1package fileop
  2
  3import (
  4	"math"
  5	"time"
  6
  7	"git.sr.ht/~gabrielgio/img/pkg/components/media"
  8	"github.com/barasher/go-exiftool"
  9)
 10
 11func ReadExif(path string) (*media.MediaEXIF, error) {
 12	et, err := exiftool.NewExiftool()
 13	if err != nil {
 14		return nil, err
 15	}
 16	defer et.Close()
 17
 18	newExif := &media.MediaEXIF{}
 19	fileInfo := et.ExtractMetadata(path)[0]
 20
 21	// Get description
 22	description, err := fileInfo.GetString("ImageDescription")
 23	if err == nil {
 24		newExif.Description = &description
 25	}
 26
 27	// Get camera model
 28	model, err := fileInfo.GetString("Model")
 29	if err == nil {
 30		newExif.Camera = &model
 31	}
 32
 33	// Get Camera make
 34	make, err := fileInfo.GetString("Make")
 35	if err == nil {
 36		newExif.Maker = &make
 37	}
 38
 39	// Get lens
 40	lens, err := fileInfo.GetString("LensModel")
 41	if err == nil {
 42		newExif.Lens = &lens
 43	}
 44
 45	//Get time of photo
 46	createDateKeys := []string{
 47		"CreationDate",
 48		"DateTimeOriginal",
 49		"CreateDate",
 50		"TrackCreateDate",
 51		"MediaCreateDate",
 52		"FileCreateDate",
 53		"ModifyDate",
 54		"TrackModifyDate",
 55		"MediaModifyDate",
 56		"FileModifyDate",
 57	}
 58	for _, createDateKey := range createDateKeys {
 59		date, err := fileInfo.GetString(createDateKey)
 60		if err == nil {
 61			layout := "2006:01:02 15:04:05"
 62			dateTime, err := time.Parse(layout, date)
 63			if err == nil {
 64				newExif.DateShot = &dateTime
 65			} else {
 66				layoutWithOffset := "2006:01:02 15:04:05+02:00"
 67				dateTime, err = time.Parse(layoutWithOffset, date)
 68				if err == nil {
 69					newExif.DateShot = &dateTime
 70				}
 71			}
 72			break
 73		}
 74	}
 75
 76	// Get exposure time
 77	exposureTime, err := fileInfo.GetFloat("ExposureTime")
 78	if err == nil {
 79		newExif.Exposure = &exposureTime
 80	}
 81
 82	// Get aperture
 83	aperture, err := fileInfo.GetFloat("Aperture")
 84	if err == nil {
 85		newExif.Aperture = &aperture
 86	}
 87
 88	// Get ISO
 89	iso, err := fileInfo.GetInt("ISO")
 90	if err == nil {
 91		newExif.Iso = &iso
 92	}
 93
 94	// Get focal length
 95	focalLen, err := fileInfo.GetFloat("FocalLength")
 96	if err == nil {
 97		newExif.FocalLength = &focalLen
 98	}
 99
100	// Get flash info
101	flash, err := fileInfo.GetInt("Flash")
102	if err == nil {
103		newExif.Flash = &flash
104	}
105
106	// Get orientation
107	orientation, err := fileInfo.GetInt("Orientation")
108	if err == nil {
109		newExif.Orientation = &orientation
110	}
111
112	// Get exposure program
113	expProgram, err := fileInfo.GetInt("ExposureProgram")
114	if err == nil {
115		newExif.ExposureProgram = &expProgram
116	}
117
118	// GPS coordinates - longitude
119	longitudeRaw, err := fileInfo.GetFloat("GPSLongitude")
120	if err == nil {
121		newExif.GPSLongitude = &longitudeRaw
122	}
123
124	// GPS coordinates - latitude
125	latitudeRaw, err := fileInfo.GetFloat("GPSLatitude")
126	if err == nil {
127		newExif.GPSLatitude = &latitudeRaw
128	}
129
130	sanitizeEXIF(newExif)
131
132	return newExif, nil
133}
134
135// isFloatReal returns true when the float value represents a real number
136// (different than +Inf, -Inf or NaN)
137func isFloatReal(v float64) bool {
138	if math.IsInf(v, 1) {
139		return false
140	} else if math.IsInf(v, -1) {
141		return false
142	} else if math.IsNaN(v) {
143		return false
144	}
145	return true
146}
147
148// sanitizeEXIF removes any EXIF float64 field that is not a real number (+Inf,
149// -Inf or Nan)
150func sanitizeEXIF(exif *media.MediaEXIF) {
151	if exif.Exposure != nil && !isFloatReal(*exif.Exposure) {
152		exif.Exposure = nil
153	}
154	if exif.Aperture != nil && !isFloatReal(*exif.Aperture) {
155		exif.Aperture = nil
156	}
157	if exif.FocalLength != nil && !isFloatReal(*exif.FocalLength) {
158		exif.FocalLength = nil
159	}
160	if (exif.GPSLatitude != nil && !isFloatReal(*exif.GPSLatitude)) ||
161		(exif.GPSLongitude != nil && !isFloatReal(*exif.GPSLongitude)) {
162		exif.GPSLatitude = nil
163		exif.GPSLongitude = nil
164	}
165}