refactor: use Params struct for imageprocessor constructor

Rename NewImageProcessor(maxInputBytes) to New(Params{}) with a Params
struct containing MaxInputBytes. Zero-value Params{} uses sensible
defaults (DefaultMaxInputBytes). All callers updated.

Addresses review feedback on PR #37.

README.md

@@ -67,10 +67,7 @@ hosts require an HMAC-SHA256 signature.
 #### Signature Specification
 
 Signatures use HMAC-SHA256 and include an expiration timestamp to
-prevent replay attacks. Signatures are **exact match only**: every
+prevent replay attacks.
-component (host, path, query, dimensions, format, expiration) must
-match exactly what was signed. No suffix matching, wildcard matching,
-or partial matching is supported.
 
 **Signed data format** (colon-separated):
 

cmd/pixad/main.go

@@ -17,7 +17,10 @@ import (
 	"sneak.berlin/go/pixa/internal/server"
 )
 
-var Version string //nolint:gochecknoglobals // set by ldflags
+var (
+	Appname = "pixad" //nolint:gochecknoglobals // set by ldflags
+	Version string    //nolint:gochecknoglobals // set by ldflags
+)
 
 var configPath string //nolint:gochecknoglobals // cobra flag
 
@@ -37,6 +40,7 @@ func main() {
 }
 
 func run(_ *cobra.Command, _ []string) {
+	globals.Appname = Appname
 	globals.Version = Version
 
 	// Set config path in environment if specified via flag

internal/database/database.go

@@ -9,7 +9,6 @@ import (
 	"log/slog"
 	"path/filepath"
 	"sort"
-	"strconv"
 	"strings"
 
 	"go.uber.org/fx"
@@ -22,10 +21,6 @@ import (
 //go:embed schema/*.sql
 var schemaFS embed.FS
 
-// bootstrapVersion is the migration that creates the schema_migrations
-// table itself. It is applied before the normal migration loop.
-const bootstrapVersion = 0
-
 // Params defines dependencies for Database.
 type Params struct {
 	fx.In
@@ -43,40 +38,35 @@ type Database struct {
 // ParseMigrationVersion extracts the numeric version prefix from a migration
 // filename. Filenames must follow the pattern "<version>.sql" or
 // "<version>_<description>.sql", where version is a zero-padded numeric
-// string (e.g. "001", "002"). Returns the version as an integer and an
+// string (e.g. "001", "002"). Returns the version string and an error if
-// error if the filename does not match the expected pattern.
+// the filename does not match the expected pattern.
-func ParseMigrationVersion(filename string) (int, error) {
+func ParseMigrationVersion(filename string) (string, error) {
 	name := strings.TrimSuffix(filename, filepath.Ext(filename))
 	if name == "" {
-		return 0, fmt.Errorf("invalid migration filename %q: empty name", filename)
+		return "", fmt.Errorf("invalid migration filename %q: empty name", filename)
 	}
 
 	// Split on underscore to separate version from description.
 	// If there's no underscore, the entire stem is the version.
-	versionStr := name
+	version := name
 	if idx := strings.IndexByte(name, '_'); idx >= 0 {
-		versionStr = name[:idx]
+		version = name[:idx]
 	}
 
-	if versionStr == "" {
+	if version == "" {
-		return 0, fmt.Errorf("invalid migration filename %q: empty version prefix", filename)
+		return "", fmt.Errorf("invalid migration filename %q: empty version prefix", filename)
 	}
 
 	// Validate the version is purely numeric.
-	for _, ch := range versionStr {
+	for _, ch := range version {
 		if ch < '0' || ch > '9' {
-			return 0, fmt.Errorf(
+			return "", fmt.Errorf(
 				"invalid migration filename %q: version %q contains non-numeric character %q",
-				filename, versionStr, string(ch),
+				filename, version, string(ch),
 			)
 		}
 	}
 
-	version, err := strconv.Atoi(versionStr)
-	if err != nil {
-		return 0, fmt.Errorf("invalid migration filename %q: %w", filename, err)
-	}
-
 	return version, nil
 }
 
@@ -153,34 +143,17 @@ func collectMigrations() ([]string, error) {
 	return migrations, nil
 }
 
-// bootstrapMigrationsTable ensures the schema_migrations table exists
+// ensureMigrationsTable creates the schema_migrations tracking table if
-// by applying 000.sql if the table is missing.
+// it does not already exist.
-func bootstrapMigrationsTable(ctx context.Context, db *sql.DB, log *slog.Logger) error {
+func ensureMigrationsTable(ctx context.Context, db *sql.DB) error {
-	var tableExists int
+	_, err := db.ExecContext(ctx, `
-
+		CREATE TABLE IF NOT EXISTS schema_migrations (
-	err := db.QueryRowContext(ctx,
+			version TEXT PRIMARY KEY,
-		"SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='schema_migrations'",
+			applied_at DATETIME DEFAULT CURRENT_TIMESTAMP
-	).Scan(&tableExists)
+		)
+	`)
 	if err != nil {
-		return fmt.Errorf("failed to check for migrations table: %w", err)
+		return fmt.Errorf("failed to create migrations table: %w", err)
-	}
-
-	if tableExists > 0 {
-		return nil
-	}
-
-	content, err := schemaFS.ReadFile("schema/000.sql")
-	if err != nil {
-		return fmt.Errorf("failed to read bootstrap migration 000.sql: %w", err)
-	}
-
-	if log != nil {
-		log.Info("applying bootstrap migration", "version", bootstrapVersion)
-	}
-
-	_, err = db.ExecContext(ctx, string(content))
-	if err != nil {
-		return fmt.Errorf("failed to apply bootstrap migration: %w", err)
 	}
 
