How to handle MIME content type mapping and conversion in Go web applications?

In Go web applications, you can handle MIME content type mapping and conversion using the net/http package. Here's how you can do it:

Define a mapping of file extensions to MIME types in your application. You can use a simple map for this:

var mimeTypes = map[string]string{
    ".html": "text/html",
    ".css": "text/css",
    ".js": "application/javascript",
    ".png": "image/png",
    // add more mappings as needed
}

Create a http.FileServer handler to serve static files from a directory:

fileServer := http.FileServer(http.Dir("path/to/static/files"))

Wrap the file server handler with a new handler that performs the MIME type lookup and sets the Content-Type header accordingly:

http.Handle("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
    // Get the file path from the URL
    filePath := string(r.URL.Path[1:])

    // Lookup the MIME type based on the file extension
    mimeType := mimeTypes[path.Ext(filePath)]

    // Set the Content-Type header
    w.Header().Set("Content-Type", mimeType)

    // Serve the static file using the file server handler
    fileServer.ServeHTTP(w, r)
}))

Start your web server:

http.ListenAndServe(":8080", nil)

With this setup, your web application will serve static files with the appropriate Content-Type header based on their file extensions. You can extend the mimeTypes map with additional mappings as needed for your application's specific file types.