.htaccess mod_rewrite variables through redirect

Short Version:

I wrote the question, and realized most people wouldn't want to read that much text. Consider the below reference, here's the TL;DR:

I need to 301 redirect this url http://app.com/search/foo-bar/

to this url http://app.com/#!/search/foo-bar/

and send this: /foo-bar/, or anything else past /search/ to a server side script. In this case, it's written in php.

Edit for clarity:

Current answers seem to focus on the rewrite to hashbang. That part is not the problem. The problem is that I lose any associated data when rewriting to a hashbang url, as the server side will see app.php as the location, not app.php/#!/foo-bar/ - So I need to capture foo-bar, and send it to the server somewhere other than in the URL. The rewrite works, and is not the issue. Thanks for your answers though!

Long Version:

Ok, so I have an interesting issue that has been tough for me to figure out.

The Scenario:

I have a backbone.js app that uses the hashbang for state:

app.com/#!/search/search-term/key-value/foo-bar/

In addition, I have google traffic coming to the site from the previous version that will be hitting "pretty url" style urls:

app.com/search/search-term/key-value/foo-bar/

I use an .htaccess mod_rewrite to swap the old url out for a hashbanged one if a user hits the legacy url.

I recently introduced a javascript-less bootstrapped version of the site that the site will be built on top of to gracefully downgrade and support crawlers. This is written using php.

For the php site to work, I need to pass in the values past the hashbang to the server side script, so I can figure out what to display.

The Problem:

When I transform a url and add an anchor, everything past the anchor (hashbang) is no longer sent to the request, so I don't have access to it in php.

RewriteRule search/?(.*) #!/search/$1 [R=301,NC,L]

My options for sending things to the server side then are reduced to: 1. Query String 2. Environment Variables 3. Headers

So, I tried sending things via the query string

RewriteRule search/?(.*) #!/search/$1?filter=$1 [R=301,NC,L]

Obviously that didn't work (the query is behind the anchor), so I tried it in front of the hashbang

RewriteRule search/?(.*) ?filter=$1/#!/search/$1 [R=301,NC,L]

That works, but is hideous and redundant to the end user. So, I thought I might try using environment variables.

RewriteRule search/?(.*) /!#/search/$1 [R=301,NC,L,E=FILTER:$1]

That failed, because environment variables aren't preserved through a redirect (duh). I turned to using headers:

RewriteRule search/?(.*) /#!/search/$1 [R=301,NC,L,E=FILTER:$1]

Header set filterParams "%{FILTER}e"

But for some reason, the headers aren't received by the page through the redirect. That seemed to make sense (although I've now stepped well outside of my comfort level with apache directives), so I tried echoing the header, in hopes that it would be passed, received by the second rewrite (that didn't find search), and echoed out.

RewriteRule search/?(.*) /#!/search/$1 [R=301,NC,L,E=FILTER:$1]

Header set filterParams "%{FILTER}e"

Header echo filterParams

Nada - the filter doesn't exist, so although it makes it to the server, it is null. My next thought was to attempt to employ some sort of conditional. Here was my attempt:

RewriteRule search/?(.*) legacy.php/#!/search/$1 [R=301,NC,L,E=FILTER$1]`

<FilesMatch "legacy.php">
    Header set filterParams "%{FILTER}e"
</FilesMatch>

Header echo filterParams

That didn't seem to work either, so I'm stumped. I realize that I've spent so long on this that I probably have the solution within my grasp and I'm just tired of looking at it, or it's not even remotely possible, even with gross header hacking.

Anyone have a clue how to to this?

rfc1738.txt says # is not a valid url character

additionally the apache docs says # signals a comment in apache config files.

short answer is your solution is broken not your implementation

AFAIK, there's no good way to preserve variables through redirect without sticking them in the query string...