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 org.apache.camel.component.file;
  
  import java.io.File;
  import java.io.InputStream;
  import java.util.Map;
  import java.util.concurrent.locks.Lock;
  import java.util.concurrent.locks.ReentrantLock;
  
  import org.apache.camel.AsyncCallback;
  import org.apache.camel.Exchange;
  import org.apache.camel.Expression;
  import org.apache.camel.support.DefaultAsyncProducer;
  import org.apache.camel.support.DefaultExchange;
  import org.apache.camel.support.LRUCacheFactory;
  import org.apache.camel.support.MessageHelper;
  import org.apache.camel.support.service.ServiceHelper;
  import org.apache.camel.util.FileUtil;
  import org.apache.camel.util.ObjectHelper;
  import org.apache.camel.util.StringHelper;
  import org.apache.commons.codec.digest.DigestUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Generic file producer
   */
  public class GenericFileProducer<T> extends DefaultAsyncProducer {
      private static final Logger LOG = LoggerFactory.getLogger(GenericFileProducer.class);
  
      protected final GenericFileEndpoint<T> endpoint;
      protected GenericFileOperations<T> operations;
      // assume writing to 100 different files concurrently at most for the same
      // file producer
      private final Map<String, Lock> locks = LRUCacheFactory.newLRUCache(100);
  
      protected GenericFileProducer(GenericFileEndpoint<T> endpoint, GenericFileOperations<T> operations) {
          super(endpoint);
          this.endpoint = endpoint;
          this.operations = operations;
      }
  
      public String getFileSeparator() {
          return File.separator;
      }
  
      public String normalizePath(String name) {
          return FileUtil.normalizePath(name);
      }
  
      @Override
      public boolean process(Exchange exchange, AsyncCallback callback) {
          try {
              doProcess(exchange);
          } catch (Exception e) {
              exchange.setException(e);
          } finally {
              callback.done(true);
          }
          return true;
      }
  
      protected void doProcess(Exchange exchange) throws Exception {
          // store any existing file header which we want to keep and propagate
          final String existing = exchange.getIn().getHeader(FileConstants.FILE_NAME, String.class);
  
          // create the target file name
          String target = createFileName(exchange);
  
          // use lock for same file name to avoid concurrent writes to the same
          // file
          // for example when you concurrently append to the same file
          Lock lock = locks.computeIfAbsent(target, f -> new ReentrantLock());
  
          lock.lock();
          try {
              processExchange(exchange, target);
          } catch (Exception e) {
              exchange.setException(e);
          } finally {
              // do not remove as the locks cache has an upper bound
              // this ensure the locks is appropriate reused
              lock.unlock();
              // and remove the write file name header as we only want to use it
              // once (by design)
              exchange.getIn().removeHeader(Exchange.OVERRULE_FILE_NAME);
              // and restore existing file name
              exchange.getIn().setHeader(FileConstants.FILE_NAME, existing);
          }
      }
  
      /**
       * Sets the operations to be used.
       * <p/>
       * Can be used to set a fresh operations in case of recovery attempts
       *
       * @param operations the operations
       */
      public void setOperations(GenericFileOperations<T> operations) {
          this.operations = operations;
      }
  
      /**
       * Perform the work to process the fileExchange
       *
       * @param  exchange  fileExchange
       * @param  target    the target filename
       * @throws Exception is thrown if some error
       */
      protected void processExchange(Exchange exchange, String target) throws Exception {
          LOG.trace("Processing file: {} for exchange: {}", target, exchange);
  
          try {
              preWriteCheck(exchange);
  
              // should we write to a temporary name and then afterwards rename to
              // real target
              boolean writeAsTempAndRename = ObjectHelper.isNotEmpty(endpoint.getTempFileName());
              String tempTarget = null;
              // remember if target exists to avoid checking twice
              boolean targetExists;
              if (writeAsTempAndRename) {
                  // compute temporary name with the temp prefix
                  tempTarget = createTempFileName(exchange, target);
  
                  LOG.trace("Writing using tempNameFile: {}", tempTarget);
  
                  // if we should eager delete target file before deploying
                  // temporary file
                  if (endpoint.getFileExist() != GenericFileExist.TryRename && endpoint.isEagerDeleteTargetFile()) {
  
                      // cater for file exists option on the real target as
                      // the file operations code will work on the temp file
  
