refactor: extract httpfetcher package from imgcache

Move HTTPFetcher, Config (was FetcherConfig), SSRF-safe dialer, rate
limiting, content-type validation, and related error vars from
internal/imgcache/fetcher.go into new internal/httpfetcher/ package.

The Fetcher interface and FetchResult type also move to httpfetcher
to avoid circular imports (imgcache imports httpfetcher, not the other
way around).

Renames to avoid stuttering:
  NewHTTPFetcher -> httpfetcher.New
  FetcherConfig  -> httpfetcher.Config
  NewMockFetcher -> httpfetcher.NewMock

The ServiceConfig.FetcherConfig field is retained (it describes what
kind of config it holds, not a stutter).

Pure refactor - no behavior changes. Unit tests for the httpfetcher
package are included.

refs #39

.dockerignore

@@ -6,4 +6,3 @@
 node_modules
 bin/
 data/
-deploy/

Dockerfile

@@ -75,7 +75,4 @@ WORKDIR /var/lib/pixa
 
 EXPOSE 8080
 
-HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
-    CMD wget -q --spider http://localhost:8080/.well-known/healthcheck.json
-
 ENTRYPOINT ["/usr/local/bin/pixad", "--config", "/etc/pixa/config.yml"]

README.md

@@ -67,7 +67,10 @@ hosts require an HMAC-SHA256 signature.
 #### Signature Specification
 
 Signatures use HMAC-SHA256 and include an expiration timestamp to
-prevent replay attacks.
+prevent replay attacks. Signatures are **exact match only**: every
+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):
 
@@ -125,17 +128,6 @@ See `config.example.yml` for all options with defaults.
 - **Metrics**: Prometheus
 - **Logging**: stdlib slog
 
-## Deployment
-
-Pixa is deployed via
-[µPaaS](https://git.eeqj.de/sneak/upaas) on `fsn1app1`
-(paas.datavi.be). Pushes to `main` trigger automatic builds and
-deployments. The Dockerfile includes a `HEALTHCHECK` that probes
-`/.well-known/healthcheck.json`.
-
-See [deploy/README.md](deploy/README.md) for the full µPaaS app
-configuration, volume mounts, and production setup instructions.
-
 ## TODO
 
 See [TODO.md](TODO.md) for the full prioritized task list.

cmd/pixad/main.go

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

deploy/README.md

@@ -1,78 +0,0 @@
-# Pixa Deployment via µPaaS
-
-Pixa is deployed on `fsn1app1` via
-[µPaaS](https://git.eeqj.de/sneak/upaas) (paas.datavi.be).
-
-## µPaaS App Configuration
-
-Create the app in the µPaaS web UI with these settings:
-
-| Setting | Value |
-| --- | --- |
-| **App name** | `pixa` |
-| **Repo URL** | `git@git.eeqj.de:sneak/pixa.git` |
-| **Branch** | `main` |
-| **Dockerfile path** | `Dockerfile` |
-
-### Environment Variables
-
-| Variable | Description | Required |
-| --- | --- | --- |
-| `PORT` | HTTP listen port (default: 8080) | No |
-
-Configuration is provided via the config file baked into the Docker
-image at `/etc/pixa/config.yml`. To override it, mount a custom
-config file as a volume (see below).
-
-### Volumes
-
-| Host Path | Container Path | Description |
-| --- | --- | --- |
-| `/srv/pixa/data` | `/var/lib/pixa` | SQLite database and image cache |
-| `/srv/pixa/config.yml` | `/etc/pixa/config.yml` | Production config (signing key, whitelist, etc.) |
-
-### Ports
-
-| Host Port | Container Port | Protocol |
-| --- | --- | --- |
-| (assigned) | 8080 | TCP |
-
-### Docker Network
-
-Attach to the shared reverse-proxy network if using Caddy/Traefik
-for TLS termination.
-
-## Production Configuration
-
-Copy `config.example.yml` from the repo root and customize for
-production:
-
-```yaml
-port: 8080
-debug: false
-maintenance_mode: false
-state_dir: /var/lib/pixa
-signing_key: "<generate with: openssl rand -base64 32>"
-whitelist_hosts:
-    - s3.sneak.cloud
-    - static.sneak.cloud
-    - sneak.berlin
-allow_http: false
-```
-
-**Important:** Generate a unique `signing_key` for production. Never
-use the default placeholder value.
-
-## Health Check
-
-The Dockerfile includes a `HEALTHCHECK` instruction that probes
-`/.well-known/healthcheck.json` every 30 seconds. µPaaS verifies
-container health 60 seconds after deployment.
-
-## Deployment Flow
-
-1. Push to `main` triggers the Gitea webhook
-2. µPaaS clones the repo and runs `docker build .`
-3. The Dockerfile runs `make check` (format, lint, test) during build
-4. On success, µPaaS stops the old container and starts the new one
-5. After 60 seconds, µPaaS checks container health

internal/allowlist/allowlist.go

@@ -1,25 +1,26 @@
-package imgcache
+// Package allowlist provides host-based URL allow-listing for the image proxy.
+package allowlist
 
 import (
 	"net/url"
 	"strings"
 )
 
-// HostWhitelist implements the Whitelist interface for checking allowed source hosts.
+// HostAllowList checks whether source hosts are permitted.
-type HostWhitelist struct {
+type HostAllowList struct {
 	// exactHosts contains hosts that must match exactly (e.g., "cdn.example.com")
 	exactHosts map[string]struct{}
 	// suffixHosts contains domain suffixes to match (e.g., ".example.com" matches "cdn.example.com")
 	suffixHosts []string
 }
 
-// NewHostWhitelist creates a whitelist from a list of host patterns.
+// New creates a HostAllowList from a list of host patterns.
 // Patterns starting with "." are treated as suffix matches.
 // Examples:
 //   - "cdn.example.com" - exact match only
 //   - ".example.com" - matches cdn.example.com, images.example.com, etc.
-func NewHostWhitelist(patterns []string) *HostWhitelist {
+func New(patterns []string) *HostAllowList {
-	w := &HostWhitelist{
+	w := &HostAllowList{
 		exactHosts:  make(map[string]struct{}),
 		suffixHosts: make([]string, 0),
 	}
@@ -40,8 +41,8 @@ func NewHostWhitelist(patterns []string) *HostWhitelist {
 	return w
 }
 
-// IsWhitelisted checks if a URL's host is in the whitelist.
+// IsAllowed checks if a URL's host is in the allow list.
-func (w *HostWhitelist) IsWhitelisted(u *url.URL) bool {
+func (w *HostAllowList) IsAllowed(u *url.URL) bool {
 	if u == nil {
 		return false
 	}
@@ -71,12 +72,12 @@ func (w *HostWhitelist) IsWhitelisted(u *url.URL) bool {
 	return false
 }
 
-// IsEmpty returns true if the whitelist has no entries.
+// IsEmpty returns true if the allow list has no entries.
-func (w *HostWhitelist) IsEmpty() bool {
+func (w *HostAllowList) IsEmpty() bool {
 	return len(w.exactHosts) == 0 && len(w.suffixHosts) == 0
 }
 
-// Count returns the total number of whitelist entries.
+// Count returns the total number of allow list entries.
-func (w *HostWhitelist) Count() int {
+func (w *HostAllowList) Count() int {
 	return len(w.exactHosts) + len(w.suffixHosts)
 }

internal/allowlist/allowlist_test.go

@@ -1,11 +1,13 @@
-package imgcache
+package allowlist_test
 
 import (
 	"net/url"
 	"testing"
+
+	"sneak.berlin/go/pixa/internal/allowlist"
 )
 
