mime¶

Implements the freedesktop.org Shared MIME-info Database — answer the one question "what type is this file?" From a file's name, its content (magic), or both, it returns a canonical MIME type against the on-disk shared database. Pure Go, CGO_ENABLED=0.

Fast name-only classification (the path a listing view uses).
Content sniffing (magic) and combined name + content resolution.
Type relationships: alias resolution and subclass (is-a) checks.

Install¶

go get github.com/go-freedesktop/mime

Usage¶

package main

import (
    "fmt"
    "os"

    "github.com/go-freedesktop/mime"
)

func main() {
    // Name only — the fast path a listing view uses.
    fmt.Println(mime.TypeByName("report.pdf")) // application/pdf

    // Name + a content sniff — what "Get Info" / "Open With" should use.
    f, _ := os.Open("/tmp/download")
    head := make([]byte, 256)
    n, _ := f.Read(head)
    fmt.Println(mime.TypeByNameAndContent("download", head[:n]))

    // Relationships.
    fmt.Println(mime.Unalias("application/x-gzip"))               // application/gzip
    fmt.Println(mime.IsSubclassOf("image/svg+xml", "text/plain")) // true
}

The full API is on pkg.go.dev. Source: github.com/go-freedesktop/mime.