content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package com.aliyun.api.gateway.demo.util;
  
  import java.util.Collections;
  import java.util.List;
  import java.util.Map;
  import java.util.TreeMap;
  
  import javax.crypto.Mac;
  import javax.crypto.spec.SecretKeySpec;
  
  import org.apache.commons.codec.binary.Base64;
  import org.apache.commons.lang.StringUtils;
  
  import com.aliyun.api.gateway.demo.constant.Constants;
  import com.aliyun.api.gateway.demo.constant.HttpHeader;
  import com.aliyun.api.gateway.demo.constant.SystemHeader;
  
  /**
   * 签名工具
   */
  public class SignUtil {
  
      /**
       * 计算签名
       *
       * @param secret APP密钥
       * @param method HttpMethod
       * @param path
       * @param headers
       * @param querys
       * @param bodys
       * @param signHeaderPrefixList 自定义参与签名Header前缀
       * @return 签名后的字符串
       */
      public static String sign(String secret, String method, String path, 
      							Map<String, String> headers, 
      							Map<String, String> querys, 
      							Map<String, String> bodys, 
      							List<String> signHeaderPrefixList) {
          try {
              Mac hmacSha256 = Mac.getInstance(Constants.HMAC_SHA256);
              byte[] keyBytes = secret.getBytes(Constants.ENCODING);
              hmacSha256.init(new SecretKeySpec(keyBytes, 0, keyBytes.length, Constants.HMAC_SHA256));
  
              return new String(Base64.encodeBase64(
                      hmacSha256.doFinal(buildStringToSign(method, path, headers, querys, bodys, signHeaderPrefixList)
                              .getBytes(Constants.ENCODING))),
                      Constants.ENCODING);
          } catch (Exception e) {
              throw new RuntimeException(e);
          }
      }
  
      /**
       * 构建待签名字符串
       * @param method
       * @param path
       * @param headers
       * @param querys
       * @param bodys
       * @param signHeaderPrefixList
       * @return
       */
      private static String buildStringToSign(String method, String path, 
      										Map<String, String> headers, 
      										Map<String, String> querys,
      										Map<String, String> bodys,
                                              List<String> signHeaderPrefixList) {
          StringBuilder sb = new StringBuilder();
  
          sb.append(method.toUpperCase()).append(Constants.LF);
          if (null != headers) {
          	if (null != headers.get(HttpHeader.HTTP_HEADER_ACCEPT)) {
                  sb.append(headers.get(HttpHeader.HTTP_HEADER_ACCEPT));
              }
          	sb.append(Constants.LF);
          	if (null != headers.get(HttpHeader.HTTP_HEADER_CONTENT_MD5)) {
                  sb.append(headers.get(HttpHeader.HTTP_HEADER_CONTENT_MD5));
              }
              sb.append(Constants.LF);
              if (null != headers.get(HttpHeader.HTTP_HEADER_CONTENT_TYPE)) {
                  sb.append(headers.get(HttpHeader.HTTP_HEADER_CONTENT_TYPE));
              }
              sb.append(Constants.LF);
              if (null != headers.get(HttpHeader.HTTP_HEADER_DATE)) {
                  sb.append(headers.get(HttpHeader.HTTP_HEADER_DATE));
              }
          }
          sb.append(Constants.LF);
          sb.append(buildHeaders(headers, signHeaderPrefixList));
          sb.append(buildResource(path, querys, bodys));
          
          return sb.toString();
      }
  
      /**
       * 构建待签名Path+Query+BODY
       *
       * @param path
       * @param querys
       * @param bodys
       * @return 待签名
       */
      private static String buildResource(String path, Map<String, String> querys, Map<String, String> bodys) {
      	StringBuilder sb = new StringBuilder();
      	
      	if (!StringUtils.isBlank(path)) {
      		sb.append(path);
          }
          Map<String, String> sortMap = new TreeMap<String, String>();
          if (null != querys) {
          	for (Map.Entry<String, String> query : querys.entrySet()) {
          		if (!StringUtils.isBlank(query.getKey())) {
          			sortMap.put(query.getKey(), query.getValue());
                  }
          	}
          }
          
          if (null != bodys) {
          	for (Map.Entry<String, String> body : bodys.entrySet()) {
          		if (!StringUtils.isBlank(body.getKey())) {
          			sortMap.put(body.getKey(), body.getValue());
                  }
          	}
          }
          
          StringBuilder sbParam = new StringBuilder();
          for (Map.Entry<String, String> item : sortMap.entrySet()) {
      		if (!StringUtils.isBlank(item.getKey())) {
      			if (0 < sbParam.length()) {
      				sbParam.append(Constants.SPE3);
      			}
      			sbParam.append(item.getKey());
      			if (!StringUtils.isBlank(item.getValue())) {
      				sbParam.append(Constants.SPE4).append(item.getValue());
      			}
              }
      	}
          if (0 < sbParam.length()) {
          	sb.append(Constants.SPE5);
          	sb.append(sbParam);
          }
          
          return sb.toString();
      }
  
      /**
       * 构建待签名Http头
       *
       * @param headers 请求中所有的Http头
       * @param signHeaderPrefixList 自定义参与签名Header前缀
       * @return 待签名Http头
       */
      private static String buildHeaders(Map<String, String> headers, List<String> signHeaderPrefixList) {
      	StringBuilder sb = new StringBuilder();
      	
      	if (null != signHeaderPrefixList) {
      		signHeaderPrefixList.remove(SystemHeader.X_CA_SIGNATURE);
      		signHeaderPrefixList.remove(HttpHeader.HTTP_HEADER_ACCEPT);
      		signHeaderPrefixList.remove(HttpHeader.HTTP_HEADER_CONTENT_MD5);
      		signHeaderPrefixList.remove(HttpHeader.HTTP_HEADER_CONTENT_TYPE);
      		signHeaderPrefixList.remove(HttpHeader.HTTP_HEADER_DATE);
      		Collections.sort(signHeaderPrefixList);
      		if (null != headers) {
      			Map<String, String> sortMap = new TreeMap<String, String>();
      			sortMap.putAll(headers);
      			StringBuilder signHeadersStringBuilder = new StringBuilder();
      			for (Map.Entry<String, String> header : sortMap.entrySet()) {
                      if (isHeaderToSign(header.getKey(), signHeaderPrefixList)) {
                      	sb.append(header.getKey());
                      	sb.append(Constants.SPE2);
                          if (!StringUtils.isBlank(header.getValue())) {
                          	sb.append(header.getValue());
                          }
                          sb.append(Constants.LF);
                          if (0 < signHeadersStringBuilder.length()) {
                          	signHeadersStringBuilder.append(Constants.SPE1);
                          }
                          signHeadersStringBuilder.append(header.getKey());
                      }
                  }
      			headers.put(SystemHeader.X_CA_SIGNATURE_HEADERS, signHeadersStringBuilder.toString());
      		}
      	}
          
          return sb.toString();
      }
  
      /**
       * Http头是否参与签名 return
       */
      private static boolean isHeaderToSign(String headerName, List<String> signHeaderPrefixList) {
          if (StringUtils.isBlank(headerName)) {
              return false;
          }
  
          if (headerName.startsWith(Constants.CA_HEADER_TO_SIGN_PREFIX_SYSTEM)) {
              return true;
          }
  
          if (null != signHeaderPrefixList) {
              for (String signHeaderPrefix : signHeaderPrefixList) {
                  if (headerName.equalsIgnoreCase(signHeaderPrefix)) {
                      return true;
                  }
              }
          }
  
          return false;
      }
  }
  