-func TestHostWhitelist_IsWhitelisted(t *testing.T) {
+func TestHostAllowList_IsAllowed(t *testing.T) {
 	tests := []struct {
 		name     string
 		patterns []string
@@ -67,7 +69,7 @@ func TestHostWhitelist_IsWhitelisted(t *testing.T) {
 			want:     true,
 		},
 		{
-			name:     "empty whitelist",
+			name:     "empty allow list",
 			patterns: []string{},
 			testURL:  "https://cdn.example.com/image.jpg",
 			want:     false,
@@ -94,7 +96,7 @@ func TestHostWhitelist_IsWhitelisted(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			w := NewHostWhitelist(tt.patterns)
+			w := allowlist.New(tt.patterns)
 
 			var u *url.URL
 			if tt.testURL != "" {
@@ -105,15 +107,15 @@ func TestHostWhitelist_IsWhitelisted(t *testing.T) {
 				}
 			}
 
-			got := w.IsWhitelisted(u)
+			got := w.IsAllowed(u)
 			if got != tt.want {
-				t.Errorf("IsWhitelisted() = %v, want %v", got, tt.want)
+				t.Errorf("IsAllowed() = %v, want %v", got, tt.want)
 			}
 		})
 	}
 }
 
-func TestHostWhitelist_IsEmpty(t *testing.T) {
+func TestHostAllowList_IsEmpty(t *testing.T) {
 	tests := []struct {
 		name     string
 		patterns []string
@@ -143,7 +145,7 @@ func TestHostWhitelist_IsEmpty(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			w := NewHostWhitelist(tt.patterns)
+			w := allowlist.New(tt.patterns)
 			if got := w.IsEmpty(); got != tt.want {
 				t.Errorf("IsEmpty() = %v, want %v", got, tt.want)
 			}
@@ -151,7 +153,7 @@ func TestHostWhitelist_IsEmpty(t *testing.T) {
 	}
 }
 
-func TestHostWhitelist_Count(t *testing.T) {
+func TestHostAllowList_Count(t *testing.T) {
 	tests := []struct {
 		name     string
 		patterns []string
@@ -181,7 +183,7 @@ func TestHostWhitelist_Count(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			w := NewHostWhitelist(tt.patterns)
+			w := allowlist.New(tt.patterns)
 			if got := w.Count(); got != tt.want {
 				t.Errorf("Count() = %v, want %v", got, tt.want)
 			}

internal/database/database.go

@@ -9,6 +9,7 @@ import (
 	"log/slog"
 	"path/filepath"
 	"sort"
+	"strconv"
 	"strings"
 
 	"go.uber.org/fx"
@@ -21,6 +22,10 @@ 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
@@ -35,6 +40,46 @@ type Database struct {
 	config *config.Config
 }
 
+// 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
+// error if the filename does not match the expected pattern.
+func ParseMigrationVersion(filename string) (int, error) {
+	name := strings.TrimSuffix(filename, filepath.Ext(filename))
+	if name == "" {
+		return 0, 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
+	if idx := strings.IndexByte(name, '_'); idx >= 0 {
+		versionStr = name[:idx]
+	}
+
+	if versionStr == "" {
+		return 0, fmt.Errorf("invalid migration filename %q: empty version prefix", filename)
+	}
+
+	// Validate the version is purely numeric.
+	for _, ch := range versionStr {
+		if ch < '0' || ch > '9' {
+			return 0, fmt.Errorf(
+				"invalid migration filename %q: version %q contains non-numeric character %q",
+				filename, versionStr, string(ch),
+			)
+		}
+	}
+
+	version, err := strconv.Atoi(versionStr)
+	if err != nil {
+		return 0, fmt.Errorf("invalid migration filename %q: %w", filename, err)
+	}
+
+	return version, nil
+}
+
 // New creates a new Database instance.
 func New(lc fx.Lifecycle, params Params) (*Database, error) {
 	s := &Database{
@@ -84,127 +129,86 @@ func (s *Database) connect(ctx context.Context) error {
 	s.db = db
 	s.log.Info("database connected")
 
-	return s.runMigrations(ctx)
+	return ApplyMigrations(ctx, s.db, s.log)
 }
 
-func (s *Database) runMigrations(ctx context.Context) error {
+// collectMigrations reads the embedded schema directory and returns
-	// Create migrations tracking table
+// migration filenames sorted lexicographically.
-	_, err := s.db.ExecContext(ctx, `
+func collectMigrations() ([]string, error) {
-		CREATE TABLE IF NOT EXISTS schema_migrations (
-			version TEXT PRIMARY KEY,
-			applied_at DATETIME DEFAULT CURRENT_TIMESTAMP
-		)
-	`)
-	if err != nil {
-		return fmt.Errorf("failed to create migrations table: %w", err)
-	}
-
-	// Get list of migration files
 	entries, err := schemaFS.ReadDir("schema")
 	if err != nil {
-		return fmt.Errorf("failed to read schema directory: %w", err)
+		return nil, fmt.Errorf("failed to read schema directory: %w", err)
 	}
 
-	// Sort migration files by name (001.sql, 002.sql, etc.)
 	var migrations []string
+
 	for _, entry := range entries {
 		if !entry.IsDir() && strings.HasSuffix(entry.Name(), ".sql") {
 			migrations = append(migrations, entry.Name())
 		}
 	}
+
 	sort.Strings(migrations)
 
-	// Apply each migration that hasn't been applied yet
+	return migrations, nil
-	for _, migration := range migrations {
+}
-		version := strings.TrimSuffix(migration, filepath.Ext(migration))
 
-		// Check if already applied
+// bootstrapMigrationsTable ensures the schema_migrations table exists
-		var count int
+// by applying 000.sql if the table is missing.
-		err := s.db.QueryRowContext(ctx,
+func bootstrapMigrationsTable(ctx context.Context, db *sql.DB, log *slog.Logger) error {
-			"SELECT COUNT(*) FROM schema_migrations WHERE version = ?",
+	var tableExists int
-			version,
+
-		).Scan(&count)
+	err := db.QueryRowContext(ctx,
+		"SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='schema_migrations'",
+	).Scan(&tableExists)
 	if err != nil {
-			return fmt.Errorf("failed to check migration status: %w", err)
+		return fmt.Errorf("failed to check for migrations table: %w", err)
 	}
 
-		if count > 0 {
+	if tableExists > 0 {
-			s.log.Debug("migration already applied", "version", version)
+		return nil
-
-			continue
 	}
 
-		// Read and apply migration
+	content, err := schemaFS.ReadFile("schema/000.sql")
-		content, err := schemaFS.ReadFile(filepath.Join("schema", migration))
 	if err != nil {
-			return fmt.Errorf("failed to read migration %s: %w", migration, err)
+		return fmt.Errorf("failed to read bootstrap migration 000.sql: %w", err)
 	}
 
-		s.log.Info("applying migration", "version", version)
+	if log != nil {
+		log.Info("applying bootstrap migration", "version", bootstrapVersion)
+	}
 
-		_, err = s.db.ExecContext(ctx, string(content))
+	_, err = db.ExecContext(ctx, string(content))
 	if err != nil {
-			return fmt.Errorf("failed to apply migration %s: %w", migration, err)
+		return fmt.Errorf("failed to apply bootstrap migration: %w", err)
-		}
-
-		// Record migration as applied
-		_, err = s.db.ExecContext(ctx,
-			"INSERT INTO schema_migrations (version) VALUES (?)",
-			version,
-		)
-		if err != nil {
-			return fmt.Errorf("failed to record migration %s: %w", migration, err)
-		}
-
-		s.log.Info("migration applied successfully", "version", version)
 	}
 
 	return nil
 }
 
-// DB returns the underlying sql.DB.
+// ApplyMigrations applies all pending migrations to db. An optional logger
-func (s *Database) DB() *sql.DB {
+// may be provided for informational output; pass nil for silent operation.
-	return s.db
+// 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 {
+		return err
 	}
 
-// ApplyMigrations applies all migrations to the given database.
+	migrations, err := collectMigrations()
-// This is useful for testing where you want to use the real schema
-// without the full fx lifecycle.
-func ApplyMigrations(db *sql.DB) error {
-	ctx := context.Background()
-
-	// Create migrations tracking table
-	_, err := db.ExecContext(ctx, `
-		CREATE TABLE IF NOT EXISTS schema_migrations (
-			version TEXT PRIMARY KEY,
-			applied_at DATETIME DEFAULT CURRENT_TIMESTAMP
-		)
-	`)
 	if err != nil {
-		return fmt.Errorf("failed to create migrations table: %w", err)
+		return err
 	}
 
