/*
* ====================================================================
* 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.Closeable;
import java.io.IOException;
import java.net.SocketTimeoutException;
import org.apache.http.ConnectionReuseStrategy;
import org.apache.http.HttpConnection;
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.ProtocolException;
import org.apache.http.annotation.Immutable;
import org.apache.http.nio.ContentDecoder;
import org.apache.http.nio.ContentEncoder;
import org.apache.http.nio.NHttpClientConnection;
import org.apache.http.nio.NHttpClientEventHandler;
import org.apache.http.nio.NHttpConnection;
import org.apache.http.params.CoreProtocolPNames;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.protocol.ExecutionContext;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.HttpProcessor;
/**
* <tt>HttpAsyncRequestExecutor</tt> is a fully asynchronous HTTP client side
* protocol handler based on the NIO (non-blocking) I/O model.
* <tt>HttpAsyncRequestExecutor</tt> translates individual events fired through
* the {@link NHttpClientEventHandler} interface into logically related HTTP
* message exchanges.
* <p/>
* <tt>HttpAsyncRequestExecutor</tt> relies on {@link HttpProcessor}
* to generate mandatory protocol headers for all outgoing messages and apply
* common, cross-cutting message transformations to all incoming and outgoing
* messages, whereas individual {@link HttpAsyncRequestExecutionHandler}s
* are expected to implement application specific content generation and
* processing. The caller is expected to pass an instance of
* {@link HttpAsyncRequestExecutionHandler} to be used for the next series
* of HTTP message exchanges through the connection context using
* {@link #HTTP_HANDLER} attribute. HTTP exchange sequence is considered
* complete when the {@link HttpAsyncRequestExecutionHandler#isDone()} method
* returns <code>true</code>. The {@link HttpAsyncRequester} utility class can
* be used to facilitate initiation of asynchronous HTTP request execution.
* <p/>
* The following parameters can be used to customize the behavior of this
* class:
* <ul>
* <li>{@link org.apache.http.params.CoreProtocolPNames#WAIT_FOR_CONTINUE}</li>
* <li>{@link org.apache.http.params.CoreConnectionPNames#SO_TIMEOUT}</li>
* </ul>
*
* @see HttpAsyncRequestExecutionHandler
*
* @since 4.2
*/
@Immutable
public class HttpAsyncRequestExecutor implements NHttpClientEventHandler {
public static final String HTTP_HANDLER = "http.nio.exchange-handler";
public HttpAsyncRequestExecutor() {
super();
}
public void connected(
final NHttpClientConnection conn,
final Object attachment) throws IOException, HttpException {
State state = new State();
HttpContext context = conn.getContext();
context.setAttribute(HTTP_EXCHANGE_STATE, state);
requestReady(conn);
}
public void closed(final NHttpClientConnection conn) {
State state = getState(conn);
HttpAsyncRequestExecutionHandler<?> handler = getHandler(conn);
if (state != null) {
state.reset();
} else {
closeHandler(handler, null);
}
}
public void exception(
final NHttpClientConnection conn, final Exception cause) {
shutdownConnection(conn);
HttpAsyncRequestExecutionHandler<?> handler = getHandler(conn);
if (handler != null) {
closeHandler(handler, cause);
} else {
log(cause);
}
}
public void requestReady(
final NHttpClientConnection conn) throws IOException, HttpException {
State state = ensureNotNull(getState(conn));
if (state.getRequestState() != MessageState.READY) {
return;
}
HttpAsyncRequestExecutionHandler<?> handler = getHandler(conn);
if (handler != null && handler.isDone()) {
closeHandler(handler, null);
state.reset();
handler = null;
}
if (handler == null) {
return;
}
HttpContext context = handler.getContext();
context.setAttribute(ExecutionContext.HTTP_CONNECTION, conn);
HttpRequest request = handler.generateRequest();
context.setAttribute(ExecutionContext.HTTP_REQUEST, request);
conn.setSocketTimeout(HttpConnectionParams.getSoTimeout(request.getParams()));
HttpProcessor httppocessor = handler.getHttpProcessor();
