feat: filebrowser with encfs

img/service.go

@@ -0,0 +1,244 @@
+//go:generate go-enum --sql --marshal --file $GOFILE
+package img
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"image"
+	"io"
+
+	"github.com/disintegration/imaging"
+	"github.com/dsoprea/go-exif/v3"
+	"github.com/marusama/semaphore/v2"
+
+	exifcommon "github.com/dsoprea/go-exif/v3/common"
+)
+
+// ErrUnsupportedFormat means the given image format is not supported.
+var ErrUnsupportedFormat = errors.New("unsupported image format")
+
+// Service
+type Service struct {
+	sem semaphore.Semaphore
+}
+
+func New(workers int) *Service {
+	return &Service{
+		sem: semaphore.New(workers),
+	}
+}
+
+// Format is an image file format.
+/*
+ENUM(
+jpeg
+png
+gif
+tiff
+bmp
+)
+*/
+type Format int
+
+func (x Format) toImaging() imaging.Format {
+	switch x {
+	case FormatJpeg:
+		return imaging.JPEG
+	case FormatPng:
+		return imaging.PNG
+	case FormatGif:
+		return imaging.GIF
+	case FormatTiff:
+		return imaging.TIFF
+	case FormatBmp:
+		return imaging.BMP
+	default:
+		return imaging.JPEG
+	}
+}
+
+/*
+ENUM(
+high
+medium
+low
+)
+*/
+type Quality int
+
+func (x Quality) resampleFilter() imaging.ResampleFilter {
+	switch x {
+	case QualityHigh:
+		return imaging.Lanczos
+	case QualityMedium:
+		return imaging.Box
+	case QualityLow:
+		return imaging.NearestNeighbor
+	default:
+		return imaging.Box
+	}
+}
+
+/*
+ENUM(
+fit
+fill
+)
+*/
+type ResizeMode int
+
+func (s *Service) FormatFromExtension(ext string) (Format, error) {
+	format, err := imaging.FormatFromExtension(ext)
+	if err != nil {
+		return -1, ErrUnsupportedFormat
+	}
+	switch format {
+	case imaging.JPEG:
+		return FormatJpeg, nil
+	case imaging.PNG:
+		return FormatPng, nil
+	case imaging.GIF:
+		return FormatGif, nil
+	case imaging.TIFF:
+		return FormatTiff, nil
+	case imaging.BMP:
+		return FormatBmp, nil
+	}
+	return -1, ErrUnsupportedFormat
+}
+
+type resizeConfig struct {
+	format     Format
+	resizeMode ResizeMode
+	quality    Quality
+}
+
+type Option func(*resizeConfig)
+
+func WithFormat(format Format) Option {
+	return func(config *resizeConfig) {
+		config.format = format
+	}
+}
+
+func WithMode(mode ResizeMode) Option {
+	return func(config *resizeConfig) {
+		config.resizeMode = mode
+	}
+}
+
+func WithQuality(quality Quality) Option {
+	return func(config *resizeConfig) {
+		config.quality = quality
+	}
+}
+
+func (s *Service) Resize(ctx context.Context, in io.Reader, width, height int, out io.Writer, options ...Option) error {
+	if err := s.sem.Acquire(ctx, 1); err != nil {
+		return err
+	}
+	defer s.sem.Release(1)
+
+	format, wrappedReader, err := s.detectFormat(in)
+	if err != nil {
+		return err
+	}
+
+	config := resizeConfig{
+		format:     format,
+		resizeMode: ResizeModeFit,
+		quality:    QualityMedium,
+	}
+	for _, option := range options {
+		option(&config)
+	}
+
+	if config.quality == QualityLow && format == FormatJpeg {
+		thm, newWrappedReader, errThm := getEmbeddedThumbnail(wrappedReader)
+		wrappedReader = newWrappedReader
+		if errThm == nil {
+			_, err = out.Write(thm)
+			if err == nil {
+				return nil
+			}
+		}
+	}
+
+	img, err := imaging.Decode(wrappedReader, imaging.AutoOrientation(true))
+	if err != nil {
+		return err
+	}
+
+	switch config.resizeMode {
+	case ResizeModeFill:
+		img = imaging.Fill(img, width, height, imaging.Center, config.quality.resampleFilter())
+	case ResizeModeFit:
+		fallthrough //nolint:gocritic
+	default:
+		img = imaging.Fit(img, width, height, config.quality.resampleFilter())
+	}
+
+	return imaging.Encode(out, img, config.format.toImaging())
+}
+
+func (s *Service) detectFormat(in io.Reader) (Format, io.Reader, error) {
+	buf := &bytes.Buffer{}
+	r := io.TeeReader(in, buf)
