back-pack-jack / hello-websocket

Webcam over WebSocket in Python using OpenCV and Tornado

hello-websocket

Webcam over websocket in Python using OpenCV and Tornado.

How it works

A recorder process continuously reads images from a webcam. Upon every capture, it writes the image to a Redis key-value store.

A separate server process (running Tornado) handles websocket requests sent by a client (web browser). Upon receiving a request, it retrieves the latest image from the Redis database and sends it to the client over the established websocket connection.

The client web page is dead simple: It sends an initial request on a websocket. When image data arrives, it assigns it to src attribute of the <img> tag, then simply sends the next request. That's it!

Installation

The code uses Python in a virtualenv. Since OpenCV is not officially in the Python Package Index, we manually copy the system OpenCV library into the virtualenv.

First, install OpenCV for Python system-wide:

apt-get install python-opencv

Also install Redis server:

apt-get install redis-server

Build the virtual environment with all needed modules:

make

Usage

Two separate programs need to be running: 1) the recorder which captures and writes to Redis database, and 2) the server which reads the current image from the database and serves to requesting WebSocket clients.

Run the recorder:

make recorder

Now (in a different shell) run the server:

make server

Go to http://localhost:9000 to view the webcam.