Scripting News: A node.js module that does JSONP

Home > Archive > 2010 > December > 23

A node.js module that does JSONP

By Dave Winer on Thursday, December 23, 2010 at 10:22 AM.

JSONP turns a bit of JSON into a bit of JavaScript.

BTW, when I was trying to figure out what JSONP was I kept encountering long-winded explanations that told me ad nauseum something that I already knew about cross-domain data access and the loophole that allows scripts to be run cross-domain. Basically this is a flaw in browser design that should probably be fixed instead of worked-around. But that's how it goes sometimes in software.

In between all the history, the idea of JSONP usually never is actually explained. It's as if the writer used up all his or her energy explaining the crappy reason why we need JSONP in the first place.

So I put all the crappy whining in this bit of sub-text and kept it simple "up there."

"> ">

I want a node.js module that does that. A web app that takes two params, the URL of a JSON file and the name of a callback. Example:

http://hello.com/world?url=http://oy.org/random.json&callback=myLocalSubroutine

What it would return is this:

myLocalSubroutine (["Oregon", "Pizza", "Wheat"])

Assuming random.json contains a list: ["Oregon", "Pizza", "Wheat"].

Then Step 2 would simplify it to:

http://oy.org/random.json?callback=myLocalSubroutine

This, as I understand it, is what works best for JavaScript programmers working in the browser.

I wanted to provide this functionality in Frontier, but my guys are polling this thing ever 5 seconds (which is BS, they shouldn't do that, but WTF) and that would cost me $90 per month and it wouldn't run very well as soon as their stuff got a few hundred users, which is what we hope happens. A lose-lose-lose.

What we need is a bare-bones machine language thing that does this. Node.js would be ideal.

Caveat: Of course, I'm sure something like this already exists!

Follow @davewiner

Previous / Next