+
+	_, imgFormat, err := image.DecodeConfig(r)
+	if err != nil {
+		return 0, nil, fmt.Errorf("%s: %w", err.Error(), ErrUnsupportedFormat)
+	}
+
+	format, err := ParseFormat(imgFormat)
+	if err != nil {
+		return 0, nil, ErrUnsupportedFormat
+	}
+
+	return format, io.MultiReader(buf, in), nil
+}
+
+func getEmbeddedThumbnail(in io.Reader) ([]byte, io.Reader, error) {
+	buf := &bytes.Buffer{}
+	r := io.TeeReader(in, buf)
+	wrappedReader := io.MultiReader(buf, in)
+
+	offset := 0
+	offsets := []int{12, 30}
+	head := make([]byte, 0xffff) //nolint:gomnd
+
+	_, err := r.Read(head)
+	if err != nil {
+		return nil, wrappedReader, err
+	}
+
+	for _, offset = range offsets {
+		if _, err = exif.ParseExifHeader(head[offset:]); err == nil {
+			break
+		}
+	}
+
+	if err != nil {
+		return nil, wrappedReader, err
+	}
+
+	im, err := exifcommon.NewIfdMappingWithStandard()
+	if err != nil {
+		return nil, wrappedReader, err
+	}
+
+	_, index, err := exif.Collect(im, exif.NewTagIndex(), head[offset:])
+	if err != nil {
+		return nil, wrappedReader, err
+	}
+
+	ifd := index.RootIfd.NextIfd()
+	if ifd == nil {
+		return nil, wrappedReader, exif.ErrNoThumbnail
+	}
+
+	thm, err := ifd.Thumbnail()
+	return thm, wrappedReader, err
+}

img/service_enum.go

@@ -0,0 +1,259 @@
+// Code generated by go-enum
+// DO NOT EDIT!
+
+package img
+
+import (
+	"database/sql/driver"
+	"fmt"
+)
+
+const (
+	// FormatJpeg is a Format of type Jpeg
+	FormatJpeg Format = iota
+	// FormatPng is a Format of type Png
+	FormatPng
+	// FormatGif is a Format of type Gif
+	FormatGif
+	// FormatTiff is a Format of type Tiff
+	FormatTiff
+	// FormatBmp is a Format of type Bmp
+	FormatBmp
+)
+
+const _FormatName = "jpegpnggiftiffbmp"
+
+var _FormatMap = map[Format]string{
+	0: _FormatName[0:4],
+	1: _FormatName[4:7],
+	2: _FormatName[7:10],
+	3: _FormatName[10:14],
+	4: _FormatName[14:17],
+}
+
+// String implements the Stringer interface.
+func (x Format) String() string {
+	if str, ok := _FormatMap[x]; ok {
+		return str
+	}
+	return fmt.Sprintf("Format(%d)", x)
+}
+
+var _FormatValue = map[string]Format{
+	_FormatName[0:4]:   0,
+	_FormatName[4:7]:   1,
+	_FormatName[7:10]:  2,
+	_FormatName[10:14]: 3,
+	_FormatName[14:17]: 4,
+}
+
+// ParseFormat attempts to convert a string to a Format
+func ParseFormat(name string) (Format, error) {
+	if x, ok := _FormatValue[name]; ok {
+		return x, nil
+	}
+	return Format(0), fmt.Errorf("%s is not a valid Format", name)
+}
+
+// MarshalText implements the text marshaller method
+func (x Format) MarshalText() ([]byte, error) {
+	return []byte(x.String()), nil
+}
+
+// UnmarshalText implements the text unmarshaller method
+func (x *Format) UnmarshalText(text []byte) error {
+	name := string(text)
+	tmp, err := ParseFormat(name)
+	if err != nil {
+		return err
+	}
+	*x = tmp
+	return nil
+}
+
+// Scan implements the Scanner interface.
+func (x *Format) Scan(value interface{}) error {
+	var name string
+
+	switch v := value.(type) {
+	case string:
+		name = v
+	case []byte:
+		name = string(v)
+	case nil:
+		*x = Format(0)
+		return nil
+	}
+
+	tmp, err := ParseFormat(name)
+	if err != nil {
+		return err
+	}
+	*x = tmp
+	return nil
+}
+
+// Value implements the driver Valuer interface.
+func (x Format) Value() (driver.Value, error) {
+	return x.String(), nil
+}
+
+const (
+	// QualityHigh is a Quality of type High
+	QualityHigh Quality = iota
+	// QualityMedium is a Quality of type Medium
+	QualityMedium
+	// QualityLow is a Quality of type Low
+	QualityLow
+)
+
+const _QualityName = "highmediumlow"
+
+var _QualityMap = map[Quality]string{
+	0: _QualityName[0:4],
+	1: _QualityName[4:10],
+	2: _QualityName[10:13],
+}
+
+// String implements the Stringer interface.
