Repository files navigation

This is an updated fork of adamfisk's LittleProxy. The original project appearsto have been abondoned. Because it's so incredibly useful, it's being broughtback to life in this repository.

LittleProxy is a high performance HTTP proxy written in Java atop Trustin Lee'sexcellentNetty event-based networking library. It's quitestable, performs well, and is easy to integrate into your projects.

One option is to clone LittleProxy and run it from the command line. This is as simple as:

$ git clone git@github.com:mrog/LittleProxy.git$ cd LittleProxy$ ./run.bash

You can embed LittleProxy in your own projects through Maven with the following:

    <dependency>        <groupId>xyz.rogfam</groupId>        <artifactId>littleproxy</artifactId>        <version>2.0.0-beta-5</version>    </dependency>

Or with Gradle like this

compile "xyz.rogfam:littleproxy:2.0.0-beta-5"

Once you've included LittleProxy, you can start the server with the following:

HttpProxyServerserver =DefaultHttpProxyServer.bootstrap()        .withPort(8080)        .start();

To intercept and manipulate HTTPS traffic, LittleProxy uses a man-in-the-middle (MITM) manager. LittleProxy's defaultimplementation (SelfSignedMitmManager) has a fairly limited feature set. For greater control over certificate impersonation,browser trust, the TLS handshake, and more, use a the LittleProxy-compatible MITM extension:

• LittleProxy-mitm - A LittleProxy MITM extension that aims to support every Java platform including Android
• mitm - A LittleProxy MITM extension that supports elliptic curve cryptography and custom trust stores

To filter HTTP traffic, you can add request and response filters using aHttpFiltersSource(Adapter), for example:

HttpProxyServerserver =DefaultHttpProxyServer.bootstrap()        .withPort(8080)        .withFiltersSource(newHttpFiltersSourceAdapter() {publicHttpFiltersfilterRequest(HttpRequestoriginalRequest,ChannelHandlerContextctx) {returnnewHttpFiltersAdapter(originalRequest) {@OverridepublicHttpResponseclientToProxyRequest(HttpObjecthttpObject) {// TODO: implement your filtering herereturnnull;                    }@OverridepublicHttpObjectserverToProxyResponse(HttpObjecthttpObject) {// TODO: implement your filtering herereturnhttpObject;                    }                };            }        })        .start();

Please refer to the Javadoc oforg.littleshoot.proxy.HttpFilters to see themethods you can use.

To enable aggregator and inflater you have to return a value greater than 0 inyourHttpFiltersSource#get(Request/Response)BufferSizeInBytes() methods. Thisprovides to you a `FullHttp(Request/Response)' with the complete content in yourfilter uncompressed. Otherwise you have to handle the chunks yourself.

@OverridepublicintgetMaximumResponseBufferSizeInBytes() {return10 *1024 *1024;    }

This size limit applies to every connection. To disable aggregating by URL at*.iso or *dmg files for example, you can return in your filters source a filterlike this:

returnnewHttpFiltersAdapter(originalRequest,serverCtx) {@OverridepublicvoidproxyToServerConnectionSucceeded(ChannelHandlerContextserverCtx) {ChannelPipelinepipeline =serverCtx.pipeline();if (pipeline.get("inflater") !=null) {pipeline.remove("inflater");        }if (pipeline.get("aggregator") !=null) {pipeline.remove("aggregator");        }super.proxyToServerConnectionSucceeded(serverCtx);    }};

This enables huge downloads in an application, which regular handles sizelimitedFullHttpResponses to modify its content, HTML for example.

A proxy server like LittleProxy contains always a web server, too. If you get anURI without scheme, host and port inoriginalRequest it's a direct request toyour proxy. You can return aHttpFilters implementation which answersresponses with HTML content or redirects inclientToProxyRequest like this:

publicclassAnswerRequestFilterextendsHttpFiltersAdapter {privatefinalStringanswer;publicAnswerRequestFilter(HttpRequestoriginalRequest,Stringanswer) {super(originalRequest,null);this.answer =answer;}@OverridepublicHttpResponseclientToProxyRequest(HttpObjecthttpObject) {ByteBufbuffer =Unpooled.wrappedBuffer(answer.getBytes("UTF-8"));HttpResponseresponse =newDefaultFullHttpResponse(HttpVersion.HTTP_1_1,HttpResponseStatus.OK,buffer);HttpHeaders.setContentLength(response,buffer.readableBytes());HttpHeaders.setHeader(response,HttpHeaders.Names.CONTENT_TYPE,"text/html");returnresponse;}}

On answering a redirect, you should add a Connection: close header, to avoidblocking behavior:

HttpHeaders.setHeader(response,Names.CONNECTION,Values.CLOSE);

With this trick, you can implement an UI to your application very easy.

If you want to create additional proxy servers with similar configuration butlistening on different ports, you can clone an existing server. The clonedservers will share event loops to reduce resource usage and when one clone isstopped, all are stopped.

existingServer.clone().withPort(8081).start()

For examples of configuring logging, seesrc/test/resources/log4j.xml.

If you have questions, please visit our Google Group here:

https://groups.google.com/forum/#!forum/littleproxy2

(The original group athttps://groups.google.com/forum/#!forum/littleproxy isn'taccepting posts from new users. But it's still a great resource if you'researching for older answers.)

To subscribe, send an e-mail toLittleProxy2+subscribe@googlegroups.com.

Many thanks toThe Measurement Factory for theuse ofCo-Advisor for HTTP standardscompliance testing.