-	// Get list of migration files
-	entries, err := schemaFS.ReadDir("schema")
-	if err != nil {
-		return fmt.Errorf("failed to read schema directory: %w", err)
-	}
-
-	// Sort migration files by name (001.sql, 002.sql, etc.)
-	var migrations []string
-	for _, entry := range entries {
-		if !entry.IsDir() && strings.HasSuffix(entry.Name(), ".sql") {
-			migrations = append(migrations, entry.Name())
-		}
-	}
-	sort.Strings(migrations)
-
-	// Apply each migration that hasn't been applied yet
 	for _, migration := range migrations {
-		version := strings.TrimSuffix(migration, filepath.Ext(migration))
+		version, parseErr := ParseMigrationVersion(migration)
+		if parseErr != nil {
+			return parseErr
+		}
 
-		// Check if already applied
+		// Check if already applied.
 		var count int
+
 		err := db.QueryRowContext(ctx,
 			"SELECT COUNT(*) FROM schema_migrations WHERE version = ?",
 			version,
@@ -214,29 +218,46 @@ func ApplyMigrations(db *sql.DB) error {
 		}
 
 		if count > 0 {
+			if log != nil {
+				log.Debug("migration already applied", "version", version)
+			}
+
 			continue
 		}
 
-		// Read and apply migration
+		// Read and apply migration.
-		content, err := schemaFS.ReadFile(filepath.Join("schema", migration))
+		content, readErr := schemaFS.ReadFile(filepath.Join("schema", migration))
-		if err != nil {
+		if readErr != nil {
-			return fmt.Errorf("failed to read migration %s: %w", migration, err)
+			return fmt.Errorf("failed to read migration %s: %w", migration, readErr)
 		}
 
-		_, err = db.ExecContext(ctx, string(content))
+		if log != nil {
-		if err != nil {
+			log.Info("applying migration", "version", version)
-			return fmt.Errorf("failed to apply migration %s: %w", migration, err)
 		}
 
-		// Record migration as applied
+		_, execErr := db.ExecContext(ctx, string(content))
-		_, err = db.ExecContext(ctx,
+		if execErr != nil {
+			return fmt.Errorf("failed to apply migration %s: %w", migration, execErr)
+		}
+
+		// Record migration as applied.
+		_, recErr := db.ExecContext(ctx,
 			"INSERT INTO schema_migrations (version) VALUES (?)",
 			version,
 		)
-		if err != nil {
+		if recErr != nil {
-			return fmt.Errorf("failed to record migration %s: %w", migration, err)
+			return fmt.Errorf("failed to record migration %s: %w", migration, recErr)
+		}
+
+		if log != nil {
+			log.Info("migration applied successfully", "version", version)
 		}
 	}
 
 	return nil
 }
+
+// DB returns the underlying sql.DB.
+func (s *Database) DB() *sql.DB {
+	return s.db
+}

internal/database/database_test.go

@@ -0,0 +1,224 @@
+package database
+
+import (
+	"context"
+	"database/sql"
+	"testing"
+
+	_ "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
+		wantErr  bool
+	}{
+		{
+			name:     "version only",
+			filename: "001.sql",
+			want:     1,
+		},
+		{
+			name:     "version with description",
+			filename: "001_initial_schema.sql",
+			want:     1,
+		},
+		{
+			name:     "multi-digit version",
+			filename: "042_add_indexes.sql",
+			want:     42,
+		},
+		{
+			name:     "long version number",
+			filename: "00001_long_prefix.sql",
+			want:     1,
+		},
+		{
+			name:     "description with multiple underscores",
+			filename: "003_add_user_auth_tables.sql",
+			want:     3,
+		},
+		{
+			name:     "empty filename",
+			filename: ".sql",
+			wantErr:  true,
+		},
+		{
+			name:     "leading underscore",
+			filename: "_description.sql",
+			wantErr:  true,
+		},
+		{
+			name:     "non-numeric version",
+			filename: "abc_migration.sql",
+			wantErr:  true,
+		},
+		{
+			name:     "mixed alphanumeric version",
+			filename: "001a_migration.sql",
+			wantErr:  true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(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)
+				}
+
+				return
+			}
+
+			if err != nil {
+				t.Errorf("ParseMigrationVersion(%q) unexpected error: %v", tt.filename, err)
+
+				return
+			}
+
+			if got != tt.want {
+				t.Errorf("ParseMigrationVersion(%q) = %d, want %d", tt.filename, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestApplyMigrations_CreatesSchemaAndTables(t *testing.T) {
+	db := openTestDB(t)
+	ctx := context.Background()
+
+	if err := ApplyMigrations(ctx, db, nil); err != nil {
+		t.Fatalf("ApplyMigrations failed: %v", err)
+	}
+
+	// The schema_migrations table must exist and contain at least
+	// version 0 (the bootstrap) and 1 (the initial schema).
+	rows, err := db.Query("SELECT version FROM schema_migrations ORDER BY version")
+	if err != nil {
+		t.Fatalf("failed to query schema_migrations: %v", err)
+	}
+	defer rows.Close()
+
+	var versions []int
+	for rows.Next() {
+		var v int
+		if err := rows.Scan(&v); err != nil {
+			t.Fatalf("failed to scan version: %v", err)
+		}
+
+		versions = append(versions, v)
+	}
+
+	if err := rows.Err(); err != nil {
+		t.Fatalf("row iteration error: %v", err)
+	}
+
+	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)
+		}
+
+		if count != 1 {
+			t.Errorf("table %s does not exist after migrations", table)
+		}
+	}
+}
+
+func TestApplyMigrations_Idempotent(t *testing.T) {
+	db := openTestDB(t)
+	ctx := context.Background()
+
+	if err := ApplyMigrations(ctx, db, nil); err != nil {
+		t.Fatalf("first ApplyMigrations failed: %v", err)
+	}
+
+	// Running a second time must succeed without errors.
+	if err := ApplyMigrations(ctx, db, nil); err != nil {
+		t.Fatalf("second ApplyMigrations failed: %v", err)
+	}
+
+	// Verify no duplicate rows in schema_migrations.
+	var count int
+
+	err := db.QueryRow("SELECT COUNT(*) FROM schema_migrations WHERE version = 0").Scan(&count)
+	if err != nil {
+		t.Fatalf("failed to count version 0 rows: %v", err)
+	}
+
+	if count != 1 {
+		t.Errorf("expected exactly 1 row for version 0, 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

@@ -0,0 +1,9 @@
+-- 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

@@ -5,11 +5,10 @@ import (
 	"go.uber.org/fx"
 )
 
-// Build-time variables populated from main() via ldflags.
+const appname = "pixad"
-var (
+
-	Appname string //nolint:gochecknoglobals // set from main
+// Version is populated from main() via ldflags.
-	Version string //nolint:gochecknoglobals // set from main
+var Version string //nolint:gochecknoglobals // set from main
-)
 
 // Globals holds application-wide constants.
 type Globals struct {
@@ -20,7 +19,7 @@ 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/handlers/handlers.go

@@ -13,6 +13,7 @@ import (
 	"sneak.berlin/go/pixa/internal/database"
 	"sneak.berlin/go/pixa/internal/encurl"
 	"sneak.berlin/go/pixa/internal/healthcheck"
+	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/logger"
 	"sneak.berlin/go/pixa/internal/session"
@@ -72,7 +73,7 @@ func (s *Handlers) initImageService() error {
 	s.imgCache = cache
 
 	// Create the fetcher config
-	fetcherCfg := imgcache.DefaultFetcherConfig()
+	fetcherCfg := httpfetcher.DefaultConfig()
 	fetcherCfg.AllowHTTP = s.config.AllowHTTP
 	if s.config.UpstreamConnectionsPerHost > 0 {
 		fetcherCfg.MaxConnectionsPerHost = s.config.UpstreamConnectionsPerHost

internal/handlers/handlers_test.go

@@ -18,6 +18,7 @@ import (
 
 	"github.com/go-chi/chi/v5"
 	"sneak.berlin/go/pixa/internal/database"
+	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imgcache"
 )
 
