add basic auth support to proxy chain

[rrauschenbach]

I want to be able to create a proxy chain to a remote proxy which is not under my control and is configured to use http basic authentication.

Here is the usage code for the changes I made.

bootstrap.withChainProxyManager(new ChainedProxyManager() {

    @Override
    public void lookupChainedProxies(HttpRequest httpRequest, Queue<ChainedProxy> chainedProxies) {
        chainedProxies.add(new ChainedProxyAdapter() {

            @Override
            public InetSocketAddress getChainedProxyAddress() {
                try {
                    return new InetSocketAddress(InetAddress.getByName(chainingProxyHost), chainingProxyPort);
                } catch (UnknownHostException uhe) {
                    throw new RuntimeException(uhe);
                }
            }

            @Override
            public String getBasicAuthUser() {
                return chainingProxyUser;
            }

            @Override
            public String getBasicAuthPassword() {
                return chainingProxyPass;
            }

        });
    }
});

[jekh]

Chained proxy authorization is already supported. There's no need to change the LittleProxy code at all, simply add a filter to the chained proxy manager. Here's an example of how BMP does this.

[rrauschenbach]

Thank you for the fast answer and the example. It will do what I want and it is totally ok for me to close this PR.

What I didn't like at the example is that it's a very generic way to do something special. It's not intuitive to implement the filter method to do authentication and it results in a code that is difficult to understand and is doing things I would expect has to be done by the framework.

By the way, having two methods which depends to each other, as I suggest, is also not a beauty solution and way too special. I would prefere some authentication interface which can be returned by a new ChainedProxy method which would be generic enough to allow different authentication types but results in less usage code with a higher knowability. But this is a question of architecture I can't really estimate with my little knowledge about LittleProxy.