410903 - unknown plugin text/html after "Install missing plugins"

Status: RESOLVED WONTFIX

(Toolkit Graveyard :: Plugin Finder Service, defect)

Description

[mozbugs]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9b3pre) Gecko/2008010405 Minefield/3.0b3pre
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9b3pre) Gecko/2008010405 Minefield/3.0b3pre

When visiting the URL given in the URL field, the "Additional plugins are required to display all the media on this page" bar comes up. If I do "Install missing plugins..." it searches for a plugin, but then reports "unknown plugin text/html". If I reload the page afterwards, the plugins bar does not come up. 

I experienced the problem only on the spiegel.de site (which is probably the most often visited news site in Germany) up to now. The problem also occured with the last build I used (which was a 3.0 nightly about 6-8 weeks old).

Although spiegel.de is typically well-behaving concerning ads and web-standards (they report the high Firefox usage on their site regularly), I think this could have to do with one of their ad providers trying to overcome the popup blocker.

Reproducible: Sometimes

Steps to Reproduce:
1. open URL
2. click plugin bar

Actual Results:  
see "unknown plugin text/html"

Expected Results:  
No plugin bar, or if it is caused by a popup, block/report it as a popup.

Active Addons:

The only addon that is non-standard and active in my Minefield installation is "Flashblock 1.5.5". Other active ones are DOM Inspector and Javascript Debugger.

Installed plugins:

Shockwave Flash  Shockwave Flash 9.0 r47
DivX® Web Player
RealPlayer(tm) G2 LiveConnect-Enabled Plug-In (32-bit) 
RealPlayer Version Plugin  6.0.12.1739
VLC Multimedia Plugin Version 0.8.6b
Java(TM) 2 Platform Standard Edition 5.0 Update 6
Adobe Acrobat Plug-In Version 7.00 for Netscape

Comment 1

[Matthias Versen [:Matti]]

wfm with a 2 days old Seamonkey trunk and also with FF2.0.11 (hit reload a few times)
BTW: You should upgrade your plugins because of possible security problems (Flash r47, Java5.0 and Acrobat 7.0 are old)

Comment 2

[mozbugs]

Is Seamonkey trunk on par with Minefield concerning plugin handling or the plugin finder? Also notice that the plugin bar is gone on reload even for my installation.

Are there any traces I can enable that would bring additional info? Anything I can check in the source code of the page, when the problem occurs?

Also updated the plugins (although that's probably unrelated).

Comment 3

[Matthias Versen [:Matti]]

That a plugin find process is started depends on Gecko and that means that there are no differences between Seamonkey and Firefox.

You can trigger this if you have a page with:
<embed src="http://mozilla.org" autostart="true" hidden="true">

In short: if you have a <embed> and maybe also a <object> URL where the server responds with a text/html mime-type.That can also be a broken ad-server which responds with a text/html instead of a flash file (html error code pages should not be affected by this)

Comment 4

[mozbugs]

I'll check the embed and object tags next time I see it.

Shouldn't the browser display text/html embedded objects itself? At least that would make the problem more obvious.

Could the ad-server try to use text/html instead of flash, because it notices that flash is blocked? I. e. could Flashblock be a prerequisite (while having Flash installed) to see the problem?

Comment 5

[Matthias Versen [:Matti]]

using a plugin for text/html could be used for examaple for a svg plugin...

It could be caused by flashblock and disabling flashblock may only help if you also clear the browser cache.

Comment 6

[mozbugs]

Attachment: OBJLC Log of a Beta2 Debug build, shortened

Attaching an OBJLC log of a debug build based on Beta2. IMHO the following is the relevant part:

0[bb4b20]: OBJLC [c3ea26c]: Loading object: URI string=<about:blank> notify=1 type=<> forceload=1
0[bb4b20]: OBJLC [c3ea26c]: Loading object: URI=<9da37e0> notify=1 type=<> forceload=1
0[bb4b20]: OBJLC [c3ea26c]: Capabilities: 002b
0[bb4b20]: OBJLC [c3ea26c]: Channel opened.
0[bb4b20]: OBJLC [c3ea26c]: Notifying about state change: (2, 0) -> (0, 200000) (sync=0)
0[bb4b20]: WARNING: Components.lookupMethod deprecated, use Components.utils.lookupMethod: file c:/mozilla-build/mozilla/ff-debug/js/src/xpconnect/src/../../../../../js/src/xpconnect/src/xpccomponents.cpp, line 4039
0[bb4b20]: OBJLC [c3ea26c]: OnStartRequest: Content Type=<text/html> Old type=0 New Type=4
0[bb4b20]: OBJLC [c3ea26c]: Unsupported type, falling back
0[bb4b20]: OBJLC [c3ea26c]: Falling back (Notify=0)
0[bb4b20]: OBJLC []: Dispatching nsPluginErrorEvent for content c3ea250
0[bb4b20]: OBJLC [c3ea26c]: Notifying about state change: (0, 200000) -> (4, 440000) (sync=0)
0[bb4b20]: OBJLC []: Firing plugin not found event for content c3ea250

I could not reproduce it since then, not sure whether it was because of using a more recent nightly or the site fixing some content-type issue.

Comment 7

[Roman R.]

I've seen this on FF 3 beta with the latest one being 2008030405. For me, it happens on the new Yahoo Mail. Happens very often.

Comment 8

[Roman R.]

Using 20080312 on new Yahoo Mail. Is this a Firefox's bug or is Yahoo doing something wrong?

Please confirm this report and set its priority to higher than normal as this is very annoying.

Comment 9

[Andrew Marshall]

I can confirm that this occurs on Mac OS 10.5.3 using Firefox 3 RC1 as well. This happened about two days ago. I have also experienced it many times occurring on WinXP in FF2 and the FF3 betas.

Comment 10

[Roman R.]

I haven't experienced this for a long time.

Comment 11

[Denis Bigeard]

I have the same error with firefox3 and NOT with previous versions.....
html pages of my site have a meta-balise as :
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
and firefox3 says "plugin necessary" then "plugin text/html not found"

I don't think this plugin exists nor it is necessary.... (not in firefox2....)

balise "embed" in other frame for midi music is correctly played in each versions of firefox and does't seem to be the problem....

so i had a downgrade to firefox 2.0.0.14 to avoid the messages.....
thanks...

Comment 12

[Denis Bigeard]

my site :
http://dodosvolants.free.fr

Comment 13

[mozbugs]

I think this is due to the 
<embed src="" autostart="true" volume="100" align="center" width="10" height="10" loop=""> 
that you have in
http://dodosvolants.free.fr/mailto.htm

Firefox seems to move the <embed src="">, although it is inside a comment after the </html> tag, inside the HTML to display (you can see this using DOM Inspector). As the src="" refers to the mailto.htm page, you get the plugin finder request. So just remove this part completely and the plugin finder request should be gone.

Comment 14

[Justin Dolske [:Dolske]]

Bug 836415 has now removed the Plugin Finder Service (PFS) from Firefox. As a result, I'm closing all the remaining PFS bugs.

If you're getting this bugmail for an ancient PFS bug, the basic summary of the world today is:

* NPAPI plugins are a dying technology
* PFS was already restricted to assisting with only the 4 most common plugins
* Sites commonly provide their own UI for install a required plugin
* Mozilla is generally focusing on  improving the web platform so that proprietary plugins are not required.

(Note that "plugins" are a completely separate from "browser extensions", such at those found on addons.mozilla.org. The latter are not going anywhere, and are not impacted by the removal of PFS.)