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package mimetype_test
import (
"bytes"
"fmt"
"os"
"github.com/gabriel-vasile/mimetype"
)
func Example_detect() {
testBytes := []byte("This random text has a MIME type of text/plain; charset=utf-8.")
mtype := mimetype.Detect(testBytes)
fmt.Println(mtype.Is("text/plain"), mtype.String(), mtype.Extension())
mtype, err := mimetype.DetectReader(bytes.NewReader(testBytes))
fmt.Println(mtype.Is("text/plain"), mtype.String(), mtype.Extension(), err)
mtype, err = mimetype.DetectFile("a nonexistent file")
fmt.Println(mtype.Is("application/octet-stream"), mtype.String(), os.IsNotExist(err))
// Output: true text/plain; charset=utf-8 .txt
// true text/plain; charset=utf-8 .txt <nil>
// true application/octet-stream true
}
// Considering the definition of a binary file as "a computer file that is not
// a text file", they can differentiated by searching for the text/plain MIME
// in their MIME hierarchy.
func Example_textVsBinary() {
testBytes := []byte("This random text has a MIME type of text/plain; charset=utf-8.")
detectedMIME := mimetype.Detect(testBytes)
isBinary := true
for mtype := detectedMIME; mtype != nil; mtype = mtype.Parent() {
if mtype.Is("text/plain") {
isBinary = false
}
}
fmt.Println(isBinary, detectedMIME)
// Output: false text/plain; charset=utf-8
}
func Example_whitelist() {
testBytes := []byte("This random text has a MIME type of text/plain; charset=utf-8.")
allowed := []string{"text/plain", "application/zip", "application/pdf"}
mtype := mimetype.Detect(testBytes)
if mimetype.EqualsAny(mtype.String(), allowed...) {
fmt.Printf("%s is allowed\n", mtype)
} else {
fmt.Printf("%s is now allowed\n", mtype)
}
// Output: text/plain; charset=utf-8 is allowed
}
// Use Extend to add support for a file format which is not detected by mimetype.
//
// https://www.garykessler.net/library/file_sigs.html and
// https://github.com/file/file/tree/master/magic/Magdir
// have signatures for a multitude of file formats.
func Example_extend() {
foobarDetector := func(raw []byte, limit uint32) bool {
return bytes.HasPrefix(raw, []byte("foobar"))
}
mimetype.Lookup("text/plain").Extend(foobarDetector, "text/foobar", ".fb")
mtype := mimetype.Detect([]byte("foobar file content"))
fmt.Println(mtype.String(), mtype.Extension())
// Output: text/foobar .fb
}
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