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package org.apache.http.protocol;

import java.io.IOException;

import org.apache.http.HttpClientConnection;
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.Contract;
import org.apache.http.annotation.ThreadingBehavior;
import org.apache.http.util.Args;

/**
 * {@code HttpRequestExecutor} is a client side HTTP protocol handler based
 * on the blocking (classic) I/O model.
 * 

* {@code HttpRequestExecutor} 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. * Application specific processing can be implemented outside * {@code HttpRequestExecutor} once the request has been executed and * a response has been received. * * @since 4.0 */ @Contract(threading = ThreadingBehavior.IMMUTABLE) public class HttpRequestExecutor { public static final int DEFAULT_WAIT_FOR_CONTINUE = 3000; private final int waitForContinue; /** * Creates new instance of HttpRequestExecutor. * * @since 4.3 */ public HttpRequestExecutor(final int waitForContinue) { super(); this.waitForContinue = Args.positive(waitForContinue, "Wait for continue time"); } public HttpRequestExecutor() { this(DEFAULT_WAIT_FOR_CONTINUE); } /** * Decide whether a response comes with an entity. * The implementation in this class is based on RFC 2616. *

* 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; } final 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; } /** * Sends the request and obtain a response. * * @param request the request to execute. * @param conn the connection over which to execute the request. * * @return the response to the request. * * @throws IOException in case of an I/O error. * @throws HttpException in case of HTTP protocol violation or a processing * problem. */ public HttpResponse execute( final HttpRequest request, final HttpClientConnection conn, final HttpContext context) throws IOException, HttpException { Args.notNull(request, "HTTP request"); Args.notNull(conn, "Client connection"); Args.notNull(context, "HTTP context"); try { HttpResponse response = doSendRequest(request, conn, context); if (response == null) { response = doReceiveResponse(request, conn, context); } return response; } catch (final IOException ex) { closeConnection(conn); throw ex; } catch (final HttpException ex) { closeConnection(conn); throw ex; } catch (final RuntimeException ex) { closeConnection(conn); throw ex; } } private static void closeConnection(final HttpClientConnection conn) { try { conn.close(); } catch (final IOException ignore) { } } /** * Pre-process the given request using the given protocol processor and * initiates the process of request execution. * * @param request the request to prepare * @param processor the processor to use * @param context the context for sending the request * * @throws IOException in case of an I/O error. * @throws HttpException in case of HTTP protocol violation or a processing * problem. */ public void preProcess( final HttpRequest request, final HttpProcessor processor, final HttpContext context) throws HttpException, IOException { Args.notNull(request, "HTTP request"); Args.notNull(processor, "HTTP processor"); Args.notNull(context, "HTTP context"); context.setAttribute(HttpCoreContext.HTTP_REQUEST, request); processor.process(request, context); } /** * Send the given request over the given 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 #preProcess preprocessed} * @param conn the connection over which to send the request, * already established * @param context the context for sending the request * * @return a terminal response received as part of an expect-continue * handshake, or * {@code null} if the expect-continue handshake is not used * * @throws IOException in case of an I/O error. * @throws HttpException in case of HTTP protocol violation or a processing * problem. */ protected HttpResponse doSendRequest( final HttpRequest request, final HttpClientConnection conn, final HttpContext context) throws IOException, HttpException { Args.notNull(request, "HTTP request"); Args.notNull(conn, "Client connection"); Args.notNull(context, "HTTP context"); HttpResponse response = null; context.setAttribute(HttpCoreContext.HTTP_CONNECTION, conn); context.setAttribute(HttpCoreContext.HTTP_REQ_SENT, Boolean.FALSE); conn.sendRequestHeader(request); if (request instanceof HttpEntityEnclosingRequest) { // 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 ProtocolVersion ver = request.getRequestLine().getProtocolVersion(); if (((HttpEntityEnclosingRequest) request).expectContinue() && !ver.lessEquals(HttpVersion.HTTP_1_0)) { 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(this.waitForContinue)) { response = conn.receiveResponseHeader(); if (canResponseHaveBody(request, response)) { conn.receiveResponseEntity(response); } final int status = response.getStatusLine().getStatusCode(); if (status < 200) { if (status != HttpStatus.SC_CONTINUE) { throw new ProtocolException( "Unexpected response: " + response.getStatusLine()); } // discard 100-continue response = null; } else { sendentity = false; } } } if (sendentity) { conn.sendRequestEntity((HttpEntityEnclosingRequest) request); } } conn.flush(); context.setAttribute(HttpCoreContext.HTTP_REQ_SENT, Boolean.TRUE); return response; } /** * Waits for and receives 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 terminal response, not yet post-processed * * @throws IOException in case of an I/O error. * @throws HttpException in case of HTTP protocol violation or a processing * problem. */ protected HttpResponse doReceiveResponse( final HttpRequest request, final HttpClientConnection conn, final HttpContext context) throws HttpException, IOException { Args.notNull(request, "HTTP request"); Args.notNull(conn, "Client connection"); Args.notNull(context, "HTTP context"); HttpResponse response = null; int statusCode = 0; while (response == null || statusCode < HttpStatus.SC_OK) { response = conn.receiveResponseHeader(); statusCode = response.getStatusLine().getStatusCode(); if (statusCode < HttpStatus.SC_CONTINUE) { throw new ProtocolException("Invalid response: " + response.getStatusLine()); } if (canResponseHaveBody(request, response)) { conn.receiveResponseEntity(response); } } // while intermediate response return response; } /** * Post-processes the given response using the given protocol processor and * completes the process of request execution. *

* This method does not read the response entity, if any. * The connection over which content of the response entity is being * streamed from cannot be reused until * {@link org.apache.http.util.EntityUtils#consume(org.apache.http.HttpEntity)} * has been invoked. * * @param response the response object to post-process * @param processor the processor to use * @param context the context for post-processing the response * * @throws IOException in case of an I/O error. * @throws HttpException in case of HTTP protocol violation or a processing * problem. */ public void postProcess( final HttpResponse response, final HttpProcessor processor, final HttpContext context) throws HttpException, IOException { Args.notNull(response, "HTTP response"); Args.notNull(processor, "HTTP processor"); Args.notNull(context, "HTTP context"); context.setAttribute(HttpCoreContext.HTTP_RESPONSE, response); processor.process(response, context); } } // class HttpRequestExecutor





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