jsgi-node

JSGI 0.3 Adapter for Node

JSGI-Node provides an interface for running JSGI middleware on Node. JSGI is an asynchronous middleware interface based on solid mature middleware design principles, and the asynchronous design fits perfectly with Node. JSGI uses idiomatic JavaScript, leveraging closures for simple and fast middleware connectivity. This project does not include any JSGI components itself, but a substantial set of JSGI middleware components that are available, many can be found in Pintura.

Installation

JSGI-Node can be installed with NPM:

npm install jsgi-node

Usage

To use, provide a JSGI application (can be application stack) to the start function:

require("jsgi-node").start(function(request){
  return {
    status:200,
    headers:{},
    body:["Hello World!"]
  };
});

This adapter should conform to the JSGI 0.3 (with promises) for full asynchronous support. For example, here is an echo server that asynchronously waits for the request and asynchonously provides it as the response:

require("jsgi-node").start(function(request){
  return request.body.join().then(function(requestBody){
    return {
      status:200,
      headers:{},
      body:["echo: " + requestBody]
    };
  });
});

And here is an example of using a promises from another source (from promised-io's fs) and piping them to the response:

var fs = require("promised-io/fs");
require("jsgi-node").start(function(request){
  return fs.readFile("jsgi-node.js").then(function(body){
    return {
      status: 200,
      headers: {},
      body: [body]
    };
  });
});

File objects returned from promised-io's fs can be directly provided as body for automated streaming of data to the client from the filesystem:

var fs = require("promised-io/fs");
require("jsgi-node").start(function(request){
  return {
    status: 200,
    headers: {},
    body: fs.open("some-file.txt","r")
  };
});

This package also includes an adapter for running Node HTTP apps on top of JSGI middleware:

var fs = require("promised-io/fs"),
    Node = require("jsgi/node").Node;
require("jsgi-node").start(
  SomeJSGIMiddleWare(
    OtherJSGIMiddleWare(
      Node(function(request, response){
       // request and response conform to Node's HTTP API
      })
    )
  )
);

WebSocket with JSGI

JSGI middleware can be used to handle incoming WebSocket messages. While JSGI is designed for HTTP, WebSocket includes HTTP elements and JSGI's streaming capabilities are well-suited for socket communication. JSGI delegation can be achieved by using the "ws-jsgi" module in conjunction with the node-websocket-server package. This "ws-jsgi" module exports a function that can be called with a socket server and a JSGI handler. For example:

	var http = require("http").createServer(
			require("jsgi-node").Listener(jsgiApp)
		);
	http.listen(80);
	require("jsgi/ws-jsgi")(ws.createServer({
		server: http
	}), jsgiApp);

Licensing

The JSGI-Node package is an implementation of JSGI. JSGI is a standard that was developed in collaboration by many developers through the forums of JackJS, CommonJS, and Persevere. The implementation in this package is part of the Persevere project, and therefore is licensed under the AFL or BSD license. The Persevere project is administered under the Dojo foundation, and all contributions require a Dojo CLA.

Authors include Kris Zyp and Jed Schmidt.