DChat

Node.js chat service based on websockets.

Features

• Operates on both websocket and flashsocket client.
• It starts several chat processes, equal the number of your CPUs.
• All communications between chat instances are provided via Redis pub/sub.
• Operates with several Redis instances via hashring.
• Provide unlimited number of chat rooms.
• Store message history, delete old messages after the time has passed.
• Provide users-per-room counting.
• Read-only user mode for load reduction.

Load Capabilities

Max connection count is limited by 'ulimit' and amount of memory. Each connection you expect should be provided with 1 MB of RAM.

Max number of clients is also limited by CPU. Small test on ubuntu VM with 4 CPUs (2.5 GHz Intel Core i5) showed, that 30.000 is ok.

Requirements

• Node.js >= 0.8.0 (KO, thank you!)
• Redis

Node.js Modules

• websocket >= 1.0.7
• redis >= 0.7.1
• hash_ring >= 0.2.0
• policyfile >= 0.0.5 (For flash policy)
• mongodb >= 1.1.8 (Only for utility purposes. Chat uses ObjectID for the generation of connection IDs)
• underscore >= 1.4.1 (For cool object-operating methods)

All Node.js modules should be installed by 'npm install'.

Be careful!

All redis '*:users_count' collections should be deleted before chat is started for correct user counting.

Suggestions and Feedback

We will be very pleased if you'll send us some feedback, suggestions and feature-request. It surely will help this project to evolve.