racker/node-moruga

Name: node-moruga

Owner: racker

Description: HTTP proxy for API unit-testing and debugging

Created: 2012-08-23 21:08:40.0

Updated: 2013-11-07 18:20:38.0

Pushed: 2012-09-21 18:44:42.0

Homepage: null

Size: 132

Language: JavaScript

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README

Moruga

Moruga is a spider genus, a district in Trinidad, the hottest pepper in the world, and a transparent HTTP proxy for API unit-testing and debugging.

A few things remain to be done, but Moruga is far enough along to be useful.

Installation

Moruga requires Node.js and NPM.

To install Moruga as a binary in your PATH, run this in your console:

 npm install moruga -g

Run moruga without any parameters to view available options.

ga

HTTP Example

ga -u http://duckduckgo.com -f filters.example.js -v

• Listen for HTTP requests on all IP addresses, using port 80
• Import the filters.example.js module and load its filters array
• Proxy requests to http://duckduckgo.com[PATH_AND_QUERY_STRING]
• E.g.: http://moruga.example.com/chunky?meat=bacon —> http://duckduckgo.com/chunky?meat=bacon
• Print requests/responses to/from the user agent

HTTPS Example

ga -u http://duckduckgo.com -f filters.example.js --ssl-key=server-key.pem --ssl-cert=server-cert.pem

• Listen for HTTPS requests on all IP addresses, using port 443
• Use default list of CAs, including well-known ones like Verisign
• mport the filters.example.js module and load its filters array
• Proxy requests to http://duckduckgo.com[PATH_AND_QUERY_STRING]

Built-in Filters

Moruga comes with two built-in filters. The first is a request/response logger, which is enabled with the -v option on the command line. Currently, the build-in logger only outputs headers, but adding an option to write out message bodies.

The second built-in filter is a handler for the custom X-Moruga-Control header. Using this header, you can trigger specific actions for each request. This is useful for writing unit tests.

The built-in X-Moruga-Control handler recognizes the following directives:

ort-circuit, status=(\d+)$/
pty-reply, wait-sec=(\d+)$/
uncate-body, location=(one-off|beginning|middle)$/

For example, to test response handling in your code for a particular HTTP status code, include this header line in the client's request:

ruga-Control: short-circuit, status=403

To cause Moruga to drop the connection after 2 seconds without returning anything:

ruga-Control: empty-reply, wait-sec=2

Or, to return only about half the body:

ruga-Control: truncate-body, location=middle

Alternatively, use `location=one-offto return all but the last byte of the response body, or ``location=beginning``` to return an empty body.

Filter Pipeline

Moruga uses the popular Connect library to create a filter pipeline for proxied HTTP requests. Each filter contains a human-readable name, URL path to match on, and an action. A custom actions may terminate the filter pipeline and return its own response, or allow processing to continue down the pipe.

For example, if I want to short-circuit every request to '/chunky-bacon' in order to express my approval of a certain type of breakfast meat, the following filter will do the trick:

me: 'Chunky Bacon',
th: '/chunky-bacon',

 Connect-compatible middleware function
tion: function(req, res, next) {
res.writeHead(200, {'X-Short-Circuit': true});
res.end('Soooooo chunky.');

// Uncomment if you want to allow remaining filters
// to run, but usually you won't do this after
// calling res.end()

// next();

The path may be a string or a RegEx-compatible object. In the latter case, the only requirment is that the object expose a test function that returns a truthy value for a successful match.

Here is another filter that matches all URLs except the root path, logs a message, and passes control to the next filter in the pipeline, if any.

me: 'Noop',
th: /^\/.+/,

tion: function(req, res, next) {
console.log('noop');

// Pass control to the next filter in the pipeline, if any
next();

And, finally, a more complex example showing how you can trigger different behaviors from a unit-test using a custom header:

me: 'Handler for X-Moruga-Control',
th: /^\/.*/,
tion: function(req, res, next) {
var control = req.headers['x-moruga-control'];

if (!control) {
  next();
  return;
}

var match = /^short-circuit, status=(\d+)/.exec(control);

if (match) {
  var code = parseInt(match[1]);
  res.writeHead(code, {'X-Short-Circuit': true});
  res.end();
  return;
}

next();

Custom Filters module

Moruga can load custom filters from a filter module file. The module simply needs to export an array named filters, containing a list of filter objects.

Note: Filters are installed in the pipeline in the same order as they appear in the array.

An example filters module:

his is a regular Node module, so you can do anything you like
util = require('util');

rts.filters = [

name: 'Chunky Bacon',
path: '/chunky-bacon',

// Connect middleware
action: function(req, res, next) {
  res.writeHead(200, {'X-Short-Circuit': true});
  res.end('Soooooo chunky.');
}


name: 'Breakfast',
path: new RegExp('/(bacon|eggs|ham|sausage|pancakes|toast|juice|milk|coffee|spam|/)+$', 'i'),

// Connect middleware
action: function(req, res, next) {
  res.writeHead(200, {'X-Short-Circuit': true});
  res.end("Let's eat!");
}


name: '503 on initial auth and randomly thereafter',
path: /^\/v\d+.\d+\/agent\/auth$/i,
action: function(req, res, next) {
  var userAgent = req.headers['user-agent'];

  // Return 503 10% of the time
  var trigger = Math.random() > 0.90;

  if (trigger || !this._authedByAgent[userAgent]) {
    this._authedByAgent[userAgent] = true;
    res.writeHead(503, {'X-Short-Circuit': true});
    res.end();
  }
  else {
    next();
  }
},

_authedByAgent: {}