What is MIME type "application/x-ruby"?

A MIME type is a string that tells browsers and other tools how to handle a particular kind of file.

The MIME type application/x-ruby is used to identify files containing Ruby source code. It tells systems that the file is a text file filled with Ruby instructions.
Files using this MIME type typically have the extension RB. This helps software correctly process and display the content.

This MIME type is important because it ensures proper handling of Ruby programs. Its main uses include:

Code Execution: Interpreters read the file to run Ruby scripts.
Editing & Syntax Highlighting: Editors use it to highlight Ruby-specific syntax.
Content Identification: Systems and web servers recognize Ruby source code for processing.

Developers work with it when building applications, automating tasks, or developing web frameworks. For additional technical insights, you can visit the Ruby Documentation.

Associated file extensions

.rb

Usage Examples

HTTP Header

When serving content with this MIME type, set the Content-Type header:


    Content-Type: application/x-ruby

HTML

In HTML, you can specify the MIME type in various elements:


    <a href="file.dat" type="application/x-ruby">Download file</a>

Server-side (Node.js)

Setting the Content-Type header in Node.js:


    const http = require('http');    
    
    http.createServer((req, res) => {    
      res.setHeader('Content-Type', 'application/x-ruby');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.rb

FAQs

Does my web browser execute application/x-ruby files?

No, web browsers do not natively execute Ruby code. Ruby is a server-side language, meaning the server processes the application/x-ruby file and sends the resulting HTML to the client. If you navigate directly to a file with this MIME type, most browsers will ask you to download it rather than run it.

How do I configure Apache to serve Ruby files with the correct MIME type?

To ensure Apache identifies Ruby files correctly, add the line AddType application/x-ruby .rb to your configuration file or .htaccess. Note that this only identifies the file type; to actually execute the script on the web, you typically need a CGI setup or an application server like Phusion Passenger.

What is the difference between application/x-ruby and text/x-ruby?

Both MIME types refer to Ruby source code and are often used interchangeably. text/x-ruby emphasizes that the content is human-readable text, while application/x-ruby generally implies the file is intended for execution by an interpreter. Both are associated with the .rb extension.

Why am I seeing an error when trying to open an application/x-ruby file?

This usually happens if your operating system does not have a default application associated with the .rb extension. You can resolve this by installing the Ruby runtime environment or by right-clicking the file and selecting a text editor (like VS Code or Notepad) to view the source code.

Is it safe to run files marked as application/x-ruby?

You should exercise caution. Files with the application/x-ruby MIME type are executable scripts that can modify files or access the network. Only run these scripts if you trust the source or have reviewed the code in a text editor first.

How do I add MIME support for Ruby in Nginx?

In your mime.types file (usually located in /etc/nginx/), ensure the line application/x-ruby rb; exists. This tells Nginx to send the application/x-ruby header whenever it serves a file ending in .rb.

General FAQ

What is a MIME type?

A MIME (Multipurpose Internet Mail Extensions) type is a standard that indicates the nature and format of a document, file, or assortment of bytes. MIME types are defined and standardized in IETF's RFC 6838.

MIME types are important because they help browsers and servers understand how to process a file. When a browser receives a file from a server, it uses the MIME type to determine how to display or handle the content, whether it's an image to display, a PDF to open in a viewer, or a video to play.

MIME types consist of a type and a subtype, separated by a slash (e.g., text/html, image/jpeg, application/pdf). Some MIME types also include optional parameters.

How do I find the MIME type for a file?

You can check the file extension or use a file identification tool such as file --mime-type on the command line. Many programming languages also provide libraries to detect MIME types.

Why are multiple MIME types listed for one extension?

Different applications and historical conventions may use alternative MIME identifiers for the same kind of file. Showing them all helps ensure compatibility across systems.