@@ -82,7 +83,7 @@ func setupTestDB(t *testing.T) *sql.DB {
 		t.Fatalf("failed to open test db: %v", err)
 	}
 
-	if err := database.ApplyMigrations(db); err != nil {
+	if err := database.ApplyMigrations(context.Background(), db, nil); err != nil {
 		t.Fatalf("failed to apply migrations: %v", err)
 	}
 
@@ -116,16 +117,16 @@ func newMockFetcher(fs fs.FS) *mockFetcher {
 	return &mockFetcher{fs: fs}
 }
 
-func (f *mockFetcher) Fetch(ctx context.Context, url string) (*imgcache.FetchResult, error) {
+func (f *mockFetcher) Fetch(ctx context.Context, url string) (*httpfetcher.FetchResult, error) {
 	// Remove https:// prefix
 	path := url[8:] // Remove "https://"
 
 	data, err := fs.ReadFile(f.fs, path)
 	if err != nil {
-		return nil, imgcache.ErrUpstreamError
+		return nil, httpfetcher.ErrUpstreamError
 	}
 
-	return &imgcache.FetchResult{
+	return &httpfetcher.FetchResult{
 		Content:       io.NopCloser(bytes.NewReader(data)),
 		ContentLength: int64(len(data)),
 		ContentType:   "image/jpeg",

internal/handlers/image.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/go-chi/chi/v5"
+	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imgcache"
 )
 
@@ -97,13 +98,13 @@ func (s *Handlers) HandleImage() http.HandlerFunc {
 			)
 
 			// Check for specific error types
-			if errors.Is(err, imgcache.ErrSSRFBlocked) {
+			if errors.Is(err, httpfetcher.ErrSSRFBlocked) {
 				s.respondError(w, "forbidden", http.StatusForbidden)
 
 				return
 			}
 
-			if errors.Is(err, imgcache.ErrUpstreamError) {
+			if errors.Is(err, httpfetcher.ErrUpstreamError) {
 				s.respondError(w, "upstream error", http.StatusBadGateway)
 
 				return

internal/handlers/imageenc.go

@@ -11,6 +11,7 @@ import (
 	"github.com/go-chi/chi/v5"
 
 	"sneak.berlin/go/pixa/internal/encurl"
+	"sneak.berlin/go/pixa/internal/httpfetcher"
 	"sneak.berlin/go/pixa/internal/imgcache"
 )
 
@@ -100,11 +101,11 @@ func (s *Handlers) HandleImageEnc() http.HandlerFunc {
 // handleImageError converts image service errors to HTTP responses.
 func (s *Handlers) handleImageError(w http.ResponseWriter, err error) {
 	switch {
-	case errors.Is(err, imgcache.ErrSSRFBlocked):
+	case errors.Is(err, httpfetcher.ErrSSRFBlocked):
 		s.respondError(w, "forbidden", http.StatusForbidden)
-	case errors.Is(err, imgcache.ErrUpstreamError):
+	case errors.Is(err, httpfetcher.ErrUpstreamError):
 		s.respondError(w, "upstream error", http.StatusBadGateway)
-	case errors.Is(err, imgcache.ErrUpstreamTimeout):
+	case errors.Is(err, httpfetcher.ErrUpstreamTimeout):
 		s.respondError(w, "upstream timeout", http.StatusGatewayTimeout)
 	default:
 		s.log.Error("image request failed", "error", err)

internal/httpfetcher/httpfetcher.go

@@ -1,4 +1,6 @@
-package imgcache
+// Package httpfetcher fetches content from upstream HTTP origins with SSRF
+// protection, per-host connection limits, and content-type validation.
+package httpfetcher
 
 import (
 	"context"
@@ -37,25 +39,55 @@ var (
 	ErrUpstreamTimeout    = errors.New("upstream request timeout")
 )
 
-// FetcherConfig holds configuration for the upstream fetcher.
+// Fetcher retrieves content from upstream origins.
-type FetcherConfig struct {
+type Fetcher interface {
-	// Timeout for upstream requests
+	// Fetch retrieves content from the given URL.
+	Fetch(ctx context.Context, url string) (*FetchResult, error)
+}
+
+// FetchResult contains the result of fetching from upstream.
+type FetchResult struct {
+	// Content is the raw image data.
+	Content io.ReadCloser
+	// ContentLength is the size in bytes (-1 if unknown).
+	ContentLength int64
+	// ContentType is the MIME type from upstream.
+	ContentType string
+	// Headers contains all response headers from upstream.
+	Headers map[string][]string
+	// StatusCode is the HTTP status code from upstream.
+	StatusCode int
+	// FetchDurationMs is how long the fetch took in milliseconds.
+	FetchDurationMs int64
+	// RemoteAddr is the IP:port of the upstream server.
+	RemoteAddr string
+	// HTTPVersion is the protocol version (e.g., "1.1", "2.0").
+	HTTPVersion string
+	// TLSVersion is the TLS protocol version (e.g., "TLS 1.3").
+	TLSVersion string
+	// TLSCipherSuite is the negotiated cipher suite name.
+	TLSCipherSuite string
+}
+
+// Config holds configuration for the upstream fetcher.
+type Config struct {
+	// Timeout for upstream requests.
 	Timeout time.Duration
-	// MaxResponseSize is the maximum allowed response body size
+	// MaxResponseSize is the maximum allowed response body size.
 	MaxResponseSize int64
-	// UserAgent to send to upstream servers
+	// UserAgent to send to upstream servers.
 	UserAgent string
-	// AllowedContentTypes is a whitelist of MIME types to accept
+	// AllowedContentTypes is an allow list of MIME types to accept.
 	AllowedContentTypes []string
-	// AllowHTTP allows non-TLS connections (for testing only)
+	// AllowHTTP allows non-TLS connections (for testing only).
 	AllowHTTP bool
-	// MaxConnectionsPerHost limits concurrent connections to each upstream host
+	// MaxConnectionsPerHost limits concurrent connections to each upstream host.
 	MaxConnectionsPerHost int
 }
 
-// DefaultFetcherConfig returns sensible defaults.
+// DefaultConfig returns a Config with sensible defaults.
-func DefaultFetcherConfig() *FetcherConfig {
+func DefaultConfig() *Config {
-	return &FetcherConfig{
+	return &Config{
 		Timeout:         DefaultFetchTimeout,
 		MaxResponseSize: DefaultMaxResponseSize,
 		UserAgent:       "pixa/1.0",
@@ -72,18 +104,18 @@ func DefaultFetcherConfig() *FetcherConfig {
 	}
 }
 
-// HTTPFetcher implements the Fetcher interface with SSRF protection.
+// HTTPFetcher implements Fetcher with SSRF protection and per-host connection limits.
 type HTTPFetcher struct {
 	client    *http.Client
-	config    *FetcherConfig
+	config    *Config
 	hostSems  map[string]chan struct{} // per-host semaphores
 	hostSemMu sync.Mutex               // protects hostSems map
 }
 
-// NewHTTPFetcher creates a new fetcher with SSRF protection.
+// New creates a new HTTPFetcher with SSRF protection.
-func NewHTTPFetcher(config *FetcherConfig) *HTTPFetcher {
+func New(config *Config) *HTTPFetcher {
 	if config == nil {
-		config = DefaultFetcherConfig()
+		config = DefaultConfig()
 	}
 
 	// Create transport with SSRF-safe dialer
@@ -250,7 +282,7 @@ func (f *HTTPFetcher) Fetch(ctx context.Context, url string) (*FetchResult, erro
 	}, nil
 }
 
