http-proxy-rules

http-proxy-rules is an add-on module to the node-http-proxy library. It lets you define a set of rules to translate matching routes to target routes that the reverse proxy service will talk to on the client's behalf.

Installation

npm install http-proxy-rules --save

Example Use Case

  var http = require('http'),
      httpProxy = require('http-proxy'),
      HttpProxyRules = require('http-proxy-rules');

  // Set up proxy rules instance
  var proxyRules = new HttpProxyRules({
    rules: {
      '.*/test': 'http://localhost:8080/cool', // Rule (1)
      '.*/test2/': 'http://localhost:8080/cool2/' // Rule (2)
    },
    default: 'http://localhost:8080' // default target
  });

  // Create reverse proxy instance
  var proxy = httpProxy.createProxy();

  // Create http server that leverages reverse proxy instance
  // and proxy rules to proxy requests to different targets
  http.createServer(function(req, res) {

    // a match method is exposed on the proxy rules instance
    // to test a request to see if it matches against one of the specified rules
    var target = proxyRules.match(req);
    if (target) {
      return proxy.web(req, res, {
        target: target
      });
    }

    res.writeHead(500, { 'Content-Type': 'text/plain' });
    res.end('The request url and path did not match any of the listed rules!');
  }).listen(6010, cb);

Given the object we used to initialize the HttpProxyRules instance above, here are some examples of how sample url paths would be translated.

Options

You can initialize a new http-proxy-rules instance with the following options:

{
  rules: {}, // See notes below
  default: '' // (optional) if no rules matched, translate url path to specified default
}

The rules object contains a set of key-value pairs mapping a regex-supported url path to a target route. The module only tries to match the visited url path, and not the entire url, with a specified rule. The target route must include the protocol (e.g., http) and the FQDN. See the tests for examples of how incoming route url paths may be translated with the use of this module.

Other Notes

• (?:\\W|$) is appended to the end of the regex-supported url path, so that if there is a key like .*/test in the rules, the module matches paths /test, /test/, /test? but not /testing.
• As long as object keys continued to be ordered in V8, if there are multiple rules that match against a given url path, the module will pick the matching rule listed first for the translation.