Does anyone have any suggestions (or a regular expression) for parsing the HTTP Accept header?
I am trying to do some content-type negotiation in ASP.NET MVC. There doesn't seem to be a built in way (which is fine, because there are a lot of schools of thought here), but the parsing is not entirely trivial and I would rather not re-invent the wheel if someone has already done it well and is willing to share.
The RFC is quite complex. If the regex where to follow these rules to the letter, it would become several lines long.
If you already have the Accept-header, and ignore the quotes and the parameters, you could do something like this to match each pair:
/([^()<>@,;:\\"\/[\]?={} \t]+)\/([^()<>@,;:\\"\/[\]?={} \t]+)/
* is included in the character class, so it does not need any special case in the regex.
Have you seen this article? It gives a pretty comprehensive implementation for parsing the Accept header and subsequently doing something useful with it.
I've written a parser in PHP. It's not complex, but it will give you an array of mime types in order of preference.