Refactor EXIF parsing

api/scanner/exif/exif.go

@@ -0,0 +1,51 @@
+package exif
+
+import (
+	"log"
+
+	"github.com/pkg/errors"
+	"gorm.io/gorm"
+
+	"github.com/photoview/photoview/api/graphql/models"
+)
+
+type exifParser interface {
+	ParseExif(media *models.Media) (*models.MediaEXIF, error)
+}
+
+// SaveEXIF scans the media file for exif metadata and saves it in the database if found
+func SaveEXIF(tx *gorm.DB, media *models.Media) (*models.MediaEXIF, error) {
+
+	log.Printf("Scanning for EXIF: %s", media.Path)
+
+	{
+		// Check if EXIF data already exists
+		if media.ExifID != nil {
+
+			var exif models.MediaEXIF
+			if err := tx.First(&exif, media.ExifID).Error; err != nil {
+				return nil, errors.Wrap(err, "get EXIF for media from database")
+			}
+
+			return &exif, nil
+		}
+	}
+
+	var parser exifParser = &internalExifParser{}
+
+	exif, err := parser.ParseExif(media)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to parse exif data")
+	}
+
+	if exif == nil {
+		return nil, nil
+	}
+
+	// Add EXIF to database and link to media
+	if err := tx.Model(&media).Association("Exif").Replace(exif); err != nil {
+		return nil, errors.Wrap(err, "save media exif to database")
+	}
+
+	return exif, nil
+}

api/scanner/exif/exif_parser_internal.go

@@ -1,4 +1,4 @@
-package scanner
+package exif
 
 import (
 	"fmt"
@@ -6,31 +6,16 @@ import (
 	"math/big"
 	"os"
 
-	"github.com/pkg/errors"
-	"gorm.io/gorm"
-
 	"github.com/photoview/photoview/api/graphql/models"
+	"github.com/pkg/errors"
 	"github.com/xor-gate/goexif2/exif"
 	"github.com/xor-gate/goexif2/mknote"
 )
 
-func ScanEXIF(tx *gorm.DB, media *models.Media) (returnExif *models.MediaEXIF, returnErr error) {
-
-	log.Printf("Scanning for EXIF")
-
-	{
-		// Check if EXIF data already exists
-		if media.ExifID != nil {
-
-			var exif models.MediaEXIF
-			if err := tx.First(&exif, media.ExifID).Error; err != nil {
-				return nil, errors.Wrap(err, "get EXIF for media from database")
-			}
-
-			return &exif, nil
-		}
-	}
+// internalExifParser is an exif parser that parses the media without the use of external tools
+type internalExifParser struct{}
 
+func (p *internalExifParser) ParseExif(media *models.Media) (returnExif *models.MediaEXIF, returnErr error) {
 	photoFile, err := os.Open(media.Path)
 	if err != nil {
 		return nil, err
@@ -53,17 +38,17 @@ func ScanEXIF(tx *gorm.DB, media *models.Media) (returnExif *models.MediaEXIF, r
 
 	newExif := models.MediaEXIF{}
 
-	model, err := readStringTag(exifTags, exif.Model, media)
+	model, err := p.readStringTag(exifTags, exif.Model, media)
 	if err == nil {
 		newExif.Camera = model
 	}
 
-	maker, err := readStringTag(exifTags, exif.Make, media)
+	maker, err := p.readStringTag(exifTags, exif.Make, media)
 	if err == nil {
 		newExif.Maker = maker
 	}
 
-	lens, err := readStringTag(exifTags, exif.LensModel, media)
+	lens, err := p.readStringTag(exifTags, exif.LensModel, media)
 	if err == nil {
 		newExif.Lens = lens
 	}
@@ -73,13 +58,13 @@ func ScanEXIF(tx *gorm.DB, media *models.Media) (returnExif *models.MediaEXIF, r
 		newExif.DateShot = &date
 	}
 
-	exposure, err := readRationalTag(exifTags, exif.ExposureTime, media)
+	exposure, err := p.readRationalTag(exifTags, exif.ExposureTime, media)
 	if err == nil {
 		exposureStr := exposure.RatString()
 		newExif.Exposure = &exposureStr
 	}
 
