greyhound.js

This is a Node.js and browser library for consuming Greyhound data.

Installation

npm install greyhound.js

Usage

The library provides two classes named GreyhoundReader and Schema.

GreyhoundReader

Creating a Session

This is the main class to read data from Greyhound. You start by creating a session on the Greyhound server and then querying it for data.

var GreyhoundReader = require('greyhound.js').GreyhoundReader

var reader = GreyhoundReader("server.com");
reader.createSession("pipeline-id", function(err, sessionId) {
    if (err) return console.log("Error creating pipeline:", err);
    console.log("Created a new session with id:", sessionId);
});

Reading from a Session

Once you have a session you can start reading data from it, right now the reader supports reading all of the data in one go.

reader.read(sessionId, function(err, data) {
    if (err) return console.log("Failed to read:", err);
    console.log("Got", data.length, "total bytes");
});

You can additionally specify a schema as well:

var Schema = require('greyhound.js').Schema;

reader.read(sessionId, {
    schema: Schema.standard()
}, function(err, data) {
    if (err) return console.log("Failed to read:", err);
    console.log("Got", data.length, "total bytes");
});

Destroying a session

You should finally destroy the session:

reader.destroy(sessionId, function(err) {
    if (err) return console.log("Failed to destroy session:", err);
    console.log("Session was destroyed");
});

Schema

A Schema class is provided to construct schemas on the fly. This class provides two standard schemas accessible through functions: standard() and XYZ(). To construct a schema you could use one of these as starting points or build your own.

As an example, a schema definition for just the X value, along with Intensity and Red color channel would look like:

Schema.X().Intensity().Red();

These fields have default types, but you can always specify your own:

Schema.X("floating", 8).Intensity("unsigned", 2).Red("float", 4);

Hacking

Just checkout the code and run

gulp tdd

This will give you URL which you can visit to see the output of unit-tests. Additionally,

npm test

will run the test suite for node.js.

License

MIT