/*
* ====================================================================
* 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 java.net.SocketTimeoutException;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
import org.apache.http.ConnectionClosedException;
import org.apache.http.ExceptionLogger;
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.HttpVersion;
import org.apache.http.ProtocolException;
import org.apache.http.ProtocolVersion;
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.protocol.HttpContext;
import org.apache.http.util.Args;
import org.apache.http.util.Asserts;
/**
* {@code HttpAsyncRequestExecutor} is a fully asynchronous HTTP client side
* protocol handler based on the NIO (non-blocking) I/O model.
* {@code HttpAsyncRequestExecutor} translates individual events fired through
* the {@link NHttpClientEventHandler} interface into logically related HTTP
* message exchanges.
* <p> The caller is expected to pass an instance of
* {@link HttpAsyncClientExchangeHandler} 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 HttpAsyncClientExchangeHandler#isDone()} method
* returns {@code true}. The {@link HttpAsyncRequester} utility class can
* be used to facilitate initiation of asynchronous HTTP request execution.
* <p>
* Individual {@code HttpAsyncClientExchangeHandler} are expected to make use of
* a {@link org.apache.http.protocol.HttpProcessor} to generate mandatory protocol
* headers for all outgoing messages and apply common, cross-cutting message
* transformations to all incoming and outgoing messages.
* {@code HttpAsyncClientExchangeHandler}s can delegate implementation of
* application specific content generation and processing to
* a {@link HttpAsyncRequestProducer} and a {@link HttpAsyncResponseConsumer}.
*
* @see HttpAsyncClientExchangeHandler
*
* @since 4.2
*/
@Immutable
public class HttpAsyncRequestExecutor implements NHttpClientEventHandler {
public static final int DEFAULT_WAIT_FOR_CONTINUE = 3000;
public static final String HTTP_HANDLER = "http.nio.exchange-handler";
private final int waitForContinue;
private final ExceptionLogger exceptionLogger;
/**
* Creates new instance of {@code HttpAsyncRequestExecutor}.
* @param waitForContinue wait for continue time period.
* @param exceptionLogger Exception logger. If {@code null}
* {@link ExceptionLogger#NO_OP} will be used. Please note that the exception
* logger will be only used to log I/O exception thrown while closing
* {@link java.io.Closeable} objects (such as {@link org.apache.http.HttpConnection}).
*
* @since 4.4
*/
public HttpAsyncRequestExecutor(
final int waitForContinue,
final ExceptionLogger exceptionLogger) {
super();
this.waitForContinue = Args.positive(waitForContinue, "Wait for continue time");
this.exceptionLogger = exceptionLogger != null ? exceptionLogger : ExceptionLogger.NO_OP;
}
/**
* Creates new instance of HttpAsyncRequestExecutor.
*
* @since 4.3
*/
public HttpAsyncRequestExecutor(final int waitForContinue) {
this(waitForContinue, null);
}
public HttpAsyncRequestExecutor() {
this(DEFAULT_WAIT_FOR_CONTINUE, null);
}
@Override
public void connected(
final NHttpClientConnection conn,
final Object attachment) throws IOException, HttpException {
final State state = new State();
final HttpContext context = conn.getContext();
context.setAttribute(HTTP_EXCHANGE_STATE, state);
requestReady(conn);
}
@Override
public void closed(final NHttpClientConnection conn) {
final State state = getState(conn);
final HttpAsyncClientExchangeHandler handler = getHandler(conn);
if (state != null) {
if (state.getRequestState() != MessageState.READY || state.getResponseState() != MessageState.READY) {
if (handler != null) {
handler.failed(new ConnectionClosedException("Connection closed unexpectedly"));
}
}
}
if (state == null || (handler != null && handler.isDone())) {
closeHandler(handler);
}
}
@Override
public void exception(
final NHttpClientConnection conn, final Exception cause) {
shutdownConnection(conn);
final HttpAsyncClientExchangeHandler handler = getHandler(conn);
if (handler != null) {
handler.failed(cause);
} else {
log(cause);
}
}
@Override
public void requestReady(
final NHttpClientConnection conn) throws IOException, HttpException {
final State state = getState(conn);
Asserts.notNull(state, "Connection state");
Asserts.check(state.getRequestState() == MessageState.READY ||
state.getRequestState() == MessageState.COMPLETED,
"Unexpected request state %s", state.getRequestState());
if (state.getRequestState() == MessageState.COMPLETED) {
conn.suspendOutput();
return;
}
final HttpContext context = conn.getContext();
final HttpAsyncClientExchangeHandler handler;
synchronized (context) {
handler = getHandler(conn);
if (handler == null || handler.isDone()) {
conn.suspendOutput();
return;
}
}
