      try {
        return new InputStreamReader(stream(), getValidCharset(charset));
      } catch (UnsupportedEncodingException e) {
        throw new HttpRequestException(e);
      }
    }
  
    /**
     * Get reader to response body using the character set returned from
     * {@link #charset()}
     *
     * @return reader
     * @throws HttpRequestException
     */
    public InputStreamReader reader() throws HttpRequestException {
      return reader(charset());
    }
  
    /**
     * Get buffered reader to response body using the given character set r and
     * the configured buffer size
     *
     *
     * @see #bufferSize(int)
     * @param charset
     * @return reader
     * @throws HttpRequestException
     */
    public BufferedReader bufferedReader(final String charset)
        throws HttpRequestException {
      return new BufferedReader(reader(charset), bufferSize);
    }
  
    /**
     * Get buffered reader to response body using the character set returned from
     * {@link #charset()} and the configured buffer size
     *
     * @see #bufferSize(int)
     * @return reader
     * @throws HttpRequestException
     */
    public BufferedReader bufferedReader() throws HttpRequestException {
      return bufferedReader(charset());
    }
  
    /**
     * Stream response body to file
     *
     * @param file
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest receive(final File file) throws HttpRequestException {
      final OutputStream output;
      try {
        output = new BufferedOutputStream(new FileOutputStream(file), bufferSize);
      } catch (FileNotFoundException e) {
        throw new HttpRequestException(e);
      }
      return new CloseOperation<HttpRequest>(output, ignoreCloseExceptions) {
  
        @Override
        protected HttpRequest run() throws HttpRequestException, IOException {
          return receive(output);
        }
      }.call();
    }
  
    /**
     * Stream response to given output stream
     *
     * @param output
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest receive(final OutputStream output)
        throws HttpRequestException {
      try {
        return copy(buffer(), output);
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
    }
  
    /**
     * Stream response to given print stream
     *
     * @param output
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest receive(final PrintStream output)
        throws HttpRequestException {
      return receive((OutputStream) output);
    }
  
    /**
     * Receive response into the given appendable
     *
     * @param appendable
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest receive(final Appendable appendable)
        throws HttpRequestException {
      final BufferedReader reader = bufferedReader();
      return new CloseOperation<HttpRequest>(reader, ignoreCloseExceptions) {
  
        @Override
        public HttpRequest run() throws IOException {
          final CharBuffer buffer = CharBuffer.allocate(bufferSize);
          int read;
          while ((read = reader.read(buffer)) != -1) {
            buffer.rewind();
            appendable.append(buffer, 0, read);
            buffer.rewind();
          }
          return HttpRequest.this;
        }
      }.call();
    }
  
    /**
     * Receive response into the given writer
     *
     * @param writer
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest receive(final Writer writer) throws HttpRequestException {
      final BufferedReader reader = bufferedReader();
      return new CloseOperation<HttpRequest>(reader, ignoreCloseExceptions) {
  
        @Override
        public HttpRequest run() throws IOException {
          return copy(reader, writer);
        }
      }.call();
    }
  
    /**
     * Set read timeout on connection to given value
     *
     * @param timeout
     * @return this request
     */
    public HttpRequest readTimeout(final int timeout) {
      getConnection().setReadTimeout(timeout);
      return this;
    }
  
    /**
     * Set connect timeout on connection to given value
     *
     * @param timeout
     * @return this request
     */
    public HttpRequest connectTimeout(final int timeout) {
      getConnection().setConnectTimeout(timeout);
      return this;
    }
  
    /**
     * Set header name to given value
     *
     * @param name
     * @param value
     * @return this request
     */
    public HttpRequest header(final String name, final String value) {
      getConnection().setRequestProperty(name, value);
      return this;
    }
  
    /**
     * Set header name to given value
     *
     * @param name
     * @param value
     * @return this request
     */
    public HttpRequest header(final String name, final Number value) {
      return header(name, value != null ? value.toString() : null);
    }
  
    /**
     * Set all headers found in given map where the keys are the header names and
     * the values are the header values
     *
     * @param headers
     * @return this request
     */
    public HttpRequest headers(final Map<String, String> headers) {
      if (!headers.isEmpty())
        for (Entry<String, String> header : headers.entrySet())
          header(header);
      return this;
    }
  