                      // if an existing file already exists what should we do?
                      targetExists = operations.existsFile(target);
                      if (targetExists) {
  
                          if (handleExistingTargetEager(target)) {
                              return;
                          }
                      }
                  }
  
                  // delete any pre existing temp file
                  if (endpoint.getFileExist() != GenericFileExist.TryRename && operations.existsFile(tempTarget)) {
                      LOG.trace("Deleting existing temp file: {}", tempTarget);
                      tryOverridingFile(tempTarget);
                  }
              }
  
              // write/upload the file
              writeFile(exchange, tempTarget != null ? tempTarget : target);
  
              // if we did write to a temporary name then rename it to the real
              // name after we have written the file
              if (tempTarget != null) {
                  // if we did not eager delete the target file
                  if (endpoint.getFileExist() != GenericFileExist.TryRename && !endpoint.isEagerDeleteTargetFile()) {
  
                      // if an existing file already exists what should we do?
                      targetExists = operations.existsFile(target);
                      if (targetExists) {
  
                          if (handleExistingTarget(target)) {
                              return;
                          }
                      }
                  }
  
                  // now we are ready to rename the temp file to the target file
                  LOG.trace("Renaming file: [{}] to: [{}]", tempTarget, target);
                  boolean renamed = operations.renameFile(tempTarget, target);
                  if (!renamed) {
                      throw new GenericFileOperationFailedException("Cannot rename file from: " + tempTarget + " to: " + target);
                  }
              }
  
              // any checksum file to write?
              if (endpoint.getChecksumFileAlgorithm() != null) {
                  writeChecksumFile(exchange, target);
              }
  
              // any done file to write?
              if (endpoint.getDoneFileName() != null) {
                  writeDoneFile(exchange, target);
              }
  
              // let's store the name we really used in the header, so end-users
              // can retrieve it
              exchange.getIn().setHeader(FileConstants.FILE_NAME_PRODUCED, target);
          } catch (Exception e) {
              handleFailedWrite(exchange, e);
          }
  
          postWriteCheck(exchange);
      }
  
      private static void throwFileAlreadyExistException(String target) {
          throw new GenericFileOperationFailedException(
                  "File already exist: " + target + ". Cannot write new file.");
      }
  
      private static boolean doIgnore(String target) {
          // ignore but indicate that the file was written
          LOG.trace("An existing file already exists: {}. Ignore and do not override it.", target);
          return true;
      }
  
      private void tryOverridingFile(String target) {
          if (!operations.deleteFile(target)) {
              throw new GenericFileOperationFailedException("Cannot delete file: " + target);
          }
      }
  
      private boolean handleExistingTargetEager(String target) {
          LOG.trace("EagerDeleteTargetFile, target exists");
  
          if (endpoint.getFileExist() == GenericFileExist.Ignore) {
              return doIgnore(target);
          } else if (endpoint.getFileExist() == GenericFileExist.Fail) {
              throwFileAlreadyExistException(target);
          } else if (endpoint.getFileExist() == GenericFileExist.Move) {
              // move any existing file first
              this.endpoint.getMoveExistingFileStrategy().moveExistingFile(endpoint, operations, target);
          } else if (endpoint.isEagerDeleteTargetFile() && endpoint.getFileExist() == GenericFileExist.Override) {
              // we override the target so we do this by deleting
              // it so the temp file can be renamed later
              // with success as the existing target file have
              // been deleted
              LOG.trace("Eagerly deleting existing file: {}", target);
              tryOverridingFile(target);
          }
          return false;
      }
  
      private boolean handleExistingTarget(String target) {
          LOG.trace("Not using EagerDeleteTargetFile, target exists");
  
          if (endpoint.getFileExist() == GenericFileExist.Ignore) {
              // ignore but indicate that the file was written
              return doIgnore(target);
          } else if (endpoint.getFileExist() == GenericFileExist.Fail) {
              throwFileAlreadyExistException(target);
          } else if (endpoint.getFileExist() == GenericFileExist.Override) {
              // we override the target so we do this by deleting
              // it so the temp file can be renamed later
              // with success as the existing target file have
              // been deleted
              LOG.trace("Deleting existing file: {}", target);
              tryOverridingFile(target);
          }
          return false;
      }
  
      private void writeDoneFile(Exchange exchange, String target) {
          String doneFileName = endpoint.createDoneFileName(target);
          StringHelper.notEmpty(doneFileName, "doneFileName", endpoint);
  