+func (x Quality) String() string {
+	if str, ok := _QualityMap[x]; ok {
+		return str
+	}
+	return fmt.Sprintf("Quality(%d)", x)
+}
+
+var _QualityValue = map[string]Quality{
+	_QualityName[0:4]:   0,
+	_QualityName[4:10]:  1,
+	_QualityName[10:13]: 2,
+}
+
+// ParseQuality attempts to convert a string to a Quality
+func ParseQuality(name string) (Quality, error) {
+	if x, ok := _QualityValue[name]; ok {
+		return x, nil
+	}
+	return Quality(0), fmt.Errorf("%s is not a valid Quality", name)
+}
+
+// MarshalText implements the text marshaller method
+func (x Quality) MarshalText() ([]byte, error) {
+	return []byte(x.String()), nil
+}
+
+// UnmarshalText implements the text unmarshaller method
+func (x *Quality) UnmarshalText(text []byte) error {
+	name := string(text)
+	tmp, err := ParseQuality(name)
+	if err != nil {
+		return err
+	}
+	*x = tmp
+	return nil
+}
+
+// Scan implements the Scanner interface.
+func (x *Quality) Scan(value interface{}) error {
+	var name string
+
+	switch v := value.(type) {
+	case string:
+		name = v
+	case []byte:
+		name = string(v)
+	case nil:
+		*x = Quality(0)
+		return nil
+	}
+
+	tmp, err := ParseQuality(name)
+	if err != nil {
+		return err
+	}
+	*x = tmp
+	return nil
+}
+
+// Value implements the driver Valuer interface.
+func (x Quality) Value() (driver.Value, error) {
+	return x.String(), nil
+}
+
+const (
+	// ResizeModeFit is a ResizeMode of type Fit
+	ResizeModeFit ResizeMode = iota
+	// ResizeModeFill is a ResizeMode of type Fill
+	ResizeModeFill
+)
+
+const _ResizeModeName = "fitfill"
+
+var _ResizeModeMap = map[ResizeMode]string{
+	0: _ResizeModeName[0:3],
+	1: _ResizeModeName[3:7],
+}
+
+// String implements the Stringer interface.
+func (x ResizeMode) String() string {
+	if str, ok := _ResizeModeMap[x]; ok {
+		return str
+	}
+	return fmt.Sprintf("ResizeMode(%d)", x)
+}
+
+var _ResizeModeValue = map[string]ResizeMode{
+	_ResizeModeName[0:3]: 0,
+	_ResizeModeName[3:7]: 1,
+}
+
+// ParseResizeMode attempts to convert a string to a ResizeMode
+func ParseResizeMode(name string) (ResizeMode, error) {
+	if x, ok := _ResizeModeValue[name]; ok {
+		return x, nil
+	}
+	return ResizeMode(0), fmt.Errorf("%s is not a valid ResizeMode", name)
+}
+
+// MarshalText implements the text marshaller method
+func (x ResizeMode) MarshalText() ([]byte, error) {
+	return []byte(x.String()), nil
+}
+
+// UnmarshalText implements the text unmarshaller method
+func (x *ResizeMode) UnmarshalText(text []byte) error {
+	name := string(text)
+	tmp, err := ParseResizeMode(name)
+	if err != nil {
+		return err
+	}
+	*x = tmp
+	return nil
+}
+
+// Scan implements the Scanner interface.
+func (x *ResizeMode) Scan(value interface{}) error {
+	var name string
+
+	switch v := value.(type) {
+	case string:
+		name = v
+	case []byte:
+		name = string(v)
+	case nil:
+		*x = ResizeMode(0)
+		return nil
+	}
+
+	tmp, err := ParseResizeMode(name)
+	if err != nil {
+		return err
+	}
+	*x = tmp
+	return nil
+}
+
+// Value implements the driver Valuer interface.
