Topic on Extension talk:MultimediaViewer

Does MultimediaViewer work on private wiki?

Seanchen (talkcontribs)
Tgr (WMF) (talkcontribs)

It should work fine, If it doesn't, please file a bug with the details.

Seanchen (talkcontribs)

@Tgr thanks for the quick reply!

Here are some more details about this issue, could you help take a look to see if you have any clue.

I am working on the MediaWiki version 1.26.2 and download MultimediaViewer at version 0.3.0.

I did set up the img_auth.php to protect the access to media files. As long as user logged in, user could view the media file without problem. For example: But when logged in user try to view the same image on MultimediaViewer, we got this massage:

There seems to be a technical issue. You can retry or report the issue if it persists. Error: could not load image from

And I could see failed to load resource error on Chrome console:

Failed to load resource: the server responded with a status of 403 (Forbidden)

It might have something to do with my Ngnix's configuration. I will double check...

Is there any configuration on MultimediaViewer related to this?

If you still think it is a issue, I will file a bug for it.

thanks a lot,


Tgr (WMF) (talkcontribs)

Disabling $wgMediaViewerUseThumbnailGuessing might help, but it should not be necessary, and it's the default anyway.

Might be a problem with how MediaViewer uses CORS. Could you try to edit resources/mmv/provider/mmv.provider.Image.js to change imagePreloadingSupported to always return false, and see if that fixes it?

Nelmonk (talkcontribs)

I had the same issue as @Seanchen, and set to false as follows (which solved the problem):

if ( !this.cache[ cacheKey ] ) {

if ( this.imagePreloadingSupported() ) {

rawGet = provider.rawGet.bind( provider, url, false );

this.cache[ cacheKey ] = this.performance.record( 'image', url, extraStatsDeferred ).then( rawGet, rawGet );

} else {

start = ( new Date() ).getTime();

this.cache[ cacheKey ] = this.rawGet( url );

this.cache[ cacheKey ].always( function () {

provider.performance.recordEntry( 'image', ( new Date() ).getTime() - start, url, undefined, extraStatsDeferred );

} );

Seanchen (talkcontribs)

disabling $wgMediaViewerUseThumbnailGuessing does help.

set imagePreloadingSupported to false fixed it!

Also I did test on Firefox. Everything is working on Firefox without any code change.

it seems like Chrome and Firefox handle CORS slightly different!

let me know if you want me file a bug for this.



Subfader (talkcontribs)

Thanks. Had the same problem. Incorrect CORS error on working 404 handler (images are on subdomain).

Returning imagePreloadingSupported false fixed it. $wgMediaViewerUseThumbnailGuessing could stay true.

MW 1.25 --Subfader (talk) 11:39, 4 November 2017 (UTC)

Tgr (WMF) (talkcontribs)

Please do. The bug would probably affect Firefox too, if your images were on a separate domain. MV sets cors="anonymous" on the images for various hacky reasons, for private wikis that should probably be cors="use-credentials" instead.

Seanchen (talkcontribs) (talkcontribs)

This is still a relevant help for the latest LTS-MediaWiki (1.31.2).

Thanks for this workaround. Setting <pre>imagePreloadungSupported</pre> to <pre>false</pre> helped a lot and fixed my problem.

Jesperjoachims (talkcontribs)

Hi there,

Yes it also fixed my problem (MediaWiki-1.34.1). Thanks for that!

MyWikis-JeffreyWang (talkcontribs)
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