    /**
     * Set header to have given entry's key as the name and value as the value
     *
     * @param header
     * @return this request
     */
    public HttpRequest header(final Entry<String, String> header) {
      return header(header.getKey(), header.getValue());
    }
  
    /**
     * Get a response header
     *
     * @param name
     * @return response header
     * @throws HttpRequestException
     */
    public String header(final String name) throws HttpRequestException {
      closeOutputQuietly();
      return getConnection().getHeaderField(name);
    }
  
    /**
     * Get all the response headers
     *
     * @return map of response header names to their value(s)
     * @throws HttpRequestException
     */
    public Map<String, List<String>> headers() throws HttpRequestException {
      closeOutputQuietly();
      return getConnection().getHeaderFields();
    }
  
    /**
     * Get a date header from the response falling back to returning -1 if the
     * header is missing or parsing fails
     *
     * @param name
     * @return date, -1 on failures
     * @throws HttpRequestException
     */
    public long dateHeader(final String name) throws HttpRequestException {
      return dateHeader(name, -1L);
    }
  
    /**
     * Get a date header from the response falling back to returning the given
     * default value if the header is missing or parsing fails
     *
     * @param name
     * @param defaultValue
     * @return date, default value on failures
     * @throws HttpRequestException
     */
    public long dateHeader(final String name, final long defaultValue)
        throws HttpRequestException {
      closeOutputQuietly();
      return getConnection().getHeaderFieldDate(name, defaultValue);
    }
  
    /**
     * Get an integer header from the response falling back to returning -1 if the
     * header is missing or parsing fails
     *
     * @param name
     * @return header value as an integer, -1 when missing or parsing fails
     * @throws HttpRequestException
     */
    public int intHeader(final String name) throws HttpRequestException {
      return intHeader(name, -1);
    }
  
    /**
     * Get an integer header value from the response falling back to the given
     * default value if the header is missing or if parsing fails
     *
     * @param name
     * @param defaultValue
     * @return header value as an integer, default value when missing or parsing
     *         fails
     * @throws HttpRequestException
     */
    public int intHeader(final String name, final int defaultValue)
        throws HttpRequestException {
      closeOutputQuietly();
      return getConnection().getHeaderFieldInt(name, defaultValue);
    }
  
    /**
     * Get all values of the given header from the response
     *
     * @param name
     * @return non-null but possibly empty array of {@link String} header values
     */
    public String[] headers(final String name) {
      final Map<String, List<String>> headers = headers();
      if (headers == null || headers.isEmpty())
        return EMPTY_STRINGS;
  
      final List<String> values = headers.get(name);
      if (values != null && !values.isEmpty())
        return values.toArray(new String[values.size()]);
      else
        return EMPTY_STRINGS;
    }
  
    /**
     * Get parameter with given name from header value in response
     *
     * @param headerName
     * @param paramName
     * @return parameter value or null if missing
     */
    public String parameter(final String headerName, final String paramName) {
      return getParam(header(headerName), paramName);
    }
  
    /**
     * Get all parameters from header value in response
     * <p>
     * This will be all key=value pairs after the first ';' that are separated by
     * a ';'
     *
     * @param headerName
     * @return non-null but possibly empty map of parameter headers
     */
    public Map<String, String> parameters(final String headerName) {
      return getParams(header(headerName));
    }
  
    /**
     * Get parameter values from header value
     *
     * @param header
     * @return parameter value or null if none
     */
    protected Map<String, String> getParams(final String header) {
      if (header == null || header.length() == 0)
        return Collections.emptyMap();
  
      final int headerLength = header.length();
      int start = header.indexOf(';') + 1;
      if (start == 0 || start == headerLength)
        return Collections.emptyMap();
  
      int end = header.indexOf(';', start);
      if (end == -1)
        end = headerLength;
  
