Excel Icon is not shown for Content Links

Ah! The penny has dropped. Thanks.

This is for content links, not embeds; I'm just parroting what Hedrick said above.

So Add Content -> Add Content Link.

I cannot see this on Trunk. I tried embedding content by uploading a file as part of the linking process. I also upload files into resources and then tried to link to them when using "Embed Content" neither approach showed any icons for MS Access, DOC or DOCX, or PPTX, or XLS or XLSX files. not a single icon shown.

Tested in trunk. and looks good.

https://trunk-mysql.nightly.sakaiproject.org

OS: Windows 10 Browser- chrome

The file uploaded by Kyle Blythe that didn't show the icon should now show the icon.
Files newly uploaded should also show the icon.

There are two separate fixes, neither of which has anything specific to Excel.

1) When there isn't a MIME type, Lessons uses a kernel function that maps file extension to MIME type. Unfortunately it doesn't always produce the commonly accepted MIME type. I've added entries to the Lessons table so it will accept all of the MIME types that the kernel can return.

2) When uploading the file, Chrome on the Mac claims a mime type of application/octet-string. I now ignore application/octet-string, since it give no useful information. When no MIME type is specified, the kernel will look at the file and try to figure out what it is. It seems to recognize Excel files. I now use the type that the kernel guesses when the browser didn't specify a type or specified application/octet-string.