/*
* $HeadURL: https://svn.apache.org/repos/asf/jakarta/httpcomponents/httpcore/tags/4.0-alpha2/src/java/org/apache/http/protocol/HttpRequestExecutor.java $
* $Revision: 385867 $
* $Date: 2006-03-14 21:04:55 +0100 (Tue, 14 Mar 2006) $
*
* ====================================================================
*
* Copyright 1999-2006 The Apache Software Foundation
*
* 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.
* ====================================================================
*
* 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.protocol;
import java.io.IOException;
import java.net.ProtocolException;
import org.apache.http.HttpClientConnection;
import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpException;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.HttpVersion;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;
/**
* Sends HTTP requests and receives the responses.
* Takes care of request preprocessing and response postprocessing
* by the respective interceptors.
*
* @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
*
* @version $Revision: 385867 $
*
* @since 4.0
*/
public class HttpRequestExecutor extends AbstractHttpProcessor {
protected static final int WAIT_FOR_CONTINUE_MS = 10000;
/** The context holding the default context information. */
protected final HttpContext defaultContext;
private HttpParams params = null;
private HttpRequestRetryHandler retryhandler = null;
/**
* Create a new request executor with default context information.
* The attributes in the argument context will be made available
* in the context used for executing a request.
*
* @param parentContext the default context information,
* or <code>null</code>
*/
public HttpRequestExecutor(final HttpContext parentContext) {
super();
this.defaultContext = new HttpExecutionContext(parentContext);
}
/**
* Create a new request executor.
*/
public HttpRequestExecutor() {
this(null);
}
/**
* Obtain the default context information.
* This is not necessarily the same object passed to the constructor,
* but the default context information will be available here.
*
* @return the context holding the default context information
*/
public final HttpContext getContext() {
return this.defaultContext;
}
/**
* Obtain the parameters for executing requests.
*
* @return the currently installed parameters
*/
public final HttpParams getParams() {
return this.params;
}
/**
* Set new parameters for executing requests.
*
* @param params the new parameters to use from now on
*/
public final void setParams(final HttpParams params) {
this.params = params;
}
/**
* Obtain the retry handler.
*
* @return the handler deciding whether a request should be retried
*/
public final HttpRequestRetryHandler getRetryHandler() {
return this.retryhandler;
}
/**
* Set the retry handler.
*
* @param retryhandler the handler to decide whether a request
* should be retried
*/
public final void setRetryHandler(final HttpRequestRetryHandler retryhandler) {
this.retryhandler = retryhandler;
}
/**
* Decide whether a response comes with an entity.
* The implementation in this class is based on RFC 2616.
* Unknown methods and response codes are supposed to
* indicate responses with an entity.
* <br/>
* Derived executors can override this method to handle
* methods and response codes not specified in RFC 2616.
*
* @param request the request, to obtain the executed method
* @param response the response, to obtain the status code
*/
protected boolean canResponseHaveBody(final HttpRequest request,
final HttpResponse response) {
if ("HEAD".equalsIgnoreCase(request.getRequestLine().getMethod())) {
return false;
}
int status = response.getStatusLine().getStatusCode();
return status >= HttpStatus.SC_OK
&& status != HttpStatus.SC_NO_CONTENT
&& status != HttpStatus.SC_NOT_MODIFIED
&& status != HttpStatus.SC_RESET_CONTENT;
}
/**
* Synchronously send a request and obtain the response.
*
* @param request the request to send. It will be preprocessed.
* @param conn the connection over which to send.
* The {@link HttpClientConnection#setTargetHost target}
* host has to be set before calling this method.
