Fixing Chrome's content-disposition comma issue in IIS - google-chrome

Question

Chrome from version 16 became pretty strict on content-disposition headers having unquoted commas. While most sites out on the web will face user pressure to fix their servers this is not so easy for small or in-house intranet applications that no one is quite willing to touch.
Thread on Chrome's forum about the issue, what works and what doesn't.
Short answer is that the Content-Disposition header, if included, needs to either not have commas in the filename or have filenames quoted.
We have one such system handling document management, touching the codebase is NOT an option, but any files with commas in their names will throw an error in Chrome. how can I fix this?
Doing a bit of a Jeopardy! thing here but not 100% confident on my answer and would appreciate comments/alternatives

Answer 1

You could do this using IIS's URL Rewrite module which can also work on headers.
The key will be to match on Content-Disposition which includes filename= and doesn't have quotemarks for the filename.
<system.webServer>
<rewrite>
<outboundRules>
<rule name="Chrome Comma Fix">
<match serverVariable="RESPONSE_Content_Disposition" pattern="^(.*)(filename=)(?!")([^"]*)(;.*)?$" />
<action type="Rewrite" value="{R:1}{R:2}"{R:3}"{R:4}" />
</rule>
</outboundRules>
</rewrite>
</system.webServer>
I haven't yet tested this though.