+func (x ResizeMode) Value() (driver.Value, error) {
+	return x.String(), nil
+}

img/service_test.go

@@ -0,0 +1,446 @@
+package img
+
+import (
+	"bytes"
+	"context"
+	"image"
+	"image/gif"
+	"image/jpeg"
+	"image/png"
+	"io"
+	"testing"
+
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/require"
+	"golang.org/x/image/bmp"
+	"golang.org/x/image/tiff"
+)
+
+func TestService_Resize(t *testing.T) {
+	testCases := map[string]struct {
+		options []Option
+		width   int
+		height  int
+		source  func(t *testing.T) afero.File
+		matcher func(t *testing.T, reader io.Reader)
+		wantErr bool
+	}{
+		"fill upscale": {
+			options: []Option{WithMode(ResizeModeFill)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 50, 20)
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"fill downscale": {
+			options: []Option{WithMode(ResizeModeFill)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"fit upscale": {
+			options: []Option{WithMode(ResizeModeFit)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 50, 20)
+			},
+			matcher: sizeMatcher(50, 20),
+		},
+		"fit downscale": {
+			options: []Option{WithMode(ResizeModeFit)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: sizeMatcher(100, 75),
+		},
+		"keep original format": {
+			options: []Option{},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayPng(t, 200, 150)
+			},
+			matcher: formatMatcher(FormatPng),
+		},
+		"convert to jpeg": {
+			options: []Option{WithFormat(FormatJpeg)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: formatMatcher(FormatJpeg),
+		},
+		"convert to png": {
+			options: []Option{WithFormat(FormatPng)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: formatMatcher(FormatPng),
+		},
+		"convert to gif": {
+			options: []Option{WithFormat(FormatGif)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: formatMatcher(FormatGif),
+		},
+		"convert to tiff": {
+			options: []Option{WithFormat(FormatTiff)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: formatMatcher(FormatTiff),
+		},
+		"convert to bmp": {
+			options: []Option{WithFormat(FormatBmp)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: formatMatcher(FormatBmp),
+		},
+		"convert to unknown": {
+			options: []Option{WithFormat(Format(-1))},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: formatMatcher(FormatJpeg),
+		},
+		"resize png": {
+			options: []Option{WithMode(ResizeModeFill)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayPng(t, 200, 150)
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"resize gif": {
+			options: []Option{WithMode(ResizeModeFill)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayGif(t, 200, 150)
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"resize tiff": {
+			options: []Option{WithMode(ResizeModeFill)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayTiff(t, 200, 150)
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"resize bmp": {
+			options: []Option{WithMode(ResizeModeFill)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayBmp(t, 200, 150)
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"resize with high quality": {
+			options: []Option{WithMode(ResizeModeFill), WithQuality(QualityHigh)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"resize with medium quality": {
+			options: []Option{WithMode(ResizeModeFill), WithQuality(QualityMedium)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"resize with low quality": {
+			options: []Option{WithMode(ResizeModeFill), WithQuality(QualityLow)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"resize with unknown quality": {
+			options: []Option{WithMode(ResizeModeFill), WithQuality(Quality(-1))},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return newGrayJpeg(t, 200, 150)
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"get thumbnail from file with APP0 JFIF": {
+			options: []Option{WithMode(ResizeModeFill), WithQuality(QualityLow)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return openFile(t, "testdata/gray-sample.jpg")
+			},
+			matcher: sizeMatcher(125, 128),
+		},
+		"get thumbnail from file without APP0 JFIF": {
+			options: []Option{WithMode(ResizeModeFill), WithQuality(QualityLow)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return openFile(t, "testdata/20130612_142406.jpg")
+			},
+			matcher: sizeMatcher(320, 240),
+		},
+		"resize from file without IFD1 thumbnail": {
+			options: []Option{WithMode(ResizeModeFill), WithQuality(QualityLow)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return openFile(t, "testdata/IMG_2578.JPG")
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"resize for higher quality levels": {
+			options: []Option{WithMode(ResizeModeFill), WithQuality(QualityMedium)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				return openFile(t, "testdata/gray-sample.jpg")
+			},
+			matcher: sizeMatcher(100, 100),
+		},
+		"broken file": {
+			options: []Option{WithMode(ResizeModeFit)},
+			width:   100,
+			height:  100,
+			source: func(t *testing.T) afero.File {
+				t.Helper()
+				fs := afero.NewMemMapFs()
+				file, err := fs.Create("image.jpg")
+				require.NoError(t, err)
+
+				_, err = file.WriteString("this is not an image")
+				require.NoError(t, err)
+
+				return file
+			},
+			wantErr: true,
+		},
+	}
+
+	for name, test := range testCases {
+		t.Run(name, func(t *testing.T) {
+			svc := New(1)
+			source := test.source(t)
+			defer source.Close()
+
+			buf := &bytes.Buffer{}
+			err := svc.Resize(context.Background(), source, test.width, test.height, buf, test.options...)
