File uploads fail in IE without Flash

[johnbillion]

Using IE7 or IE8 (haven't tested IE9) without Flash installed, the multi-file uploader freezes on 0%, fails to upload the file, and attempts to download async-upload.php.

The regular browser uploader works as expected. Maybe we should enforce that and disallow the multi-file uploader?

[azaozz]

When no runtimes are available Plupload falls back to html4 mode: the button looks the same but the user can select only one file and of course there's no progress. That seems to work properly here (and also on WordPress.com).

Perhaps look into what is being sent to the server or any JS errors?

[SergeyBiryukov]

the multi-file uploader freezes on 0%, fails to upload the file, and attempts to download async-upload.php.

Can reproduce freezing: 19494.ie8-without-flash.png​. But the file turns out to be uploaded. Downloading of async-upload.php doesn't happen on my install.

[johnbillion]

Replying to SergeyBiryukov:

Can reproduce freezing: 19494.ie8-without-flash.png​. But the file turns out to be uploaded. Downloading of async-upload.php doesn't happen on my install.

Yeah the file is actually being uploaded in IE8. I was testing IE7 using IETester and I think the browser was crashing before the upload happened.

I can reliably reproduce the freezing and the attempted download of async-upload.php on three devices across two sites running trunk.

[johnbillion]

Tested on IE9 and a preview of IE10 and everything seems to be ok.

[johnbillion]

Replying to azaozz:

Perhaps look into what is being sent to the server or any JS errors?

Looking at the HTTP traffic, the request and response are fine (multipart upload sent, server responds with the ID of the new attachment). No JS errors reported by IE.

[johnbillion]

Replying to azaozz:

the button looks the same but the user can select only one file and of course there's no progress.

Looks like the name is misleading in that case as it's called the multi-file uploader in the UI.

[azaozz]

Replying to johnbillion:

Looking at the HTTP traffic, the request and response are fine (multipart upload sent, server responds with the ID of the new attachment). No JS errors reported by IE.

That makes it harder to pinpoint the problem. The attempted download of async-upload.php suggests the server is crashing for some reason. Is there anything in the server logs (if you have access to them).

In any case we can probably hide Plupload and show the browser uploader when the only available runtime is 'html4'. The difference is that the file properties won't show after the file has finished uploading.

[SergeyBiryukov]

Replying to SergeyBiryukov:

Downloading of async-upload.php doesn't happen on my install.

Can reproduce the attempted download of async-upload.php on another server.

[johnbillion]

Replying to azaozz:

That makes it harder to pinpoint the problem. The attempted download of async-upload.php suggests the server is crashing for some reason. Is there anything in the server logs (if you have access to them).

Nope, nothing in the error logs on either site.

Replying to SergeyBiryukov:

Can reproduce the attempted download of async-upload.php on another server.

After a bit of Googling it seems others have had this issue with Plupload too: ​http://www.plupload.com/punbb/viewtopic.php?id=43

[johnbillion]

Replying to SergeyBiryukov:

Can reproduce the attempted download of async-upload.php on another server.

I can also reproduce this on wordpress.com using IE8 on Win7 on two separate devices.

[azaozz]

Looking through Plupload's forum, there's a suggestion that IE < 9 doesn't like line 26 in async-upload.php:

header('Content-Type: text/plain; charset=' . get_option('blog_charset'));

and expects content type of text/html.

Could you test if that fixes it (it's still working as expected here... no way to test).

[SergeyBiryukov]

Switching to text/html seems to solve both issues (the freezing and the attempted download of async-upload.php).

[johnbillion]

Replying to SergeyBiryukov:

Switching to text/html seems to solve both issues (the freezing and the attempted download of async-upload.php).

Yep, I get the same results here.

[johnbillion]

Just tested the HTML5 uploaders in Firefox and Chrome and they continue to work as expected when async-upload.php uses the text/html content type. Might need testing with the Flash and Silverlight runtimes for completeness.

[azaozz]

Confirmed content type of text/html doesn't affect other browsers/runtimes. Would be good to have another confirmation too I think.

[ryan]

In [19586]:

Use text/html to appease IE < 9. Props azaozz. fixes #19494