mimetype – github.com/gabriel-vasile/mimetype Index | Examples | Files | Directories

package mimetype

import "github.com/gabriel-vasile/mimetype"

Package mimetype uses magic number signatures to detect the MIME type of a file.

mimetype stores the list of MIME types in a tree structure with "application/octet-stream" at the root of the hierarchy. The hierarchy approach minimizes the number of checks that need to be done on the input and allows for more precise results once the base type of file has been identified.

Example (Check)

To check if some bytes/reader/file has a specific MIME type, first perform a detect on the input and then test against the MIME. `Is` also works with MIME aliases.

Code:play  

package main

import (
	"fmt"

	"github.com/gabriel-vasile/mimetype"
)

func main() {
	mime, err := mimetype.DetectFile("testdata/zip.zip")
	// application/x-zip is an alias of application/zip,
	// therefore Is returns true both times.
	fmt.Println(mime.Is("application/zip"), mime.Is("application/x-zip"), err)

}

Output:

true true <nil>
Example (Detect)

To find the MIME type of some bytes/reader/file, perform a detect on the input.

Code:play  

package main

import (
	"fmt"
	"io/ioutil"
	"os"

	"github.com/gabriel-vasile/mimetype"
)

func main() {
	file := "testdata/pdf.pdf"
	reader, _ := os.Open(file)
	data, _ := ioutil.ReadFile(file)

	dmime := mimetype.Detect(data)
	rmime, rerr := mimetype.DetectReader(reader)
	fmime, ferr := mimetype.DetectFile(file)

	fmt.Println(dmime, rmime, fmime)
	fmt.Println(rerr, ferr)

}

Output:

application/pdf application/pdf application/pdf
<nil> <nil>
Example (Parent)

To check if some bytes/reader/file has a base MIME type, first perform a detect on the input and then navigate the parents until the base MIME type is found.

Code:play  

package main

import (
	"fmt"

	"github.com/gabriel-vasile/mimetype"
)

func main() {
	// Ex: if you are interested in text/plain and all of its subtypes:
	// text/html, text/xml, text/csv, etc.
	mime, err := mimetype.DetectFile("testdata/html.html")

	isText := false
	for ; mime != nil; mime = mime.Parent() {
		if mime.Is("text/plain") {
			isText = true
		}
	}

	// isText is true, even if the detected MIME was text/html.
	fmt.Println(isText, err)

}

Output:

true <nil>

Index

Examples

Types

type MIME 

type MIME struct {
	// contains filtered or unexported fields
}

MIME represents a file format in the tree structure of formats.

func Detect 

func Detect(in []byte) (mime *MIME)

Detect returns the MIME type found from the provided byte slice.

Failure to identify the format results in application/octet-stream being returned.

Example

Code:play  

package main

import (
	"fmt"
	"io/ioutil"

	"github.com/gabriel-vasile/mimetype"
)

func main() {
	data, err := ioutil.ReadFile("testdata/zip.zip")
	mime := mimetype.Detect(data)

	fmt.Println(mime, err)

}

Output:

application/zip <nil>

func DetectFile 

func DetectFile(file string) (mime *MIME, err error)

DetectFile returns the MIME type of the provided file.

The result is always a valid MIME type, with application/octet-stream returned when identification failed with or without an error. Any error returned is related to the opening and reading from the input file.

Example

Code:play  

package main

import (
	"fmt"

	"github.com/gabriel-vasile/mimetype"
)

func main() {
	mime, err := mimetype.DetectFile("testdata/zip.zip")

	fmt.Println(mime, err)

}

Output:

application/zip <nil>

func DetectReader 

func DetectReader(r io.Reader) (mime *MIME, err error)

DetectReader returns the MIME type of the provided reader.

The result is always a valid MIME type, with application/octet-stream returned when identification failed with or without an error. Any error returned is related to the reading from the input reader.

Example

Code:play  

package main

import (
	"fmt"
	"os"

	"github.com/gabriel-vasile/mimetype"
)

func main() {
	data, oerr := os.Open("testdata/zip.zip")
	mime, merr := mimetype.DetectReader(data)

	fmt.Println(mime, oerr, merr)

}

Output:

application/zip <nil> <nil>

func (*MIME) Extension 

func (n *MIME) Extension() string

Extension returns the file extension associated with the MIME type. It includes the leading dot, as in ".html". When the file format does not have an extension, the empty string is returned.

func (*MIME) Is 

func (n *MIME) Is(expectedMIME string) bool

Is checks whether this MIME type, or any of its aliases, is equal to the expected MIME type. MIME type equality test is done on the "type/subtype" sections, ignores any optional MIME parameters, ignores any leading and trailing whitespace, and is case insensitive.

Example

Code:play  

package main

import (
	"fmt"

	"github.com/gabriel-vasile/mimetype"
)

func main() {
	mime, err := mimetype.DetectFile("testdata/pdf.pdf")

	pdf := mime.Is("application/pdf")
	xpdf := mime.Is("application/x-pdf")
	txt := mime.Is("text/plain")
	fmt.Println(pdf, xpdf, txt, err)

}

Output:

true true false <nil>

func (*MIME) Parent 

func (n *MIME) Parent() *MIME

Parent returns the parent MIME type from the tree structure. Each MIME type has a non-nil parent, except for the root MIME type.

func (*MIME) String 

func (n *MIME) String() string

String returns the string representation of the MIME type, e.g., "application/zip".

Source Files

mime.go mimetype.go tree.go

Directories

PathSynopsis
internal
Version
v1.0.0
Published
Dec 11, 2019
Platform
darwin/amd64
Imports
4 packages
Last checked
2 hours ago –

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