+			if (err != nil) != test.wantErr {
+				t.Fatalf("GetMarketSpecs() error = %v, wantErr %v", err, test.wantErr)
+			}
+			if err != nil {
+				return
+			}
+			test.matcher(t, buf)
+		})
+	}
+}
+
+func sizeMatcher(width, height int) func(t *testing.T, reader io.Reader) {
+	return func(t *testing.T, reader io.Reader) {
+		resizedImg, _, err := image.Decode(reader)
+		require.NoError(t, err)
+
+		require.Equal(t, width, resizedImg.Bounds().Dx())
+		require.Equal(t, height, resizedImg.Bounds().Dy())
+	}
+}
+
+func formatMatcher(format Format) func(t *testing.T, reader io.Reader) {
+	return func(t *testing.T, reader io.Reader) {
+		_, decodedFormat, err := image.DecodeConfig(reader)
+		require.NoError(t, err)
+
+		require.Equal(t, format.String(), decodedFormat)
+	}
+}
+
+func newGrayJpeg(t *testing.T, width, height int) afero.File {
+	fs := afero.NewMemMapFs()
+	file, err := fs.Create("image.jpg")
+	require.NoError(t, err)
+
+	img := image.NewGray(image.Rect(0, 0, width, height))
+	err = jpeg.Encode(file, img, &jpeg.Options{Quality: 90})
+	require.NoError(t, err)
+
+	_, err = file.Seek(0, io.SeekStart)
+	require.NoError(t, err)
+
+	return file
+}
+
+func newGrayPng(t *testing.T, width, height int) afero.File {
+	fs := afero.NewMemMapFs()
+	file, err := fs.Create("image.png")
+	require.NoError(t, err)
+
+	img := image.NewGray(image.Rect(0, 0, width, height))
+	err = png.Encode(file, img)
+	require.NoError(t, err)
+
+	_, err = file.Seek(0, io.SeekStart)
+	require.NoError(t, err)
+
+	return file
+}
+
+func newGrayGif(t *testing.T, width, height int) afero.File {
+	fs := afero.NewMemMapFs()
+	file, err := fs.Create("image.gif")
+	require.NoError(t, err)
+
+	img := image.NewGray(image.Rect(0, 0, width, height))
+	err = gif.Encode(file, img, nil)
+	require.NoError(t, err)
+
+	_, err = file.Seek(0, io.SeekStart)
+	require.NoError(t, err)
+
+	return file
+}
+
+func newGrayTiff(t *testing.T, width, height int) afero.File {
+	fs := afero.NewMemMapFs()
+	file, err := fs.Create("image.tiff")
+	require.NoError(t, err)
+
+	img := image.NewGray(image.Rect(0, 0, width, height))
+	err = tiff.Encode(file, img, nil)
+	require.NoError(t, err)
+
+	_, err = file.Seek(0, io.SeekStart)
+	require.NoError(t, err)
+
+	return file
+}
+
+func newGrayBmp(t *testing.T, width, height int) afero.File {
+	fs := afero.NewMemMapFs()
+	file, err := fs.Create("image.bmp")
+	require.NoError(t, err)
+
+	img := image.NewGray(image.Rect(0, 0, width, height))
+	err = bmp.Encode(file, img)
+	require.NoError(t, err)
+
+	_, err = file.Seek(0, io.SeekStart)
+	require.NoError(t, err)
+
+	return file
+}
+
+func openFile(t *testing.T, name string) afero.File {
+	appfs := afero.NewOsFs()
+	file, err := appfs.Open(name)
+
+	require.NoError(t, err)
+
+	return file
+}
+
+func TestService_FormatFromExtension(t *testing.T) {
+	testCases := map[string]struct {
+		ext     string
+		want    Format
+		wantErr error
+	}{
+		"jpg": {
+			ext:  ".jpg",
+			want: FormatJpeg,
+		},
+		"jpeg": {
+			ext:  ".jpeg",
+			want: FormatJpeg,
+		},
+		"png": {
+			ext:  ".png",
+			want: FormatPng,
+		},
+		"gif": {
+			ext:  ".gif",
+			want: FormatGif,
+		},
+		"tiff": {
+			ext:  ".tiff",
+			want: FormatTiff,
+		},
+		"bmp": {
+			ext:  ".bmp",
+			want: FormatBmp,
+		},
+		"unknown": {
+			ext:     ".mov",
+			wantErr: ErrUnsupportedFormat,
+		},
+	}
+
+	for name, test := range testCases {
+		t.Run(name, func(t *testing.T) {
+			svc := New(1)
+			got, err := svc.FormatFromExtension(test.ext)
+			require.ErrorIsf(t, err, test.wantErr, "error = %v, wantErr %v", err, test.wantErr)
+			if err != nil {
+				return
+			}
+			require.Equal(t, test.want, got)
+		})
+	}
+}