Mooch

A simple Twitter OAuth proxy.

What is Mooch?

Mooch is a simple app designed to allow unauthenticated access to the Twitter API for web apps that have no server-side components. Mooch is designed to be deployed as a Heroku app, which makes deployment of a new Mooch service extremely simple.

Why is this necessary?

In June 2013, Twitter officially retired version 1.0 of their API. Since version 1.1 of the Twitter API requires OAuth authentication for every request, this effectively meant the end of client-side only Twitter applications.

This is still the case. It is still impossible to write a secure, client-side only application that uses the Twitter API, even for information that is publicly available without authentication from the Twitter website. That's where Mooch comes in.

Mooch is the simplest possible server-side component for creating primarily client-side Twitter applications.

Demo Mooch service

For a demonstration of Mooch's capabilities, check out the example Mooch service. This service only allows access to the tweets of @CountingCrows_; all other accounts will result in a 403 error.

Setup

Setting up a new Mooch service is very simple, and utilizes Heroku. The deployment process requires the Heroku Toolbelt application.

Step 1: Create a Twitter app

• Visit https://dev.twitter.com/.
• Sign in with a Twitter account.
• Create a new application.

Step 2: Get Mooch

• Obtain Mooch by one of the following methods:
  • Clone the Git repository (git clone [email protected]:eloquent/mooch.git).
  • Download the latest release and extract it.
  • Install via NPM (npm install mooch).
• Change into the Mooch root directory.

Step 3: Create a Heroku app

• Sign in with Heroku Toolbelt (heroku login).
• Create a new app with heroku create (must be in the Mooch root directory).

Step 4: Configuration

Step 4.1: Set up allowed and forbidden paths (optional)

Variables: MOOCH_ALLOW and MOOCH_DENY.

By default Mooch allows access to any part of the Twitter API. This is not always ideal as anyone could find and use the service for their own requirements, potentially contributing to the Twitter application being rate limited.

Mooch uses a simple 'whitelist' (MOOCH_ALLOW) and 'blacklist' (MOOCH_DENY) of regular expressions to restrict access. Any incoming request that is disallowed will be immediately sent a HTTP 403 response with an imitation Twitter API error response as the body.

Mooch accepts these lists as a JSON array of regular expression strings suitable for passing to JavaScript's RegExp constructor. In other words, do not surround the expressions in forward slashes ('/'), and there is no need to escape forward slashes within expressions either. Remember that backslashes are also used by JSON for escaping, so to pass a single backslash to the RegExp constructor requires two backslashes in the JSON string.

Mooch first tries to find a matching 'allow' pattern for the request. If none of the patterns match, the request is denied. Mooch then tries to find a matching 'deny' pattern for the request. If any of the patterns match, the request is denied.

Example access control configuration

This configuration would allow access to any user's timeline or statuses, with the exclusion of Justin Bieber.

heroku config:set MOOCH_ALLOW='["^/1\\.1/statuses/user_timeline\\.json","^/1\\.1/statuses/show\\.json"]'
heroku config:set MOOCH_DENY='["justinbieber"]'

Step 4.2 Set up OAuth credentials

Variables: MOOCH_CONSUMER_KEY and MOOCH_CONSUMER_SECRET.

Mooch authenticates requests to the Twitter API using the application-only authentication method. This requires the consumer key and secret from the Twitter application created in step 1.

Example authentication configuration

heroku config:set MOOCH_CONSUMER_KEY=nQUZqUgo3lCAMBjBKPYRA
heroku config:set MOOCH_CONSUMER_SECRET=Na9zq5alYmit2iBIA8Wp04qyqiw3mH0tT9cdYVEcuM

Setup complete

The new Mooch service should now be ready for use. Check the Heroku dashboard for the service's location.

Running locally

Mooch can be started locally using npm start, but it requires some environment variables to be present. Fortunately it is possible to do all of this in a single line (at least in bash):

MOOCH_CONSUMER_KEY=nQUZqUgo3lCAMBjBKPYRA MOOCH_CONSUMER_SECRET=Na9zq5alYmit2iBIA8Wp04qyqiw3mH0tT9cdYVEcuM npm start