refactor(mediameta): table-driven EXIF tag extraction

ExtractExifMap repeated the same lookup-append block ~14 times, with
first-non-uint fallback chains for camera/lens tags. A declarative tag
table plus a small extraction loop covers both patterns; the complex
value transforms (exposure, focal length, dates) stay explicit.
Includes a regression test covering fallbacks, defaults and formats.

Authored By: TDvorak <info@tdvorak.dev>

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

pkg/mediameta/exif.go

@@ -263,90 +263,51 @@ func (e *exifExtractor) Extract(ctx context.Context, ext string, source entityso
 	return metas, nil
 }
 
-func ExtractExifMap(exifMap map[string]string, gpsTime time.Time) []driver.MediaMeta {
+// exifTagTable maps EXIF tag names (in fallback order) to MediaMeta keys.
-	metas := make([]driver.MediaMeta, 0)
+// skipUint entries ignore pure-integer values, which vendor APIs sometimes
-	if value, ok := exifMap["Artist"]; ok {
+// return instead of the real string value.
-		metas = append(metas, driver.MediaMeta{
+var exifTagTable = []struct {
-			Key:   Artist,
+	keys     []string
-			Value: SanitizeMeta(value),
+	metaKey  string
-		})
+	clean    func(string) string
-	}
+	skipUint bool
-
+}{
-	if value, ok := exifMap["Copyright"]; ok {
+	{[]string{"Artist"}, Artist, SanitizeMeta, false},
-		metas = append(metas, driver.MediaMeta{
+	{[]string{"Copyright"}, Copyright, SanitizeString, false},
-			Key:   Copyright,
+	{[]string{"CameraModel", "Model", "UniqueCameraModel"}, CameraModel, SanitizeString, true},
-			Value: SanitizeString(value),
+	{[]string{"CameraMake", "Make"}, CameraMake, SanitizeString, true},
-		})
+	{[]string{"CameraOwnerName"}, CameraOwnerName, SanitizeString, false},
-	}
+	{[]string{"BodySerialNumber"}, BodySerialNumber, SanitizeString, false},
-
+	{[]string{"LensMake"}, LensMake, SanitizeString, true},
-	cameraMode := ""
+	{[]string{"LensModel", "Lens"}, LensModel, SanitizeString, true},
-	if value, ok := exifMap["CameraModel"]; ok && !IsUInt(value) {
+	{[]string{"Software"}, Software, SanitizeString, false},
-		cameraMode = SanitizeString(value)
+	{[]string{"ISOSpeedRatings"}, ISOSpeedRatings, nil, false},
-	} else if value, ok = exifMap["Model"]; ok && !IsUInt(value) {
+	{[]string{"PixelXDimension", "ImageWidth"}, PixelXDimension, nil, false},
-		cameraMode = SanitizeString(value)
+	{[]string{"PixelYDimension", "ImageLength"}, PixelYDimension, nil, false},
-	} else if value, ok = exifMap["UniqueCameraModel"]; ok && !IsUInt(value) {
+	{[]string{"ImageDescription"}, ImageDescription, SanitizeDescription, false},
-		cameraMode = SanitizeString(value)
+	{[]string{"ProjectionType"}, ProjectionType, SanitizeString, false},
-	}
+}
-	if cameraMode != "" {
-		metas = append(metas, driver.MediaMeta{
-			Key:   CameraModel,
-			Value: cameraMode,
-		})
-	}
-
-	cameraMake := ""
-	if value, ok := exifMap["CameraMake"]; ok && !IsUInt(value) {
-		cameraMake = SanitizeString(value)
-	} else if value, ok = exifMap["Make"]; ok && !IsUInt(value) {
-		cameraMake = SanitizeString(value)
-	}
-	if cameraMake != "" {
-		metas = append(metas, driver.MediaMeta{
-			Key:   CameraMake,
-			Value: cameraMake,
-		})
-	}
-
-	if value, ok := exifMap["CameraOwnerName"]; ok {
-		metas = append(metas, driver.MediaMeta{
-			Key:   CameraOwnerName,
-			Value: SanitizeString(value),
-		})
-	}
 
-	if value, ok := exifMap["BodySerialNumber"]; ok {
+func extractExifTags(metas []driver.MediaMeta, exifMap map[string]string, from, to int) []driver.MediaMeta {
-		metas = append(metas, driver.MediaMeta{
+	for _, e := range exifTagTable[from:to] {
-			Key:   BodySerialNumber,
+		for _, k := range e.keys {
-			Value: SanitizeString(value),
+			v, ok := exifMap[k]
-		})
+			if !ok || (e.skipUint && IsUInt(v)) {
+				continue
 			}
-
+			if e.clean != nil {
-	if value, ok := exifMap["LensMake"]; ok && !IsUInt(value) {
+				v = e.clean(v)
-		metas = append(metas, driver.MediaMeta{
-			Key:   LensMake,
-			Value: SanitizeString(value),
-		})
 			}
-
+			metas = append(metas, driver.MediaMeta{Key: e.metaKey, Value: v})
-	lens := ""
+			break
-	if value, ok := exifMap["LensModel"]; ok && !IsUInt(value) {
-		lens = SanitizeString(value)
-	} else if value, ok = exifMap["Lens"]; ok && !IsUInt(value) {
-		lens = SanitizeString(value)
 		}
-	if lens != "" {
-		metas = append(metas, driver.MediaMeta{
-			Key:   LensModel,
-			Value: lens,
-		})
 	}
+	return metas
+}
 
