exiftool

README

go-exiftool

go-exiftool is a golang library that wraps ExifTool.

ExifTool's purpose is to extract and update as much metadata as possible (EXIF, IPTC, XMP, GPS, ...) from a lots of differents file types (Office documents, pictures, movies, PDF, ...).

go-exiftool uses ExifTool's stay_open feature to optimize performance.

Requirements

go-exiftool needs ExifTool to be installed.

• On Debian : sudo apt-get install exiftool

By default, go-exiftool binary will look for exiftool binary in $PATH, but another location can be specified (see SetExiftoolBinaryPath functional option).

Usage

Metadata extraction

et, err := exiftool.NewExiftool()
if err != nil {
    fmt.Printf("Error when intializing: %v\n", err)
    return
}
defer et.Close()

fileInfos := et.ExtractMetadata("testdata/20190404_131804.jpg")

for _, fileInfo := range fileInfos {
    if fileInfo.Err != nil {
        fmt.Printf("Error concerning %v: %v\n", fileInfo.File, fileInfo.Err)
        continue
    }

    for k, v := range fileInfo.Fields {
        fmt.Printf("[%v] %v\n", k, v)
    }
}

Output :

[FOV] 69.4 deg
[Orientation] Rotate 90 CW
[ColorSpace] sRGB
[Compression] JPEG (old-style)
[YCbCrSubSampling] YCbCr4:2:2 (2 1)
[Aperture] 1.7
[ColorComponents] 3
[SubSecCreateDate] 2019:04:04 13:18:03.0937
[FileSize] 26 kB
[FileAccessDate] 2019:05:17 22:44:26+02:00
[DateTimeOriginal] 2019:04:04 13:18:03
[CreateDate] 2019:04:04 13:18:03
(...)

Metadata update

See example function ExampleExiftool_Write in exiftool_sample_test.go

Changelog

• v1.1.0 : initial release
• v1.1.1
  • add typed getters for filemetadata fields
• v1.1.3
  • add Mac & Windows support (thanks to @PROger4ever)
  • increase errors readability (thanks to @PROger4ever)
• v1.2.0
  • add stdout and stderr buffer configuration capabilities (thank to @asannikov)
• v1.3.0
  • Add functionnal option to set ExifTool's -charset parameter (thank to @PROger4ever)
• v1.3.1
  • fix line separator on macOS
• v1.3.2
  • add Freebsd support (thanks to @ghyman1)
• v1.4.0
  • "NoPrintConversion" functional option (thanks to Kjeldgaard)
• v1.5.0
  • "ExtractEmbedded" functional option
• v1.6.0
  • "ExtractAllBinaryMetadata" functional option
• v1.6.1
  • "SetExiftoolBinaryPath" functional option : specify where to find exiftool binary (default : $path)
• v1.6.2
  • Several improvements (thanks to Dale Hui)
• v1.7.0
  • Add metadata writing capabilities (thanks to Dale Hui)
• v1.8.0
  • Fix a bug that was blocking go-exiftool when a folder was provided. Folder metadata extraction will now return a new sentinel error (ErrNotFile).
  • Add a new sentinel error (ErrBufferTooSmall) that is returned when go-exiftool's buffer isn't big enough for a specifi file (countermeasure: initialize go-exiftool with the Buffer option)
  • New option to specify a date format (DateFormat) (thanks to Andy Gorman)
  • New option to output format for GPS coordinates (CoordFormat) (thanks to Andy Gorman)
• v1.9.0
  • New option to specify -api parameter to Exiftool (thanks to Blesmol)
• v1.10.0
  • New option to prefix metadata keys with group names (specifies -G parameter to Exiftool) (thanks to Andy Gorman)