-// isAllowedContentType checks if the content type is in the whitelist.
+// isAllowedContentType checks if the content type is in the allow list.
 func (f *HTTPFetcher) isAllowedContentType(contentType string) bool {
 	// Extract the MIME type without parameters
 	mediaType := strings.TrimSpace(strings.Split(contentType, ";")[0])

internal/httpfetcher/httpfetcher_test.go

@@ -0,0 +1,329 @@
+package httpfetcher
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net"
+	"testing"
+	"testing/fstest"
+)
+
+func TestDefaultConfig(t *testing.T) {
+	cfg := DefaultConfig()
+
+	if cfg.Timeout != DefaultFetchTimeout {
+		t.Errorf("Timeout = %v, want %v", cfg.Timeout, DefaultFetchTimeout)
+	}
+
+	if cfg.MaxResponseSize != DefaultMaxResponseSize {
+		t.Errorf("MaxResponseSize = %d, want %d", cfg.MaxResponseSize, DefaultMaxResponseSize)
+	}
+
+	if cfg.MaxConnectionsPerHost != DefaultMaxConnectionsPerHost {
+		t.Errorf("MaxConnectionsPerHost = %d, want %d",
+			cfg.MaxConnectionsPerHost, DefaultMaxConnectionsPerHost)
+	}
+
+	if cfg.AllowHTTP {
+		t.Error("AllowHTTP should default to false")
+	}
+
+	if len(cfg.AllowedContentTypes) == 0 {
+		t.Error("AllowedContentTypes should not be empty")
+	}
+}
+
+func TestNewWithNilConfigUsesDefaults(t *testing.T) {
+	f := New(nil)
+
+	if f == nil {
+		t.Fatal("New(nil) returned nil")
+	}
+
+	if f.config == nil {
+		t.Fatal("config should be populated from DefaultConfig")
+	}
+
+	if f.config.Timeout != DefaultFetchTimeout {
+		t.Errorf("Timeout = %v, want %v", f.config.Timeout, DefaultFetchTimeout)
+	}
+}
+
+func TestIsAllowedContentType(t *testing.T) {
+	f := New(DefaultConfig())
+
+	tests := []struct {
+		contentType string
+		want        bool
+	}{
+		{"image/jpeg", true},
+		{"image/png", true},
+		{"image/webp", true},
+		{"image/jpeg; charset=utf-8", true},
+		{"IMAGE/JPEG", true},
+		{"text/html", false},
+		{"application/octet-stream", false},
+		{"", false},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.contentType, func(t *testing.T) {
+			got := f.isAllowedContentType(tc.contentType)
+			if got != tc.want {
+				t.Errorf("isAllowedContentType(%q) = %v, want %v", tc.contentType, got, tc.want)
+			}
+		})
+	}
+}
+
+func TestExtractHost(t *testing.T) {
+	tests := []struct {
+		url  string
+		want string
+	}{
+		{"https://example.com/path", "example.com"},
+		{"http://example.com:8080/path", "example.com:8080"},
+		{"https://example.com", "example.com"},
+		{"https://example.com?q=1", "example.com"},
+		{"example.com/path", "example.com"},
+		{"", ""},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.url, func(t *testing.T) {
+			got := extractHost(tc.url)
+			if got != tc.want {
+				t.Errorf("extractHost(%q) = %q, want %q", tc.url, got, tc.want)
+			}
+		})
+	}
+}
+
+func TestIsLocalhost(t *testing.T) {
+	tests := []struct {
+		host string
+		want bool
+	}{
+		{"localhost", true},
+		{"LOCALHOST", true},
+		{"127.0.0.1", true},
+		{"::1", true},
+		{"[::1]", true},
+		{"foo.localhost", true},
+		{"foo.local", true},
+		{"example.com", false},
+		{"127.0.0.2", false}, // Handled by isPrivateIP, not isLocalhost string match
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.host, func(t *testing.T) {
+			got := isLocalhost(tc.host)
+			if got != tc.want {
+				t.Errorf("isLocalhost(%q) = %v, want %v", tc.host, got, tc.want)
+			}
+		})
+	}
+}
+
+func TestIsPrivateIP(t *testing.T) {
+	tests := []struct {
+		ip   string
+		want bool
+	}{
+		{"127.0.0.1", true},             // loopback
+		{"10.0.0.1", true},              // private
+		{"192.168.1.1", true},           // private
+		{"172.16.0.1", true},            // private
+		{"169.254.1.1", true},           // link-local
+		{"0.0.0.0", true},               // unspecified
+		{"224.0.0.1", true},             // multicast
+		{"::1", true},                   // IPv6 loopback
+		{"fe80::1", true},               // IPv6 link-local
+		{"8.8.8.8", false},              // public
+		{"2001:4860:4860::8888", false}, // public IPv6
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.ip, func(t *testing.T) {
+			ip := net.ParseIP(tc.ip)
+			if ip == nil {
+				t.Fatalf("failed to parse IP %q", tc.ip)
+			}
+
+			got := isPrivateIP(ip)
+			if got != tc.want {
+				t.Errorf("isPrivateIP(%q) = %v, want %v", tc.ip, got, tc.want)
+			}
+		})
+	}
+
+	if !isPrivateIP(nil) {
+		t.Error("isPrivateIP(nil) should return true")
+	}
+}
+
+func TestValidateURL_RejectsNonHTTPS(t *testing.T) {
+	err := validateURL("http://example.com/path", false)
+	if !errors.Is(err, ErrUnsupportedScheme) {
+		t.Errorf("validateURL http = %v, want ErrUnsupportedScheme", err)
+	}
+}
+
+func TestValidateURL_AllowsHTTPWhenConfigured(t *testing.T) {
+	// Use a host that won't resolve (explicit .invalid TLD) so we don't hit DNS.
+	err := validateURL("http://nonexistent.invalid/path", true)
+	// We expect a host resolution error, not ErrUnsupportedScheme.
+	if errors.Is(err, ErrUnsupportedScheme) {
+		t.Error("validateURL with AllowHTTP should not return ErrUnsupportedScheme")
+	}
+}
+
+func TestValidateURL_RejectsLocalhost(t *testing.T) {
+	err := validateURL("https://localhost/path", false)
+	if !errors.Is(err, ErrSSRFBlocked) {
+		t.Errorf("validateURL localhost = %v, want ErrSSRFBlocked", err)
+	}
+}
+
+func TestValidateURL_EmptyHost(t *testing.T) {
+	err := validateURL("https:///path", false)
+	if !errors.Is(err, ErrInvalidHost) {
+		t.Errorf("validateURL empty host = %v, want ErrInvalidHost", err)
+	}
+}
+
+func TestMockFetcher_FetchesFile(t *testing.T) {
+	mockFS := fstest.MapFS{
+		"example.com/images/photo.jpg": &fstest.MapFile{Data: []byte("fake-jpeg-data")},
+	}
+
+	m := NewMock(mockFS)
+
+	result, err := m.Fetch(context.Background(), "https://example.com/images/photo.jpg")
+	if err != nil {
+		t.Fatalf("Fetch() error = %v", err)
+	}
+	defer func() { _ = result.Content.Close() }()
+
+	if result.ContentType != "image/jpeg" {
+		t.Errorf("ContentType = %q, want image/jpeg", result.ContentType)
+	}
+
+	data, err := io.ReadAll(result.Content)
+	if err != nil {
+		t.Fatalf("read content: %v", err)
+	}
+
+	if string(data) != "fake-jpeg-data" {
+		t.Errorf("Content = %q, want %q", string(data), "fake-jpeg-data")
+	}
+
+	if result.ContentLength != int64(len("fake-jpeg-data")) {
+		t.Errorf("ContentLength = %d, want %d", result.ContentLength, len("fake-jpeg-data"))
+	}
+}
+
+func TestMockFetcher_MissingFileReturnsUpstreamError(t *testing.T) {
+	mockFS := fstest.MapFS{}
+	m := NewMock(mockFS)
+
+	_, err := m.Fetch(context.Background(), "https://example.com/missing.jpg")
+	if !errors.Is(err, ErrUpstreamError) {
+		t.Errorf("Fetch() error = %v, want ErrUpstreamError", err)
+	}
+}
+
+func TestMockFetcher_RespectsContextCancellation(t *testing.T) {
+	mockFS := fstest.MapFS{
+		"example.com/photo.jpg": &fstest.MapFile{Data: []byte("data")},
+	}
+	m := NewMock(mockFS)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	_, err := m.Fetch(ctx, "https://example.com/photo.jpg")
+	if !errors.Is(err, context.Canceled) {
+		t.Errorf("Fetch() error = %v, want context.Canceled", err)
+	}
+}
+
+func TestDetectContentTypeFromPath(t *testing.T) {
+	tests := []struct {
+		path string
+		want string
+	}{
+		{"foo/bar.jpg", "image/jpeg"},
+		{"foo/bar.JPG", "image/jpeg"},
+		{"foo/bar.jpeg", "image/jpeg"},
+		{"foo/bar.png", "image/png"},
+		{"foo/bar.gif", "image/gif"},
+		{"foo/bar.webp", "image/webp"},
+		{"foo/bar.avif", "image/avif"},
+		{"foo/bar.svg", "image/svg+xml"},
+		{"foo/bar.bin", "application/octet-stream"},
+		{"foo/bar", "application/octet-stream"},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.path, func(t *testing.T) {
+			got := detectContentTypeFromPath(tc.path)
+			if got != tc.want {
+				t.Errorf("detectContentTypeFromPath(%q) = %q, want %q", tc.path, got, tc.want)
+			}
+		})
+	}
+}
+
+func TestLimitedReader_EnforcesLimit(t *testing.T) {
+	src := make([]byte, 100)
+	r := &limitedReader{
+		reader:    &byteReader{data: src},
+		remaining: 50,
+	}
+
+	buf := make([]byte, 100)
+
+	n, err := r.Read(buf)
+	if err != nil {
+		t.Fatalf("first Read error = %v", err)
+	}
+
+	if n > 50 {
+		t.Errorf("read %d bytes, should be capped at 50", n)
+	}
+
+	// Drain until limit is exhausted.
+	total := n
+	for total < 50 {
+		nn, err := r.Read(buf)
+		total += nn
+		if err != nil {
+			t.Fatalf("during drain: %v", err)
+		}
+	}
+
+	// Now the limit is exhausted — next read should error.
+	_, err = r.Read(buf)
+	if !errors.Is(err, ErrResponseTooLarge) {
+		t.Errorf("exhausted Read error = %v, want ErrResponseTooLarge", err)
+	}
+}
+
+// byteReader is a minimal io.Reader over a byte slice for testing.
+type byteReader struct {
+	data []byte
+	pos  int
+}
+
+func (r *byteReader) Read(p []byte) (int, error) {
+	if r.pos >= len(r.data) {
+		return 0, io.EOF
+	}
+
+	n := copy(p, r.data[r.pos:])
+	r.pos += n
+
+	return n, nil
+}