 	return nil
@@ -191,7 +164,7 @@ func bootstrapMigrationsTable(ctx context.Context, db *sql.DB, log *slog.Logger)
 // This is exported so tests can apply the real schema without the full fx
 // lifecycle.
 func ApplyMigrations(ctx context.Context, db *sql.DB, log *slog.Logger) error {
-	if err := bootstrapMigrationsTable(ctx, db, log); err != nil {
+	if err := ensureMigrationsTable(ctx, db); err != nil {
 		return err
 	}
 

internal/database/database_test.go

@@ -8,51 +8,37 @@ import (
 	_ "modernc.org/sqlite" // SQLite driver registration
 )
 
-// openTestDB returns a fresh in-memory SQLite database.
-func openTestDB(t *testing.T) *sql.DB {
-	t.Helper()
-
-	db, err := sql.Open("sqlite", ":memory:")
-	if err != nil {
-		t.Fatalf("failed to open test db: %v", err)
-	}
-
-	t.Cleanup(func() { db.Close() })
-
-	return db
-}
-
 func TestParseMigrationVersion(t *testing.T) {
 	tests := []struct {
 		name     string
 		filename string
-		want     int
+		want     string
 		wantErr  bool
 	}{
 		{
 			name:     "version only",
 			filename: "001.sql",
-			want:     1,
+			want:     "001",
 		},
 		{
 			name:     "version with description",
 			filename: "001_initial_schema.sql",
-			want:     1,
+			want:     "001",
 		},
 		{
 			name:     "multi-digit version",
 			filename: "042_add_indexes.sql",
-			want:     42,
+			want:     "042",
 		},
 		{
 			name:     "long version number",
 			filename: "00001_long_prefix.sql",
-			want:     1,
+			want:     "00001",
 		},
 		{
 			name:     "description with multiple underscores",
 			filename: "003_add_user_auth_tables.sql",
-			want:     3,
+			want:     "003",
 		},
 		{
 			name:     "empty filename",
@@ -81,7 +67,7 @@ func TestParseMigrationVersion(t *testing.T) {
 			got, err := ParseMigrationVersion(tt.filename)
 			if tt.wantErr {
 				if err == nil {
-					t.Errorf("ParseMigrationVersion(%q) expected error, got %d", tt.filename, got)
+					t.Errorf("ParseMigrationVersion(%q) expected error, got %q", tt.filename, got)
 				}
 
 				return
@@ -94,131 +80,76 @@ func TestParseMigrationVersion(t *testing.T) {
 			}
 
 			if got != tt.want {
-				t.Errorf("ParseMigrationVersion(%q) = %d, want %d", tt.filename, got, tt.want)
+				t.Errorf("ParseMigrationVersion(%q) = %q, want %q", tt.filename, got, tt.want)
 			}
 		})
 	}
 }
 
-func TestApplyMigrations_CreatesSchemaAndTables(t *testing.T) {
+func TestApplyMigrations(t *testing.T) {
-	db := openTestDB(t)
+	db, err := sql.Open("sqlite", ":memory:")
-	ctx := context.Background()
+	if err != nil {
+		t.Fatalf("failed to open in-memory database: %v", err)
+	}
+	defer db.Close()
 
-	if err := ApplyMigrations(ctx, db, nil); err != nil {
+	// Apply migrations should succeed.
+	if err := ApplyMigrations(context.Background(), db, nil); err != nil {
 		t.Fatalf("ApplyMigrations failed: %v", err)
 	}
 
-	// The schema_migrations table must exist and contain at least
+	// Verify the schema_migrations table recorded the version.
-	// version 0 (the bootstrap) and 1 (the initial schema).
+	var version string
-	rows, err := db.Query("SELECT version FROM schema_migrations ORDER BY version")
+
+	err = db.QueryRowContext(context.Background(),
+		"SELECT version FROM schema_migrations LIMIT 1",
+	).Scan(&version)
 	if err != nil {
 		t.Fatalf("failed to query schema_migrations: %v", err)
 	}
-	defer rows.Close()
 
-	var versions []int
+	if version != "001" {
-	for rows.Next() {
+		t.Errorf("expected version %q, got %q", "001", version)
-		var v int
-		if err := rows.Scan(&v); err != nil {
-			t.Fatalf("failed to scan version: %v", err)
 	}
 
-		versions = append(versions, v)
+	// Verify a table from the migration exists (source_content).
-	}
+	var tableName string
 
-	if err := rows.Err(); err != nil {
+	err = db.QueryRowContext(context.Background(),
-		t.Fatalf("row iteration error: %v", err)
+		"SELECT name FROM sqlite_master WHERE type='table' AND name='source_content'",
-	}
+	).Scan(&tableName)
-
-	if len(versions) < 2 {
-		t.Fatalf("expected at least 2 migrations recorded, got %d: %v", len(versions), versions)
-	}
-
-	if versions[0] != 0 {
-		t.Errorf("first recorded migration = %d, want %d", versions[0], 0)
-	}
-
-	if versions[1] != 1 {
-		t.Errorf("second recorded migration = %d, want %d", versions[1], 1)
-	}
-
-	// Verify that the application tables created by 001.sql exist.
-	for _, table := range []string{"source_content", "source_metadata", "output_content", "request_cache", "negative_cache", "cache_stats"} {
-		var count int
-
-		err := db.QueryRow(
-			"SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name=?",
-			table,
-		).Scan(&count)
 	if err != nil {
-			t.Fatalf("failed to check for table %s: %v", table, err)
+		t.Fatalf("expected source_content table to exist: %v", err)
-		}
-
-		if count != 1 {
-			t.Errorf("table %s does not exist after migrations", table)
-		}
 	}
 }
 
