Talk:Opening files using plugins

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Intro

Alice, I have changed a couple of words in this article. I have tried to make a distinction between downloaded files and directly-visited files, since the MIME type sent with visited files comes from the web server whereas the MIME type associated with a downloaded file is either provided by the operating system or does not exist. Are you happy with this?

Also, the first paragraph of the Flash section could be tweaked so that it is not Flash-specific, and then I think it could be added to the intro of the article. What do you think? --Mozcerize 10:26, 31 May 2006 (UTC)

Thanks for bringing up that the term "downloaded files" wasn't very specific, as it can also be applied all files downloaded as part of a web page, even embedded files, while "directly-visited" specifies direct links ending in the name of the file, if I understand it right. Go ahead and tweak the rest of article any way you think works best, it's turning out nice :) Alice Wyman 11:59, 31 May 2006 (UTC)
Yep, that's what I meant by "directly-visited". (I don't much like the term, but I can't think of anything nicer that conveys the idea as well.) I agree that it's turning out nice; this iterative approach is exactly the way I always hoped that editing the KB would work! :-)

Misconfigured web server

[Alice wrote (below)] I'm thinking to change the "Windows Media Player" heading from the article to "Misconfigured server" and talk about text/plain mimetypes resulting in plugins not being used, with Mozilla prompting you to chose an application or save the file. I like this approach. --Mozcerize

Macromedia Flash

Mozcerize, I was wondering where you came across this issue and solution. I was hoping you might have a forum thread reference, or maybe, since you described this as a "bug", you might have a bugzilla report. Also, you say that this ... will cause the File Download dialog box to be displayed, asking the user to choose whether to save the file or open it in a suitable application. (If this occurs, there is no way of instructing the browser to run the file directly. What about suggesting that the user try the "Resetting media file handling" solution given in the Changing_media_handling_behaviour article as a first step? Resetting those two preferences (not sure if he also deleted the mimetypes.rdf) DID work for someone with a similar problem with the Quicktime plugin not opening a direct link, reported here. Alice Wyman 21:21, 15 May 2006 (UTC)

Hi Alice. This issue affected all the Win9x machines that I administer. Posts from others experiencing this problem can be found here and here, and there were several other threads that I found. (Search for swf or Flash, together with the words open or download or run.) There is one relevant unconfirmed bug report here, but I didn't link to it because I was the proposer of a solution there, and it seemed a bit silly pointing to a page which just mimics the solution of this article, at least until the bug gets confirmed status. If you dislike my use of the word "bug" in this article, feel free to change it to "reported issue" or whatever.
Note that this issue is rather different from the usual Flash-related issues in that Flash will work properly when embedded, but will fail to load in the plugin when run directly within the browser. In particular, the other posters experiencing the problem all report that it occurs after upgrading to Fx 1.5 from Fx 1.0 without first uninstalling Flash. The QuickTime problem certainly seems to be similar; however, reinstalling QuickTime did not solve the problem, whereas reinstalling Flash did, so perhaps they are not identical.
I did not suggest resetting the preferences as per the Changing media handling behaviour because that route is more destructive than reinstalling Flash, in that it affects other settings (unrelated to Flash) that the user may have in place. However, it would certainly be interesting to find out whether resetting those preferences can solve the problem, or whether the mimetypes.rdf file is relevant here. Unfortunately I no longer have any unfixed machines to test this on.
I suggest that the Changing media handling behaviour article should be linked to from this article, perhaps as a See Also. --Mozcerize 17:31, 22 May 2006 (UTC)
Thanks for the references. I changed the Flash "bug" to "reported issue" and linked to the bugzilla report (hope that was OK) plus I added the QT issue to the article. Alice Wyman 00:04, 23 May 2006 (UTC)

Disabled plugin for download actions

[Alice wrote (below)] I was also thinking to change the Quicktime heading to something like "Disabled plugin for download actions" because those preferences have to do with other plugins. I think we should perhaps divide this section into two. Presumably one problem that can occur is that a user forgets that they've disabled the plugin for certain downloads, and can solve the issue by simply enabling it again. This would correspond to the first sentence of the section. The QuickTime issue seems to me to be separate, in that the user might think that he's disabled the plugin via Download Actions, but it turns out that he hasn't (at least, not intentionally) and has to resort to resetting preferences etc. --Mozcerize 10:26, 31 May 2006 (UTC)

I have split this into two sections accordingly: these are "Plugin disabled for certain files via Download Actions" and "Problematic browser preferences". --Mozcerize 15:07, 31 May 2006 (UTC)

How does Firefox deal with MIME types?