internal/httpfetcher/mock.go

@@ -1,4 +1,4 @@
-package imgcache
+package httpfetcher
 
 import (
 	"context"
@@ -10,15 +10,15 @@ import (
 	"strings"
 )
 
-// MockFetcher implements the Fetcher interface using an embedded filesystem.
+// MockFetcher implements Fetcher using an embedded filesystem.
 // Files are organized as: hostname/path/to/file.ext
-// URLs like https://example.com/images/photo.jpg map to example.com/images/photo.jpg
+// URLs like https://example.com/images/photo.jpg map to example.com/images/photo.jpg.
 type MockFetcher struct {
 	fs fs.FS
 }
 
-// NewMockFetcher creates a new mock fetcher backed by the given filesystem.
+// NewMock creates a new mock fetcher backed by the given filesystem.
-func NewMockFetcher(fsys fs.FS) *MockFetcher {
+func NewMock(fsys fs.FS) *MockFetcher {
 	return &MockFetcher{fs: fsys}
 }
 

internal/imageprocessor/imageprocessor.go

@@ -1,4 +1,5 @@
-package imgcache
+// Package imageprocessor provides image format conversion and resizing using libvips.
+package imageprocessor
 
 import (
 	"bytes"
@@ -22,38 +23,133 @@ 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
 
+// DefaultMaxInputBytes is the default maximum input size in bytes (50 MiB).
+// This matches the default upstream fetcher limit.
+const DefaultMaxInputBytes = 50 << 20
+
 // ErrInputTooLarge is returned when input image dimensions exceed MaxInputDimension.
 var ErrInputTooLarge = errors.New("input image dimensions exceed maximum")
 
+// ErrInputDataTooLarge is returned when the raw input data exceeds the configured byte limit.
+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 the Processor interface using libvips via govips.
+// ImageProcessor implements image transformation using libvips via govips.
-type ImageProcessor struct{}
+type ImageProcessor struct {
+	maxInputBytes int64
+}
 
-// NewImageProcessor creates a new image processor.
+// Params holds configuration for creating an ImageProcessor.
-func NewImageProcessor() *ImageProcessor {
+// Zero values use sensible defaults (MaxInputBytes defaults to DefaultMaxInputBytes).
+type Params struct {
+	// MaxInputBytes is the maximum allowed input size in bytes.
+	// If <= 0, DefaultMaxInputBytes is used.
+	MaxInputBytes int64
+}
+
+// New creates a new image processor with the given parameters.
+// A zero-value Params{} uses sensible defaults.
+func New(params Params) *ImageProcessor {
 	initVips()
 
-	return &ImageProcessor{}
+	maxInputBytes := params.MaxInputBytes
+	if maxInputBytes <= 0 {
+		maxInputBytes = DefaultMaxInputBytes
+	}
+
+	return &ImageProcessor{
+		maxInputBytes: maxInputBytes,
+	}
 }
 
 // Process transforms an image according to the request.
 func (p *ImageProcessor) Process(
 	_ context.Context,
 	input io.Reader,
-	req *ImageRequest,
+	req *Request,
-) (*ProcessResult, error) {
+) (*Result, error) {
-	// Read input
+	// Read input with a size limit to prevent unbounded memory consumption.
-	data, err := io.ReadAll(input)
+	// We read at most maxInputBytes+1 so we can detect if the input exceeds
+	// the limit without consuming additional memory.
+	limited := io.LimitReader(input, p.maxInputBytes+1)
+
+	data, err := io.ReadAll(limited)
 	if err != nil {
 		return nil, fmt.Errorf("failed to read input: %w", err)
 	}
 
+	if int64(len(data)) > p.maxInputBytes {
+		return nil, ErrInputDataTooLarge
+	}
+
 	// Decode image
 	img, err := vips.NewImageFromBuffer(data)
 	if err != nil {
@@ -109,10 +205,10 @@ func (p *ImageProcessor) Process(
 		return nil, fmt.Errorf("failed to encode: %w", err)
 	}
 
-	return &ProcessResult{
+	return &Result{
 		Content:       io.NopCloser(bytes.NewReader(output)),
 		ContentLength: int64(len(output)),
-		ContentType:   ImageFormatToMIME(outputFormat),
+		ContentType:   FormatToMIME(outputFormat),
 		Width:         img.Width(),
 		Height:        img.Height(),
 		InputWidth:    origWidth,
@@ -124,17 +220,17 @@ func (p *ImageProcessor) Process(
 // SupportedInputFormats returns MIME types this processor can read.
 func (p *ImageProcessor) SupportedInputFormats() []string {
 	return []string{
-		string(MIMETypeJPEG),
+		"image/jpeg",
-		string(MIMETypePNG),
+		"image/png",
-		string(MIMETypeGIF),
+		"image/gif",
-		string(MIMETypeWebP),
+		"image/webp",
-		string(MIMETypeAVIF),
+		"image/avif",
 	}
 }
 
 // SupportedOutputFormats returns formats this processor can write.
-func (p *ImageProcessor) SupportedOutputFormats() []ImageFormat {
+func (p *ImageProcessor) SupportedOutputFormats() []Format {
-	return []ImageFormat{
+	return []Format{
 		FormatJPEG,
 		FormatPNG,
 		FormatGIF,
@@ -143,6 +239,24 @@ func (p *ImageProcessor) SupportedOutputFormats() []ImageFormat {
 	}
 }
 
