Where Do I Find The Update URL For Google Chrome Extensions?

Question

I'm trying to setup group policy for Google Chrome (http://support.google.com/installer/bin/answer.py?hl=en&answer=146164) particularily I'm working on setting up the Configuring the list of force-installed extensions. I can find the extension ID by looking in tools-extensions in Google Chrome but I cannot find the update URL for extensions like Adblock or Google Mail Checker, where would I find these?

Answer 1

I can't help you with group-policy, but each extension includes its update URL in manifest.json.

So, for the current version of adblock (id: gighmmpiobklfepjocnamgkkbiglidom):

%USERPROFILE%\AppData\Local\Google\Chrome\User Data\Default\Extensions\gighmmpiobklfepjocnamgkkbiglidom\2.5.14_0\manifest.json

Contains:

"update_url": "http://clients2.google.com/service/update2/crx"

The extension will query that URL for updates, as per the documentation.

We can therefore construct a URL that will return the update XML from the above URL (just change the ID as needed) - for adblock:

http://clients2.google.com/service/update2/crx?response=updatecheck&x=id%3Dgighmmpiobklfepjocnamgkkbiglidom%26uc

The XML that is returned reads:

<?xml version="1.0" encoding="UTF-8"?>
<gupdate xmlns="http://www.google.com/update2/response" protocol="2.0" server="prod">
    <daystart elapsed_seconds="49387"/>
    <app appid="gighmmpiobklfepjocnamgkkbiglidom" status="ok">
        <updatecheck codebase="http://clients2.googleusercontent.com/crx/download/OAAAAFpzXu4buuGNADfzIKiz34SLARZdBLiXQ2zo50sAlzoBpEz77foH-XT3yHpPureXtHcQSYU2z4ZNstiuKJi-LD8AxlKa5VgufvySdIb5b9U333P0upRk1YPb/extension_2_5_14.crx" hash="" size="529317" status="ok" version="2.5.14"/>
    </app>
</gupdate>

We are interested in the codebase attribute of updatecheck, which provides us the direct URL to the latest CRX file.