-func TestApplyMigrations_Idempotent(t *testing.T) {
+func TestApplyMigrationsIdempotent(t *testing.T) {
-	db := openTestDB(t)
+	db, err := sql.Open("sqlite", ":memory:")
-	ctx := context.Background()
+	if err != nil {
+		t.Fatalf("failed to open in-memory database: %v", err)
+	}
+	defer db.Close()
 
-	if err := ApplyMigrations(ctx, db, nil); err != nil {
+	// Apply twice should succeed (idempotent).
+	if err := ApplyMigrations(context.Background(), db, nil); err != nil {
 		t.Fatalf("first ApplyMigrations failed: %v", err)
 	}
 
-	// Running a second time must succeed without errors.
+	if err := ApplyMigrations(context.Background(), db, nil); err != nil {
-	if err := ApplyMigrations(ctx, db, nil); err != nil {
 		t.Fatalf("second ApplyMigrations failed: %v", err)
 	}
 
-	// Verify no duplicate rows in schema_migrations.
+	// Should still have exactly one migration recorded.
 	var count int
 
-	err := db.QueryRow("SELECT COUNT(*) FROM schema_migrations WHERE version = 0").Scan(&count)
+	err = db.QueryRowContext(context.Background(),
+		"SELECT COUNT(*) FROM schema_migrations",
+	).Scan(&count)
 	if err != nil {
-		t.Fatalf("failed to count version 0 rows: %v", err)
+		t.Fatalf("failed to count schema_migrations: %v", err)
 	}
 
 	if count != 1 {
-		t.Errorf("expected exactly 1 row for version 0, got %d", count)
+		t.Errorf("expected 1 migration record, got %d", count)
-	}
-}
-
-func TestBootstrapMigrationsTable_FreshDatabase(t *testing.T) {
-	db := openTestDB(t)
-	ctx := context.Background()
-
-	if err := bootstrapMigrationsTable(ctx, db, nil); err != nil {
-		t.Fatalf("bootstrapMigrationsTable failed: %v", err)
-	}
-
-	// schema_migrations table must exist.
-	var tableCount int
-
-	err := db.QueryRow(
-		"SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='schema_migrations'",
-	).Scan(&tableCount)
-	if err != nil {
-		t.Fatalf("failed to check for table: %v", err)
-	}
-
-	if tableCount != 1 {
-		t.Fatalf("schema_migrations table not created")
-	}
-
-	// Version 0 must be recorded.
-	var recorded int
-
-	err = db.QueryRow(
-		"SELECT COUNT(*) FROM schema_migrations WHERE version = 0",
-	).Scan(&recorded)
-	if err != nil {
-		t.Fatalf("failed to check version: %v", err)
-	}
-
-	if recorded != 1 {
-		t.Errorf("expected version 0 to be recorded, got count %d", recorded)
 	}
 }

internal/database/schema/000.sql

@@ -1,9 +0,0 @@
--- Migration 000: Schema migrations tracking table
--- Applied as a bootstrap step before the normal migration loop.
-
-CREATE TABLE IF NOT EXISTS schema_migrations (
-    version INTEGER PRIMARY KEY,
-    applied_at DATETIME DEFAULT CURRENT_TIMESTAMP
-);
-
-INSERT OR IGNORE INTO schema_migrations (version) VALUES (0);

internal/globals/globals.go

@@ -5,10 +5,11 @@ import (
 	"go.uber.org/fx"
 )
 
-const appname = "pixad"
+// Build-time variables populated from main() via ldflags.
-
+var (
-// Version is populated from main() via ldflags.
+	Appname string //nolint:gochecknoglobals // set from main
-var Version string //nolint:gochecknoglobals // set from main
+	Version string //nolint:gochecknoglobals // set from main
+)
 
 // Globals holds application-wide constants.
 type Globals struct {
@@ -19,7 +20,7 @@ type Globals struct {
 // New creates a new Globals instance from build-time variables.
 func New(_ fx.Lifecycle) (*Globals, error) {
 	return &Globals{
-		Appname: appname,
+		Appname: Appname,
 		Version: Version,
 	}, nil
 }

internal/imgcache/imgcache.go

@@ -199,6 +199,36 @@ type FetchResult struct {
 	TLSCipherSuite string
 }
 
+// Processor handles image transformation (resize, format conversion)
+type Processor interface {
+	// Process transforms an image according to the request
+	Process(ctx context.Context, input io.Reader, req *ImageRequest) (*ProcessResult, error)
+	// SupportedInputFormats returns MIME types this processor can read
+	SupportedInputFormats() []string
+	// SupportedOutputFormats returns formats this processor can write
+	SupportedOutputFormats() []ImageFormat
+}
+
+// ProcessResult contains the result of image processing
+type ProcessResult struct {
+	// Content is the processed image data
+	Content io.ReadCloser
+	// ContentLength is the size in bytes
+	ContentLength int64
+	// ContentType is the MIME type of the output
+	ContentType string
+	// Width is the output image width
+	Width int
+	// Height is the output image height
+	Height int
+	// InputWidth is the original image width before processing
+	InputWidth int
+	// InputHeight is the original image height before processing
+	InputHeight int
+	// InputFormat is the detected input format (e.g., "jpeg", "png")
+	InputFormat string
+}
+
 // Storage handles persistent storage of cached content
 type Storage interface {
 	// Store saves content and returns its hash

