Quelltext proxy

    package com.mycompany.project.server;
    
    /**
     * Copyright 2010 Kenneth Jorgensen (kennethjorgensen.com) (modifications)
     * - original code can be found at http://www.siafoo.net/snippet/258
     * Copyright 2009 Stou Sandalski (Siafoo.net)
     * Copyright 1999-2008 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.
     *
     */
    
    import java.io.InputStream;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.net.URI;
    import java.net.URISyntaxException;
    import java.util.Enumeration;
    
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.ServletException;
    
    import org.apache.http.client.HttpClient;
    import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
    import org.apache.http.client.methods.HttpRequestBase;
    import org.apache.http.entity.InputStreamEntity;
    import org.apache.http.Header;
    import org.apache.http.HttpEntity;
    import org.apache.http.HttpResponse;
    import org.apache.http.impl.client.DefaultHttpClient;
    import org.apache.http.StatusLine;
    
    /**
    * This servlet provides a proxy to other servers for use in development with GWT devmode.
    * It is not meant, in any way shape or form, to be used in production.
    */
    public class ProxyServlet extends HttpServlet {
    
    private static final String targetServer = "http://localhost:8080";
    
    @Override
    @SuppressWarnings("unchecked")
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    // Create new client to perform the proxied request
    HttpClient httpclient = new DefaultHttpClient();
    
    // Determine final URL
    StringBuffer uri = new StringBuffer();
    uri.append(targetServer);
    uri.append(req.getRequestURI());
    
    // Add any supplied query strings
    String queryString = req.getQueryString();
    if (queryString != null){
    uri.append("?" + queryString);
    }
    
    // Get HTTP method
    final String method = req.getMethod();
    // Create new HTTP request container
    HttpRequestBase request = null;
    
    // Get content length
    int contentLength = req.getContentLength();
    // Unknown content length ...
    // if (contentLength == -1)
    // throw new ServletException("Cannot handle unknown content length");
    // If we don't have an entity body, things are quite simple
    if (contentLength < 1) {
        request = new HttpRequestBase() {
            public String getMethod() {
                return method;
            }
        };
    }
    else {
    // Prepare request
        HttpEntityEnclosingRequestBase tmpRequest = new HttpEntityEnclosingRequestBase() {
            public String getMethod() {
                return method;
            }
    };
    
    // Transfer entity body from the received request to the new request
    InputStreamEntity entity = new InputStreamEntity(req.getInputStream(), contentLength);
    tmpRequest.setEntity(entity);
    
    request = tmpRequest;
    }
    
    // Set URI
    try {
    request.setURI(new URI(uri.toString()));
    }
    catch (URISyntaxException e) {
    throw new ServletException("URISyntaxException: " + e.getMessage());
    }
    
    // Copy headers from old request to new request
    // @todo not sure how this handles multiple headers with the same name
    Enumeration<String> headers = req.getHeaderNames();
    while (headers.hasMoreElements()) {
        String headerName = headers.nextElement();
        String headerValue = req.getHeader(headerName);
        // Skip Content-Length and Host
        String lowerHeader = headerName.toLowerCase();
        if (lowerHeader.equals("content-length") == false && lowerHeader.equals("host") == false) {
            // System.out.println(headerName.toLowerCase() + ": " + headerValue);
            request.addHeader(headerName, headerValue);
        }
        System.out.print(headerName + " ");
        System.out.println(headerValue);
    }
    
    // Execute the request
    HttpResponse response = httpclient.execute(request);
    
    // Transfer status code to the response
    StatusLine status = response.getStatusLine();
    resp.setStatus(status.getStatusCode());
    // resp.setStatus(status.getStatusCode(), status.getReasonPhrase()); // This seems to be deprecated. Yes status message is "ambigous", but I don't approve
    
    // Transfer headers to the response
    Header[] responseHeaders = response.getAllHeaders();
    for (int i=0 ; i<responseHeaders.length ; i++) {
    Header header = responseHeaders[i];
    resp.addHeader(header.getName(), header.getValue());
    }
    
    // Transfer proxy response entity to the servlet response
    HttpEntity entity = response.getEntity();
    InputStream input = entity.getContent();
    OutputStream output = resp.getOutputStream();
    int b = input.read();
    while (b != -1) {
    output.write(b);
    b = input.read();
    }
    
    // Clean up
    input.close();
    output.close();
    httpclient.getConnectionManager().shutdown();
    }
    }