package meta import ( "fmt" "math" "path" "strconv" "strings" "time" "github.com/dsoprea/go-exif/v2" "github.com/dsoprea/go-exif/v2/common" "github.com/dsoprea/go-jpeg-image-structure" "github.com/dsoprea/go-png-image-structure" "gopkg.in/ugjka/go-tz.v2/tz" ) // Exif parses an image file for Exif meta data and returns as Data struct. func Exif(filename string) (data Data, err error) { defer func() { if e := recover(); e != nil { data = Data{} err = fmt.Errorf("meta: %s", e) } }() // Extract raw EXIF block. var rawExif []byte fileExtension := path.Ext(filename) fileExtension = strings.ToLower(fileExtension) if fileExtension == ".jpg" || fileExtension == ".jpeg" { jmp := jpegstructure.NewJpegMediaParser() sl, err := jmp.ParseFile(filename) if err != nil { return data, err } _, rawExif, err = sl.Exif() if err != nil { return data, err } } else if fileExtension == ".png" { pmp := pngstructure.NewPngMediaParser() cs, err := pmp.ParseFile(filename) if err != nil { return data, err } _, rawExif, err = cs.Exif() if err != nil { return data, err } } else { // Fallback to an optimistic, brute-force search. var err error rawExif, err = exif.SearchFileAndExtractExif(filename) if err != nil { return data, err } } // Enumerate tags in EXIF block. ti := exif.NewTagIndex() if err := exif.LoadStandardTags(ti); err != nil { return data, err } tags := make(map[string]string) visitor := func(fqIfdPath string, ifdIndex int, ite *exif.IfdTagEntry) (err error) { tagId := ite.TagId() tagType := ite.TagType() ifdPath, err := im.StripPathPhraseIndices(fqIfdPath) if err != nil { return nil } it, err := ti.Get(ifdPath, tagId) if err != nil { return nil } valueString := "" if tagType != exifcommon.TypeUndefined { valueString, err = ite.FormatFirst() if err != nil { log.Errorf("exif: %s", err.Error()) return nil } if it.Name != "" && valueString != "" { tags[it.Name] = strings.Split(valueString, "\x00")[0] } } return nil } _, err = exif.Visit(exifcommon.IfdStandard, im, ti, rawExif, visitor) if err != nil { return data, err } // Cherry-pick the values that we care about. if value, ok := tags["Artist"]; ok { data.Artist = strings.Replace(value, "\"", "", -1) } if value, ok := tags["Copyright"]; ok { data.Copyright = strings.Replace(value, "\"", "", -1) } if value, ok := tags["Model"]; ok { data.CameraModel = strings.Replace(value, "\"", "", -1) } if value, ok := tags["Make"]; ok { data.CameraMake = strings.Replace(value, "\"", "", -1) } if value, ok := tags["CameraOwnerName"]; ok { data.CameraOwner = strings.Replace(value, "\"", "", -1) } if value, ok := tags["BodySerialNumber"]; ok { data.CameraSerial = strings.Replace(value, "\"", "", -1) } if value, ok := tags["LensMake"]; ok { data.LensMake = strings.Replace(value, "\"", "", -1) } if value, ok := tags["LensModel"]; ok { data.LensModel = strings.Replace(value, "\"", "", -1) } if value, ok := tags["ExposureTime"]; ok { data.Exposure = value } if value, ok := tags["FNumber"]; ok { values := strings.Split(value, "/") if len(values) == 2 && values[1] != "0" && values[1] != "" { number, _ := strconv.ParseFloat(values[0], 64) denom, _ := strconv.ParseFloat(values[1], 64) data.FNumber = math.Round((number/denom)*1000) / 1000 } } if value, ok := tags["ApertureValue"]; ok { values := strings.Split(value, "/") if len(values) == 2 && values[1] != "0" && values[1] != "" { number, _ := strconv.ParseFloat(values[0], 64) denom, _ := strconv.ParseFloat(values[1], 64) data.Aperture = math.Round((number/denom)*1000) / 1000 } } if value, ok := tags["FocalLengthIn35mmFilm"]; ok { if i, err := strconv.Atoi(value); err == nil { data.FocalLength = i } } else if value, ok := tags["FocalLength"]; ok { values := strings.Split(value, "/") if len(values) == 2 && values[1] != "0" && values[1] != "" { number, _ := strconv.ParseFloat(values[0], 64) denom, _ := strconv.ParseFloat(values[1], 64) data.FocalLength = int(math.Round((number/denom)*1000) / 1000) } } if value, ok := tags["ISOSpeedRatings"]; ok { if i, err := strconv.Atoi(value); err == nil { data.Iso = i } } if value, ok := tags["ImageUniqueID"]; ok { data.UniqueID = value } if value, ok := tags["ImageWidth"]; ok { if i, err := strconv.Atoi(value); err == nil { data.Width = i } } else if value, ok := tags["PixelXDimension"]; ok { if i, err := strconv.Atoi(value); err == nil { data.Width = i } } if value, ok := tags["ImageLength"]; ok { if i, err := strconv.Atoi(value); err == nil { data.Height = i } } else if value, ok := tags["PixelYDimension"]; ok { if i, err := strconv.Atoi(value); err == nil { data.Height = i } } if value, ok := tags["Orientation"]; ok { if i, err := strconv.Atoi(value); err == nil { data.Orientation = i } } else { data.Orientation = 1 } _, index, err := exif.Collect(im, ti, rawExif) if err != nil { return data, err } if ifd, err := index.RootIfd.ChildWithIfdPath(exifcommon.IfdPathStandardGps); err == nil { if gi, err := ifd.GpsInfo(); err == nil { data.Lat = gi.Latitude.Decimal() data.Lng = gi.Longitude.Decimal() data.Altitude = gi.Altitude } } if data.Lat != 0 && data.Lng != 0 { zones, err := tz.GetZone(tz.Point{ Lat: data.Lat, Lon: data.Lng, }) if err != nil { data.TimeZone = "UTC" } data.TimeZone = zones[0] } if value, ok := tags["DateTimeOriginal"]; ok { data.TakenAtLocal, _ = time.Parse("2006:01:02 15:04:05", value) loc, err := time.LoadLocation(data.TimeZone) if err != nil { data.TakenAt = data.TakenAtLocal log.Warnf("no location for timezone: %s", err.Error()) } else if tl, err := time.ParseInLocation("2006:01:02 15:04:05", value, loc); err == nil { data.TakenAt = tl.UTC() } else { log.Warnf("could parse time: %s", err.Error()) } } if value, ok := tags["Flash"]; ok { if i, err := strconv.Atoi(value); err == nil && i&1 == 1 { data.Flash = true } } if value, ok := tags["ImageDescription"]; ok { data.Description = strings.Replace(value, "\"", "", -1) } data.All = tags return data, nil }