*
* @return the response to the request, postprocessed
*
* @throws HttpException in case of a protocol or processing problem
* @throws IOException in case of an I/O problem
*/
public HttpResponse execute(
final HttpRequest request,
final HttpClientConnection conn)
throws IOException, HttpException {
if (request == null) {
throw new IllegalArgumentException("HTTP request may not be null");
}
if (conn == null) {
throw new IllegalArgumentException("Client connection may not be null");
}
//@@@ behavior if proxying - set real target or proxy, or both?
this.defaultContext.setAttribute(HttpExecutionContext.HTTP_TARGET_HOST,
conn.getTargetHost());
this.defaultContext.setAttribute(HttpExecutionContext.HTTP_CONNECTION,
conn);
doPrepareRequest(request, this.defaultContext);
this.defaultContext.setAttribute(HttpExecutionContext.HTTP_REQUEST,
request);
HttpResponse response = null;
// loop until the method is successfully processed, the retryHandler
// returns false or a non-recoverable exception is thrown
for (int execCount = 0; ; execCount++) {
try {
doEstablishConnection(conn, conn.getTargetHost(),
request.getParams());
response = doSendRequest(request, conn, this.defaultContext);
if (response == null) {
response = doReceiveResponse(request, conn,
this.defaultContext);
}
// exit retry loop
break;
} catch (IOException ex) {
conn.close();
if (this.retryhandler == null) {
throw ex;
}
if (!this.retryhandler.retryRequest(ex, execCount, null)) {
throw ex;
}
} catch (HttpException ex) {
conn.close();
throw ex;
} catch (RuntimeException ex) {
conn.close();
throw ex;
}
}
doFinishResponse(response, this.defaultContext);
return response;
}
/**
* Prepare a request for sending.
*
* @param request the request to prepare
* @param context the context for sending the request
*
* @throws HttpException in case of a protocol or processing problem
* @throws IOException in case of an I/O problem
*/
protected void doPrepareRequest(
final HttpRequest request,
final HttpContext context)
throws HttpException, IOException {
if (request == null) {
throw new IllegalArgumentException("HTTP request may not be null");
}
if (context == null) {
throw new IllegalArgumentException("HTTP context may not be null");
}
// link default parameters
request.getParams().setDefaults(this.params);
preprocessRequest(request, context);
}
/**
* Establish a connection with the target host.
*
* @param conn the HTTP connection
* @param target the target host for the request, or
* <code>null</code> to send to the host already
* set as the connection target
*
* @throws HttpException in case of a problem
* @throws IOException in case of an IO problem
*/
protected void doEstablishConnection(
final HttpClientConnection conn,
final HttpHost target,
final HttpParams params)
throws HttpException, IOException {
if (conn == null) {
throw new IllegalArgumentException("HTTP connection may not be null");
}
if (target == null) {
throw new IllegalArgumentException("Target host may not be null");
}
if (params == null) {
throw new IllegalArgumentException("HTTP parameters may not be null");
}
// make sure the connection is open and points to the target host
if ((target == null) || target.equals(conn.getTargetHost())) {
// host and port ok, check whether connection needs to be opened
if (HttpConnectionParams.isStaleCheckingEnabled(params)) {
if (conn.isOpen() && conn.isStale()) {
conn.close();
}
}
if (!conn.isOpen()) {
conn.open(params);
//TODO: Implement secure tunnelling (@@@ HttpRequestExecutor)
}
} else {
// wrong target, point connection to target
if (conn.isOpen()) {
conn.close();
}
conn.setTargetHost(target);
conn.open(params);
} // if connection points to target else
}
/**
* Send a request over a connection.
* This method also handles the expect-continue handshake if necessary.
* If it does not have to handle an expect-continue handshake, it will
* not use the connection for reading or anything else that depends on
* data coming in over the connection.