internal/imgcache/processor.go

@@ -1,5 +1,4 @@
-// Package imageprocessor provides image format conversion and resizing using libvips.
+package imgcache
-package imageprocessor
 
 import (
 	"bytes"
@@ -23,68 +22,6 @@ func initVips() {
 	})
 }
 
-// Format represents supported output image formats.
-type Format string
-
-// Supported image output formats.
-const (
-	FormatOriginal Format = "orig"
-	FormatJPEG     Format = "jpeg"
-	FormatPNG      Format = "png"
-	FormatWebP     Format = "webp"
-	FormatAVIF     Format = "avif"
-	FormatGIF      Format = "gif"
-)
-
-// FitMode represents how to fit an image into requested dimensions.
-type FitMode string
-
-// Supported image fit modes.
-const (
-	FitCover   FitMode = "cover"
-	FitContain FitMode = "contain"
-	FitFill    FitMode = "fill"
-	FitInside  FitMode = "inside"
-	FitOutside FitMode = "outside"
-)
-
-// ErrInvalidFitMode is returned when an invalid fit mode is provided.
-var ErrInvalidFitMode = errors.New("invalid fit mode")
-
-// Size represents requested image dimensions.
-type Size struct {
-	Width  int
-	Height int
-}
-
-// Request holds the parameters for image processing.
-type Request struct {
-	Size    Size
-	Format  Format
-	Quality int
-	FitMode FitMode
-}
-
-// Result contains the output of image processing.
-type Result struct {
-	// Content is the processed image data.
-	Content io.ReadCloser
-	// ContentLength is the size in bytes.
-	ContentLength int64
-	// ContentType is the MIME type of the output.
-	ContentType string
-	// Width is the output image width.
-	Width int
-	// Height is the output image height.
-	Height int
-	// InputWidth is the original image width before processing.
-	InputWidth int
-	// InputHeight is the original image height before processing.
-	InputHeight int
-	// InputFormat is the detected input format (e.g., "jpeg", "png").
-	InputFormat string
-}
-
 // MaxInputDimension is the maximum allowed width or height for input images.
 // Images larger than this are rejected to prevent DoS via decompression bombs.
 const MaxInputDimension = 8192
@@ -102,7 +39,7 @@ var ErrInputDataTooLarge = errors.New("input data exceeds maximum allowed size")
 // ErrUnsupportedOutputFormat is returned when the requested output format is not supported.
 var ErrUnsupportedOutputFormat = errors.New("unsupported output format")
 
-// ImageProcessor implements image transformation using libvips via govips.
+// ImageProcessor implements the Processor interface using libvips via govips.
 type ImageProcessor struct {
 	maxInputBytes int64
 }
@@ -134,8 +71,8 @@ func New(params Params) *ImageProcessor {
 func (p *ImageProcessor) Process(
 	_ context.Context,
 	input io.Reader,
-	req *Request,
+	req *ImageRequest,
-) (*Result, error) {
+) (*ProcessResult, error) {
 	// Read input with a size limit to prevent unbounded memory consumption.
 	// We read at most maxInputBytes+1 so we can detect if the input exceeds
 	// the limit without consuming additional memory.
@@ -205,10 +142,10 @@ func (p *ImageProcessor) Process(
 		return nil, fmt.Errorf("failed to encode: %w", err)
 	}
 
-	return &Result{
+	return &ProcessResult{
 		Content:       io.NopCloser(bytes.NewReader(output)),
 		ContentLength: int64(len(output)),
-		ContentType:   FormatToMIME(outputFormat),
+		ContentType:   ImageFormatToMIME(outputFormat),
 		Width:         img.Width(),
 		Height:        img.Height(),
 		InputWidth:    origWidth,
@@ -220,17 +157,17 @@ func (p *ImageProcessor) Process(
 // SupportedInputFormats returns MIME types this processor can read.
 func (p *ImageProcessor) SupportedInputFormats() []string {
 	return []string{
-		"image/jpeg",
+		string(MIMETypeJPEG),
-		"image/png",
+		string(MIMETypePNG),
-		"image/gif",
+		string(MIMETypeGIF),
-		"image/webp",
+		string(MIMETypeWebP),
-		"image/avif",
+		string(MIMETypeAVIF),
 	}
 }
 
 // SupportedOutputFormats returns formats this processor can write.
-func (p *ImageProcessor) SupportedOutputFormats() []Format {
+func (p *ImageProcessor) SupportedOutputFormats() []ImageFormat {
-	return []Format{
+	return []ImageFormat{
 		FormatJPEG,
 		FormatPNG,
 		FormatGIF,
@@ -239,24 +176,6 @@ func (p *ImageProcessor) SupportedOutputFormats() []Format {
 	}
 }
 
