Java tutorial
/* * 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. */ package edu.ucsd.xmlrpc.xmlrpc.client; import java.io.BufferedOutputStream; import java.io.FilterOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import org.apache.commons.httpclient.Credentials; import org.apache.commons.httpclient.Header; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.HttpException; import org.apache.commons.httpclient.HttpMethod; import org.apache.commons.httpclient.HttpStatus; import org.apache.commons.httpclient.HttpVersion; import org.apache.commons.httpclient.URI; import org.apache.commons.httpclient.URIException; import org.apache.commons.httpclient.UsernamePasswordCredentials; import org.apache.commons.httpclient.auth.AuthScope; import org.apache.commons.httpclient.methods.PostMethod; import org.apache.commons.httpclient.methods.RequestEntity; import org.apache.commons.httpclient.params.HttpMethodParams; import org.xml.sax.SAXException; import edu.ucsd.xmlrpc.xmlrpc.XmlRpcException; import edu.ucsd.xmlrpc.xmlrpc.XmlRpcRequest; import edu.ucsd.xmlrpc.xmlrpc.common.XmlRpcStreamConfig; import edu.ucsd.xmlrpc.xmlrpc.common.XmlRpcStreamRequestConfig; import edu.ucsd.xmlrpc.xmlrpc.util.HttpUtil; import edu.ucsd.xmlrpc.xmlrpc.util.XmlRpcIOException; /** An HTTP transport factory, which is based on the Jakarta Commons * HTTP Client. */ public class XmlRpcCommonsTransport extends XmlRpcHttpTransport { /** * Maximum number of allowed redirects. */ private static final int MAX_REDIRECT_ATTEMPTS = 100; protected final HttpClient client; private static final String userAgent = USER_AGENT + " (Jakarta Commons httpclient Transport)"; protected PostMethod method; private int contentLength = -1; private XmlRpcHttpClientConfig config; /** Creates a new instance. * @param pFactory The factory, which created this transport. */ public XmlRpcCommonsTransport(XmlRpcCommonsTransportFactory pFactory) { super(pFactory.getClient(), userAgent); HttpClient httpClient = pFactory.getHttpClient(); if (httpClient == null) { httpClient = newHttpClient(); } client = httpClient; } protected void setContentLength(int pLength) { contentLength = pLength; } protected HttpClient newHttpClient() { return new HttpClient(); } protected void initHttpHeaders(XmlRpcRequest pRequest) throws XmlRpcClientException { config = (XmlRpcHttpClientConfig) pRequest.getConfig(); method = newPostMethod(config); super.initHttpHeaders(pRequest); if (config.getConnectionTimeout() != 0) client.getHttpConnectionManager().getParams().setConnectionTimeout(config.getConnectionTimeout()); if (config.getReplyTimeout() != 0) client.getHttpConnectionManager().getParams().setSoTimeout(config.getReplyTimeout()); method.getParams().setVersion(HttpVersion.HTTP_1_1); } protected PostMethod newPostMethod(XmlRpcHttpClientConfig pConfig) { return new PostMethod(pConfig.getServerURL().toString()); } protected void setRequestHeader(String pHeader, String pValue) { method.setRequestHeader(new Header(pHeader, pValue)); } protected boolean isResponseGzipCompressed() { Header h = method.getResponseHeader("Content-Encoding"); if (h == null) { return false; } else { return HttpUtil.isUsingGzipEncoding(h.getValue()); } } protected InputStream getInputStream() throws XmlRpcException { try { checkStatus(method); return method.getResponseBodyAsStream(); } catch (HttpException e) { throw new XmlRpcClientException("Error in HTTP transport: " + e.getMessage(), e); } catch (IOException e) { throw new XmlRpcClientException("I/O error in server communication: " + e.getMessage(), e); } } protected void setCredentials(XmlRpcHttpClientConfig pConfig) throws XmlRpcClientException { String userName = pConfig.getBasicUserName(); if (userName != null) { String enc = pConfig.getBasicEncoding(); if (enc == null) { enc = XmlRpcStreamConfig.UTF8_ENCODING; } client.getParams().setParameter(HttpMethodParams.CREDENTIAL_CHARSET, enc); Credentials creds = new UsernamePasswordCredentials(userName, pConfig.getBasicPassword()); AuthScope scope = new AuthScope(null, AuthScope.ANY_PORT, null, AuthScope.ANY_SCHEME); client.getState().setCredentials(scope, creds); client.getParams().setAuthenticationPreemptive(true); } } protected void close() throws XmlRpcClientException { method.releaseConnection(); } protected boolean isResponseGzipCompressed(XmlRpcStreamRequestConfig pConfig) { Header h = method.getResponseHeader("Content-Encoding"); if (h == null) { return false; } else { return HttpUtil.isUsingGzipEncoding(h.getValue()); } } protected boolean isRedirectRequired() { switch (method.getStatusCode()) { case HttpStatus.SC_MOVED_TEMPORARILY: case HttpStatus.SC_MOVED_PERMANENTLY: case HttpStatus.SC_SEE_OTHER: case HttpStatus.SC_TEMPORARY_REDIRECT: return true; default: return false; } } protected void resetClientForRedirect() throws XmlRpcException { //get the location header to find out where to redirect to Header locationHeader = method.getResponseHeader("location"); if (locationHeader == null) { throw new XmlRpcException("Invalid redirect: Missing location header"); } String location = locationHeader.getValue(); URI redirectUri = null; URI currentUri = null; try { currentUri = method.getURI(); String charset = currentUri.getProtocolCharset(); redirectUri = new URI(location, true, charset); method.setURI(redirectUri); } catch (URIException ex) { throw new XmlRpcException(ex.getMessage(), ex); } //And finally invalidate the actual authentication scheme method.getHostAuthState().invalidate(); } protected void writeRequest(final ReqWriter pWriter) throws XmlRpcException { method.setRequestEntity(new RequestEntity() { public boolean isRepeatable() { return true; } public void writeRequest(OutputStream pOut) throws IOException { try { /* Make sure, that the socket is not closed by replacing it with our * own BufferedOutputStream. */ OutputStream ostream; if (isUsingByteArrayOutput(config)) { // No need to buffer the output. ostream = new FilterOutputStream(pOut) { public void close() throws IOException { flush(); } }; } else { ostream = new BufferedOutputStream(pOut) { public void close() throws IOException { flush(); } }; } pWriter.write(ostream); } catch (XmlRpcException e) { throw new XmlRpcIOException(e); } catch (SAXException e) { throw new XmlRpcIOException(e); } } public long getContentLength() { return contentLength; } public String getContentType() { return "text/xml"; } }); try { int redirectAttempts = 0; for (;;) { client.executeMethod(method); if (!isRedirectRequired()) { break; } if (redirectAttempts++ > MAX_REDIRECT_ATTEMPTS) { throw new XmlRpcException("Too many redirects."); } resetClientForRedirect(); } } catch (XmlRpcIOException e) { Throwable t = e.getLinkedException(); if (t instanceof XmlRpcException) { throw (XmlRpcException) t; } else { throw new XmlRpcException("Unexpected exception: " + t.getMessage(), t); } } catch (IOException e) { throw new XmlRpcException("I/O error while communicating with HTTP server: " + e.getMessage(), e); } } /** * Check the status of the HTTP request and throw an XmlRpcHttpTransportException if it * indicates that there is an error. * @param pMethod the method that has been executed * @throws XmlRpcHttpTransportException if the status of the method indicates that there is an error. */ private void checkStatus(HttpMethod pMethod) throws XmlRpcHttpTransportException { final int status = pMethod.getStatusCode(); // All status codes except SC_OK are handled as errors. Perhaps some should require special handling (e.g., SC_UNAUTHORIZED) if (status < 200 || status > 299) { throw new XmlRpcHttpTransportException(status, pMethod.getStatusText()); } } }