I posted a brief snippet of code on Friday which was my initial stab at a reverse HTTP proxy in Javascript (using node.js).

Over the past couple of days I've tidied it up, added a command line parser, and made it flexible enough that it works for me.

My node reverse HTTP proxy is now both documented ( a little ) and available for further eyeballs.

Usage is pretty much:

$ node ./node-reverse-proxy.js --config ./path/to/config.file.js

The configuration file defines lists of virtual hosts along with the destination back-ends to proxy to - which is usually going to be a server running upon a high port on the loopback adapter, but might not be.

In addition to that we can perform rewrites such as:

/**
  * Handler for wildcard host: *.repository.steve.org.uk
  *
  */
'([^.]*).repository.steve.org.uk':
    {
        /**
         * Rewrites for static files - these will be handled via a
         * separate virtual host.
         */
        'rules': {
            '^/robots.txt':  'http://repository.steve.org.uk/robots.txt',
            '^/favicon.ico': 'http://repository.steve.org.uk/favicon.ico',
        },
     },

That says requests for http://chronicle.repository.steve.org.uk/robots.txt will be redirected to http://repository.steve.org.uk/robots.txt.

Alternatively we can invoke javascript for each request matching a pattern:

    /**
     * static.steve.org.uk will mostly proxy to 127.0.0.1:1008
     * but files beneath /private/ have an IP-based ACL.
     */
    'static.steve.org.uk':
    {
        host: 'localhost',
        port: '1008',

        'functions': {
            '/private': (function(orig_host, vhost,req,res) {
                var remote = req.connection.remoteAddress;;

                if ( ( remote != "80.68.85.46" ) &&
                     ( remote != "82.41.51.252" ) &&
                     ( remote != "89.16.161.34") &&
                     ( remote != "89.16.161.98" ) )
                {
                    res.writeHead(403);
                    res.write( "Denied access to " + req.url  + " from " + remote );
                    res.end();
                }
           }),
        }
    },

Fun stuff. It was live for my server, replacing apache, for a few hours today. I need to add some trivial HTTP Basic-Auth handling then it will go back.

Otherwise I hope it is vaguely useful to others, and that the provided examples explain things neatly.

ObQuote: "Only one thing alive with less than four legs can hear this frequency" - Superman.

Tags: node-reverse-proxy, nodejs, software | 4 comments