-// FormatToMIME converts a Format to its MIME type string.
-func FormatToMIME(format Format) string {
-	switch format {
-	case FormatJPEG:
-		return "image/jpeg"
-	case FormatPNG:
-		return "image/png"
-	case FormatWebP:
-		return "image/webp"
-	case FormatGIF:
-		return "image/gif"
-	case FormatAVIF:
-		return "image/avif"
-	default:
-		return "application/octet-stream"
-	}
-}
-
 // detectFormat returns the format string from a vips image.
 func (p *ImageProcessor) detectFormat(img *vips.ImageRef) string {
 	format := img.Format()
@@ -285,6 +204,7 @@ func (p *ImageProcessor) resize(img *vips.ImageRef, width, height int, fit FitMo
 
 	case FitContain:
 		// Resize to fit within dimensions, maintaining aspect ratio
+		// Calculate target dimensions maintaining aspect ratio
 		imgW, imgH := img.Width(), img.Height()
 		scaleW := float64(width) / float64(imgW)
 		scaleH := float64(height) / float64(imgH)
@@ -295,7 +215,7 @@ func (p *ImageProcessor) resize(img *vips.ImageRef, width, height int, fit FitMo
 		return img.Thumbnail(newW, newH, vips.InterestingNone)
 
 	case FitFill:
-		// Resize to exact dimensions (may distort)
+		// Resize to exact dimensions (may distort) - use ThumbnailWithSize with Force
 		return img.ThumbnailWithSize(width, height, vips.InterestingNone, vips.SizeForce)
 
 	case FitInside:
@@ -331,7 +251,7 @@ func (p *ImageProcessor) resize(img *vips.ImageRef, width, height int, fit FitMo
 const defaultQuality = 85
 
 // encode encodes an image to the specified format.
-func (p *ImageProcessor) encode(img *vips.ImageRef, format Format, quality int) ([]byte, error) {
+func (p *ImageProcessor) encode(img *vips.ImageRef, format ImageFormat, quality int) ([]byte, error) {
 	if quality <= 0 {
 		quality = defaultQuality
 	}
@@ -379,8 +299,8 @@ func (p *ImageProcessor) encode(img *vips.ImageRef, format Format, quality int)
 	return output, nil
 }
 
-// formatFromString converts a format string to Format.
+// formatFromString converts a format string to ImageFormat.
-func (p *ImageProcessor) formatFromString(format string) Format {
+func (p *ImageProcessor) formatFromString(format string) ImageFormat {
 	switch format {
 	case "jpeg":
 		return FormatJPEG

internal/imgcache/processor_test.go

@@ -1,4 +1,4 @@
-package imageprocessor
+package imgcache
 
 import (
 	"bytes"
@@ -70,36 +70,13 @@ func createTestPNG(t *testing.T, width, height int) []byte {
 	return buf.Bytes()
 }
 
-// detectMIME is a minimal magic-byte detector for test assertions.
-func detectMIME(data []byte) string {
-	if len(data) >= 3 && data[0] == 0xFF && data[1] == 0xD8 && data[2] == 0xFF {
-		return "image/jpeg"
-	}
-	if len(data) >= 8 && string(data[:8]) == "\x89PNG\r\n\x1a\n" {
-		return "image/png"
-	}
-	if len(data) >= 4 && string(data[:4]) == "GIF8" {
-		return "image/gif"
-	}
-	if len(data) >= 12 && string(data[:4]) == "RIFF" && string(data[8:12]) == "WEBP" {
-		return "image/webp"
-	}
-	if len(data) >= 12 && string(data[4:8]) == "ftyp" {
-		brand := string(data[8:12])
-		if brand == "avif" || brand == "avis" {
-			return "image/avif"
-		}
-	}
-	return ""
-}
-
 func TestImageProcessor_ResizeJPEG(t *testing.T) {
 	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestJPEG(t, 800, 600)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 400, Height: 300},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -130,9 +107,13 @@ func TestImageProcessor_ResizeJPEG(t *testing.T) {
 		t.Fatalf("failed to read result: %v", err)
 	}
 
-	mime := detectMIME(data)
+	mime, err := DetectFormat(data)
-	if mime != "image/jpeg" {
+	if err != nil {
-		t.Errorf("Output format = %v, want image/jpeg", mime)
+		t.Fatalf("DetectFormat() error = %v", err)
+	}
+
+	if mime != MIMETypeJPEG {
+		t.Errorf("Output format = %v, want %v", mime, MIMETypeJPEG)
 	}
 }
 
@@ -142,7 +123,7 @@ func TestImageProcessor_ConvertToPNG(t *testing.T) {
 
 	input := createTestJPEG(t, 200, 150)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 200, Height: 150},
 		Format:  FormatPNG,
 		FitMode: FitCover,
@@ -159,9 +140,13 @@ func TestImageProcessor_ConvertToPNG(t *testing.T) {
 		t.Fatalf("failed to read result: %v", err)
 	}
 
-	mime := detectMIME(data)
+	mime, err := DetectFormat(data)
-	if mime != "image/png" {
+	if err != nil {
-		t.Errorf("Output format = %v, want image/png", mime)
+		t.Fatalf("DetectFormat() error = %v", err)
+	}
+
+	if mime != MIMETypePNG {
+		t.Errorf("Output format = %v, want %v", mime, MIMETypePNG)
 	}
 }
 
