231886 - Allow extensions to add extension->type mappings

Status: RESOLVED FIXED

(Core Graveyard :: File Handling, enhancement)

Description

[Christian :Biesinger (don't email me, ping me on IRC)]

(especially useful for image decoders)

It would be nice if there was a way for extensions to add a extension->mimetype
mapping, so that mozilla can find the right content type for local files.

I have a patch that allows adding an entry in the mimetype-mapping category,
name is the extension, value the mime type.

would be used by getTypeFromExtension when the other methods fail.

Comment 1

[Christian :Biesinger (don't email me, ping me on IRC)]

Attachment: patch

note that this makes GetTypeFromExtension return NS_ERROR_NOT_AVAILABLE in all
cases when it can't find a mapping.

Comment 2

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 139696 [details] [diff] [review]
patch

r=bzbarsky if you rename the category to "ext-to-type-mapping".

I wish we could make plugins use this so we don't have to special-case them
earlier in this code...

Comment 3

[Christian :Biesinger (don't email me, ping me on IRC)]

Comment on attachment 139696 [details] [diff] [review]
patch

hm, that sounds like a good idea... I'll file a new bug to make plugins use
this code, once I checked this in

Comment 4

[Darin Fisher]

Comment on attachment 139696 [details] [diff] [review]
patch

>Index: nsExternalHelperAppService.cpp

>+  if (NS_SUCCEEDED(rv)) {
>+    return info->GetMIMEType(aContentType);
>+  }
>+  // Let's see if an extension added something
>+  nsCOMPtr<nsICategoryManager> catMan(do_GetService("@mozilla.org/categorymanager;1"));
>+  if (!catMan)
>+    return NS_ERROR_NOT_AVAILABLE;
> 
>+  return catMan->GetCategoryEntry("mimetype-mapping", aFileExt, aContentType);
> }

how about writing this like so:

  ...
    if (NS_SUCCEEDED(rv))
      rv = info->GetMIMEType(aContentType);
    else {
      // Let's see if an extension added something
      nsCOMPtr<nsICategoryManager>
catMan(do_GetService("@mozilla.org/categorymanager;1"));
      if (!catMan)
	rv = NS_ERROR_NOT_AVAILABLE;
      else
	rv = catMan->GetCategoryEntry("mimetype-mapping", aFileExt,
aContentType);
    }
    return rv;
  }

i think this is plenty clear, and it'll help GCC reduce codesize.  you can do
what
you like with the braces... the file doesn't seem to be very consistent :-/

sr=darin

Comment 5

[Darin Fisher]

hmm.. should the category name use some sort of namespace?  nsICategoryManager
is frozen and technically embeddors can come up with whatever category names
they like.  i don't think we have much of a convention in our source code, but
it seems like we should.  <== this probably deserves another bug

Comment 6

[Christian :Biesinger (don't email me, ping me on IRC)]

ok, patch checked in with the changes from comment 2 and comment 4 done.

Bug 233289 filed for the plugin question from comment 2.
Bug 233290 filed re comment 5.

Comment 7

[Eric Liga]

The description claims that this mapping is to help find the right content type
for local files-- should it also work for files served up remotely without a
MIME type?

If not, is there a way to provide default mappings for those?

Comment 8

[Eric Liga]

Or perhaps what I'm running up against is the situation where something is
getting served up with MIME type 'text' because of the Apache default settings
and Moz is detecting that it's not really text and kicking it back to the user.

I'm guessing that process doesn't check against this list?  Is there some way
for an extension to get involved in that process and claim the file?

Comment 9

[Christian :Biesinger (don't email me, ping me on IRC)]

yes, files sent without a mime type should also be covered by this.

content sent as text/plain but sniffed as non-text will never get handled by the
browser.