Documentation

Index

• Variables
• func Api(apiValue string) func(*Exiftool) error
• func BackupOriginal() func(*Exiftool) error
• func Buffer(buf []byte, max int) func(*Exiftool) error
• func Charset(charset string) func(*Exiftool) error
• func ClearFieldsBeforeWriting() func(*Exiftool) error
• func CoordFormant(format string) func(*Exiftool) error
• func DateFormant(format string) func(*Exiftool) error
• func ExtractAllBinaryMetadata() func(*Exiftool) error
• func ExtractEmbedded() func(*Exiftool) error
• func NoPrintConversion() func(*Exiftool) error
• func PrintGroupNames(groupNumbers string) func(*Exiftool) error
• func SetExiftoolBinaryPath(p string) func(*Exiftool) error
• type Exiftool
  • func NewExiftool(opts ...func(*Exiftool) error) (*Exiftool, error)
  • func (e *Exiftool) Close() error
  • func (e *Exiftool) ExtractMetadata(files ...string) []FileMetadata
  • func (e *Exiftool) WriteMetadata(fileMetadata []FileMetadata)
• type FileMetadata
  • func EmptyFileMetadata() FileMetadata
  • func (fm FileMetadata) Clear(k string)
  • func (fm FileMetadata) ClearAll()
  • func (fm FileMetadata) GetFloat(k string) (float64, error)
  • func (fm FileMetadata) GetInt(k string) (int64, error)
  • func (fm FileMetadata) GetString(k string) (string, error)
  • func (fm FileMetadata) GetStrings(k string) ([]string, error)
  • func (fm FileMetadata) SetFloat(k string, v float64)
  • func (fm FileMetadata) SetInt(k string, v int64)
  • func (fm FileMetadata) SetString(k string, v string)
  • func (fm FileMetadata) SetStrings(k string, v []string)

Variables

var ErrBufferTooSmall = errors.New("exiftool's buffer too small (see Buffer init option)")

ErrBufferTooSmall is a sentinel error that is returned when the buffer used to store Exiftool's output is too small.

var ErrKeyNotFound = errors.New("key not found")

ErrKeyNotFound is a sentinel error used when a queried key does not exist

var ErrNotExist = errors.New("file does not exist")

ErrNotExist is a sentinel error for non existing file

var ErrNotFile = errors.New("can't extract metadata from folder")

ErrNotFile is a sentinel error that is returned when a folder is provided instead of a rerular file

var WaitTimeout = time.Second

WaitTimeout specifies the duration to wait for exiftool to exit when closing before timing out

Functions

func Api

func Api(apiValue string) func(*Exiftool) error

Api defines an -api value to pass to Exiftool, see https://www.exiftool.org/exiftool_pod.html#Advanced-options Sample :

e, err := NewExiftool(Api("QuickTimeUTC"))

func BackupOriginal

func BackupOriginal() func(*Exiftool) error

BackupOriginal backs up the original file when writing the file metadata instead of overwriting the original (activates Exiftool's '-overwrite_original' parameter) Sample :

e, err := NewExiftool(BackupOriginal())

func Buffer

func Buffer(buf []byte, max int) func(*Exiftool) error

Buffer defines the buffer used to read from stdout and stderr, see https://golang.org/pkg/bufio/#Scanner.Buffer Sample :

buf := make([]byte, 128*1000)
e, err := NewExiftool(Buffer(buf, 64*1000))

func Charset

func Charset(charset string) func(*Exiftool) error

Charset defines the -charset value to pass to Exiftool, see https://exiftool.org/faq.html#Q10 and https://exiftool.org/faq.html#Q18 Sample :

e, err := NewExiftool(Charset("filename=utf8"))

func ClearFieldsBeforeWriting

func ClearFieldsBeforeWriting() func(*Exiftool) error

ClearFieldsBeforeWriting will clear existing fields (e.g. tags) in the file before writing any new tags Sample :

e, err := NewExiftool(ClearFieldsBeforeWriting())

func CoordFormant

func CoordFormant(format string) func(*Exiftool) error

CoordFormant defines the -coordFormat value to pass to Exiftool, see https://exiftool.org/ExifTool.html#CoordFormat Sample :

e, err := NewExiftool(CoordFormant("%+f"))

func DateFormant

func DateFormant(format string) func(*Exiftool) error

DateFormant defines the -dateFormat value to pass to Exiftool, see https://exiftool.org/ExifTool.html#DateFormat Sample :

e, err := NewExiftool(DateFormant("%s"))

func ExtractAllBinaryMetadata

func ExtractAllBinaryMetadata() func(*Exiftool) error

ExtractAllBinaryMetadata extracts all binary metadata (activates Exiftool's '-b' paramater) Sample :