+// 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()
@@ -171,7 +285,6 @@ 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)
@@ -182,7 +295,7 @@ 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) - use ThumbnailWithSize with Force
+		// Resize to exact dimensions (may distort)
 		return img.ThumbnailWithSize(width, height, vips.InterestingNone, vips.SizeForce)
 
 	case FitInside:
@@ -218,7 +331,7 @@ 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 ImageFormat, quality int) ([]byte, error) {
+func (p *ImageProcessor) encode(img *vips.ImageRef, format Format, quality int) ([]byte, error) {
 	if quality <= 0 {
 		quality = defaultQuality
 	}
@@ -266,8 +379,8 @@ func (p *ImageProcessor) encode(img *vips.ImageRef, format ImageFormat, quality
 	return output, nil
 }
 
-// formatFromString converts a format string to ImageFormat.
+// formatFromString converts a format string to Format.
-func (p *ImageProcessor) formatFromString(format string) ImageFormat {
+func (p *ImageProcessor) formatFromString(format string) Format {
 	switch format {
 	case "jpeg":
 		return FormatJPEG

internal/imageprocessor/imageprocessor_test.go

@@ -1,4 +1,4 @@
-package imgcache
+package imageprocessor
 
 import (
 	"bytes"
@@ -70,13 +70,36 @@ 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 := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestJPEG(t, 800, 600)
 
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 400, Height: 300},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -107,23 +130,19 @@ func TestImageProcessor_ResizeJPEG(t *testing.T) {
 		t.Fatalf("failed to read result: %v", err)
 	}
 
-	mime, err := DetectFormat(data)
+	mime := detectMIME(data)
-	if err != nil {
+	if mime != "image/jpeg" {
-		t.Fatalf("DetectFormat() error = %v", err)
+		t.Errorf("Output format = %v, want image/jpeg", mime)
-	}
-
-	if mime != MIMETypeJPEG {
-		t.Errorf("Output format = %v, want %v", mime, MIMETypeJPEG)
 	}
 }
 
 func TestImageProcessor_ConvertToPNG(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestJPEG(t, 200, 150)
 
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 200, Height: 150},
 		Format:  FormatPNG,
 		FitMode: FitCover,
@@ -140,23 +159,19 @@ func TestImageProcessor_ConvertToPNG(t *testing.T) {
 		t.Fatalf("failed to read result: %v", err)
 	}
 
-	mime, err := DetectFormat(data)
+	mime := detectMIME(data)
-	if err != nil {
+	if mime != "image/png" {
-		t.Fatalf("DetectFormat() error = %v", err)
+		t.Errorf("Output format = %v, want image/png", mime)
-	}
-
-	if mime != MIMETypePNG {
-		t.Errorf("Output format = %v, want %v", mime, MIMETypePNG)
 	}
 }
 
 func TestImageProcessor_OriginalSize(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestJPEG(t, 640, 480)
 
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 0, Height: 0}, // Original size
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -179,14 +194,14 @@ func TestImageProcessor_OriginalSize(t *testing.T) {
 }
 
 func TestImageProcessor_FitContain(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// 800x400 image (2:1 aspect) into 400x400 box with contain
 	// Should result in 400x200 (maintaining aspect ratio)
 	input := createTestJPEG(t, 800, 400)
 
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 400, Height: 400},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -206,14 +221,14 @@ func TestImageProcessor_FitContain(t *testing.T) {
 }
 
 func TestImageProcessor_ProportionalScale_WidthOnly(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// 800x600 image, request width=400 height=0
 	// Should scale proportionally to 400x300
 	input := createTestJPEG(t, 800, 600)
 
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 400, Height: 0},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -236,14 +251,14 @@ func TestImageProcessor_ProportionalScale_WidthOnly(t *testing.T) {
 }
 
 func TestImageProcessor_ProportionalScale_HeightOnly(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// 800x600 image, request width=0 height=300
 	// Should scale proportionally to 400x300
 	input := createTestJPEG(t, 800, 600)
 
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 0, Height: 300},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -266,12 +281,12 @@ func TestImageProcessor_ProportionalScale_HeightOnly(t *testing.T) {
 }
 
 func TestImageProcessor_ProcessPNG(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestPNG(t, 400, 300)
 
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 200, Height: 150},
 		Format:  FormatPNG,
 		FitMode: FitCover,
@@ -292,13 +307,8 @@ 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 := NewImageProcessor()
+	proc := New(Params{})
 
 	inputFormats := proc.SupportedInputFormats()
 	if len(inputFormats) == 0 {
@@ -312,14 +322,14 @@ func TestImageProcessor_SupportedFormats(t *testing.T) {
 }
 
 func TestImageProcessor_RejectsOversizedInput(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// Create an image that exceeds MaxInputDimension (e.g., 10000x100)
 	// This should be rejected before processing to prevent DoS
 	input := createTestJPEG(t, 10000, 100)
 
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 100, Height: 100},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -337,13 +347,13 @@ func TestImageProcessor_RejectsOversizedInput(t *testing.T) {
 }
 
 func TestImageProcessor_RejectsOversizedInputHeight(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// Create an image with oversized height
 	input := createTestJPEG(t, 100, 10000)
 
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 100, Height: 100},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -361,14 +371,13 @@ func TestImageProcessor_RejectsOversizedInputHeight(t *testing.T) {
 }
 
 func TestImageProcessor_AcceptsMaxDimensionInput(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	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 := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 100, Height: 100},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -383,12 +392,12 @@ func TestImageProcessor_AcceptsMaxDimensionInput(t *testing.T) {
 }
 
 func TestImageProcessor_EncodeWebP(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestJPEG(t, 200, 150)
 
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 100, Height: 75},
 		Format:  FormatWebP,
 		Quality: 80,
@@ -407,13 +416,9 @@ func TestImageProcessor_EncodeWebP(t *testing.T) {
 		t.Fatalf("failed to read result: %v", err)
 	}
 
-	mime, err := DetectFormat(data)
+	mime := detectMIME(data)
-	if err != nil {
+	if mime != "image/webp" {
-		t.Fatalf("DetectFormat() error = %v", err)
+		t.Errorf("Output format = %v, want image/webp", mime)
-	}
-
-	if mime != MIMETypeWebP {
-		t.Errorf("Output format = %v, want %v", mime, MIMETypeWebP)
 	}
 
 	// Verify dimensions
@@ -426,7 +431,7 @@ func TestImageProcessor_EncodeWebP(t *testing.T) {
 }
 
 func TestImageProcessor_DecodeAVIF(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	// Load test AVIF file
@@ -436,7 +441,7 @@ func TestImageProcessor_DecodeAVIF(t *testing.T) {
 	}
 
 	// Request resize and convert to JPEG
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 2, Height: 2},
 		Format:  FormatJPEG,
 		Quality: 85,
@@ -455,23 +460,84 @@ func TestImageProcessor_DecodeAVIF(t *testing.T) {
 		t.Fatalf("failed to read result: %v", err)
 	}
 
-	mime, err := DetectFormat(data)
+	mime := detectMIME(data)
-	if err != nil {
+	if mime != "image/jpeg" {
-		t.Fatalf("DetectFormat() error = %v", err)
+		t.Errorf("Output format = %v, want image/jpeg", mime)
+	}
 }
 