@@ -171,7 +156,7 @@ func TestImageProcessor_OriginalSize(t *testing.T) {
 
 	input := createTestJPEG(t, 640, 480)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 0, Height: 0}, // Original size
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -201,7 +186,7 @@ func TestImageProcessor_FitContain(t *testing.T) {
 	// Should result in 400x200 (maintaining aspect ratio)
 	input := createTestJPEG(t, 800, 400)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 400, Height: 400},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -228,7 +213,7 @@ func TestImageProcessor_ProportionalScale_WidthOnly(t *testing.T) {
 	// Should scale proportionally to 400x300
 	input := createTestJPEG(t, 800, 600)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 400, Height: 0},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -258,7 +243,7 @@ func TestImageProcessor_ProportionalScale_HeightOnly(t *testing.T) {
 	// Should scale proportionally to 400x300
 	input := createTestJPEG(t, 800, 600)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 0, Height: 300},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -286,7 +271,7 @@ func TestImageProcessor_ProcessPNG(t *testing.T) {
 
 	input := createTestPNG(t, 400, 300)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 200, Height: 150},
 		Format:  FormatPNG,
 		FitMode: FitCover,
@@ -307,6 +292,11 @@ func TestImageProcessor_ProcessPNG(t *testing.T) {
 	}
 }
 
+func TestImageProcessor_ImplementsInterface(t *testing.T) {
+	// Verify ImageProcessor implements Processor interface
+	var _ Processor = (*ImageProcessor)(nil)
+}
+
 func TestImageProcessor_SupportedFormats(t *testing.T) {
 	proc := New(Params{})
 
@@ -329,7 +319,7 @@ func TestImageProcessor_RejectsOversizedInput(t *testing.T) {
 	// This should be rejected before processing to prevent DoS
 	input := createTestJPEG(t, 10000, 100)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 100, Height: 100},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -353,7 +343,7 @@ func TestImageProcessor_RejectsOversizedInputHeight(t *testing.T) {
 	// Create an image with oversized height
 	input := createTestJPEG(t, 100, 10000)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 100, Height: 100},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -375,9 +365,10 @@ func TestImageProcessor_AcceptsMaxDimensionInput(t *testing.T) {
 	ctx := context.Background()
 
 	// Create an image at exactly MaxInputDimension - should be accepted
+	// Using smaller dimensions to keep test fast
 	input := createTestJPEG(t, MaxInputDimension, 100)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 100, Height: 100},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -397,7 +388,7 @@ func TestImageProcessor_EncodeWebP(t *testing.T) {
 
 	input := createTestJPEG(t, 200, 150)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 100, Height: 75},
 		Format:  FormatWebP,
 		Quality: 80,
@@ -416,9 +407,13 @@ func TestImageProcessor_EncodeWebP(t *testing.T) {
 		t.Fatalf("failed to read result: %v", err)
 	}
 
-	mime := detectMIME(data)
+	mime, err := DetectFormat(data)
-	if mime != "image/webp" {
+	if err != nil {
-		t.Errorf("Output format = %v, want image/webp", mime)
+		t.Fatalf("DetectFormat() error = %v", err)
+	}
+
+	if mime != MIMETypeWebP {
+		t.Errorf("Output format = %v, want %v", mime, MIMETypeWebP)
 	}
 
 	// Verify dimensions
@@ -441,7 +436,7 @@ func TestImageProcessor_DecodeAVIF(t *testing.T) {
 	}
 
 	// Request resize and convert to JPEG
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 2, Height: 2},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -460,9 +455,13 @@ func TestImageProcessor_DecodeAVIF(t *testing.T) {
 		t.Fatalf("failed to read result: %v", err)
 	}
 
-	mime := detectMIME(data)
+	mime, err := DetectFormat(data)
-	if mime != "image/jpeg" {
+	if err != nil {
-		t.Errorf("Output format = %v, want image/jpeg", mime)
+		t.Fatalf("DetectFormat() error = %v", err)
+	}
+
+	if mime != MIMETypeJPEG {
+		t.Errorf("Output format = %v, want %v", mime, MIMETypeJPEG)
 	}
 }
 
@@ -478,7 +477,7 @@ func TestImageProcessor_RejectsOversizedInputData(t *testing.T) {
 		t.Fatalf("test JPEG must exceed %d bytes, got %d", limit, len(input))
 	}
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 100, Height: 75},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -503,7 +502,7 @@ func TestImageProcessor_AcceptsInputWithinLimit(t *testing.T) {
 	proc := New(Params{MaxInputBytes: limit})
 	ctx := context.Background()
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 10, Height: 10},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -537,7 +536,7 @@ func TestImageProcessor_EncodeAVIF(t *testing.T) {
 
 	input := createTestJPEG(t, 200, 150)
 
-	req := &Request{
+	req := &ImageRequest{
 		Size:    Size{Width: 100, Height: 75},
 		Format:  FormatAVIF,
 		Quality: 85,
@@ -556,9 +555,13 @@ func TestImageProcessor_EncodeAVIF(t *testing.T) {
 		t.Fatalf("failed to read result: %v", err)
 	}
 
-	mime := detectMIME(data)
+	mime, err := DetectFormat(data)
-	if mime != "image/avif" {
+	if err != nil {
-		t.Errorf("Output format = %v, want image/avif", mime)
+		t.Fatalf("DetectFormat() error = %v", err)
+	}
+
+	if mime != MIMETypeAVIF {
+		t.Errorf("Output format = %v, want %v", mime, MIMETypeAVIF)
 	}
 
 	// Verify dimensions

internal/imgcache/service.go

@@ -11,14 +11,13 @@ import (
 	"time"
 
 	"github.com/dustin/go-humanize"
-	"sneak.berlin/go/pixa/internal/imageprocessor"
 )
 