e, err := NewExiftool(ExtractAllBinaryMetadata())

func ExtractEmbedded

func ExtractEmbedded() func(*Exiftool) error

ExtractEmbedded extracts embedded metadata from files (activates Exiftool's '-ee' paramater) Sample :

e, err := NewExiftool(ExtractEmbedded())

func NoPrintConversion

func NoPrintConversion() func(*Exiftool) error

NoPrintConversion enables 'No print conversion' mode, see https://exiftool.org/exiftool_pod.html. Sample :

e, err := NewExiftool(NoPrintConversion())

func PrintGroupNames

func PrintGroupNames(groupNumbers string) func(*Exiftool) error

PrintGroupNames prints the group names for each tag based on the pass group number(s), (activates Exiftool's '-G' paramater) Sample :

e, err := NewExiftool(PrintGroupNames("0"))

func SetExiftoolBinaryPath

func SetExiftoolBinaryPath(p string) func(*Exiftool) error

SetExiftoolBinaryPath sets exiftool's binary path. When not specified, the binary will have to be in $PATH Sample :

e, err := NewExiftool(SetExiftoolBinaryPath("/usr/bin/exiftool"))

Types

type Exiftool

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

Exiftool is the exiftool utility wrapper

func NewExiftool

func NewExiftool(opts ...func(*Exiftool) error) (*Exiftool, error)

NewExiftool instanciates a new Exiftool with configuration functions. If anything went wrong, a non empty error will be returned.

func (*Exiftool) Close

func (e *Exiftool) Close() error

Close closes exiftool. If anything went wrong, a non empty error will be returned

func (*Exiftool) ExtractMetadata

func (e *Exiftool) ExtractMetadata(files ...string) []FileMetadata

ExtractMetadata extracts metadata from files

func (*Exiftool) WriteMetadata

func (e *Exiftool) WriteMetadata(fileMetadata []FileMetadata)

WriteMetadata writes the given metadata for each file. Any errors will be saved to FileMetadata.Err Note: If you're reusing an existing FileMetadata instance,

you should nil the Err before passing it to WriteMetadata

type FileMetadata

type FileMetadata struct {
	File   string
	Fields map[string]interface{}
	Err    error
}

FileMetadata is a structure that represents an exiftool extraction. File contains the filename that had to be extracted. If anything went wrong, Err will not be nil. Fields stores extracted fields.

func EmptyFileMetadata

func EmptyFileMetadata() FileMetadata

EmptyFileMetadata creates an empty FileMetadata struct

func (FileMetadata) Clear

func (fm FileMetadata) Clear(k string)

Clear removes value for a specific metadata field

func (FileMetadata) ClearAll

func (fm FileMetadata) ClearAll()

ClearAll removes all medatadata

func (FileMetadata) GetFloat

func (fm FileMetadata) GetFloat(k string) (float64, error)

GetFloat returns a field value as float64 and an error if one occurred. KeyNotFoundError will be returned if the key can't be found.

func (FileMetadata) GetInt

func (fm FileMetadata) GetInt(k string) (int64, error)

GetInt returns a field value as int64 and an error if one occurred. KeyNotFoundError will be returned if the key can't be found, ParseError if a parsing error occurs.

func (FileMetadata) GetString

func (fm FileMetadata) GetString(k string) (string, error)

GetString returns a field value as string and an error if one occurred. KeyNotFoundError will be returned if the key can't be found

func (FileMetadata) GetStrings

func (fm FileMetadata) GetStrings(k string) ([]string, error)

GetStrings returns a field value as []string and an error if one occurred. KeyNotFoundError will be returned if the key can't be found.

func (FileMetadata) SetFloat

func (fm FileMetadata) SetFloat(k string, v float64)

SetFloat sets a float value for a specific field

func (FileMetadata) SetInt

func (fm FileMetadata) SetInt(k string, v int64)

SetInt sets a int value for a specific field

func (FileMetadata) SetString

func (fm FileMetadata) SetString(k string, v string)

SetString sets a string value for a specific field

func (FileMetadata) SetStrings

func (fm FileMetadata) SetStrings(k string, v []string)

SetStrings sets a []String value for a specific field