magicmime is a Go package which allows you to discover a file's mimetype by looking for magic numbers in its content. It could be used as a supplementary for Go's mime package which only interprets the file extension to detect mimetypes. Internally, it implements libmagic(3) bindings.
Tested on Linux and Mac OS X, should be working on BSD. You could be able to build and make it working with Cygwin on Windows.
This uses the libmagic library from the file tool, so you might need to install the development package for libmagic. On Debian or Ubuntu: apt-get install libmagic-dev. On RHEL, CentOS or Fedora: yum install file-devel. On Mac OS X: brew install libmagic. If you don't have the required package, compilation will be terminated by an error saying magic.h cannot be found.
In order to start, go get this repository:
go get github.com/rakyll/magicmimeSee godoc examples.
https://godoc.org/github.com/rakyll/magicmime
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