httppocessor.process(request, context);
state.setRequest(request);
conn.submitRequest(request);
if (request instanceof HttpEntityEnclosingRequest) {
if (((HttpEntityEnclosingRequest) request).expectContinue()) {
int timeout = conn.getSocketTimeout();
state.setTimeout(timeout);
timeout = request.getParams().getIntParameter(
CoreProtocolPNames.WAIT_FOR_CONTINUE, 3000);
conn.setSocketTimeout(timeout);
state.setRequestState(MessageState.ACK_EXPECTED);
} else {
state.setRequestState(MessageState.BODY_STREAM);
}
} else {
handler.requestCompleted(context);
state.setRequestState(MessageState.COMPLETED);
}
}
public void outputReady(
final NHttpClientConnection conn,
final ContentEncoder encoder) throws IOException {
State state = ensureNotNull(getState(conn));
HttpAsyncRequestExecutionHandler<?> handler = ensureNotNull(getHandler(conn));
if (state.getRequestState() == MessageState.ACK_EXPECTED) {
conn.suspendOutput();
return;
}
HttpContext context = handler.getContext();
handler.produceContent(encoder, conn);
state.setRequestState(MessageState.BODY_STREAM);
if (encoder.isCompleted()) {
handler.requestCompleted(context);
state.setRequestState(MessageState.COMPLETED);
}
}
public void responseReceived(
final NHttpClientConnection conn) throws HttpException, IOException {
State state = ensureNotNull(getState(conn));
HttpAsyncRequestExecutionHandler<?> handler = ensureNotNull(getHandler(conn));
HttpResponse response = conn.getHttpResponse();
HttpRequest request = state.getRequest();
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode < HttpStatus.SC_OK) {
// 1xx intermediate response
if (statusCode != HttpStatus.SC_CONTINUE) {
throw new ProtocolException(
"Unexpected response: " + response.getStatusLine());
}
if (state.getRequestState() == MessageState.ACK_EXPECTED) {
int timeout = state.getTimeout();
conn.setSocketTimeout(timeout);
conn.requestOutput();
state.setRequestState(MessageState.ACK);
}
return;
}
state.setResponse(response);
if (state.getRequestState() == MessageState.ACK_EXPECTED) {
int timeout = state.getTimeout();
conn.setSocketTimeout(timeout);
conn.resetOutput();
state.setRequestState(MessageState.COMPLETED);
} else if (state.getRequestState() == MessageState.BODY_STREAM) {
// Early response
conn.resetOutput();
conn.suspendOutput();
state.setRequestState(MessageState.COMPLETED);
state.invalidate();
}
handler.responseReceived(response);
HttpContext context = handler.getContext();
HttpProcessor httpprocessor = handler.getHttpProcessor();
context.setAttribute(ExecutionContext.HTTP_RESPONSE, response);
httpprocessor.process(response, context);
state.setResponseState(MessageState.BODY_STREAM);
if (!canResponseHaveBody(request, response)) {
conn.resetInput();
processResponse(conn, state, handler);
}
}
public void inputReady(
final NHttpClientConnection conn,
final ContentDecoder decoder) throws IOException {
State state = ensureNotNull(getState(conn));
HttpAsyncRequestExecutionHandler<?> handler = ensureNotNull(getHandler(conn));
handler.consumeContent(decoder, conn);
state.setResponseState(MessageState.BODY_STREAM);
if (decoder.isCompleted()) {
processResponse(conn, state, handler);
}
}
public void endOfInput(final NHttpClientConnection conn) throws IOException {
conn.close();
}
public void timeout(
final NHttpClientConnection conn) throws IOException {
State state = getState(conn);
if (state != null) {
if (state.getRequestState() == MessageState.ACK_EXPECTED) {
int timeout = state.getTimeout();
conn.setSocketTimeout(timeout);
conn.requestOutput();
state.setRequestState(MessageState.BODY_STREAM);
return;
} else {
state.invalidate();
closeHandler(getHandler(conn), new SocketTimeoutException());
}
}
if (conn.getStatus() == NHttpConnection.ACTIVE) {
conn.close();
if (conn.getStatus() == NHttpConnection.CLOSING) {
// Give the connection some grace time to
// close itself nicely
conn.setSocketTimeout(250);
}
} else {
conn.shutdown();
}
}
/**
* This method can be used to log I/O exception thrown while closing {@link Closeable}
* objects (such as {@link HttpConnection}}).
