/*
* $HeadURL: https://svn.apache.org/repos/asf/httpcomponents/httpcore/tags/4.0.1/httpcore-nio/src/main/java/org/apache/http/nio/protocol/AsyncNHttpClientHandler.java $
* $Revision: 747992 $
* $Date: 2009-02-26 04:03:22 +0100 (Thu, 26 Feb 2009) $
*
* ====================================================================
* 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.http.nio.protocol;
import java.io.IOException;
import org.apache.http.ConnectionReuseStrategy;
import org.apache.http.HttpEntity;
import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpException;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.nio.ContentDecoder;
import org.apache.http.nio.ContentEncoder;
import org.apache.http.nio.NHttpClientConnection;
import org.apache.http.nio.NHttpClientHandler;
import org.apache.http.nio.entity.ConsumingNHttpEntity;
import org.apache.http.nio.entity.ConsumingNHttpEntityTemplate;
import org.apache.http.nio.entity.NHttpEntityWrapper;
import org.apache.http.nio.entity.ProducingNHttpEntity;
import org.apache.http.nio.entity.SkipContentListener;
import org.apache.http.nio.util.ByteBufferAllocator;
import org.apache.http.nio.util.HeapByteBufferAllocator;
import org.apache.http.params.CoreProtocolPNames;
import org.apache.http.params.DefaultedHttpParams;
import org.apache.http.params.HttpParams;
import org.apache.http.protocol.ExecutionContext;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.HttpProcessor;
/**
* Fully asynchronous HTTP client side protocol handler that implements the
* essential requirements of the HTTP protocol for the server side message
* processing as described by RFC 2616. It is capable of executing HTTP requests
* with nearly constant memory footprint. Only HTTP message heads are stored in
* memory, while content of message bodies is streamed directly from the entity
* to the underlying channel (and vice versa) using {@link ConsumingNHttpEntity}
* and {@link ProducingNHttpEntity} interfaces.
*
* When using this implementation, it is important to ensure that entities
* supplied for writing implement !ProducingNHttpEntity. Doing so will allow
* the entity to be written out asynchronously. If entities supplied for writing
* do not implement the {@link ProducingNHttpEntity} interface, a delegate is
* added that buffers the entire contents in memory. Additionally, the
* buffering might take place in the I/O dispatch thread, which could cause I/O
* to block temporarily. For best results, one must ensure that all entities
* set on {@link HttpRequest}s from {@link NHttpRequestExecutionHandler}
* implement {@link ProducingNHttpEntity}.
*
* If incoming responses enclose a content entity,
* {@link NHttpRequestExecutionHandler} are expected to return a
* {@link ConsumingNHttpEntity} for reading the content. After the entity is
* finished reading the data,
* {@link NHttpRequestExecutionHandler#handleResponse(HttpResponse, HttpContext)}
* method is called to process the response.
*
* @see ConsumingNHttpEntity
* @see ProducingNHttpEntity
*
* @since 4.0
*/
public class AsyncNHttpClientHandler extends NHttpHandlerBase
implements NHttpClientHandler {
protected NHttpRequestExecutionHandler execHandler;
public AsyncNHttpClientHandler(
final HttpProcessor httpProcessor,
final NHttpRequestExecutionHandler execHandler,
final ConnectionReuseStrategy connStrategy,
final ByteBufferAllocator allocator,
final HttpParams params) {
super(httpProcessor, connStrategy, allocator, params);
if (execHandler == null) {
throw new IllegalArgumentException("HTTP request execution handler may not be null.");
}
this.execHandler = execHandler;
}
public AsyncNHttpClientHandler(
final HttpProcessor httpProcessor,
final NHttpRequestExecutionHandler execHandler,
final ConnectionReuseStrategy connStrategy,
final HttpParams params) {
this(httpProcessor, execHandler, connStrategy,
new HeapByteBufferAllocator(), params);
}
public void connected(final NHttpClientConnection conn, final Object attachment) {
HttpContext context = conn.getContext();
initialize(conn, attachment);
ClientConnState connState = new ClientConnState();
context.setAttribute(CONN_STATE, connState);
if (this.eventListener != null) {
this.eventListener.connectionOpen(conn);
}
requestReady(conn);
}
public void closed(final NHttpClientConnection conn) {
HttpContext context = conn.getContext();
ClientConnState connState = (ClientConnState) context.getAttribute(CONN_STATE);
try {
connState.reset();
} catch (IOException ex) {
if (this.eventListener != null) {
