Rewrite rules in ISS's web.config - iis

Question

I'm just trying to get some code running on ISS that has been running on Apache for a long time.
A particular mod_rewrite rule is proving difficult to get working.
In Apache I've used:
RewriteRule ^media/(js|css|img|font)/(.+)\.(\d+)\.(js|css|png|jpg|gif)$ /media/$1/$2.$4
[L]
To turn a URL like /media/css/style.1367406756.css into /media/css/style.css, letting me put timestamps in the files to avoid caching issues.
In my web.config file I've added:
<rule name="Cache bust assets" stopProcessing="true">
<match url="^(.*)$"/>
<conditions>
<add input="{URL}" pattern="^media/(js|css|img|font)/(.+)\.(\d+)\.(js|css|png|jpg|gif)$"/>
</conditions>
<action type="Rewrite" url="/media/{R:1}/{R:2}.{R:4}" appendQueryString="true" />
</rule>
Which, looks like it should work. (It's alongside another rule, which works fine, so it's not that the server isn't parsing it or anything).
I don't get any errors, other than visiting /media/css/style.1367406756.css gives me a 404 error.
How Can I make this work?

Answer 1

You use {R:N} back references in your action when you should use {C:N} since the information comes from the conditions. See Using Back-references in Rewrite Rules for more information.
You can see this error if you open the iismanager console:
To get your rule to work you have 2 solutions.
First you can change your action to (using {C:N}):
<action type="Rewrite" url="/media/{C:1}/{C:2}.{C:4}" appendQueryString="true" />
Or (and I do think it is a better solution), you can use the Import mod_rewrite Rules tool.
In the iismanager console, click on Import Rules... (on the right tab) and paste your apache rule:
This will create for you the following rule:
<rule name="Imported Rule 1" stopProcessing="true">
<match url="^media/(js|css|img|font)/(.+)\.(\d+)\.(js|css|png|jpg|gif)$" ignoreCase="false" />
<action type="Rewrite" url="/media/{R:1}/{R:2}.{R:4}" />
</rule>