-	apertureRat, err := readRationalTag(exifTags, exif.FNumber, media)
+	apertureRat, err := p.readRationalTag(exifTags, exif.FNumber, media)
 	if err == nil {
 		aperture, _ := apertureRat.Float64()
 		newExif.Aperture = &aperture
@@ -125,12 +110,12 @@ func ScanEXIF(tx *gorm.DB, media *models.Media) (returnExif *models.MediaEXIF, r
 		newExif.Flash = &flash
 	}
 
-	orientation, err := readIntegerTag(exifTags, exif.Orientation, media)
+	orientation, err := p.readIntegerTag(exifTags, exif.Orientation, media)
 	if err == nil {
 		newExif.Orientation = orientation
 	}
 
-	exposureProgram, err := readIntegerTag(exifTags, exif.ExposureProgram, media)
+	exposureProgram, err := p.readIntegerTag(exifTags, exif.ExposureProgram, media)
 	if err == nil {
 		newExif.ExposureProgram = exposureProgram
 	}
@@ -141,20 +126,11 @@ func ScanEXIF(tx *gorm.DB, media *models.Media) (returnExif *models.MediaEXIF, r
 		newExif.GPSLonitude = &long
 	}
 
-	// If exif is empty
-	if newExif == (models.MediaEXIF{}) {
-		return nil, nil
+	returnExif = &newExif
+	return
 }
 
-	// Add EXIF to database and link to media
-	if err := tx.Model(&media).Association("Exif").Replace(newExif); err != nil {
-		return nil, errors.Wrap(err, "save media exif to database")
-	}
-
-	return &newExif, nil
-}
-
-func readStringTag(tags *exif.Exif, name exif.FieldName, media *models.Media) (*string, error) {
+func (p *internalExifParser) readStringTag(tags *exif.Exif, name exif.FieldName, media *models.Media) (*string, error) {
 	tag, err := tags.Get(name)
 	if err != nil {
 		return nil, errors.Wrapf(err, "could not read %s from EXIF: %s", name, media.Title)
@@ -173,7 +149,7 @@ func readStringTag(tags *exif.Exif, name exif.FieldName, media *models.Media) (*
 	return nil, errors.New("exif tag returned null")
 }
 
-func readRationalTag(tags *exif.Exif, name exif.FieldName, media *models.Media) (*big.Rat, error) {
+func (p *internalExifParser) readRationalTag(tags *exif.Exif, name exif.FieldName, media *models.Media) (*big.Rat, error) {
 	tag, err := tags.Get(name)
 	if err != nil {
 		return nil, errors.Wrapf(err, "could not read %s from EXIF: %s", name, media.Title)
@@ -192,7 +168,7 @@ func readRationalTag(tags *exif.Exif, name exif.FieldName, media *models.Media)
 	return nil, errors.New("exif tag returned null")
 }
 
-func readIntegerTag(tags *exif.Exif, name exif.FieldName, media *models.Media) (*int, error) {
+func (p *internalExifParser) readIntegerTag(tags *exif.Exif, name exif.FieldName, media *models.Media) (*int, error) {
 	tag, err := tags.Get(name)
 	if err != nil {
 		return nil, errors.Wrapf(err, "could not read %s from EXIF: %s", name, media.Title)

api/scanner/scanner_media.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 
 	"github.com/photoview/photoview/api/graphql/models"
+	"github.com/photoview/photoview/api/scanner/exif"
 	"github.com/pkg/errors"
 	"gorm.io/gorm"
 )
@@ -165,9 +166,9 @@ func ScanMedia(tx *gorm.DB, mediaPath string, albumId int, cache *AlbumScannerCa
 		return nil, false, errors.Wrap(err, "could not insert media into database")
 	}
 
-	_, err = ScanEXIF(tx, &media)
+	_, err = exif.SaveEXIF(tx, &media)
 	if err != nil {
-		log.Printf("WARN: ScanEXIF for %s failed: %s\n", mediaName, err)
+		log.Printf("WARN: SaveEXIF for %s failed: %s\n", mediaName, err)
 	}
 
 	if media.Type == models.MediaTypeVideo {