Introduction¶ ↑

This application is experimental for the moment do not use it on a production server !

futon4mongo is a small Sinatra app that partially replicates CouchDB’s REST interface on top of MongoDB… Making CouchDB’s Futon web interface compatible with our beloved MongoDB (yeah !).

Futon’s code is included but has not been modified (ok… I just changed the logo). This project is an experimentation to bring a fully featured web based frontend to MongoDB.

Mongo anf Couch have a lot of similarities… but still have some fondamental differences, so I had to make some decisions to make it work. Thoses differences are listed in the “Issues & Compatibility” section of this document.

Installation¶ ↑

Requirements¶ ↑

• Ruby (tested with ruby 1.8.6 on MacOS Leopard / Snow Leopard & Ubuntu 9.04)

• Gems : sinatra, yajl-ruby, mongo, mongo_ext

To install those gems :

$ gem sources -a http://gems.github.com
$ sudo gem install bundler

Installation¶ ↑

$ git clone git://github.com/sbellity/futon4mongo.git
$ cd futon4mongo
$ bundle install
$ rackup -p 4567

Go to localhost:4567/_utils/index.html

Special features¶ ↑

Views¶ ↑

futon4mongo replicates CouchDB’s views functionality with some notable differences :

* views are stored in design documents in a special collection called "__design"
* MongoDB does not support (yet?) map/reduce operations, so the "map" part of the view is used to store filters as json documents.
* The "reduce" part is used to store other parameters (TODO : complete documentation here...)

Issues & Compatibility¶ ↑

Databases and Collections¶ ↑

CouchDB does not have “collections”, all the documents are stored directly into “databases”. futon4mongo sees mongo’s collections as databases with the following conventions :

* futon'db = "db_name/collection_name"
* futon's db list does not include mongo's system collections nor the special "__design" collections

Document IDs¶ ↑

Mongo’s _id are typed… and it make it difficult use CouchDB’s REST interface as is with Mongo. The following conventions are used to try to guess the correct _id type from the string provided in the url.

* if _id is made of numbers, tries to cast _id as a FixNum and falls back to a String if no result is found
* if _id is a valid ObjectId tries to cast _id as a Mongo::ObjectID and falls back to a String if no result is found
* else _id is considered as a String

This method is not 100% reliable, but I guess it should cover the most common situations