POST Absolute URI is sent to server by XmlHttpRequest when using Squid3 proxy

Question

I've faced strange problem now with sending http request from Chrome extension i am developing (normal JavaScript). This's a POST request with XmlHttpRequest (from background.js) with url like:

http://host.com/postform/upload

I also send this request from normal webpage (not chrome extension), and important bit is that if i open Developer Tools and check Network tab for my request (selecting raw headers display) i see first header there:

POST /postform/upload HTTP/1.1

And it works fine before i enable proxy instead of a direct conneciton. I use squid3 on my Ubuntu for this. Only one thing is different between requests when using proxy - and it makes HTTP server return 404 not found - only when using proxy..

When i force Chrome to work with my proxy based on squid3 (i use PAC script for this in my chrome extension), my request will not work. I checked many times and did all i could to reduce any difference in request body, and all i have left for now is first header.

It looks like this when request sent with proxy active (from Network tab of Developer Tools, opened from background page):

POST http://host.com/postform/upload HTTP/1.1

I've tried using chome.webRequest.onBeforeSendHeaders API, but that did not help. I also tried to remove hostname from URL in XmlHttpRequest.open but this did not help.

Yep, i am sending correct Host and Origin headers in any case. Could this be a problem in my squid3 configuration, or what should i change in my javaScript?

UPDATE Realized now that squid is not the problem in any way, and the problem is that POST request contains FULL uri (http://...) instead of "path". GET works fine. It's killing me.

I cannot use iframe workarounds. What's my problem?

Answer 1

To use the XHR API from within your Chrome extension, you need to request the permission for the target host by specifying its URL in the "permissions" manifest-attribute. For example, if the target host (to which you want to send the XHR request) is http://www.example.org, then your manifest should contain the following lines of code.

...
"permissions" : {
    "http://www.example.org",
    ...
}

If you have done so already, then obviously, the error is on the back-end part. Also read about match patterns to allow matching of multiple URLs using a single string - for example, *://www.example.org/*.