this.eventListener.fatalIOException(ex, conn);
}
}
this.execHandler.finalizeContext(context);
if (this.eventListener != null) {
this.eventListener.connectionClosed(conn);
}
}
public void exception(final NHttpClientConnection conn, final HttpException ex) {
closeConnection(conn, ex);
if (this.eventListener != null) {
this.eventListener.fatalProtocolException(ex, conn);
}
}
public void exception(final NHttpClientConnection conn, final IOException ex) {
shutdownConnection(conn, ex);
if (this.eventListener != null) {
this.eventListener.fatalIOException(ex, conn);
}
}
public void requestReady(final NHttpClientConnection conn) {
HttpContext context = conn.getContext();
ClientConnState connState = (ClientConnState) context.getAttribute(CONN_STATE);
if (connState.getOutputState() != ClientConnState.READY) {
return;
}
try {
HttpRequest request = this.execHandler.submitRequest(context);
if (request == null) {
return;
}
request.setParams(
new DefaultedHttpParams(request.getParams(), this.params));
context.setAttribute(ExecutionContext.HTTP_REQUEST, request);
this.httpProcessor.process(request, context);
HttpEntityEnclosingRequest entityReq = null;
HttpEntity entity = null;
if (request instanceof HttpEntityEnclosingRequest) {
entityReq = (HttpEntityEnclosingRequest) request;
entity = entityReq.getEntity();
}
if (entity instanceof ProducingNHttpEntity) {
connState.setProducingEntity((ProducingNHttpEntity) entity);
} else if (entity != null) {
connState.setProducingEntity(new NHttpEntityWrapper(entity));
}
connState.setRequest(request);
conn.submitRequest(request);
connState.setOutputState(ClientConnState.REQUEST_SENT);
if (entityReq != null && entityReq.expectContinue()) {
int timeout = conn.getSocketTimeout();
connState.setTimeout(timeout);
timeout = this.params.getIntParameter(
CoreProtocolPNames.WAIT_FOR_CONTINUE, 3000);
conn.setSocketTimeout(timeout);
connState.setOutputState(ClientConnState.EXPECT_CONTINUE);
}
} catch (IOException ex) {
shutdownConnection(conn, ex);
if (this.eventListener != null) {
this.eventListener.fatalIOException(ex, conn);
}
} catch (HttpException ex) {
closeConnection(conn, ex);
if (this.eventListener != null) {
this.eventListener.fatalProtocolException(ex, conn);
}
}
}
public void inputReady(final NHttpClientConnection conn, final ContentDecoder decoder) {
HttpContext context = conn.getContext();
ClientConnState connState = (ClientConnState) context.getAttribute(CONN_STATE);
ConsumingNHttpEntity consumingEntity = connState.getConsumingEntity();
try {
consumingEntity.consumeContent(decoder, conn);
if (decoder.isCompleted()) {
processResponse(conn, connState);
}
} catch (IOException ex) {
shutdownConnection(conn, ex);
if (this.eventListener != null) {
this.eventListener.fatalIOException(ex, conn);
}
} catch (HttpException ex) {
closeConnection(conn, ex);
if (this.eventListener != null) {
this.eventListener.fatalProtocolException(ex, conn);
}
}
}
public void outputReady(final NHttpClientConnection conn, final ContentEncoder encoder) {
HttpContext context = conn.getContext();
ClientConnState connState = (ClientConnState) context.getAttribute(CONN_STATE);
try {
if (connState.getOutputState() == ClientConnState.EXPECT_CONTINUE) {
conn.suspendOutput();
return;
}
ProducingNHttpEntity entity = connState.getProducingEntity();
entity.produceContent(encoder, conn);
} catch (IOException ex) {
shutdownConnection(conn, ex);
if (this.eventListener != null) {
this.eventListener.fatalIOException(ex, conn);
}
}
}
public void responseReceived(final NHttpClientConnection conn) {
HttpContext context = conn.getContext();
ClientConnState connState = (ClientConnState) context.getAttribute(CONN_STATE);
HttpResponse response = conn.getHttpResponse();
response.setParams(
new DefaultedHttpParams(response.getParams(), this.params));
HttpRequest request = connState.getRequest();
try {
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode < HttpStatus.SC_OK) {
// 1xx intermediate response
if (statusCode == HttpStatus.SC_CONTINUE
&& connState.getOutputState() == ClientConnState.EXPECT_CONTINUE) {
continueRequest(conn, connState);
}
return;
} else {
connState.setResponse(response);
if (connState.getOutputState() == ClientConnState.EXPECT_CONTINUE) {
cancelRequest(conn, connState);
}
}
context.setAttribute(ExecutionContext.HTTP_RESPONSE, response);
if (!canResponseHaveBody(request, response)) {
conn.resetInput();
response.setEntity(null);
this.httpProcessor.process(response, context);
