How to differentiate if NSData is xls, ppt or doc on objective c
问题 I'm working on a File-Handling type of app, I recently encountered a bug that is caused by links that doesn't have a file extension like this: https://drive.google.com/uc?export=download&id=1234567abcdefghijk I've been basing the file type by the filename located at the end of the link which is the direct link to the file. In the case of a redirecting link like the google drive link above, it still returns the data but the problem is since it doesn't have a file extension, the UIWebView doesn