*
* @param request the request to send, already
* {@link #doPrepareRequest prepared}
* @param conn the connection over which to send the request, already
* {@link #doEstablishConnection established}
* @param context the context for sending the request
*
* @return a terminal response received as part of an expect-continue
* handshake, or
* <code>null</code> if the expect-continue handshake is not used
*
* @throws HttpException in case of a protocol or processing problem
* @throws IOException in case of an I/O problem
*/
protected HttpResponse doSendRequest(
final HttpRequest request,
final HttpClientConnection conn,
final HttpContext context)
throws IOException, HttpException {
if (request == null) {
throw new IllegalArgumentException("HTTP request may not be null");
}
if (conn == null) {
throw new IllegalArgumentException("HTTP connection may not be null");
}
if (context == null) {
throw new IllegalArgumentException("HTTP context may not be null");
}
HttpResponse response = null;
context.setAttribute(HttpExecutionContext.HTTP_REQ_SENT, Boolean.FALSE);
conn.sendRequestHeader(request);
if (request instanceof HttpEntityEnclosingRequest) {
HttpEntityEnclosingRequest entityEnclRequest =
(HttpEntityEnclosingRequest) request;
// Check for expect-continue handshake. We have to flush the
// headers and wait for an 100-continue response to handle it.
// If we get a different response, we must not send the entity.
boolean sendentity = true;
final HttpVersion ver = request.getRequestLine().getHttpVersion();
if (entityEnclRequest.expectContinue() &&
ver.greaterEquals(HttpVersion.HTTP_1_1)) {
conn.flush();
// As suggested by RFC 2616 section 8.2.3, we don't wait for a
// 100-continue response forever. On timeout, send the entity.
if (conn.isResponseAvailable(WAIT_FOR_CONTINUE_MS)) {
response = conn.receiveResponseHeader(request.getParams());
if (canResponseHaveBody(request, response)) {
conn.receiveResponseEntity(response);
}
int status = response.getStatusLine().getStatusCode();
if (status < 200) {
//@@@ TODO: is this in line with RFC 2616, 10.1?
if (status != HttpStatus.SC_CONTINUE) {
throw new ProtocolException(
"Unexpected response: " + response.getStatusLine());
}
// discard 100-continue
response = null;
} else {
sendentity = false;
}
}
}
if (sendentity) {
conn.sendRequestEntity(entityEnclRequest);
}
}
conn.flush();
context.setAttribute(HttpExecutionContext.HTTP_REQ_SENT, Boolean.TRUE);
return response;
}
/**
* Wait for and receive a response.
* This method will automatically ignore intermediate responses
* with status code 1xx.
*
* @param request the request for which to obtain the response
* @param conn the connection over which the request was sent
* @param context the context for receiving the response
*
* @return the final response, not yet post-processed
*
* @throws HttpException in case of a protocol or processing problem
* @throws IOException in case of an I/O problem
*/
protected HttpResponse doReceiveResponse(
final HttpRequest request,
final HttpClientConnection conn,
final HttpContext context)
throws HttpException, IOException {
if (request == null) {
throw new IllegalArgumentException("HTTP request may not be null");
}
if (conn == null) {
throw new IllegalArgumentException("HTTP connection may not be null");
}
if (context == null) {
throw new IllegalArgumentException("HTTP context may not be null");
}
HttpResponse response = null;
int statuscode = 0;
while (response == null || statuscode < HttpStatus.SC_OK) {
response = conn.receiveResponseHeader(request.getParams());
if (canResponseHaveBody(request, response)) {
conn.receiveResponseEntity(response);
}
statuscode = response.getStatusLine().getStatusCode();
} // while intermediate response
return response;
}
/**
* Finish a response.
* This includes post-processing of the response object.
* It does <i>not</i> read the response entity, if any.
* It does <i>not</i> allow for immediate re-use of the
* connection over which the response is coming in.
*
* @param response the response object to finish
* @param context the context for post-processing the response
*
* @throws HttpException in case of a protocol or processing problem
* @throws IOException in case of an I/O problem
*/
protected void doFinishResponse(
final HttpResponse response,
final HttpContext context)
throws HttpException, IOException {
if (response == null) {
throw new IllegalArgumentException("HTTP response may not be null");
}
if (context == null) {
throw new IllegalArgumentException("HTTP context may not be null");
}
postprocessResponse(response, context);
}
} // class HttpRequestExecutor