*
* @param ex I/O exception thrown by {@link Closeable#close()}
*/
protected void log(final Exception ex) {
}
private State getState(final NHttpConnection conn) {
return (State) conn.getContext().getAttribute(HTTP_EXCHANGE_STATE);
}
private State ensureNotNull(final State state) {
if (state == null) {
throw new IllegalStateException("HTTP exchange state is null");
}
return state;
}
private HttpAsyncRequestExecutionHandler<?> getHandler(final NHttpConnection conn) {
return (HttpAsyncRequestExecutionHandler<?>) conn.getContext().getAttribute(HTTP_HANDLER);
}
private HttpAsyncRequestExecutionHandler<?> ensureNotNull(final HttpAsyncRequestExecutionHandler<?> handler) {
if (handler == null) {
throw new IllegalStateException("HTTP exchange handler is null");
}
return handler;
}
private void shutdownConnection(final NHttpConnection conn) {
try {
conn.shutdown();
} catch (IOException ex) {
log(ex);
}
}
private void closeHandler(final HttpAsyncRequestExecutionHandler<?> handler, final Exception ex) {
if (handler != null) {
try {
if (ex != null) {
handler.failed(ex);
}
} finally {
try {
handler.close();
} catch (IOException ioex) {
log(ioex);
}
}
}
}
private void processResponse(
final NHttpClientConnection conn,
final State state,
final HttpAsyncRequestExecutionHandler<?> handler) throws IOException {
HttpContext context = handler.getContext();
if (state.isValid()) {
HttpRequest request = state.getRequest();
HttpResponse response = state.getResponse();
String method = request.getRequestLine().getMethod();
int status = response.getStatusLine().getStatusCode();
if (!(method.equalsIgnoreCase("CONNECT") && status < 300)) {
ConnectionReuseStrategy connReuseStrategy = handler.getConnectionReuseStrategy();
if (!connReuseStrategy.keepAlive(response, context)) {
conn.close();
}
}
} else {
conn.close();
}
handler.responseCompleted(context);
state.reset();
}
private boolean canResponseHaveBody(final HttpRequest request, final HttpResponse response) {
String method = request.getRequestLine().getMethod();
int status = response.getStatusLine().getStatusCode();
if (method.equalsIgnoreCase("HEAD")) {
return false;
}
if (method.equalsIgnoreCase("CONNECT") && status < 300) {
return false;
}
return status >= HttpStatus.SC_OK
&& status != HttpStatus.SC_NO_CONTENT
&& status != HttpStatus.SC_NOT_MODIFIED
&& status != HttpStatus.SC_RESET_CONTENT;
}
static final String HTTP_EXCHANGE_STATE = "http.nio.http-exchange-state";
static class State {
private volatile MessageState requestState;
private volatile MessageState responseState;
private volatile HttpRequest request;
private volatile HttpResponse response;
private volatile boolean valid;
private volatile int timeout;
State() {
super();
this.valid = true;
this.requestState = MessageState.READY;
this.responseState = MessageState.READY;
}
public MessageState getRequestState() {
return this.requestState;
}
public void setRequestState(final MessageState state) {
this.requestState = state;
}
public MessageState getResponseState() {
return this.responseState;
}
public void setResponseState(final MessageState state) {
this.responseState = state;
}
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 reset() {
this.responseState = MessageState.READY;
this.requestState = MessageState.READY;
this.response = null;
this.request = null;
this.timeout = 0;
}
public boolean isValid() {
return this.valid;
}
public void invalidate() {
this.valid = false;
}
@Override
public String toString() {
StringBuilder buf = new StringBuilder();
buf.append("request state: ");
buf.append(this.requestState);
buf.append("; request: ");
if (this.request != null) {
buf.append(this.request.getRequestLine());
}
buf.append("; response state: ");
buf.append(this.responseState);
buf.append("; response: ");
if (this.response != null) {
buf.append(this.response.getStatusLine());
}
buf.append("; valid: ");
buf.append(this.valid);
buf.append(";");
return buf.toString();
}
}
}