streamable0.6.0 • Public • Published
Have you ever wanted to utilize
Content-Encoding: chunked in XHR, without waiting for the entire request to complete? With Streamable, you can!
HTTP/1.1 chunked encoding is a really useful feature of the protocol, however, its really disappointing that we cannot interact with it directly via XHR. Instead, we have to wait for the entire request/response cycle to be complete, before we can start interacting with the data thats coming to us over the wire!
Since we cannot rely on the HTTP protocol alone, we use a hybrid strategy that negotiates initially over HTTP at first, then coordinates chunked data transmission using asynchronous pipelines. Ideally, this is accomplished using WebSockets, but will feature detect as you would expect, thanks to socket.io. So rather than reinventing the HTTP protocol over sockets, we couple the two protocols together into a single API.
Streamable is designed to feel transparent. If you access a streamable REST endpoint without the Streamable client, native chunked encoding will happen in its place. You can also explicitly disable Streamable for a particular request by sending the
x-streamable-bypass request header. If streamable is bypassed, each message will be delimeted with
\r\n. This is also configurable by provided the
x-streamable-delimiter request header, providing the value you'd like to use instead.
install Streamable using npm:
npm install streamable
Streamable is implemented as an Express/Connect middleware, so its really simple to use. It assumes you've got both Socket.io and Express modules already included in your app.
// setup an express 3.x servervar express = ;var app = ;var server = ;// setup a socket.io server and attach it to expressvar io = ;
Once you've got that setup, its easy to setup Streamable, just pass in your socket.io server instance and the middleware is ready to go.
var streamable = ;
At this point, we just drop the Streamable middleware into our routes
The streamable API also allows you to send fatal and non-fatal errors via the
the write API also supports
json as a valid encoding, for convenience.
onData call will happen n times--once per write. The
onEnd call is guaranteed to be called one time after all
onError events have fired. If you've passed multiple values to write on the server-side, you can expect them as arguments in the same order of your
onData event handler.
Copyright (C) 2012 Derek Perez firstname.lastname@example.org
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