What is MIME type "text/x-fstar"?

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

text/x-fstar designates a plain text file that contains F* language code. It signals that the file uses a specialized syntax for functional programming and formal verification.

Files with the text/x-fstar MIME type are typically expected to have the extension FST. These files hold source code that is processed by F* tools to check program properties and ensure correctness.

Main use: Identifying and processing F* language source code.
Key functionality: Enabling proper syntax highlighting, type-checking, and formal verification in integrated development environments.
Practical application: Assisting in advanced software development and research projects that require rigorous program analysis.

For further technical details and community examples, visit the F* language official site.

Associated file extensions

.fst

Usage Examples

HTTP Header

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


    Content-Type: text/x-fstar

HTML

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


    <a href="file.dat" type="text/x-fstar">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', 'text/x-fstar');    
      res.end('Content here');    
    }).listen(3000);

Associated file extensions

.fst

FAQs

What is the purpose of the text/x-fstar MIME type?

text/x-fstar is used to identify source code files written in the F* (F-Star) programming language. It tells operating systems and web servers that the content is plain text containing specialized syntax for functional programming and program verification, usually found in files with the .fst extension.

How do I open a file with the text/x-fstar content type?

You can open these files with any text editor, but specialized environments like VS Code (with the fstar-vscode extension) or Emacs (with fstar-mode) provide the best experience. These editors use the MIME type or file extension to enable syntax highlighting and interactive proof checking.

How do I configure Nginx to serve .fst files correctly?

You should add the MIME type definition to your mime.types file or inside a specific server block. Add the line text/x-fstar fst; within the types block to ensure browsers and tools recognize the file correctly.

Why does the MIME type start with "x-"?

The prefix x- indicates that text/x-fstar is a non-standard or experimental subtype not officially registered with the IANA. It is a convention used by the developer community to distinguish F* source code from generic text/plain files.

Can web browsers execute text/x-fstar files?

No, browsers cannot execute F* code directly as it is a server-side or compile-time language for verification. If you navigate to an .fst file, the browser will typically display it as plain text or prompt you to download it, depending on the server's Content-Disposition header.

How do I add support for text/x-fstar in Apache HTTP Server?

You can add the type mapping in your .htaccess file or the main configuration file. Use the directive AddType text/x-fstar .fst to instruct Apache to serve files with the .fst extension using the correct MIME header.

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.