How do I configure LittleProxy so that it sends its requests to another proxy?

[ne...@halloleo.hailmail.net]

I want to use LittleProxy in a way that it forwards all requests to another proxy server (given via IP address and port)

Where do I configure LittleProxy for this? In "littleproxy.properties"? But where do I find documentation about this?

Many thanks, Leo

[Ox Cart]

You'll need to embed LittleProxy and set up a chained proxy.  There are various unit tests that test different configurations of chained proxies, for example:

https://github.com/adamfisk/LittleProxy/blob/master/src/test/java/org/littleshoot/proxy/EncryptedTCPChainedProxyTest.java

[ne...@halloleo.hailmail.net]

Mmmh, I had a look at EncryptedTCPChainedProxyTest.java, but couldn't find a point where I can plug in the host & port info for the target proxy I want to direct all traffic to.

Additionally I have tried to set just the System properties http.proxyHost and http.proxyPort in LittleProxy Launcher to the values of the target proxy. (Setting the system properties works for Java programs going out to the net via HttpURLConnection, beacuse all our traffic has to go through the target proxy.) But no success in LittleProxy: In the log I always get the debug messages AWAITING_INITIAL and then DISCONNECTED. And the end-user I tell to use LittleProxy gets the error message "Unexpected end of file from server"

[Ox Cart]

Those system properties won't have an effect, because LittleProxy doesn't use HttpURLConnection.

What you need to do is configure LittleProxy to use a ChainedProxyManager as shown here.

Cheers,

Ox

-----------------------------------------------------------------------------------------

"I love people who harness themselves, an ox to a heavy cart,

who pull like water buffalo, with massive patience,

who strain in the mud and the muck to move things forward,

who do what has to be done, again and again."

- Marge Piercy

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[ne...@halloleo.hailmail.net]

Hi Ox,

Getting closer! :-) Many thanks!

I created an UpstreamProxy class which extends ChainedProxyAdapter and provides address and port of the upstream proxy server. Then I added this via .withChainProxyManager to the Launcher.

I now get for the first time something back from the upstream proxy, but it is a 407 error. So I need to authenticate that upstream proxy (I have its credentials). I did find the ProxyAuthenticator interface, but I'm not sure how to add it in the extended ChainedProxyAdapter class and I'm not sure if ChainedProxyAdapter autheticates against LittleProxy (which I don't want) or against the upstream proxy (which I do want).

Cheers, Leo

[Ox Cart]

ProxyAuthenticator is used by LittleProxy to authenticate incoming requests.  ChainedProxyAdapter has a method called filterRequest that you can override to modify the request that's sent downstream.  I think you just need to add a proxy authorization header there, like this:

http://en.wikipedia.org/wiki/Basic_access_authentication#Client_side

But instead of "Authorization" you want to use "Proxy-Authorization".

Cheers,

Ox

-----------------------------------------------------------------------------------------

"I love people who harness themselves, an ox to a heavy cart,

who pull like water buffalo, with massive patience,

who strain in the mud and the muck to move things forward,

who do what has to be done, again and again."

- Marge Piercy

[ne...@halloleo.hailmail.net]

Hi Ox

I had a look at filterRequest. It has the parameter HttpObject, which I would need to modify, but I cannot figure out how to add an authentication header: The (netty) interface HttpObject has only the two methods getDecoderResult and setDecoderResult. Are there any netty examples for proxy authentication on the net or do you have an idea what to do?

Sorry to ask this!

Leo

[Ox Cart]

You need to cast HttpObject to HttpRequest.  Be aware that filterRequest is called for every chunk of the request and that only the first chunk will be an HttpRequest.  So, you need to do something like this:

if (httpObject instanceof HttpRequest) {

    HttpRequest req = (HttpRequest) httpObject;

    req.headers().add("Proxy-Authorization", ...);

}

Cheers,

Ox

-----------------------------------------------------------------------------------------

"I love people who harness themselves, an ox to a heavy cart,

who pull like water buffalo, with massive patience,

who strain in the mud and the muck to move things forward,

who do what has to be done, again and again."

- Marge Piercy

[ne...@halloleo.hailmail.net]

Thanks a lot, Ox

You are really going the extra mile!

Doesn't work, though:

When I get from the upstream proxy

HTTP/1.1 407 Proxy Access Denied
Expires: 0
Server: WebMarshal Proxy
Cache-Control: no-cache
Connection: close
Proxy-Connection: close
Via: 1.1 WEBMARSHAL
Content-Length: 2379
Content-Type: text/html; charset=utf-8
Proxy-Authenticate: Negotiate
Proxy-Authenticate: NTLM
Proxy-Authenticate: Basic realm="WebMarshal Proxy Server"
X-WebMarshal-RequestID: XXXXXXXXXXXXXX

I send:

GET http://www.w3.org HTTP/1.1
User-Agent: Java/1.6.0_37
Host: www.w3.org
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Via: 1.1.127.0.0.1
Proxy-Authorization: Basic XXXXXXXXXXXXXXXXX

But I get again a:

HTTP/1.1 407 Proxy Access Denied
Expires: 0
Server: WebMarshal Proxy
Cache-Control: no-cache
Connection: close
Proxy-Connection: close
Via: 1.1 WEBMARSHAL
Content-Length: 2379
Content-Type: text/html; charset=utf-8
Proxy-Authenticate: Negotiate
Proxy-Authenticate: NTLM
Proxy-Authenticate: Basic realm="WebMarshal Proxy Server"
X-WebMarshal-RequestID: xxxxxxxxxxxxxxxxxxxxxx

I assume that the upstream proxy does not allow for Basic Authentication. - Is there a way to configure LittleProxy to use upstream NTLM authentication?

Many thanks, Leo

[Ox Cart]

LittleProxy does not support NTLM authentication.  This would be somewhat difficult to add because it's a challenge-response scheme that's connection-oriented (rather than request oriented like Basic authentication).

http://davenport.sourceforge.net/ntlm.html

Cheers,

Ox

[ne...@halloleo.hailmail.net]

Thanks Ox.

I will try another way...