          // create empty exchange with empty body to write as the done
          // file
          Exchange empty = new DefaultExchange(exchange);
          empty.getIn().setBody("");
  
          LOG.trace("Writing done file: [{}]", doneFileName);
          // delete any existing done file
          if (operations.existsFile(doneFileName)) {
              if (!operations.deleteFile(doneFileName)) {
                  throw new GenericFileOperationFailedException("Cannot delete existing done file: " + doneFileName);
              }
          }
          writeFile(empty, doneFileName);
      }
  
      protected void writeChecksumFile(Exchange exchange, String target) throws Exception {
          String algorithm = endpoint.getChecksumFileAlgorithm();
          String checksumFileName = target + "." + algorithm;
  
          // create exchange with checksum as body to write as the checksum file
          MessageHelper.resetStreamCache(exchange.getIn());
          InputStream is = exchange.getIn().getMandatoryBody(InputStream.class);
          Exchange checksumExchange = new DefaultExchange(exchange);
          checksumExchange.getIn().setBody(new DigestUtils(algorithm).digestAsHex(is));
  
          LOG.trace("Writing checksum file: [{}]", checksumFileName);
          // delete any existing done file
          if (operations.existsFile(checksumFileName)) {
              if (!operations.deleteFile(checksumFileName)) {
                  throw new GenericFileOperationFailedException(
                          "Cannot delete existing checksum file: " + checksumFileName);
              }
          }
          writeFile(checksumExchange, checksumFileName);
      }
  
      /**
       * If we fail writing out a file, we will call this method. This hook is provided to disconnect from servers or
       * clean up files we created (if needed).
       */
      public void handleFailedWrite(Exchange exchange, Exception exception) throws Exception {
          throw exception;
      }
  
      /**
       * Perform any actions that need to occur before we write such as connecting to an FTP server etc.
       */
      public void preWriteCheck(Exchange exchange) throws Exception {
          // nothing needed to check
      }
  
      /**
       * Perform any actions that need to occur after we are done such as disconnecting.
       */
      public void postWriteCheck(Exchange exchange) {
          // nothing needed to check
      }
  
      public void writeFile(Exchange exchange, String fileName) throws GenericFileOperationFailedException {
          // build directory if auto create is enabled
          if (endpoint.isAutoCreate()) {
              // we must normalize it (to avoid having both \ and / in the name
              // which confuses java.io.File)
              String name = FileUtil.normalizePath(fileName);
  
              // use java.io.File to compute the file path
              File file = new File(name);
              String directory = file.getParent();
              boolean absolute = FileUtil.isAbsolute(file);
              if (directory != null) {
                  if (!operations.buildDirectory(directory, absolute)) {
                      LOG.debug("Cannot build directory [{}] (could be because of denied permissions)", directory);
                  }
              }
          }
  
          // upload
          if (LOG.isTraceEnabled()) {
              LOG.trace("About to write [{}] to [{}] from exchange [{}]", fileName, getEndpoint(), exchange);
          }
  
          boolean success = operations.storeFile(fileName, exchange, -1);
          if (!success) {
              throw new GenericFileOperationFailedException("Error writing file [" + fileName + "]");
          }
          LOG.debug("Wrote [{}] to [{}]", fileName, getEndpoint());
      }
  
      public String createFileName(Exchange exchange) {
          String answer;
  
          Object overrule = exchange.getIn().getHeader(FileConstants.OVERRULE_FILE_NAME);
  
          // overrule takes precedence
          final Object value = getOverrule(exchange, overrule);
  
          // if we have an overrule then override the existing header to use the
          // overrule computed name from this point forward
          if (overrule != null) {
              exchange.getIn().setHeader(FileConstants.FILE_NAME, value);
          }
  
          if (value instanceof String && StringHelper.hasStartToken((String) value, "simple")) {
              LOG.warn(
                      "Simple expression: {} detected in header: {} of type String. This feature has been removed (see CAMEL-6748).",
                      value, FileConstants.FILE_NAME);
          }
  
          // expression support
          Expression expression = endpoint.getFileName();
          if (value instanceof Expression expression1) {
              expression = expression1;
          }
  
          // evaluate the name as a String from the value
          final String name = evaluateName(exchange, expression, value);
  
