Andrej Cimperšek - diploma

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Project Name

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Version 0.6

Release date: 01/31/2008

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Project state:

experimental

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Credits

	James Burke (jburke@dojotoolkit.org)

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Project description

The XHR IFrame Proxy (xip) allows you to do cross-domain XMLHttpRequests (XHRs).

It works by using two iframes, one your domain (xip_client.html), one on the 

other domain (xip_server.html). They use fragment IDs in the iframe URLs to pass

messages to each other. The xip.js file defines dojox.io.proxy.xip. This module

intercepts XHR calls made by the Dojo XHR methods (dojo.xhr* methods). The module

returns a facade object that acts like an XHR object. Once send is called on the

facade, the facade's data is serialized, given to xip_client.html. xip_client.html

then passes the serialized data to xip_server.html by changing xip_server.html's

URL fragment ID (the #xxxx part of an URL). xip_server.html deserializes the

message fragments, and does an XHR call, gets the response, and serializes the

data. The serialized data is then passed back to xip_client.html by changing

xip_client.html's fragment ID. Then the response is deserialized and used as

the response inside the facade XHR object that was created by dojox.io.proxy.xip.

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Dependencies:

xip.js: Dojo Core, dojox.data.dom

xip_client.html: none

xip_server.html: none (but see Additional Notes section)

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Documentation

There is some documentation that applies to the Dojo 0.4.x version of these files:

http://dojotoolkit.org/book/dojo-book-0-4/part-5-connecting-pieces/i-o/cross-domain-xmlhttprequest-using-iframe-proxy

The general theory still applies to this code, but the specifics are different

for the Dojo 0.9+ codebase. Doc updates hopefully after the basic code is ported.

The current implementation destroys the iframes used for a request after the request

completes. This seems to cause a memory leak, particularly in IE. So, it is not

suited for doing polling cross-domain requests.

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Installation instructions

Grab the following from the Dojox SVN Repository:

http://svn.dojotoolkit.org/var/src/dojo/dojox/trunk/io/proxy/xip.js

http://svn.dojotoolkit.org/var/src/dojo/dojox/trunk/io/proxy/xip_client.html

Install into the following directory structure:

/dojox/io/proxy/

...which should be at the same level as your Dojo checkout.

Grab the following from the Dojox SVN Repository:

http://svn.dojotoolkit.org/var/src/dojo/dojox/trunk/io/proxy/xip_server.html

and install it on the domain that you want to allow receiving cross-domain

requests. Be sure to read the documentation, the Additional Notes below, and

the in-file comments.

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Additional Notes

xip_client.html and xip_server.html do not work right away. You need to uncomment

out the script tags in the files. Additionally, xip_server.html requires a JS file,

isAllowed.js, to be defined. See the notes in xip_server.html for more informaiton.

XDOMAIN BUILD INSTRUCTIONS:

The dojox.io.proxy module requires some setup to use with an xdomain build.

The xip_client.html file has to be served from the same domain as your web page.

It cannot be served from the domain that has the xdomain build. Download xip_client.html

and install it on your server. Then set djConfig.xipClientUrl to the local path

of xip_client.html (just use a path, not a whole URL, since it will be on the same

domain as the page). The path to the file should be the path relative to the web

page that is using dojox.io.proxy.