asp.net - Can I use commas in a URL?

Question

I typically use URL rewriting to pass content IDs to my website, so this

 Foo.1.aspx 

rewrites to

 Foo.aspx?id=1

For a specific application I need to pass in multiple IDs to a single page, so I've rewritten things to accept this:

 Foo.1,2,3,4,5.aspx

This works fine in Cassini (the built-in ad hoc web server for Visual Studio) but gives me "Internet Explorer cannot display the webpage" when I try it on a live server running IIS. Is this an IIS limitation? Should I just use dashes or underscores instead of commas?

Answer 1

Commas are allowed in the filename part of a URL, but are reserved characters in the domain*, as far as I know.

What version of IE are you using? I've come across the odd report of IE5.5 truncating URLs on a comma (link here, but have tested URLs with commas in IE7 and it seems to be OK, so if there was an IE bug, it doesn't seem to be there any more - could it be an IIS issue?

I'm wondering if the page error is due to a rule failure with the mod_rewrite - can you post the rule which is matching multiple ids and passing them off to your Foo.aspx? Is there any chance that it's only matching Foo.N,N, and failing on more commas?

---

* From the URI RFC:

2.2. Reserved Characters

Many URI include components consisting of or delimited by, certain special characters. These characters are called "reserved", since their usage within the URI component is limited to their reserved purpose. If the data for a URI component would conflict with the reserved purpose, then the conflicting data must be escaped before forming the URI.

 reserved    = ";" | "/" | "?" | ":" | "@" | "&" | "=" | "+" |
                "$" | ","

The "reserved" syntax class above refers to those characters that are allowed within a URI, but which may not be allowed within a particular component of the generic URI syntax