I have a web-app that allows users to upload and download image files by pressing buttons on a web page. A user of this page is reporting that IE 7 and 8 fail to download files when the files have Unicode pathnames. IE prompts the user with a dialog stating: “Internet explorer cannot download (file) at (webserver).”.
The problem only happens in IE. Unfortunately I have not been able to reproduce the problem using these versions on my machine.
My question is, what could cause this, and how can I prevent it from happening? I have read about problems with cache control (I currently have it set to no-cache); however, I am not using HTTP-S, and the problem only occurs with file-names containing Unicode characters.
Update: the problem appears to only happen when the user attempts to download a bmp filepath. Non-standard filepaths download successfully. Could it be that Paint is causing trouble?
The Javascript sets appends an iframe pointing at a url associated with the file.
So, the bug only occurs if you set the content-disposition header to attachment. Once I removed the header from my http response headers, the problem was resolved.
If you set the mime type to an unknown value, the bitmap will not be rendered as an image, and will be treated like an attachment.