URLRewriteFile and "#" char in URL string - gwt

Question

I'm using the Google means of making my GWT app searchable (https://developers.google.com/webmasters/ajax-crawling/docs/getting-started), which works fine. Unfortunately, it seems Bing does not follow the same pattern/rule.
I thought I'd add a URL filter, based on user-agent to map all URL's of the form
http://www.example.com/#!blah=something
to
http://www.example.com/?_escaped_fragment_=blah=something
only for BingBot so that my CrawlerServet returned the same as the GoogleBot requests. I have a URLRewrite rule like:
<rule>
<condition name="user-agent">Firefox/8.0</condition>
<from use-query-string="true">^(.*)#!(.*)$</from>
<to type="redirect">?_escaped_fragment_=$2</to>
</rule>
(I'm using a user-agent of Firefox to test)
This never matches. If I change the rule to ^(.)!(.)$ and try and match on
http://www.example.com/!blah=something
it will work, but using the same rule
http://www.example.com/#!blah=something
will not work, because it seems the URL string the filter is using is truncated at the "#".
Can anyone tell me if it's possible to make this work.

Answer 1

The browser doesn't send the hash to the server, as you've discovered. Watching a given request, you'll see that it only sends along the url before the # symbol.
GET / HTTP/1.1
Host: example.com
...
From the link you mentioned:
Hash fragments are never (by specification) sent to the server as part of an HTTP request. In other words, the crawler needs some way to let your server know that it wants the content for the URL www.example.com/ajax.html#!key=value (as opposed to simply www.example.com/ajax.html).
From the descriptions in the text, it is the server's job to translate from the 'ugly' url to a pretty one (with a hash), and to send back a snapshot of what that page might look like if loaded with a hash on the client. That page may have other links using hashes to load other documents - the crawler will automatically translate those back to ugly urls, and request more data from the server.
So in short, this is not an change you should need to make, the GoogleBot will make it automatically, provided you have opted into using hash fragments. As for other bots, apparently Bing now supports this idea as well, but that appears to be outside the scope of your question.