/*
* Copyright 2010-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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.amazonaws.http;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.entity.BasicHttpEntity;
import org.apache.http.entity.InputStreamEntity;
import com.amazonaws.Request;
import com.amazonaws.metrics.MetricInputStreamEntity;
import com.amazonaws.metrics.ServiceMetricType;
import com.amazonaws.metrics.ThroughputMetricType;
import com.amazonaws.metrics.internal.ServiceMetricTypeGuesser;
/**
* Custom implementation of {@link RequestEntity} that delegates to an
* {@link InputStreamRequestEntity}, with the one notable difference, that if
* the underlying InputStream supports being reset, this RequestEntity will
* report that it is repeatable and will reset the stream on all subsequent
* attempts to write out the request.
*/
class RepeatableInputStreamRequestEntity extends BasicHttpEntity {
/** True if the request entity hasn't been written out yet */
private boolean firstAttempt = true;
/** The underlying InputStreamEntity being delegated to */
private InputStreamEntity inputStreamRequestEntity;
/** The InputStream containing the content to write out */
private InputStream content;
/** Shared logger for more debugging information */
private static final Log log = LogFactory.getLog(AmazonHttpClient.class);
/**
* Record the original exception if we do attempt a retry, so that if the
* retry fails, we can report the original exception. Otherwise, we're most
* likely masking the real exception with an error about not being able to
* reset far enough back in the input stream.
*/
private IOException originalException;
/**
* Creates a new RepeatableInputStreamRequestEntity using the information
* from the specified request. If the input stream containing the request's
* contents is repeatable, then this RequestEntity will report as being
* repeatable.
*
* @param request
* The details of the request being written out (content type,
* content length, and content).
*/
RepeatableInputStreamRequestEntity(final Request<?> request) {
setChunked(false);
/*
* If we don't specify a content length when we instantiate our
* InputStreamRequestEntity, then HttpClient will attempt to
* buffer the entire stream contents into memory to determine
* the content length.
*
* TODO: It'd be nice to have easier access to content length and
* content type from the request, instead of having to look
* directly into the headers.
*/
long contentLength = -1;
try {
String contentLengthString = request.getHeaders().get("Content-Length");
if (contentLengthString != null) {
contentLength = Long.parseLong(contentLengthString);
}
} catch (NumberFormatException nfe) {
log.warn("Unable to parse content length from request. " +
"Buffering contents in memory.");
}
String contentType = request.getHeaders().get("Content-Type");
ThroughputMetricType type = ServiceMetricTypeGuesser
.guessThroughputMetricType(request,
ServiceMetricType.UPLOAD_THROUGHPUT_NAME_SUFFIX,
ServiceMetricType.UPLOAD_BYTE_COUNT_NAME_SUFFIX);
if (type == null) {
inputStreamRequestEntity =
new InputStreamEntity(request.getContent(), contentLength);
} else {
inputStreamRequestEntity =
new MetricInputStreamEntity(type, request.getContent(), contentLength);
}
inputStreamRequestEntity.setContentType(contentType);
content = request.getContent();
setContent(content);
setContentType(contentType);
setContentLength(contentLength);
}
@Override
public boolean isChunked() {
return false;
}
/**
* Returns true if the underlying InputStream supports marking/reseting or
* if the underlying InputStreamRequestEntity is repeatable (i.e. its
* content length has been set to
* {@link InputStreamRequestEntity#CONTENT_LENGTH_AUTO} and therefore its
* entire contents will be buffered in memory and can be repeated).
*
* @see org.apache.commons.httpclient.methods.RequestEntity#isRepeatable()
*/
@Override
public boolean isRepeatable() {
return content.markSupported() || inputStreamRequestEntity.isRepeatable();
}
/**
* Resets the underlying InputStream if this isn't the first attempt to
* write out the request, otherwise simply delegates to
* InputStreamRequestEntity to write out the data.
* <p>
* If an error is encountered the first time we try to write the request
* entity, we remember the original exception, and report that as the root
* cause if we continue to encounter errors, rather than masking the
* original error.
*
* @see org.apache.commons.httpclient.methods.RequestEntity#writeRequest(java.io.OutputStream)
*/
@Override
public void writeTo(OutputStream output) throws IOException {
try {
if (!firstAttempt && isRepeatable()) content.reset();
firstAttempt = false;
inputStreamRequestEntity.writeTo(output);
} catch (IOException ioe) {
if (originalException == null) originalException = ioe;
throw originalException;
}
}
}