final boolean pipelined = handler.getClass().getAnnotation(Pipelined.class) != null;
final HttpRequest request = handler.generateRequest();
if (request == null) {
conn.suspendOutput();
return;
}
final ProtocolVersion version = request.getRequestLine().getProtocolVersion();
if (pipelined && version.lessEquals(HttpVersion.HTTP_1_0)) {
throw new ProtocolException(version + " cannot be used with request pipelining");
}
state.setRequest(request);
if (pipelined) {
state.getRequestQueue().add(request);
}
if (request instanceof HttpEntityEnclosingRequest) {
final boolean expectContinue = ((HttpEntityEnclosingRequest) request).expectContinue();
if (expectContinue && pipelined) {
throw new ProtocolException("Expect-continue handshake cannot be used with request pipelining");
}
conn.submitRequest(request);
if (expectContinue) {
final int timeout = conn.getSocketTimeout();
state.setTimeout(timeout);
conn.setSocketTimeout(this.waitForContinue);
state.setRequestState(MessageState.ACK_EXPECTED);
} else {
final HttpEntity entity = ((HttpEntityEnclosingRequest) request).getEntity();
if (entity != null) {
state.setRequestState(MessageState.BODY_STREAM);
} else {
handler.requestCompleted();
state.setRequestState(pipelined ? MessageState.READY : MessageState.COMPLETED);
}
}
} else {
conn.submitRequest(request);
handler.requestCompleted();
state.setRequestState(pipelined ? MessageState.READY : MessageState.COMPLETED);
}
}
@Override
public void outputReady(
final NHttpClientConnection conn,
final ContentEncoder encoder) throws IOException, HttpException {
final State state = getState(conn);
Asserts.notNull(state, "Connection state");
Asserts.check(state.getRequestState() == MessageState.BODY_STREAM ||
state.getRequestState() == MessageState.ACK_EXPECTED,
"Unexpected request state %s", state.getRequestState());
final HttpAsyncClientExchangeHandler handler = getHandler(conn);
Asserts.notNull(handler, "Client exchange handler");
if (state.getRequestState() == MessageState.ACK_EXPECTED) {
conn.suspendOutput();
return;
}
handler.produceContent(encoder, conn);
if (encoder.isCompleted()) {
handler.requestCompleted();
final boolean pipelined = handler.getClass().getAnnotation(Pipelined.class) != null;
state.setRequestState(pipelined ? MessageState.READY : MessageState.COMPLETED);
}
}
@Override
public void responseReceived(
final NHttpClientConnection conn) throws HttpException, IOException {
final State state = getState(conn);
Asserts.notNull(state, "Connection state");
Asserts.check(state.getResponseState() == MessageState.READY,
"Unexpected request state %s", state.getResponseState());
final HttpAsyncClientExchangeHandler handler = getHandler(conn);
Asserts.notNull(handler, "Client exchange handler");
final boolean pipelined = handler.getClass().getAnnotation(Pipelined.class) != null;
final HttpRequest request;
if (pipelined) {
request = state.getRequestQueue().poll();
Asserts.notNull(request, "HTTP request");
} else {
request = state.getRequest();
if (request == null) {
throw new HttpException("Out of sequence response");
}
}
final HttpResponse response = conn.getHttpResponse();
final 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) {
final int timeout = state.getTimeout();
conn.setSocketTimeout(timeout);
conn.requestOutput();
state.setRequestState(MessageState.BODY_STREAM);
}
return;
}
state.setResponse(response);
if (state.getRequestState() == MessageState.ACK_EXPECTED) {
final 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);
state.setResponseState(MessageState.BODY_STREAM);
if (!canResponseHaveBody(request, response)) {
response.setEntity(null);
conn.resetInput();
processResponse(conn, state, handler);
}
}
@Override
public void inputReady(
final NHttpClientConnection conn,
final ContentDecoder decoder) throws IOException, HttpException {
final State state = getState(conn);
Asserts.notNull(state, "Connection state");
Asserts.check(state.getResponseState() == MessageState.BODY_STREAM,
"Unexpected request state %s", state.getResponseState());
final HttpAsyncClientExchangeHandler handler = getHandler(conn);
Asserts.notNull(handler, "Client exchange handler");
handler.consumeContent(decoder, conn);
if (decoder.isCompleted()) {
processResponse(conn, state, handler);
}
}
@Override
public void endOfInput(final NHttpClientConnection conn) throws IOException {
final State state = getState(conn);
if (state != null) {
if (state.getRequestState().compareTo(MessageState.READY) != 0) {
state.invalidate();
}
final HttpAsyncClientExchangeHandler handler = getHandler(conn);
if (handler != null) {
if (state.isValid()) {
handler.inputTerminated();
} else {
handler.failed(new ConnectionClosedException("Connection closed"));
}
}
}
// Closing connection in an orderly manner and
// waiting for output buffer to get flushed.
