It is the HTTP server's job to tell its client the type of content being sent. This is done by the
Content-Type header. The value of the
Content-Type header should be a valid media type (formerly known as the MIME type) registered with the Internet Assigned Numbers Authority (IANA). See the Further reading section of this chapter for a link to the IANA list of media types.
Try the following command on Linux or macOS (replace
example.txt with a real filename):
file --mime-type example.txt
The following screenshot shows its usage:
As you can see in the preceding screenshot, the
file utility told us the media type of
text/html. It also said the media type of
image/png, and the media type of
Our web server just uses the file's extension to determine the media...