Cross domain ajax using JSONP

[jwestbrook]

previous lighthouse ticket #333
by Christopher Thomas

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we should definitely look at how to port jquery's getJSON() method because it's just a very simple and easy way to obtain information from another website, without messing around building your own script handler.

I believe there was an attempt to make a <script> transport for prototype, to a degree, it worked, however it lacked the ability to use a callback when the contents of the tag were finally loaded (when usually you'd expect an onload event, there is none, so the callback method for JSONP allows you to insert a callback so when it executes, it's because the contents has loaded (otherwise the callbac wouldnt run either). The sample implementation that I tried was this:

http://ajaxian.com/archives/prototype-extension-dynamic-script-pattern-support

but it is not foolproof and with some work, it could provide us with a

The security problems this causes are merely in the hands of the developer if they should choose to use it, like in jquery, it's a gun, you point it at your website, or at your head, where you pull the trigger, is up to you. But I think this feature would really rock.</p>

[jwestbrook]

Juriy Zaytsev
September 10th, 2008 @ 03:46 AM

I think such functionality is definitely useful. The content becomes more dynamic and "mashups" - more popular. Having a robust way of fetching JSON from remote hosts is a must.
Feel free to submit patch/tests.
I'm marking it as enhancement for future releases.

[jwestbrook]

Juriy Zaytsev
October 7th, 2008 @ 06:22 AM

I was experimenting with this some time ago http://github.com/kangax/protolicious/tree/master/get_json.js
Does anyone else have a working example? Are there any caveats to watch for?

[jwestbrook]

Kyle Simpson
May 22nd, 2009 @ 06:12 PM

I've just added a plugin for Prototype to use flXHR (http://flxhr.flensed.com) for cross-domain Ajax. Since flXHR is completely the same API as native XHR, it just plugs right in and works exactly like regular Ajax calls -- no other code changes needed.
Here's the Prototype plugin, called flXHRproxy: http://flxhr.flensed.com/prototype.php
Since it's just like XHR, it can do JSON, JSONP, XML, HTML, text, even binary as requests and responses. And all with cross-domain Ajax that just couldn't get any simpler.

[jwestbrook]

Valery
June 18th, 2009 @ 08:20 PM

friends, so, there is still no JSONP for PrototypeJS?..
@kyle, did I correctly understand, that your solution needs Flash?

[jwestbrook]

Juriy Zaytsev
June 22nd, 2009 @ 07:20 PM

@valery Did the script from "protolicious" work for you?

[jwestbrook]

Dan Dean
July 15th, 2009 @ 12:32 AM

@Juriy: Is the core team still interested in adding this to Prototype? If so, would this be a suitable solution? It's based on a gist by Tobie Langel with some added functionality for various phases of the life cycle, including onFailure.
http://gist.github.com/147172
Better testing is needed, as well as some input as to whether this should hook into the Ajax.Responders callbacks.

[jwestbrook]

Dan Dean
July 15th, 2009 @ 05:15 AM

I've added this feature to Github along with documentation and explanation:
http://github.com/dandean/Ajax.JSONRequest

[jwestbrook]

Kyle Simpson
September 8th, 2009 @ 05:05 AM

I've also got another project for doing simple JSON-P cross-domain calls via the XHR API interface: jXHR http://mulletxhr.com
It works just like the native XHR object, but uses JSON-P style script tags to make the calls (so it doesn't rely on flash like flXHR does). It also adds basic error handling to the calls.

[jwestbrook]

ronin-24025 (at lighthouseapp)
September 9th, 2009 @ 04:28 PM

I did a ton of research on cross-domain ajax: flash-based techniques, JSONP, proxying techniques, Kris Zyp's WindowNameRequest technique. Executive summary:
FLASH:
Proprietary.
JSONP:
Requires support from server. Limits POST request (if supported) representation size to 4kb.
Proxy:
Requires proxy server.
WindowNameRequest:
Requires support from server. Limits POST request (if supported) representation size to 10mb.
A primitive and more complex version of WindowNameRequest was used by Google last year. Kris Zyp's version subsequently improved and simplified it: http://www.sitepen.com/blog/2008/07/22/windowname-transport/

[jwestbrook]

Amit Kumar
June 10th, 2010 @ 10:22 PM

Hey... so what's the status on the Ajax.JASONRequest.??
The whole idea of JASONP looks more like a workaround, but alas there is not other easier way.
Clearly there is a need for this and I would request to take it on priority. As mentioned above , JQuery already one.
I was interested in making a traffic monitoring mashup through twitter messages, and google maps api. After going through Crockford's JS tutorial videos, really wanted to make it javascript, thereby moving everything into a nifty javascript code which in turn could be pasted by anyone in his html page.
Unfortunately there aren't many javascript libraries for twitter. I have been working with Prototype for past few years, so being a faithful, wanted to give it a try first. But looks like the cross-domain restriction is a big roadblock for mash-up in a client-side processing environment.
And I think we should also work to make a twitter library through Prototype. But before that we really need some kind of JASONP implementation.
Regards
-AK

[jwestbrook]

Jason Laumeister
December 8th, 2010 @ 02:18 AM

I've had success with prototype 1.6.1 and Dan Dean's jsonp implementation here: https://github.com/dandean/Ajax.JSONRequest
Dan Dean's implementation is < 120 lines of javascript (< 3.9k).
jsonp is a necessary work-around for cross-domain restrictions that would otherwise prohibit a page from making an ajax call to a third party server. A real-world example would be an online game that includes ads in an DHTML popup from a third party ad network as seen in the following prototype/jsonp example.
ajax/jsonp example:
jsonp example: http://super.kitnmedia.com/publisher_api/adk_demo/prototype_ad_demo
implementation docs: http://cdn.superrewards-offers.com/docs/adk_overlay_api.html#igo_in...
source code: http://cdn.superrewards-offers.com/js/tools/interstitial/adk.inters...
This example relies on Dan Dean's jsonp implementation as described in the implementation docs.

[jwestbrook]

Alexander Vassbotn Røyne
February 3rd, 2011 @ 09:07 AM

What is the status on this issue?