Add a Parent Proxy to a LittleProxy Listener

A local application can connect to LittleProxy while LittleProxy forwards its request through a corporate parent. Configure the listener and parent together:

ChainedProxy parent = new ChainedProxyAdapter() {
    @Override
    public InetSocketAddress getChainedProxyAddress() {
        return new InetSocketAddress("proxy.office.example", 3128);
    }
};

ChainedProxyManager manager = (request, candidates) ->
    candidates.add(parent);

HttpProxyServer server = DefaultHttpProxyServer.bootstrap()
    .withAddress(new InetSocketAddress("127.0.0.1", 8080))
    .withChainProxyManager(manager)
    .start();

This Java 8-or-later fragment uses LittleProxy's public chaining interfaces. The application using the proxy connects to 127.0.0.1:8080; the adapter returns the next proxy at proxy.office.example:3128.

The manager is consulted to supply upstream candidates for a request. This example adds the same parent each time. An application's routing rule can choose another candidate for a different destination. In an isolated public-site test permitted to use an unauthenticated public parent, the HTTP proxy list can supply that adapter’s address, with no parent-proxy credentials configured.

The chaining types are in org.littleshoot.proxy; DefaultHttpProxyServer is in its impl package.