What is a MIME type?

What is a MIME type?

MIME stands for "Multipurpose Internet Mail Extensions. It's a way of identifying files on the Internet according to their nature and format. For example, using the "Content-type" header value defined in a HTTP response, the browser can open the file with the proper extension/plugin.

What is an Internet Media Type?

"Internet Media Type" is the same as a MIME type. MIME types were originally created for emails sent using the SMTP protocol. Nowadays, this standard is used in a lot of other protocols, hence the new naming convention "Internet Media Type".

What is a Content-Type?

A "Content-type" is simply a header defined in many protocols, such as HTTP, that makes use of MIME types to specify the nature of the file currently being handled.

What does a MIME type look like?

A MIME type is a string identifier composed of two parts: a "type" and a "subtype". The "type" refers to a logical grouping of many MIME types that are closely related to each other; it's no more than a high level category. "subtypes" are specific to one file type within the "type".
For example, the MIME value "application/xml" is used for XML documents and specifies that the "xml" subtype belongs in the "application" type.

Why are some MIME subtypes prefixed with "x-"?

The "x-" prefix of a MIME subtype simply means that it's non-standard, i.e. not registered with the "Internet Assigned Numbers Authority" (IANA).

Why are some MIME subtypes prefixed with "vnd"?

The "vnd" prefix means that the MIME value is vendor specific.

How can I set the Content-type header of my files?

It depends on the programming language you are using. Note that most language have a default "Content-type" of "text/html".

• Setting the Content-type in ASP:

  <% response.ContentType="text/html" %>

• Setting the Content-type in C#:

  // Response is of type System.Web.HttpResponse
  response.ContentType = "text/plain";

• Setting the Content-type in Java:

  // Response is of type javax.servlet.ServletReponse
  response.setContentType("text/plain");

• Setting the Content-type in Perl/CGI:

  print "Content-type:text/html";

• Setting the Content-type in PHP:

  <?php header('Content-type: text/html');?>