processResponse(conn, connState);
} else {
HttpEntity entity = response.getEntity();
if (entity != null) {
ConsumingNHttpEntity consumingEntity = this.execHandler.responseEntity(
response, context);
if (consumingEntity == null) {
consumingEntity = new ConsumingNHttpEntityTemplate(
entity, new SkipContentListener(this.allocator));
}
response.setEntity(consumingEntity);
connState.setConsumingEntity(consumingEntity);
this.httpProcessor.process(response, context);
}
}
} catch (IOException ex) {
shutdownConnection(conn, ex);
if (this.eventListener != null) {
this.eventListener.fatalIOException(ex, conn);
}
} catch (HttpException ex) {
closeConnection(conn, ex);
if (this.eventListener != null) {
this.eventListener.fatalProtocolException(ex, conn);
}
}
}
public void timeout(final NHttpClientConnection conn) {
HttpContext context = conn.getContext();
ClientConnState connState = (ClientConnState) context.getAttribute(CONN_STATE);
try {
if (connState.getOutputState() == ClientConnState.EXPECT_CONTINUE) {
continueRequest(conn, connState);
return;
}
} catch (IOException ex) {
shutdownConnection(conn, ex);
if (this.eventListener != null) {
this.eventListener.fatalIOException(ex, conn);
}
}
handleTimeout(conn);
}
private void initialize(
final NHttpClientConnection conn,
final Object attachment) {
HttpContext context = conn.getContext();
context.setAttribute(ExecutionContext.HTTP_CONNECTION, conn);
this.execHandler.initalizeContext(context, attachment);
}
/**
* @throws IOException - not thrown currently
*/
private void continueRequest(
final NHttpClientConnection conn,
final ClientConnState connState) throws IOException {
int timeout = connState.getTimeout();
conn.setSocketTimeout(timeout);
conn.requestOutput();
connState.setOutputState(ClientConnState.REQUEST_SENT);
}
private void cancelRequest(
final NHttpClientConnection conn,
final ClientConnState connState) throws IOException {
int timeout = connState.getTimeout();
conn.setSocketTimeout(timeout);
conn.resetOutput();
connState.resetOutput();
}
/**
* @throws HttpException - not thrown currently
*/
private void processResponse(
final NHttpClientConnection conn,
final ClientConnState connState) throws IOException, HttpException {
HttpContext context = conn.getContext();
HttpResponse response = connState.getResponse();
this.execHandler.handleResponse(response, context);
if (!this.connStrategy.keepAlive(response, context)) {
conn.close();
} else {
// Ready for another request
connState.resetInput();
connState.resetOutput();
conn.requestOutput();
}
}
protected static class ClientConnState {
public static final int READY = 0;
public static final int REQUEST_SENT = 1;
public static final int EXPECT_CONTINUE = 2;
public static final int REQUEST_BODY_STREAM = 4;
public static final int REQUEST_BODY_DONE = 8;
public static final int RESPONSE_RECEIVED = 16;
public static final int RESPONSE_BODY_STREAM = 32;
public static final int RESPONSE_BODY_DONE = 64;
private int outputState;
private HttpRequest request;
private HttpResponse response;
private ConsumingNHttpEntity consumingEntity;
private ProducingNHttpEntity producingEntity;
private int timeout;
public void setConsumingEntity(final ConsumingNHttpEntity consumingEntity) {
this.consumingEntity = consumingEntity;
}
public void setProducingEntity(final ProducingNHttpEntity producingEntity) {
this.producingEntity = producingEntity;
}
public ProducingNHttpEntity getProducingEntity() {
return producingEntity;
}
public ConsumingNHttpEntity getConsumingEntity() {
return consumingEntity;
}
public int getOutputState() {
return this.outputState;
}
public void setOutputState(int outputState) {
this.outputState = outputState;
}
public HttpRequest getRequest() {
return this.request;
}
public void setRequest(final HttpRequest request) {
this.request = request;
}
public HttpResponse getResponse() {
return this.response;
}
public void setResponse(final HttpResponse response) {
this.response = response;
}
public int getTimeout() {
return this.timeout;
}
public void setTimeout(int timeout) {
this.timeout = timeout;
}
public void resetInput() throws IOException {
this.response = null;
if (this.consumingEntity != null) {
this.consumingEntity.finish();
this.consumingEntity = null;
}
}
public void resetOutput() throws IOException {
this.request = null;
if (this.producingEntity != null) {
this.producingEntity.finish();
this.producingEntity = null;
}
this.outputState = READY;
}
public void reset() throws IOException {
resetInput();
resetOutput();
}
}
}