ErrorZilla Plus
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| A snapshot of ErrorZilla Plus on Firefox 3.0 |
A Firefox extension, replaces Firefox official error page, and adds some useful tools to aid your troubleshooting.
The tools include:
- Google Cache (view the page cached by Google)
- Coralize (use Coral CDN proxy to connect again)
- Wayback (view an earlier version of this page)
- Ping (use a server to ping the target server)
- Trace (trace the network route from you to the server)
- Whois (look up who owns the website)
- Proxify (use your custom proxy to connect)
This extension is originally based on the ErrorZilla Mod extension. I added a "Proxify" function into it. When error page shows, you can choose a web proxy from a list and browse the unreachable network address via it.
Design detail
The main idea of replacing the official error page is to override chrome://global/content/netError.xhtml with the customized file. The most straightforward way is modify the netError.xhtml file, place it in the extension directory and write down the override statment in chrome.manifest.
The proxy function allows users to specify custom proxy name and address. A way of storing the proxy data is necessary. Good candidates are XML plain file or SQLite database, both of which need access to XPCOM components. Unfortunately, netError.xhtml has special Javascript permission disallowing call to XPCOM, meaning the proxy data must be stored inside netError.xhtml. ErrorZilla Plus accomplishes this by modifying netError.xhtml from external script.
Prior to version 0.5, only the proxy data are dynamically patches, leading another problem: if user update Firefox version from 2.0 to 3.0, while the official error page is changed, the customized error page is not, and may be not compatible to the new Firefox engine. In version 0.5, every modifcation to netError.xhtml is done by patching the official error page. The patch candidates are selected by their XPath, therefore if the overall structure of netError.xhtml will not change in the future, theoretically ErrorZilla Plus 0.5 is able to support any future Firefox.