      Map<String, String> params = new LinkedHashMap<String, String>();
      while (start < end) {
        int nameEnd = header.indexOf('=', start);
        if (nameEnd != -1 && nameEnd < end) {
          String name = header.substring(start, nameEnd).trim();
          if (name.length() > 0) {
            String value = header.substring(nameEnd + 1, end).trim();
            int length = value.length();
            if (length != 0)
              if (length > 2 && '"' == value.charAt(0)
                  && '"' == value.charAt(length - 1))
                params.put(name, value.substring(1, length - 1));
              else
                params.put(name, value);
          }
        }
  
        start = end + 1;
        end = header.indexOf(';', start);
        if (end == -1)
          end = headerLength;
      }
  
      return params;
    }
  
    /**
     * Get parameter value from header value
     *
     * @param value
     * @param paramName
     * @return parameter value or null if none
     */
    protected String getParam(final String value, final String paramName) {
      if (value == null || value.length() == 0)
        return null;
  
      final int length = value.length();
      int start = value.indexOf(';') + 1;
      if (start == 0 || start == length)
        return null;
  
      int end = value.indexOf(';', start);
      if (end == -1)
        end = length;
  
      while (start < end) {
        int nameEnd = value.indexOf('=', start);
        if (nameEnd != -1 && nameEnd < end
            && paramName.equals(value.substring(start, nameEnd).trim())) {
          String paramValue = value.substring(nameEnd + 1, end).trim();
          int valueLength = paramValue.length();
          if (valueLength != 0)
            if (valueLength > 2 && '"' == paramValue.charAt(0)
                && '"' == paramValue.charAt(valueLength - 1))
              return paramValue.substring(1, valueLength - 1);
            else
              return paramValue;
        }
  
        start = end + 1;
        end = value.indexOf(';', start);
        if (end == -1)
          end = length;
      }
  
      return null;
    }
  
    /**
     * Get 'charset' parameter from 'Content-Type' response header
     *
     * @return charset or null if none
     */
    public String charset() {
      return parameter(HEADER_CONTENT_TYPE, PARAM_CHARSET);
    }
  
    /**
     * Set the 'User-Agent' header to given value
     *
     * @param userAgent
     * @return this request
     */
    public HttpRequest userAgent(final String userAgent) {
      return header(HEADER_USER_AGENT, userAgent);
    }
  
    /**
     * Set the 'Referer' header to given value
     *
     * @param referer
     * @return this request
     */
    public HttpRequest referer(final String referer) {
      return header(HEADER_REFERER, referer);
    }
  
    /**
     * Set value of {@link HttpURLConnection#setUseCaches(boolean)}
     *
     * @param useCaches
     * @return this request
     */
    public HttpRequest useCaches(final boolean useCaches) {
      getConnection().setUseCaches(useCaches);
      return this;
    }
  
    /**
     * Set the 'Accept-Encoding' header to given value
     *
     * @param acceptEncoding
     * @return this request
     */
    public HttpRequest acceptEncoding(final String acceptEncoding) {
      return header(HEADER_ACCEPT_ENCODING, acceptEncoding);
    }
  
    /**
     * Set the 'Accept-Encoding' header to 'gzip'
     *
     * @see #uncompress(boolean)
     * @return this request
     */
    public HttpRequest acceptGzipEncoding() {
      return acceptEncoding(ENCODING_GZIP);
    }
  
    /**
     * Set the 'Accept-Charset' header to given value
     *
     * @param acceptCharset
     * @return this request
     */
    public HttpRequest acceptCharset(final String acceptCharset) {
      return header(HEADER_ACCEPT_CHARSET, acceptCharset);
    }
  
    /**
     * Get the 'Content-Encoding' header from the response
     *
     * @return this request
     */
    public String contentEncoding() {
      return header(HEADER_CONTENT_ENCODING);
    }
  
    /**
     * Get the 'Server' header from the response
     *
     * @return server
     */
    public String server() {
      return header(HEADER_SERVER);
    }
  
    /**
     * Get the 'Date' header from the response
     *
     * @return date value, -1 on failures
     */
    public long date() {
      return dateHeader(HEADER_DATE);
    }
  
    /**
     * Get the 'Cache-Control' header from the response
     *
     * @return cache control
     */
    public String cacheControl() {
      return header(HEADER_CACHE_CONTROL);
    }
  
    /**
     * Get the 'ETag' header from the response
     *
     * @return entity tag
     */
    public String eTag() {
      return header(HEADER_ETAG);
    }
  
    /**
     * Get the 'Expires' header from the response
     *
     * @return expires value, -1 on failures
     */
    public long expires() {
      return dateHeader(HEADER_EXPIRES);
    }
  
    /**
     * Get the 'Last-Modified' header from the response
     *
     * @return last modified value, -1 on failures
     */
    public long lastModified() {
      return dateHeader(HEADER_LAST_MODIFIED);
    }
  