Hi Alice,

Do you know whether the "Add and Edit actions" list of of the Downloads tab of Firefox Options overrides MIME types? For example, if a WMV file is sent as text/plain but is listed in the Options as "Always open with Media Player plugin", will it be displayed as garbage or run in the plugin? Or will the user be promted to open/save it, due to the old "workaround" described in the bug you posted to opening files using plugins? --Mozcerize 11:29, 26 May 2006 (UTC)

Hi, M,
Here is how I understand it, and I'm still learning as I go along: If a wmv file is sent as text/plain it used to display as garbage in Mozilla 1.6 and Firefox 0.8 (or earlier). It made no difference what the Firefox Download Actions list had set for wmv files, as the .wmv extension is really the "video/x-ms-wmv" mimetype, and Firefox was seeing the file as text/plain, which it handles internally. The Download Actions listing is really based on mimetypes, not extensions, although mimetypes are easy to overlook in the Change Action box and are hidden in the listing unless you know where to click. In Mozilla Suite, the helper application preferences are listed ONLY by mimetype, which caused lots of confusion!
The FIX to Bug 220807 - Prompt user about invalid text/plain content - solving most incorrect MIME type issues now allows Mozilla and Firefox to guess at the correct filetype based on extension and other information when "text/plain" doesn't seem to fit, with the result being you get the "Opening" box to confirm opening the file in the default applicatiion for the guessed-at filetype. In these "special" situations where Firefox is inferring the type of file and not using the mimetype sent, it will present the "opening" dialog.
On the two preferences: From what I've gathered and from playing around with the View &Edit Actions window with an about:config screen opened , when you change the action for a mimetype normally opened in the plugin to a different action, the mimetype is entered as a value for the plugin.disable_full_page_plugin_for_types preference as shown in about:config. With ASX (two mimetype entries) and the PDF entry set to open in the default app and not the plugin, the preference value shows application/pdf,video/x-ms-asf,video/x-ms-asf-plugin. If I then reset the preference, the download action for the associated extensions changes back to the plugin. Bypassing the plugins for direct downloads is a "Firefox only" feature, and apparently gets set in prefs.js and not mimeTypes.rdf. I have no idea when the other preference, browser.download.pluginOverrideTypes is used, by the way, and I only learned of these two preferences from Vectorspace's posts. Alice Wyman 00:22, 27 May 2006 (UTC)
Hi Alice, thanks for the reply.
The Download Actions listing is really based on mimetypes, not extensions, although mimetypes are easy to overlook in the Change Action box and are hidden in the listing unless you know where to click
I didn't realise that this was still the case, seeing as the mime types are cunningly hidden unless, as you say, you choose to display that column.
[…] now allows Mozilla and Firefox to guess at the correct filetype based on extension and other information when "text/plain" doesn't seem to fit
So it could be the case that some people experiencing the "load swf files directly" problem may indeed be having the swf file sent with the wrong mime type, although there have been lots of people experiencing it where the file is definitely sent with the correct one. (So the former situation is "correct" whereas the latter is a "bug".)
If I then reset the preference, the download action for the associated extensions changes back to the plugin. Bypassing the plugins for direct downloads is a "Firefox only" feature, and apparently gets set in prefs.js and not mimeTypes.rdf
Indeed, my experiences with mimeTypes.rdf have certainly indicated to me that this file isn't actually relevant to a lot of problems which are apparently related to mime types!
There's a guy having problems over at https://bugzilla.mozilla.org/show_bug.cgi?id=304311, and it would be interesting to lead him through the steps to a possible solution, in an attempt to figure out how important those preferences are. --Mozcerize 10:46, 30 May 2006 (UTC)
So it could be the case that some people experiencing the "load swf files directly" problem may indeed be having the swf file sent with the wrong mime type, although there have been lots of people experiencing it where the file is definitely sent with the correct one. (So the former situation is "correct" whereas the latter is a "bug".)
I did a groups.google search showing that the same thing that happens with wmv files happens with .swf flies, when sent with the text/plain mimetype. I'm thinking to change the "Windows Media Player" heading from the article to "Misconfigured server" and talk about text/plain mimetypes resulting in plugins not being used, with Mozilla prompting you to chose an application or save the file. I was also thinking to change the Quicktime heading to something like "Disabled plugin for download actions" because those preferences have to do with other plugins. About that guy from the bugzilla report, why don't you refer him to the mozillazine article after I change it? Also, maybe this discussion should be copy/pasted to the talk page of the article, if that's OK with you? Alice Wyman 00:46, 31 May 2006 (UTC)
Done! --Mozcerize 10:26, 31 May 2006 (UTC)

What exactly does Download Actions do?

