Add extensions for obsolete mimetypes

[danny0838]

Sometimes we'd want to lookup a file extension from a given mimetype. For example, we want to get "js" if we are given a mimetype "text/javascript". This is currently not possible since the "extensions" key for "text/javascript" is not defined.

I'd suggest that we define an obsolete mimetype, such as "text/javascript", like this:

"text/javascript": {
  "source": "iana",
  "compressible": true,
  "obsolete": true,
  "extensions": ["js"]
},

So that the application is able to get an extension when "text/javascript" is given. If the application wants to reversely look for the mimetype for "js", it can ignore the "text/javascript" according to its "obsolete" value.

We can optionally add a "canonical": "application/javascript" to indicate what this obsolete mimetype is now redirected to.

[dougwilson]

We're not willing to manually maintain a list like this. The purpose of this database is to aggregate sources though the build scripts. Is there a source somewhere we can scrape this data from?

[danny0838]

The IANA source have most of the information. For example, the "text/javascript" template page contains a line of "File extension(s): .js" and a line of "Intended usage: OBSOLETE".

[dougwilson]

Ah, so it sounds like this can be just adding some additional scraping rules into the IANA scraper.

[danny0838]

I did a little check and it seems that many mimetypes defined by IANA also have file extensions missing, such as application/cccex (.c3ex) and text/vnd-curl (.curl).

Another problem could arise is that how do we merge the file extensions if they are defined differently in IANA, Apache, and nginx sources?

[dougwilson]

I assume just list them all unless there is another suggestion.

[danny0838]

I am not sure how you currently do it. I would suggest:

1. Add the extensions listed by IANA using the order IANA suggests.
2. Append the extensions listed by Apache and not listed by IANA using the order Apache uses.
3. Append the extensions listed by nginx and not listed by IANA and Apache using the order nginx uses.

(Assume the priority is IANA >Apache >ngnix)

[dougwilson]

I believe that is what the build script does already 👍

[danny0838]

This issue is here for a year. Any plan on it?

[dougwilson]

Just make a pull request updating the build script to pull the data on if types are obsolete from the IANA database, right?

[danny0838]

I think so. Are you going to implement it?

[dougwilson]

Perhaps one day if I have the time and desire to. If you want to see it earlier, feel free to implement 👍