    /**
     * Get the 'Location' header from the response
     *
     * @return location
     */
    public String location() {
      return header(HEADER_LOCATION);
    }
  
    /**
     * Set the 'Authorization' header to given value
     *
     * @param authorization
     * @return this request
     */
    public HttpRequest authorization(final String authorization) {
      return header(HEADER_AUTHORIZATION, authorization);
    }
  
    /**
     * Set the 'Proxy-Authorization' header to given value
     *
     * @param proxyAuthorization
     * @return this request
     */
    public HttpRequest proxyAuthorization(final String proxyAuthorization) {
      return header(HEADER_PROXY_AUTHORIZATION, proxyAuthorization);
    }
  
    /**
     * Set the 'Authorization' header to given values in Basic authentication
     * format
     *
     * @param name
     * @param password
     * @return this request
     */
    public HttpRequest basic(final String name, final String password) {
      return authorization("Basic " + Base64.encode(name + ':' + password));
    }
  
    /**
     * Set the 'Proxy-Authorization' header to given values in Basic authentication
     * format
     *
     * @param name
     * @param password
     * @return this request
     */
    public HttpRequest proxyBasic(final String name, final String password) {
      return proxyAuthorization("Basic " + Base64.encode(name + ':' + password));
    }
  
    /**
     * Set the 'If-Modified-Since' request header to the given value
     *
     * @param ifModifiedSince
     * @return this request
     */
    public HttpRequest ifModifiedSince(final long ifModifiedSince) {
      getConnection().setIfModifiedSince(ifModifiedSince);
      return this;
    }
  
    /**
     * Set the 'If-None-Match' request header to the given value
     *
     * @param ifNoneMatch
     * @return this request
     */
    public HttpRequest ifNoneMatch(final String ifNoneMatch) {
      return header(HEADER_IF_NONE_MATCH, ifNoneMatch);
    }
  
    /**
     * Set the 'Content-Type' request header to the given value
     *
     * @param contentType
     * @return this request
     */
    public HttpRequest contentType(final String contentType) {
      return contentType(contentType, null);
    }
  
    /**
     * Set the 'Content-Type' request header to the given value and charset
     *
     * @param contentType
     * @param charset
     * @return this request
     */
    public HttpRequest contentType(final String contentType, final String charset) {
      if (charset != null && charset.length() > 0) {
        final String separator = "; " + PARAM_CHARSET + '=';
        return header(HEADER_CONTENT_TYPE, contentType + separator + charset);
      } else
        return header(HEADER_CONTENT_TYPE, contentType);
    }
  
    /**
     * Get the 'Content-Type' header from the response
     *
     * @return response header value
     */
    public String contentType() {
      return header(HEADER_CONTENT_TYPE);
    }
  
    /**
     * Get the 'Content-Length' header from the response
     *
     * @return response header value
     */
    public int contentLength() {
      return intHeader(HEADER_CONTENT_LENGTH);
    }
  
    /**
     * Set the 'Content-Length' request header to the given value
     *
     * @param contentLength
     * @return this request
     */
    public HttpRequest contentLength(final String contentLength) {
      return contentLength(Integer.parseInt(contentLength));
    }
  
    /**
     * Set the 'Content-Length' request header to the given value
     *
     * @param contentLength
     * @return this request
     */
    public HttpRequest contentLength(final int contentLength) {
      getConnection().setFixedLengthStreamingMode(contentLength);
      return this;
    }
  
    /**
     * Set the 'Accept' header to given value
     *
     * @param accept
     * @return this request
     */
    public HttpRequest accept(final String accept) {
      return header(HEADER_ACCEPT, accept);
    }
  
    /**
     * Set the 'Accept' header to 'application/json'
     *
     * @return this request
     */
    public HttpRequest acceptJson() {
      return accept(CONTENT_TYPE_JSON);
    }
  
    /**
     * Copy from input stream to output stream
     *
     * @param input
     * @param output
     * @return this request
     * @throws IOException
     */
    protected HttpRequest copy(final InputStream input, final OutputStream output)
        throws IOException {
      return new CloseOperation<HttpRequest>(input, ignoreCloseExceptions) {
  
