How to reliably detect mime type of uploaded [text-based] file in asp.net?

Question

My site allows for resume upload, but I want to make sure users won't be uploading anything else but plain text, rtf or word documents (both old *.doc and new *.docx formats). Obviously I can't go entirely by extension, I need to somehow detect file's mime type by its content. Any ideas how to reliably do that for the above types?

score 1 · Answer 1 · answered Dec 22 '11 at 16:16

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The browser will send you a mime type when the file is uploaded. While not 100% consistent or reliable, that might be your best bet.

answered Dec 22 '11 at 16:16

Eric Petroelje

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score 1 · Accepted Answer · edited May 23 '17 at 12:20

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This is a duplicate of the Using .NET, how can you find the mime type of a file based on the file signature not the extension question here on stackoverflow. This one includes an answer with a code sample to use the FindMimeFromData method from urlmon.dll.

edited May 23 '17 at 12:20

Community

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answered Dec 22 '11 at 16:21

JamieSee

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How to reliably detect mime type of uploaded [text-based] file in asp.net?

2 Answers2