Or rather, if a file type (or MIME type) is missing from the list of Download Actions, what effect does this have on running media files? It appears from the QuickTime case discussed in the article that a missing Download Action does not necessarily prevent Firefox from running the file via the plugin. That's why I've put the caveat "which does not necessarily signify a problem" when discussing this. It would be good to get a comprehensive description of the nature of Download Actions, because the article Changing media handling behaviour is fairly loose at the moment. (I think further discussion of Download Actions should probably take place on that talk page.) --Mozcerize 15:07, 31 May 2006 (UTC)

I can't get into it now as hubby is pulling me out the door (we're meeting a friend in NYC) so I'll just say maybe you can ask Vectorspace to take a look at the article. I'll be back later tonight. Alice Wyman 15:00, 3 June 2006 (UTC)
To get back to your question, Download Actions as I understand it, is evolved from the old Mozilla Suite "Helper Applications" preference panel fo choosing how to deal with media files that couldn't be handled internally or via a plugin, by selecting an external "helper" application or setting the type to be saved to disk. Firefox has added the ability to disable plugins from opening direct file downloads, by letting you change the opening action from the plugin to something else. Not all MIME types are listed in the Download Actions window... by default, types without associated file extensions (such as Java MIME types) are left out unless you set the preference browser.download.hide_plugins_without_extensions to "false". I've noticed that sometimes when you change the Firefox download action, for example, for the file extension ASX (there are three ASX entries listed) for the MIME type video/x-ms-asf, that ASX entry disappears from the list, leaving the two remaining ASX entries for video/x-ms-asf-plugin and application/x-mplayer2. I've noticed entries disappearing from the Download Actions list other times after disabling the plugin in Firefox. I just tried disabling the audio/mp3 MIME type (one of six for .MP3) and three of the MP3 entries disappeared from the list! Then I changed the action for .SWF to "save to disk", and it too it disappeared from the list. Restarting Firefox (1.5.0.4) got the entries to reappear so that should be added to the article. Resetting the preference plugin.disable_full_page_plugin_for_types got the entries to reappear also, and reset the action back to the default ,opening in the plugin. I asked Vectorspace to add his thoughts. Alice Wyman 12:15, 4 June 2006 (UTC)
Hi Alice, thanks for your thoughts. On my system I have found that if I modify the Download Action for mp3 (audio/mpeg) files to either "Save to disk" or "Open in external app" then the list shows this changed action but then OKing the list and reopening it results in that MIME type not being displayed in the list. Making these manual changes causes the pref "'plugin.disable_full_page_plugin_for_types" to be created and the MIME type audio/mpeg to be added to that pref. Resetting the pref causes the MIME type to reappear in the Download Actions list (and set to open in the QuickTime plugin). However, I too am having the same problem as the poster in the forums where Vectorspace originally suggested resetting the two preferences: no matter what I do I cannot force directly-visited audio/mpeg files to open using the QuickTime plugin. Instead, I am always presented with the "Opening" dialog. Moreover, manually changing the Download Actions as I just described does not change this behaviour! It's the "Opening" dialog again. (Note that I have no such problem with non-media types: I can have e.g. PDFs, ZIPs, DOCs set to save to disk, and I can see that action in the list and I get presented with the "Save file" dialog instead of the "Opening" dialog, as expected.)
Regarding the disappearing entries in the list, I found that restarting the browser did not cause them to reappear. Resetting the prefs was the only way that I could do this.
I note here that I have never had the pref "browser.download.pluginOverrideTypes" present in about:config, and none of the messing around that I've described caused it to be created. On the other hand, I'm sure I remember seeing that pref on my other (work) computer. Additionally, deleting mimetypes.rdf made no difference at all to the situations that I described above! These plugin problems seem complex...! --Mozcerize 19:48, 4 June 2006 (UTC)


Vectorspace here: Basically, download actions are automatic settings on how to treat downloaded files.

When you download a file, there is a 'do this automatically from now on for files of this type' option. Every time you select that option, it adds the association to the Download Actions where it can be edited and deleted.

For file types for which you have a plugin, associations will have already been created - the default being to open the file in the browser using a plugin (much like how pdf files display in the browser)

You have the option of saving to disk, opening with the default external application, opening with a specified external application, or opening with the plugin. The plugin option is only available if a plugin for that file type exists.

Occasionally plugin entries will disappear from the list if changed, but I was never able to reliably reproduce it so I was never able to find the cause. Resetting the two preferences that Alice listed will restore them.

Cheers for the explanation. That sounds like how I would expect Download Actions to work. It's a pity that things don't always turn out like that though! --Mozcerize

Plugin disabled for certain files via Download Actions & WMP plugin

The first line reads: "Firefox allows you to change the Download Actions for media files,"

it's not just media files, but most any file type that you have a plugin for (but not all - I was never able to figure out why).

Which ones are missing? (Is this related to the disappearing entries problem discussed above?) As for the "media files" bit, I put that in just because that was what the article was focussed on. Alice has since changed this. --Mozcerize

Another thing - the WMP plugin, when loaded from a direct link, will not appear in the page and display the file like other plugins - it will just appear as a blank page, download the whole file, and then hand it off automatically to the default media player for that file type. --Vectorspace

Cheers for this info. We should add this to the article. --Mozcerize
I never realized that, since I've always had Windows Media Player set as the default player for wma, wmv, asf, etc. I test just now by reassociating .wma with WinAmp and then opening http://wymette.home.att.net/files/sample.wma and V is right (son-of-a-gun!). Alice Wyman 20:24, 4 June 2006 (UTC)