        @Override
        public HttpRequest run() throws IOException {
          final byte[] buffer = new byte[bufferSize];
          int read;
          while ((read = input.read(buffer)) != -1)
            output.write(buffer, 0, read);
          return HttpRequest.this;
        }
      }.call();
    }
  
    /**
     * Copy from reader to writer
     *
     * @param input
     * @param output
     * @return this request
     * @throws IOException
     */
    protected HttpRequest copy(final Reader input, final Writer output)
        throws IOException {
      return new CloseOperation<HttpRequest>(input, ignoreCloseExceptions) {
  
        @Override
        public HttpRequest run() throws IOException {
          final char[] buffer = new char[bufferSize];
          int read;
          while ((read = input.read(buffer)) != -1)
            output.write(buffer, 0, read);
          return HttpRequest.this;
        }
      }.call();
    }
  
    /**
     * Close output stream
     *
     * @return this request
     * @throws HttpRequestException
     * @throws IOException
     */
    protected HttpRequest closeOutput() throws IOException {
      if (output == null)
        return this;
      if (multipart)
        output.write(CRLF + "--" + BOUNDARY + "--" + CRLF);
      if (ignoreCloseExceptions)
        try {
          output.close();
        } catch (IOException ignored) {
          // Ignored
        }
      else
        output.close();
      output = null;
      return this;
    }
  
    /**
     * Call {@link #closeOutput()} and re-throw a caught {@link IOException}s as
     * an {@link HttpRequestException}
     *
     * @return this request
     * @throws HttpRequestException
     */
    protected HttpRequest closeOutputQuietly() throws HttpRequestException {
      try {
        return closeOutput();
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
    }
  
    /**
     * Open output stream
     *
     * @return this request
     * @throws IOException
     */
    protected HttpRequest openOutput() throws IOException {
      if (output != null)
        return this;
      getConnection().setDoOutput(true);
      final String charset = getParam(
          getConnection().getRequestProperty(HEADER_CONTENT_TYPE), PARAM_CHARSET);
      output = new RequestOutputStream(getConnection().getOutputStream(), charset,
          bufferSize);
      return this;
    }
  
    /**
     * Start part of a multipart
     *
     * @return this request
     * @throws IOException
     */
    protected HttpRequest startPart() throws IOException {
      if (!multipart) {
        multipart = true;
        contentType(CONTENT_TYPE_MULTIPART).openOutput();
        output.write("--" + BOUNDARY + CRLF);
      } else
        output.write(CRLF + "--" + BOUNDARY + CRLF);
      return this;
    }
  
    /**
     * Write part header
     *
     * @param name
     * @param filename
     * @return this request
     * @throws IOException
     */
    protected HttpRequest writePartHeader(final String name, final String filename)
        throws IOException {
      return writePartHeader(name, filename, null);
    }
  
    /**
     * Write part header
     *
     * @param name
     * @param filename
     * @param contentType
     * @return this request
     * @throws IOException
     */
    protected HttpRequest writePartHeader(final String name,
        final String filename, final String contentType) throws IOException {
      final StringBuilder partBuffer = new StringBuilder();
      partBuffer.append("form-data; name=\"").append(name);
      if (filename != null)
        partBuffer.append("\"; filename=\"").append(filename);
      partBuffer.append('"');
      partHeader("Content-Disposition", partBuffer.toString());
      if (contentType != null)
        partHeader(HEADER_CONTENT_TYPE, contentType);
      return send(CRLF);
    }
  
    /**
     * Write part of a multipart request to the request body
     *
     * @param name
     * @param part
     * @return this request
     */
    public HttpRequest part(final String name, final String part) {
      return part(name, null, part);
    }
  
    /**
     * Write part of a multipart request to the request body
     *
     * @param name
     * @param filename
     * @param part
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest part(final String name, final String filename,
        final String part) throws HttpRequestException {
      return part(name, filename, null, part);
    }
  
    /**
     * Write part of a multipart request to the request body
     *
     * @param name
     * @param filename
     * @param contentType
     *          value of the Content-Type part header
     * @param part
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest part(final String name, final String filename,
        final String contentType, final String part) throws HttpRequestException {
      try {
        startPart();
        writePartHeader(name, filename, contentType);
        output.write(part);
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
      return this;
    }
  
    /**
     * Write part of a multipart request to the request body
     *
     * @param name
     * @param part
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest part(final String name, final Number part)
        throws HttpRequestException {
      return part(name, null, part);
    }
  
