Java tutorial
/** * * Copyright 2003-2005 Core Developers Network Ltd. * * 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 started life as org.mortbay.servlet.ProxyServlet. I copied the //whole thing to use as a starting point - Thanks Greg ! // ======================================================================== // $Id: CommonsHttpProxy.java 1737 2006-04-27 15:13:16 +0100 (Thu, 27 Apr 2006) jules $ // Copyright 2004-2004 Mort Bay Consulting Pty. Ltd. // ------------------------------------------------------------------------ // 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. // ======================================================================== package org.codehaus.wadi.web.impl; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.URI; import java.util.Enumeration; import java.util.HashMap; import java.util.Map; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.httpclient.ConnectMethod; import org.apache.commons.httpclient.Cookie; import org.apache.commons.httpclient.Header; import org.apache.commons.httpclient.HostConfiguration; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.HttpMethod; import org.apache.commons.httpclient.HttpState; import org.apache.commons.httpclient.methods.DeleteMethod; import org.apache.commons.httpclient.methods.EntityEnclosingMethod; import org.apache.commons.httpclient.methods.GetMethod; import org.apache.commons.httpclient.methods.HeadMethod; import org.apache.commons.httpclient.methods.MultipartPostMethod; import org.apache.commons.httpclient.methods.OptionsMethod; import org.apache.commons.httpclient.methods.PutMethod; import org.apache.commons.httpclient.methods.TraceMethod; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; //This does not seem as performant as the StandardHttpProxy - it also seems to be able to crash Firefox reproducibly ! //commons-httpclient does not [seem to] allow us to pass Cookie headers straight through. So, we have //to deal with them explicitly - This leaves scope for cookie mutation as request passes through proxy - Bad news. //I've tried moving up to 3.0rc1, but ProxyServlet with this HttpProxy produces wierd browser effects... /** * HttpProxy implementation based on commons-httpclient * * @author <a href="mailto:jules@coredevelopers.net">Jules Gosnell</a> * @author <a href="mailto:gregw@mortbay.com">Greg Wilkins</a> * @version $Revision: 1737 $ */ public class CommonsHttpProxy extends AbstractHttpProxy { protected static final Log _log = LogFactory.getLog(CommonsHttpProxy.class); protected static final Map _methods = new HashMap(); static { _methods.put("CONNECT", ConnectMethod.class); _methods.put("DELETE", DeleteMethod.class); _methods.put("GET", GetMethod.class); _methods.put("HEAD", HeadMethod.class); _methods.put("OPTIONS", OptionsMethod.class); _methods.put("TRACE", TraceMethod.class); _methods.put("POST", MultipartPostMethod.class); _methods.put("PUT", PutMethod.class); // WebDav methods ? e.g. PROCFIND ? } public CommonsHttpProxy(String sessionPathParamKey) { super(sessionPathParamKey); } protected void doProxy(URI uri, WebInvocation context) throws ProxyingException { HttpServletRequest hreq = context.getHreq(); HttpServletResponse hres = context.getHres(); long startTime = System.currentTimeMillis(); String m = hreq.getMethod(); Class clazz = (Class) _methods.get(m); if (clazz == null) { throw new IrrecoverableException("unsupported http method: " + m); } HttpMethod hm = null; try { hm = (HttpMethod) clazz.newInstance(); } catch (Exception e) { throw new IrrecoverableException("could not create HttpMethod instance", e); // should never happen } String requestURI = getRequestURI(hreq); hm.setPath(requestURI); String queryString = hreq.getQueryString(); if (queryString != null) { hm.setQueryString(queryString); requestURI += queryString; } hm.setFollowRedirects(false); //hm.setURI(new URI(uri)); hm.setStrictMode(false); // check connection header String connectionHdr = hreq.getHeader("Connection"); // TODO - what if there are multiple values ? if (connectionHdr != null) { connectionHdr = connectionHdr.toLowerCase(); if (connectionHdr.equals("keep-alive") || connectionHdr.equals("close")) connectionHdr = null; // TODO ?? } // copy headers boolean xForwardedFor = false; boolean hasContent = false; int contentLength = 0; Enumeration enm = hreq.getHeaderNames(); while (enm.hasMoreElements()) { // TODO could be better than this! - using javax.servlet ? String hdr = (String) enm.nextElement(); String lhdr = hdr.toLowerCase(); if (_DontProxyHeaders.contains(lhdr)) continue; if (connectionHdr != null && connectionHdr.indexOf(lhdr) >= 0) continue; if ("content-length".equals(lhdr)) { try { contentLength = hreq.getIntHeader(hdr); hasContent = contentLength > 0; } catch (NumberFormatException e) { if (_log.isWarnEnabled()) _log.warn("bad Content-Length header value: " + hreq.getHeader(hdr), e); } } if ("content-type".equals(lhdr)) { hasContent = true; } Enumeration vals = hreq.getHeaders(hdr); while (vals.hasMoreElements()) { String val = (String) vals.nextElement(); if (val != null) { hm.addRequestHeader(hdr, val); // if (_log.isInfoEnabled()) _log.info("Request " + hdr + ": " + val); xForwardedFor |= "X-Forwarded-For".equalsIgnoreCase(hdr); // why is this not in the outer loop ? } } } // cookies... // although we copy cookie headers into the request abover - commons-httpclient thinks it knows better and strips them out before sending. // we have to explicitly use their interface to add the cookies - painful... // DOH! - an org.apache.commons.httpclient.Cookie is NOT a // javax.servlet.http.Cookie - and it looks like the two don't // map onto each other without data loss... HttpState state = new HttpState(); javax.servlet.http.Cookie[] cookies = hreq.getCookies(); if (cookies != null) { for (int i = 0; i < cookies.length; i++) { javax.servlet.http.Cookie c = cookies[i]; String domain = c.getDomain(); if (domain == null) { domain = hreq.getServerName(); // TODO - tmp test // _log.warn("defaulting cookie domain"); } // domain=null; String cpath = c.getPath(); if (cpath == null) { cpath = hreq.getContextPath(); // fix for Jetty // _log.warn("defaulting cookie path"); } //if (_log.isTraceEnabled()) _log.trace("PATH: value="+path+" length="+(path==null?0:path.length())); Cookie cookie = new Cookie(domain, c.getName(), c.getValue(), cpath, c.getMaxAge(), c.getSecure()); // TODO - sort out domain //if (_log.isTraceEnabled()) _log.trace("Cookie: "+cookie.getDomain()+","+ cookie.getName()+","+ cookie.getValue()+","+ cookie.getPath()+","+ cookie.getExpiryDate()+","+ cookie.getSecure()); state.addCookie(cookie); //if (_log.isTraceEnabled()) _log.trace("Cookie: "+cookie.toString()); } } // Proxy headers hm.addRequestHeader("Via", "1.1 " + hreq.getLocalName() + ":" + hreq.getLocalPort() + " \"WADI\""); if (!xForwardedFor) hm.addRequestHeader("X-Forwarded-For", hreq.getRemoteAddr()); // Max-Forwards... // a little bit of cache control // String cache_control = hreq.getHeader("Cache-Control"); // if (cache_control != null && (cache_control.indexOf("no-cache") >= 0 || cache_control.indexOf("no-store") >= 0)) // httpMethod.setUseCaches(false); // customize Connection // uc.setDoInput(true); int client2ServerTotal = 0; if (hasContent) { // uc.setDoOutput(true); try { if (hm instanceof EntityEnclosingMethod) ((EntityEnclosingMethod) hm).setRequestBody(hreq.getInputStream()); // TODO - do we need to close response stream at end... ? } catch (IOException e) { throw new IrrecoverableException("could not pss request input across proxy", e); } } try { HttpClient client = new HttpClient(); HostConfiguration hc = new HostConfiguration(); //String host=location.getAddress().getHostAddress(); // inefficient - but stops httpclient from rejecting half our cookies... String host = uri.getHost(); hc.setHost(host, uri.getPort()); client.executeMethod(hc, hm, state); } catch (IOException e) // TODO { _log.warn("problem proxying connection:", e); } InputStream fromServer = null; // handler status codes etc. int code = 502; // String message="Bad Gateway: could not read server response code or message"; code = hm.getStatusCode(); // IOException // message=hm.getStatusText(); // IOException hres.setStatus(code); // hres.setStatus(code, message); - deprecated... try { fromServer = hm.getResponseBodyAsStream(); // IOException } catch (IOException e) { _log.warn("problem acquiring http client output", e); } // clear response defaults. hres.setHeader("Date", null); hres.setHeader("Server", null); // set response headers // TODO - is it a bug in Jetty that I have to start my loop at 1 ? or that key[0]==null ? // Try this inside Tomcat... Header[] headers = hm.getResponseHeaders(); for (int i = 0; i < headers.length; i++) { String h = headers[i].toExternalForm(); int index = h.indexOf(':'); String key = h.substring(0, index).trim().toLowerCase(); String val = h.substring(index + 1, h.length()).trim(); if (val != null && !_DontProxyHeaders.contains(key)) { hres.addHeader(key, val); // if (_log.isInfoEnabled()) _log.info("Response: "+key+" - "+val); } } hres.addHeader("Via", "1.1 (WADI)"); // copy server->client int server2ClientTotal = 0; if (fromServer != null) { try { OutputStream toClient = hres.getOutputStream();// IOException server2ClientTotal += copy(fromServer, toClient, 8192);// IOException } catch (IOException e) { _log.warn("problem proxying server response back to client", e); } finally { try { fromServer.close(); } catch (IOException e) { // well - we did our best... _log.warn("problem closing server response stream", e); } } } long endTime = System.currentTimeMillis(); long elapsed = endTime - startTime; if (_log.isDebugEnabled()) { _log.debug("in:" + client2ServerTotal + ", out:" + server2ClientTotal + ", status:" + code + ", time:" + elapsed + ", uri:" + uri); } } }