 // Service implements the ImageCache interface, orchestrating cache, fetcher, and processor.
 type Service struct {
 	cache           *Cache
 	fetcher         Fetcher
-	processor       *imageprocessor.ImageProcessor
+	processor       Processor
 	signer          *Signer
 	whitelist       *HostWhitelist
 	log             *slog.Logger
@@ -83,7 +82,7 @@ func NewService(cfg *ServiceConfig) (*Service, error) {
 	return &Service{
 		cache:           cfg.Cache,
 		fetcher:         fetcher,
-		processor:       imageprocessor.New(imageprocessor.Params{MaxInputBytes: maxResponseSize}),
+		processor:       New(Params{MaxInputBytes: maxResponseSize}),
 		signer:          signer,
 		whitelist:       NewHostWhitelist(cfg.Whitelist),
 		log:             log,
@@ -301,14 +300,7 @@ func (s *Service) processAndStore(
 	// Process the image
 	processStart := time.Now()
 
-	processReq := &imageprocessor.Request{
+	processResult, err := s.processor.Process(ctx, bytes.NewReader(sourceData), req)
-		Size:    imageprocessor.Size{Width: req.Size.Width, Height: req.Size.Height},
-		Format:  imageprocessor.Format(req.Format),
-		Quality: req.Quality,
-		FitMode: imageprocessor.FitMode(req.FitMode),
-	}
-
-	processResult, err := s.processor.Process(ctx, bytes.NewReader(sourceData), processReq)
 	if err != nil {
 		return nil, fmt.Errorf("image processing failed: %w", err)
 	}

internal/imgcache/service_test.go

@@ -151,74 +151,6 @@ func TestService_Get_NonWhitelistedHost_InvalidSignature(t *testing.T) {
 	}
 }
 
-// TestService_ValidateRequest_SignatureExactHostMatch verifies that
-// ValidateRequest enforces exact host matching for signatures. A
-// signature for one host must not verify for a different host, even
-// if they share a domain suffix.
-func TestService_ValidateRequest_SignatureExactHostMatch(t *testing.T) {
-	signingKey := "test-signing-key-must-be-32-chars"
-	svc, _ := SetupTestService(t,
-		WithSigningKey(signingKey),
-		WithNoWhitelist(),
-	)
-
-	signer := NewSigner(signingKey)
-
-	// Sign a request for "cdn.example.com"
-	signedReq := &ImageRequest{
-		SourceHost: "cdn.example.com",
-		SourcePath: "/photos/cat.jpg",
-		Size:       Size{Width: 50, Height: 50},
-		Format:     FormatJPEG,
-		Quality:    85,
-		FitMode:    FitCover,
-		Expires:    time.Now().Add(time.Hour),
-	}
-	signedReq.Signature = signer.Sign(signedReq)
-
-	// The original request should pass validation
-	t.Run("exact host passes", func(t *testing.T) {
-		err := svc.ValidateRequest(signedReq)
-		if err != nil {
-			t.Errorf("ValidateRequest() exact host failed: %v", err)
-		}
-	})
-
-	// Try to reuse the signature with different hosts
-	tests := []struct {
-		name string
-		host string
-	}{
-		{"parent domain", "example.com"},
-		{"sibling subdomain", "images.example.com"},
-		{"deeper subdomain", "a.cdn.example.com"},
-		{"evil suffix domain", "cdn.example.com.evil.com"},
-		{"prefixed host", "evilcdn.example.com"},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name+" rejected", func(t *testing.T) {
-			req := &ImageRequest{
-				SourceHost:  tt.host,
-				SourcePath:  signedReq.SourcePath,
-				SourceQuery: signedReq.SourceQuery,
-				Size:        signedReq.Size,
-				Format:      signedReq.Format,
-				Quality:     signedReq.Quality,
-				FitMode:     signedReq.FitMode,
-				Expires:     signedReq.Expires,
-				Signature:   signedReq.Signature,
-			}
-
-			err := svc.ValidateRequest(req)
-			if err == nil {
-				t.Errorf("ValidateRequest() should reject signature for host %q (signed for %q)",
-					tt.host, signedReq.SourceHost)
-			}
-		})
-	}
-}
-
 func TestService_Get_InvalidFile(t *testing.T) {
 	svc, fixtures := SetupTestService(t)
 	ctx := context.Background()

internal/imgcache/signature.go

@@ -43,11 +43,6 @@ func (s *Signer) Sign(req *ImageRequest) string {
 }
 
 // Verify checks if the signature on the request is valid and not expired.
-// Signatures are exact-match only: every component of the signed data
-// (host, path, query, dimensions, format, expiration) must match exactly.
-// No suffix matching, wildcard matching, or partial matching is supported.
-// A signature for "cdn.example.com" will NOT verify for "example.com" or
-// "other.cdn.example.com", and vice versa.
 func (s *Signer) Verify(req *ImageRequest) error {
 	// Check expiration first
 	if req.Expires.IsZero() {
@@ -71,8 +66,6 @@ func (s *Signer) Verify(req *ImageRequest) error {
 