    /**
     * Write part of a multipart request to the request body
     *
     * @param name
     * @param filename
     * @param part
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest part(final String name, final String filename,
        final Number part) throws HttpRequestException {
      return part(name, filename, part != null ? part.toString() : null);
    }
  
    /**
     * Write part of a multipart request to the request body
     *
     * @param name
     * @param part
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest part(final String name, final File part)
        throws HttpRequestException {
      return part(name, null, part);
    }
  
    /**
     * Write part of a multipart request to the request body
     *
     * @param name
     * @param filename
     * @param part
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest part(final String name, final String filename,
        final File part) throws HttpRequestException {
      return part(name, filename, null, part);
    }
  
    /**
     * Write part of a multipart request to the request body
     *
     * @param name
     * @param filename
     * @param contentType
     *          value of the Content-Type part header
     * @param part
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest part(final String name, final String filename,
        final String contentType, final File part) throws HttpRequestException {
      final InputStream stream;
      try {
        stream = new BufferedInputStream(new FileInputStream(part));
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
      return part(name, filename, contentType, stream);
    }
  
    /**
     * Write part of a multipart request to the request body
     *
     * @param name
     * @param part
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest part(final String name, final InputStream part)
        throws HttpRequestException {
      return part(name, null, null, part);
    }
  
    /**
     * Write part of a multipart request to the request body
     *
     * @param name
     * @param filename
     * @param contentType
     *          value of the Content-Type part header
     * @param part
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest part(final String name, final String filename,
        final String contentType, final InputStream part)
        throws HttpRequestException {
      try {
        startPart();
        writePartHeader(name, filename, contentType);
        copy(part, output);
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
      return this;
    }
  
    /**
     * Write a multipart header to the response body
     *
     * @param name
     * @param value
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest partHeader(final String name, final String value)
        throws HttpRequestException {
      return send(name).send(": ").send(value).send(CRLF);
    }
  
    /**
     * Write contents of file to request body
     *
     * @param input
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest send(final File input) throws HttpRequestException {
      final InputStream stream;
      try {
        stream = new BufferedInputStream(new FileInputStream(input));
      } catch (FileNotFoundException e) {
        throw new HttpRequestException(e);
      }
      return send(stream);
    }
  
    /**
     * Write byte array to request body
     *
     * @param input
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest send(final byte[] input) throws HttpRequestException {
      return send(new ByteArrayInputStream(input));
    }
  
    /**
     * Write stream to request body
     * <p>
     * The given stream will be closed once sending completes
     *
     * @param input
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest send(final InputStream input) throws HttpRequestException {
      try {
        openOutput();
        copy(input, output);
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
      return this;
    }
  
    /**
     * Write reader to request body
     * <p>
     * The given reader will be closed once sending completes
     *
     * @param input
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest send(final Reader input) throws HttpRequestException {
      try {
        openOutput();
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
      final Writer writer = new OutputStreamWriter(output,
          output.encoder.charset());
      return new FlushOperation<HttpRequest>(writer) {
  
        @Override
        protected HttpRequest run() throws IOException {
          return copy(input, writer);
        }
      }.call();
    }
  
    /**
     * Write char sequence to request body
     * <p>
     * The charset configured via {@link #contentType(String)} will be used and
     * UTF-8 will be used if it is unset.
     *
     * @param value
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest send(final CharSequence value) throws HttpRequestException {
      try {
        openOutput();
        output.write(value.toString());
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
      return this;
    }
  
    /**
     * Create writer to request output stream
     *
     * @return writer
     * @throws HttpRequestException
     */
    public OutputStreamWriter writer() throws HttpRequestException {
      try {
        openOutput();
        return new OutputStreamWriter(output, output.encoder.charset());
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
    }
  
    /**
     * Write the values in the map as form data to the request body
     * <p>
     * The pairs specified will be URL-encoded in UTF-8 and sent with the
     * 'application/x-www-form-urlencoded' content-type
     *
     * @param values
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest form(final Map<?, ?> values) throws HttpRequestException {
      return form(values, CHARSET_UTF8);
    }
  
