Is there any way to validate file content before upload?

Question

I did coding for file upload in asp.net and validating a file extension (only png)

If user renames the file (before upload) from other to png (like pdf to png) then that file will valid as png because I just validate extension.

Is there any 3rd party API or service to validate file extension with valid content?

Thanks in advance

Also "Questions asking us to recommend or find a book, tool, software library, tutorial or other off-site resource are off-topic for Stack Overflow". Direct quote from the [on topic](https://stackoverflow.com/help/on-topic) help page — MindSwipe, Mar 27 '19 at 08:23
Another approach is not to validate image, but rather expect what it can be not an image when using uploaded file (to display image somewhere?). `try/catch` would do. — Sinatr, Mar 27 '19 at 08:29

score 0 · Answer 1 · answered Mar 27 '19 at 08:27

0

answered Mar 27 '19 at 08:27

MartinM43

1 Answers1