// Do not want to wait indefinitely, though, in case
// the opposite end is not reading
if (conn.getSocketTimeout() <= 0) {
conn.setSocketTimeout(1000);
}
conn.close();
}
@Override
public void timeout(
final NHttpClientConnection conn) throws IOException {
final State state = getState(conn);
if (state != null) {
if (state.getRequestState() == MessageState.ACK_EXPECTED) {
final int timeout = state.getTimeout();
conn.setSocketTimeout(timeout);
conn.requestOutput();
state.setRequestState(MessageState.BODY_STREAM);
state.setTimeout(0);
return;
} else {
state.invalidate();
final HttpAsyncClientExchangeHandler handler = getHandler(conn);
if (handler != null) {
handler.failed(new SocketTimeoutException());
handler.close();
}
}
}
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 java.io.Closeable} objects (such as
* {@link org.apache.http.HttpConnection}}).
*
* @param ex I/O exception thrown by {@link java.io.Closeable#close()}
*/
protected void log(final Exception ex) {
this.exceptionLogger.log(ex);
}
private State getState(final NHttpConnection conn) {
return (State) conn.getContext().getAttribute(HTTP_EXCHANGE_STATE);
}
private HttpAsyncClientExchangeHandler getHandler(final NHttpConnection conn) {
return (HttpAsyncClientExchangeHandler) conn.getContext().getAttribute(HTTP_HANDLER);
}
private void shutdownConnection(final NHttpConnection conn) {
try {
conn.shutdown();
} catch (final IOException ex) {
log(ex);
}
}
private void closeHandler(final HttpAsyncClientExchangeHandler handler) {
if (handler != null) {
try {
handler.close();
} catch (final IOException ioex) {
log(ioex);
}
}
}
private void processResponse(
final NHttpClientConnection conn,
final State state,
final HttpAsyncClientExchangeHandler handler) throws IOException, HttpException {
if (!state.isValid()) {
conn.close();
}
handler.responseCompleted();
final boolean pipelined = handler.getClass().getAnnotation(Pipelined.class) != null;
if (!pipelined) {
state.setRequestState(MessageState.READY);
state.setRequest(null);
}
state.setResponseState(MessageState.READY);
state.setResponse(null);
if (!handler.isDone() && conn.isOpen()) {
conn.requestOutput();
}
}
private boolean canResponseHaveBody(final HttpRequest request, final HttpResponse response) {
final String method = request.getRequestLine().getMethod();
final 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 final Queue<HttpRequest> requestQueue;
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.requestQueue = new ConcurrentLinkedQueue<HttpRequest>();
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 Queue<HttpRequest> getRequestQueue() {
return this.requestQueue;
}
public int getTimeout() {
return this.timeout;
}
public void setTimeout(final int timeout) {
this.timeout = timeout;
}
public boolean isValid() {
return this.valid;
}
public void invalidate() {
this.valid = false;
}
@Override
public String toString() {
final 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();
}
}
}