com.metamx.http.client.response.SequenceInputStreamResponseHandler Maven / Gradle / Ivy
/*
* Copyright 2011 - 2015 Metamarkets Group Inc.
*
* Licensed 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.metamx.http.client.response;
import com.google.common.base.Throwables;
import com.google.common.io.ByteSource;
import com.metamx.common.logger.Logger;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBufferInputStream;
import org.jboss.netty.handler.codec.http.HttpChunk;
import org.jboss.netty.handler.codec.http.HttpResponse;
import java.io.IOException;
import java.io.InputStream;
import java.io.SequenceInputStream;
import java.util.Enumeration;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
/**
* A HTTP response handler which uses sequence input streams to create a final InputStream.
* Any particular instance is encouraged to overwrite a method and call the super if they need extra handling of the
* method parameters.
*
* This implementation uses a blocking queue to feed a SequenceInputStream that is terminated whenever the handler's Done
* method is called or a throwable is detected.
*
* The resulting InputStream will attempt to terminate normally, but on exception in HttpResponseHandler
* may end with an IOException upon read()
*/
public class SequenceInputStreamResponseHandler implements HttpResponseHandler
{
private static final Logger log = new Logger(SequenceInputStreamResponseHandler.class);
private final AtomicLong byteCount = new AtomicLong(0);
private final BlockingQueue queue = new LinkedBlockingQueue<>();
private final AtomicBoolean done = new AtomicBoolean(false);
@Override
public ClientResponse handleResponse(HttpResponse response)
{
try {
queue.put(new ChannelBufferInputStream(response.getContent()));
}
catch (InterruptedException e) {
log.error(e, "Queue appending interrupted");
Thread.currentThread().interrupt();
throw Throwables.propagate(e);
}
byteCount.addAndGet(response.getContent().readableBytes());
return ClientResponse.finished(
new SequenceInputStream(
new Enumeration()
{
@Override
public boolean hasMoreElements()
{
// Done is always true until the last stream has be put in the queue.
// Then the stream should be spouting good InputStreams.
synchronized (done) {
return !done.get() || !queue.isEmpty();
}
}
@Override
public InputStream nextElement()
{
try {
return queue.take();
}
catch (InterruptedException e) {
log.warn(e, "Thread interrupted while taking from queue");
Thread.currentThread().interrupt();
throw Throwables.propagate(e);
}
}
}
)
);
}
@Override
public ClientResponse handleChunk(
ClientResponse clientResponse, HttpChunk chunk
)
{
final ChannelBuffer channelBuffer = chunk.getContent();
final int bytes = channelBuffer.readableBytes();
if (bytes > 0) {
try {
queue.put(new ChannelBufferInputStream(channelBuffer));
// Queue.size() can be expensive in some implementations, but LinkedBlockingQueue.size is just an AtomicLong
log.debug("Added stream. Queue length %d", queue.size());
}
catch (InterruptedException e) {
log.warn(e, "Thread interrupted while adding to queue");
Thread.currentThread().interrupt();
throw Throwables.propagate(e);
}
byteCount.addAndGet(bytes);
} else {
log.debug("Skipping zero length chunk");
}
return clientResponse;
}
@Override
public ClientResponse done(ClientResponse clientResponse)
{
synchronized (done) {
try {
// An empty byte array is put at the end to give the SequenceInputStream.close() as something to close out
// after done is set to true, regardless of the rest of the stream's state.
queue.put(ByteSource.empty().openStream());
log.debug("Added terminal empty stream");
}
catch (InterruptedException e) {
log.warn(e, "Thread interrupted while adding to queue");
Thread.currentThread().interrupt();
throw Throwables.propagate(e);
}
catch (IOException e) {
// This should never happen
log.wtf(e, "The empty stream threw an IOException");
throw Throwables.propagate(e);
}
finally {
log.debug("Done after adding %d bytes of streams", byteCount.get());
done.set(true);
}
}
return ClientResponse.finished(clientResponse.getObj());
}
@Override
public void exceptionCaught(final ClientResponse clientResponse, final Throwable e)
{
// Don't wait for lock in case the lock had something to do with the error
synchronized (done) {
done.set(true);
// Make a best effort to put a zero length buffer into the queue in case something is waiting on the take()
// If nothing is waiting on take(), this will be closed out anyways.
final boolean accepted = queue.offer(
new InputStream()
{
@Override
public int read() throws IOException
{
throw new IOException(e);
}
}
);
if (!accepted) {
log.warn("Unable to place final IOException offer in queue");
} else {
log.debug("Placed IOException in queue");
}
log.debug(e, "Exception with queue length of %d and %d bytes available", queue.size(), byteCount.get());
}
}
public final long getByteCount()
{
return byteCount.get();
}
}