 // buildSignatureData creates the string to be signed.
 // Format: "host:path:query:width:height:format:expiration"
-// All components are used verbatim (exact match). No normalization,
-// suffix matching, or wildcard expansion is performed.
 func (s *Signer) buildSignatureData(req *ImageRequest) string {
 	return fmt.Sprintf("%s:%s:%s:%d:%d:%s:%d",
 		req.SourceHost,

internal/imgcache/signature_test.go

@@ -152,178 +152,6 @@ func TestSigner_Verify(t *testing.T) {
 	}
 }
 
-// TestSigner_Verify_ExactMatchOnly verifies that signatures enforce exact
-// matching on every URL component. No suffix matching, wildcard matching,
-// or partial matching is supported.
-func TestSigner_Verify_ExactMatchOnly(t *testing.T) {
-	signer := NewSigner("test-secret-key")
-
-	// Base request that we'll sign, then tamper with individual fields.
-	baseReq := func() *ImageRequest {
-		req := &ImageRequest{
-			SourceHost:  "cdn.example.com",
-			SourcePath:  "/photos/cat.jpg",
-			SourceQuery: "token=abc",
-			Size:        Size{Width: 800, Height: 600},
-			Format:      FormatWebP,
-			Expires:     time.Now().Add(1 * time.Hour),
-		}
-		req.Signature = signer.Sign(req)
-
-		return req
-	}
-
-	tests := []struct {
-		name   string
-		tamper func(req *ImageRequest)
-	}{
-		{
-			name: "parent domain does not match subdomain",
-			tamper: func(req *ImageRequest) {
-				// Signed for cdn.example.com, try example.com
-				req.SourceHost = "example.com"
-			},
-		},
-		{
-			name: "subdomain does not match parent domain",
-			tamper: func(req *ImageRequest) {
-				// Signed for cdn.example.com, try images.cdn.example.com
-				req.SourceHost = "images.cdn.example.com"
-			},
-		},
-		{
-			name: "sibling subdomain does not match",
-			tamper: func(req *ImageRequest) {
-				// Signed for cdn.example.com, try images.example.com
-				req.SourceHost = "images.example.com"
-			},
-		},
-		{
-			name: "host with suffix appended does not match",
-			tamper: func(req *ImageRequest) {
-				// Signed for cdn.example.com, try cdn.example.com.evil.com
-				req.SourceHost = "cdn.example.com.evil.com"
-			},
-		},
-		{
-			name: "host with prefix does not match",
-			tamper: func(req *ImageRequest) {
-				// Signed for cdn.example.com, try evilcdn.example.com
-				req.SourceHost = "evilcdn.example.com"
-			},
-		},
-		{
-			name: "different path does not match",
-			tamper: func(req *ImageRequest) {
-				req.SourcePath = "/photos/dog.jpg"
-			},
-		},
-		{
-			name: "path suffix does not match",
-			tamper: func(req *ImageRequest) {
-				req.SourcePath = "/photos/cat.jpg/extra"
-			},
-		},
-		{
-			name: "path prefix does not match",
-			tamper: func(req *ImageRequest) {
-				req.SourcePath = "/other/photos/cat.jpg"
-			},
-		},
-		{
-			name: "different query does not match",
-			tamper: func(req *ImageRequest) {
-				req.SourceQuery = "token=xyz"
-			},
-		},
-		{
-			name: "added query does not match empty query",
-			tamper: func(req *ImageRequest) {
-				req.SourceQuery = "extra=1"
-			},
-		},
-		{
-			name: "removed query does not match",
-			tamper: func(req *ImageRequest) {
-				req.SourceQuery = ""
-			},
-		},
-		{
-			name: "different width does not match",
-			tamper: func(req *ImageRequest) {
-				req.Size.Width = 801
-			},
-		},
-		{
-			name: "different height does not match",
-			tamper: func(req *ImageRequest) {
-				req.Size.Height = 601
-			},
-		},
-		{
-			name: "different format does not match",
-			tamper: func(req *ImageRequest) {
-				req.Format = FormatPNG
-			},
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			req := baseReq()
-			tt.tamper(req)
-
-			err := signer.Verify(req)
-			if err != ErrSignatureInvalid {
-				t.Errorf("Verify() = %v, want %v", err, ErrSignatureInvalid)
-			}
-		})
-	}
-
-	// Verify the unmodified base request still passes
-	t.Run("unmodified request passes", func(t *testing.T) {
-		req := baseReq()
-		if err := signer.Verify(req); err != nil {
-			t.Errorf("Verify() unmodified request failed: %v", err)
-		}
-	})
-}
-
-// TestSigner_Sign_ExactHostInData verifies that Sign uses the exact host
-// string in the signature data, producing different signatures for
-// suffix-related hosts.
-func TestSigner_Sign_ExactHostInData(t *testing.T) {
-	signer := NewSigner("test-secret-key")
-
-	hosts := []string{
-		"cdn.example.com",
-		"example.com",
-		"images.example.com",
-		"images.cdn.example.com",
-		"cdn.example.com.evil.com",
-	}
-
-	sigs := make(map[string]string)
-
-	for _, host := range hosts {
-		req := &ImageRequest{
-			SourceHost:  host,
-			SourcePath:  "/photos/cat.jpg",
-			SourceQuery: "",
-			Size:        Size{Width: 800, Height: 600},
-			Format:      FormatWebP,
-			Expires:     time.Unix(1704067200, 0),
-		}
-
-		sig := signer.Sign(req)
-		if existing, ok := sigs[sig]; ok {
-			t.Errorf("hosts %q and %q produced the same signature", existing, host)
-		}
-
-		sigs[sig] = host
-	}
-}
-
 func TestSigner_DifferentKeys(t *testing.T) {
 	signer1 := NewSigner("secret-key-1")
 	signer2 := NewSigner("secret-key-2")