          // compute path by adding endpoint starting directory
          String endpointPath = endpoint.getConfiguration().getDirectory();
          String baseDir = "";
          if (!endpointPath.isEmpty()) {
              // Its a directory so we should use it as a base path for the
              // filename
              // If the path isn't empty, we need to add a trailing / if it isn't
              // already there
              baseDir = endpointPath;
              boolean trailingSlash = endpointPath.endsWith("/") || endpointPath.endsWith("\\");
              if (!trailingSlash) {
                  baseDir += getFileSeparator();
              }
          }
          if (name != null) {
              answer = baseDir + name;
          } else {
              // use a generated filename if no name provided
              answer = baseDir + endpoint.getGeneratedFileName(exchange.getIn());
          }
  
          if (endpoint.isJailStartingDirectory()) {
              jailedCheck(answer, baseDir);
          }
  
          if (endpoint.getConfiguration().needToNormalize()) {
              // must normalize path to cater for Windows and other OS
              answer = normalizePath(answer);
          }
  
          return answer;
      }
  
      private static Object getOverrule(Exchange exchange, Object overrule) {
          Object value;
  
          if (overrule != null) {
              if (overrule instanceof Expression) {
                  value = overrule;
              } else {
                  value = exchange.getContext().getTypeConverter().convertTo(String.class, exchange, overrule);
              }
          } else {
              value = exchange.getIn().getHeader(FileConstants.FILE_NAME);
          }
          return value;
      }
  
      private static void jailedCheck(String answer, String baseDir) {
          // check for file must be within starting directory (need to compact
          // first as the name can be using relative paths via ../ etc)
          String compatchAnswer = FileUtil.compactPath(answer);
          String compatchBaseDir = FileUtil.compactPath(baseDir);
          if (!compatchAnswer.startsWith(compatchBaseDir)) {
              throw new IllegalArgumentException(
                      "Cannot write file with name: " + compatchAnswer
                                                 + " as the filename is jailed to the starting directory: "
                                                 + compatchBaseDir);
          }
      }
  
      private String evaluateName(Exchange exchange, Expression expression, Object value) {
          String name;
          if (expression != null) {
              LOG.trace("Filename evaluated as expression: {}", expression);
              name = expression.evaluate(exchange, String.class);
          } else {
              name = exchange.getContext().getTypeConverter().convertTo(String.class, exchange, value);
          }
  
          // flatten name
          if (name != null && endpoint.isFlatten()) {
              name = flattenName(name);
          }
          return name;
      }
  
      private static String flattenName(String name) {
          // check for both windows and unix separators
          int pos = Math.max(name.lastIndexOf('/'), name.lastIndexOf("\\"));
          if (pos != -1) {
              name = name.substring(pos + 1);
          }
          return name;
      }
  
      public String createTempFileName(Exchange exchange, String fileName) {
          String answer = fileName;
  
          String tempName;
          if (exchange.getIn().getHeader(FileConstants.FILE_NAME) == null) {
              // its a generated filename then add it to header so we can evaluate
              // the expression
              exchange.getIn().setHeader(FileConstants.FILE_NAME, FileUtil.stripPath(fileName));
              tempName = endpoint.getTempFileName().evaluate(exchange, String.class);
              // and remove it again after evaluation
              exchange.getIn().removeHeader(FileConstants.FILE_NAME);
          } else {
              tempName = endpoint.getTempFileName().evaluate(exchange, String.class);
          }
  
          // check for both windows and unix separators
          int pos = Math.max(answer.lastIndexOf('/'), answer.lastIndexOf("\\"));
          if (pos == -1) {
              // no path so use temp name as calculated
              answer = tempName;
          } else {
              // path should be prefixed before the temp name
              final String prefix = answer.substring(0, pos + 1);
              StringBuilder sb = new StringBuilder(tempName.length() + prefix.length() + 1);
              sb.append(prefix);
              sb.append(tempName);
              answer = sb.toString();
          }
  
          if (endpoint.getConfiguration().needToNormalize()) {
              // must normalize path to cater for Windows and other OS
              answer = normalizePath(answer);
          }
  
          // stack path in case the temporary file uses .. paths
          answer = FileUtil.compactPath(answer, getFileSeparator());
  
          return answer;
      }
  
      @Override
      protected void doStart() throws Exception {
          ServiceHelper.startService(locks);
          super.doStart();
      }
  
      @Override
      protected void doStop() throws Exception {
          super.doStop();
          ServiceHelper.stopService(locks);
      }
  
  }
  