-	if value, ok := exifMap["Software"]; ok {
+func ExtractExifMap(exifMap map[string]string, gpsTime time.Time) []driver.MediaMeta {
-		metas = append(metas, driver.MediaMeta{
+	metas := make([]driver.MediaMeta, 0)
-			Key:   Software,
+	metas = extractExifTags(metas, exifMap, 0, 9)
-			Value: SanitizeString(value),
-		})
-	}
 
 	if value, ok := exifMap["ExposureTime"]; ok {
 		value = strings.TrimSuffix(value, " sec.")
@@ -427,38 +388,9 @@ func ExtractExifMap(exifMap map[string]string, gpsTime time.Time) []driver.Media
 		})
 	}
 
-	if value, ok := exifMap["ISOSpeedRatings"]; ok {
+	metas = extractExifTags(metas, exifMap, 9, 10)
-		metas = append(metas, driver.MediaMeta{
-			Key:   ISOSpeedRatings,
-			Value: value,
-		})
-	}
-
-	width := ""
-	if value, ok := exifMap["PixelXDimension"]; ok {
-		width = value
-	} else if value, ok := exifMap["ImageWidth"]; ok {
-		width = value
-	}
-	if width != "" {
-		metas = append(metas, driver.MediaMeta{
-			Key:   PixelXDimension,
-			Value: width,
-		})
-	}
 
-	height := ""
+	metas = extractExifTags(metas, exifMap, 10, 12)
-	if value, ok := exifMap["PixelYDimension"]; ok {
-		height = value
-	} else if value, ok := exifMap["ImageLength"]; ok {
-		height = value
-	}
-	if height != "" {
-		metas = append(metas, driver.MediaMeta{
-			Key:   PixelYDimension,
-			Value: height,
-		})
-	}
 
 	orientation := "1"
 	if value, ok := exifMap["Orientation"]; ok {
@@ -498,19 +430,7 @@ func ExtractExifMap(exifMap map[string]string, gpsTime time.Time) []driver.Media
 		})
 	}
 
-	if value, ok := exifMap["ImageDescription"]; ok {
+	metas = extractExifTags(metas, exifMap, 12, 14)
-		metas = append(metas, driver.MediaMeta{
-			Key:   ImageDescription,
-			Value: SanitizeDescription(value),
-		})
-	}
-
-	if value, ok := exifMap["ProjectionType"]; ok {
-		metas = append(metas, driver.MediaMeta{
-			Key:   ProjectionType,
-			Value: SanitizeString(value),
-		})
-	}
 
 	return metas
 }

pkg/mediameta/exif_extract_test.go

@@ -0,0 +1,98 @@
+package mediameta
+
+import (
+	"testing"
+	"time"
+
+	"github.com/cloudreve/Cloudreve/v4/pkg/filemanager/driver"
+	"github.com/stretchr/testify/assert"
+)
+
+func findMeta(metas []driver.MediaMeta, key string) (driver.MediaMeta, bool) {
+	for _, m := range metas {
+		if m.Key == key {
+			return m, true
+		}
+	}
+	return driver.MediaMeta{}, false
+}
+
+func TestExtractExifMap(t *testing.T) {
+	a := assert.New(t)
+	metas := ExtractExifMap(map[string]string{
+		"Artist":           "ann",
+		"CameraModel":      "12345", // pure-uint vendor garbage, must fall back
+		"Model":            "X-T5",
+		"CameraMake":       "Fuji",
+		"LensModel":        "9999", // uint, falls back
+		"Lens":             "XF35",
+		"Software":         "darktable",
+		"PixelXDimension":  "6000",
+		"ImageLength":      "4000",
+		"ImageDescription": "desc",
+		"ProjectionType":   "equirectangular",
+		"DateTimeOriginal": "2020:01:02 03:04:05",
+		"ISOSpeedRatings":  "200",
+		"Flash":            "1",
+		"FNumber":          "28/10",
+		"Orientation":      "6",
+		"ImageWidth":       "9999", // shadowed by PixelXDimension
+	}, time.Time{})
+
+	v, ok := findMeta(metas, CameraModel)
+	a.True(ok)
+	a.Equal("X-T5", v.Value)
+
+	v, ok = findMeta(metas, LensModel)
+	a.True(ok)
+	a.Equal("XF35", v.Value)
+
+	v, ok = findMeta(metas, PixelXDimension)
+	a.True(ok)
+	a.Equal("6000", v.Value)
+
+	v, ok = findMeta(metas, PixelYDimension)
+	a.True(ok)
+	a.Equal("4000", v.Value)
+
+	v, ok = findMeta(metas, Orientation)
+	a.True(ok)
+	a.Equal("6", v.Value)
+
+	v, ok = findMeta(metas, TakenAt)
+	a.True(ok)
+	a.Equal("2020-01-02T03:04:05Z", v.Value)
+
+	v, ok = findMeta(metas, Flash)
+	a.True(ok)
+	a.Equal("1", v.Value)
+
+	v, ok = findMeta(metas, FNumber)
+	a.True(ok)
+	a.Equal("2.800000", v.Value)
+
+	v, ok = findMeta(metas, ImageDescription)
+	a.True(ok)
+	a.Equal("desc", v.Value)
+
+	v, ok = findMeta(metas, ProjectionType)
+	a.True(ok)
+	a.Equal("equirectangular", v.Value)
+
+	_, ok = findMeta(metas, Copyright)
+	a.False(ok)
+}
+
+func TestExtractExifMapDefaults(t *testing.T) {
+	a := assert.New(t)
+	metas := ExtractExifMap(map[string]string{}, time.Time{})
+
+	// Orientation is always emitted, defaulting to "1".
+	v, ok := findMeta(metas, Orientation)
+	a.True(ok)
+	a.Equal("1", v.Value)
+
+	// No date tags and zero GPS time -> no TakenAt.
+	_, ok = findMeta(metas, TakenAt)
+	a.False(ok)
+}