    /**
     * Write the key and value in the entry as form data to the request body
     * <p>
     * The pair specified will be URL-encoded in UTF-8 and sent with the
     * 'application/x-www-form-urlencoded' content-type
     *
     * @param entry
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest form(final Entry<?, ?> entry) throws HttpRequestException {
      return form(entry, CHARSET_UTF8);
    }
  
    /**
     * Write the key and value in the entry as form data to the request body
     * <p>
     * The pair specified will be URL-encoded and sent with the
     * 'application/x-www-form-urlencoded' content-type
     *
     * @param entry
     * @param charset
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest form(final Entry<?, ?> entry, final String charset)
        throws HttpRequestException {
      return form(entry.getKey(), entry.getValue(), charset);
    }
  
    /**
     * Write the name/value pair as form data to the request body
     * <p>
     * The pair specified will be URL-encoded in UTF-8 and sent with the
     * 'application/x-www-form-urlencoded' content-type
     *
     * @param name
     * @param value
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest form(final Object name, final Object value)
        throws HttpRequestException {
      return form(name, value, CHARSET_UTF8);
    }
  
    /**
     * Write the name/value pair as form data to the request body
     * <p>
     * The values specified will be URL-encoded and sent with the
     * 'application/x-www-form-urlencoded' content-type
     *
     * @param name
     * @param value
     * @param charset
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest form(final Object name, final Object value, String charset)
        throws HttpRequestException {
      final boolean first = !form;
      if (first) {
        contentType(CONTENT_TYPE_FORM, charset);
        form = true;
      }
      charset = getValidCharset(charset);
      try {
        openOutput();
        if (!first)
          output.write('&');
        output.write(URLEncoder.encode(name.toString(), charset));
        output.write('=');
        if (value != null)
          output.write(URLEncoder.encode(value.toString(), charset));
      } catch (IOException e) {
        throw new HttpRequestException(e);
      }
      return this;
    }
  
    /**
     * Write the values in the map as encoded form data to the request body
     *
     * @param values
     * @param charset
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest form(final Map<?, ?> values, final String charset)
        throws HttpRequestException {
      if (!values.isEmpty())
        for (Entry<?, ?> entry : values.entrySet())
          form(entry, charset);
      return this;
    }
  
    /**
     * Configure HTTPS connection to trust all certificates
     * <p>
     * This method does nothing if the current request is not a HTTPS request
     *
     * @return this request
     * @throws HttpRequestException
     */
    public HttpRequest trustAllCerts() throws HttpRequestException {
      final HttpURLConnection connection = getConnection();
      if (connection instanceof HttpsURLConnection)
        ((HttpsURLConnection) connection)
            .setSSLSocketFactory(getTrustedFactory());
      return this;
    }
  
    /**
     * Configure HTTPS connection to trust all hosts using a custom
     * {@link HostnameVerifier} that always returns <code>true</code> for each
     * host verified
     * <p>
     * This method does nothing if the current request is not a HTTPS request
     *
     * @return this request
     */
    public HttpRequest trustAllHosts() {
      final HttpURLConnection connection = getConnection();
      if (connection instanceof HttpsURLConnection)
        ((HttpsURLConnection) connection)
            .setHostnameVerifier(getTrustedVerifier());
      return this;
    }
  
    /**
     * Get the {@link URL} of this request's connection
     *
     * @return request URL
     */
    public URL url() {
      return getConnection().getURL();
    }
  
    /**
     * Get the HTTP method of this request
     *
     * @return method
     */
    public String method() {
      return getConnection().getRequestMethod();
    }
  
    /**
     * Configure an HTTP proxy on this connection. Use {{@link #proxyBasic(String, String)} if
     * this proxy requires basic authentication.
     *
     * @param proxyHost
     * @param proxyPort
     * @return this request
     */
    public HttpRequest useProxy(final String proxyHost, final int proxyPort) {
      if (connection != null)
        throw new IllegalStateException("The connection has already been created. This method must be called before reading or writing to the request.");
  
      this.httpProxyHost = proxyHost;
      this.httpProxyPort = proxyPort;
      return this;
    }
  
    /**
     * Set whether or not the underlying connection should follow redirects in
     * the response.
     *
     * @param followRedirects - true fo follow redirects, false to not.
     * @return this request
     */
    public HttpRequest followRedirects(final boolean followRedirects) {
      getConnection().setInstanceFollowRedirects(followRedirects);
      return this;
    }
  }
  