-	if mime != MIMETypeJPEG {
+func TestImageProcessor_RejectsOversizedInputData(t *testing.T) {
-		t.Errorf("Output format = %v, want %v", mime, MIMETypeJPEG)
+	// Create a processor with a very small byte limit
+	const limit = 1024
+	proc := New(Params{MaxInputBytes: limit})
+	ctx := context.Background()
+
+	// Create a valid JPEG that exceeds the byte limit
+	input := createTestJPEG(t, 800, 600) // will be well over 1 KiB
+	if int64(len(input)) <= limit {
+		t.Fatalf("test JPEG must exceed %d bytes, got %d", limit, len(input))
+	}
+
+	req := &Request{
+		Size:    Size{Width: 100, Height: 75},
+		Format:  FormatJPEG,
+		Quality: 85,
+		FitMode: FitCover,
+	}
+
+	_, err := proc.Process(ctx, bytes.NewReader(input), req)
+	if err == nil {
+		t.Fatal("Process() should reject input exceeding maxInputBytes")
+	}
+
+	if err != ErrInputDataTooLarge {
+		t.Errorf("Process() error = %v, want ErrInputDataTooLarge", err)
+	}
+}
+
+func TestImageProcessor_AcceptsInputWithinLimit(t *testing.T) {
+	// Create a small image and set limit well above its size
+	input := createTestJPEG(t, 10, 10)
+	limit := int64(len(input)) * 10 // 10× headroom
+
+	proc := New(Params{MaxInputBytes: limit})
+	ctx := context.Background()
+
+	req := &Request{
+		Size:    Size{Width: 10, Height: 10},
+		Format:  FormatJPEG,
+		Quality: 85,
+		FitMode: FitCover,
+	}
+
+	result, err := proc.Process(ctx, bytes.NewReader(input), req)
+	if err != nil {
+		t.Fatalf("Process() error = %v, want nil", err)
+	}
+	defer result.Content.Close()
+}
+
+func TestImageProcessor_DefaultMaxInputBytes(t *testing.T) {
+	// Passing 0 should use the default
+	proc := New(Params{})
+	if proc.maxInputBytes != DefaultMaxInputBytes {
+		t.Errorf("maxInputBytes = %d, want %d", proc.maxInputBytes, DefaultMaxInputBytes)
+	}
+
+	// Passing negative should also use the default
+	proc = New(Params{MaxInputBytes: -1})
+	if proc.maxInputBytes != DefaultMaxInputBytes {
+		t.Errorf("maxInputBytes = %d, want %d", proc.maxInputBytes, DefaultMaxInputBytes)
 	}
 }
 
 func TestImageProcessor_EncodeAVIF(t *testing.T) {
-	proc := NewImageProcessor()
+	proc := New(Params{})
 	ctx := context.Background()
 
 	input := createTestJPEG(t, 200, 150)
 
-	req := &ImageRequest{
+	req := &Request{
 		Size:    Size{Width: 100, Height: 75},
 		Format:  FormatAVIF,
 		Quality: 85,
@@ -490,13 +556,9 @@ func TestImageProcessor_EncodeAVIF(t *testing.T) {
 		t.Fatalf("failed to read result: %v", err)
 	}
 
-	mime, err := DetectFormat(data)
+	mime := detectMIME(data)
-	if err != nil {
+	if mime != "image/avif" {
-		t.Fatalf("DetectFormat() error = %v", err)
+		t.Errorf("Output format = %v, want image/avif", mime)
-	}
-
-	if mime != MIMETypeAVIF {
-		t.Errorf("Output format = %v, want %v", mime, MIMETypeAVIF)
 	}
 
 	// Verify dimensions

internal/imgcache/cache.go

@@ -9,6 +9,8 @@ import (
 	"io"
 	"path/filepath"
 	"time"
+
+	"sneak.berlin/go/pixa/internal/httpfetcher"
 )
 
 // Cache errors.
@@ -111,7 +113,7 @@ func (c *Cache) StoreSource(
 	ctx context.Context,
 	req *ImageRequest,
 	content io.Reader,
-	result *FetchResult,
+	result *httpfetcher.FetchResult,
 ) (ContentHash, error) {
 	// Store content
 	contentHash, size, err := c.srcContent.Store(content)

internal/imgcache/cache_test.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	_ "modernc.org/sqlite"
+	"sneak.berlin/go/pixa/internal/httpfetcher"
 )
 
 func setupTestDB(t *testing.T) *sql.DB {
@@ -152,7 +153,7 @@ func TestCache_StoreAndLookup(t *testing.T) {
 
 	// Store source content
 	sourceContent := []byte("fake jpeg data")
-	fetchResult := &FetchResult{
+	fetchResult := &httpfetcher.FetchResult{
 		ContentType: "image/jpeg",
 		Headers:     map[string][]string{"Content-Type": {"image/jpeg"}},
 	}

internal/imgcache/imgcache.go

@@ -169,66 +169,6 @@ type Whitelist interface {
 	IsWhitelisted(u *url.URL) bool
 }
 
-// Fetcher fetches images from upstream origins
-type Fetcher interface {
-	// Fetch retrieves an image from the origin
-	Fetch(ctx context.Context, url string) (*FetchResult, error)
-}
-
-// FetchResult contains the result of fetching from upstream
-type FetchResult struct {
-	// Content is the raw image data
-	Content io.ReadCloser
-	// ContentLength is the size in bytes (-1 if unknown)
-	ContentLength int64
-	// ContentType is the MIME type from upstream
-	ContentType string
-	// Headers contains all response headers from upstream
-	Headers map[string][]string
-	// StatusCode is the HTTP status code from upstream
-	StatusCode int
-	// FetchDurationMs is how long the fetch took in milliseconds
-	FetchDurationMs int64
-	// RemoteAddr is the IP:port of the upstream server
-	RemoteAddr string
-	// HTTPVersion is the protocol version (e.g., "1.1", "2.0")
-	HTTPVersion string
-	// TLSVersion is the TLS protocol version (e.g., "TLS 1.3")
-	TLSVersion string
-	// TLSCipherSuite is the negotiated cipher suite name
-	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/service.go

@@ -11,17 +11,22 @@ import (
 	"time"
 
 	"github.com/dustin/go-humanize"
+	"sneak.berlin/go/pixa/internal/allowlist"
+	"sneak.berlin/go/pixa/internal/httpfetcher"
+	"sneak.berlin/go/pixa/internal/imageprocessor"
+	"sneak.berlin/go/pixa/internal/magic"
 )
 
 // Service implements the ImageCache interface, orchestrating cache, fetcher, and processor.
 type Service struct {
 	cache           *Cache
-	fetcher   Fetcher
+	fetcher         httpfetcher.Fetcher
-	processor Processor
+	processor       *imageprocessor.ImageProcessor
 	signer          *Signer
-	whitelist *HostWhitelist
+	allowlist       *allowlist.HostAllowList
 	log             *slog.Logger
 	allowHTTP       bool
+	maxResponseSize int64
 }
 
 // ServiceConfig holds configuration for the image service.
@@ -29,9 +34,9 @@ type ServiceConfig struct {
 	// Cache is the cache instance
 	Cache *Cache
 	// FetcherConfig configures the upstream fetcher (ignored if Fetcher is set)
-	FetcherConfig *FetcherConfig
+	FetcherConfig *httpfetcher.Config
 	// Fetcher is an optional custom fetcher (for testing)
-	Fetcher Fetcher
+	Fetcher httpfetcher.Fetcher
 	// SigningKey is the HMAC signing key (empty disables signing)
 	SigningKey string
 	// Whitelist is the list of hosts that don't require signatures
@@ -50,16 +55,18 @@ func NewService(cfg *ServiceConfig) (*Service, error) {
 		return nil, errors.New("signing key is required")
 	}
 
+	// Resolve fetcher config for defaults
+	fetcherCfg := cfg.FetcherConfig
+	if fetcherCfg == nil {
+		fetcherCfg = httpfetcher.DefaultConfig()
+	}
+
 	// Use custom fetcher if provided, otherwise create HTTP fetcher
-	var fetcher Fetcher
+	var fetcher httpfetcher.Fetcher
 	if cfg.Fetcher != nil {
 		fetcher = cfg.Fetcher
 	} else {
-		fetcherCfg := cfg.FetcherConfig
+		fetcher = httpfetcher.New(fetcherCfg)
-		if fetcherCfg == nil {
-			fetcherCfg = DefaultFetcherConfig()
-		}
-		fetcher = NewHTTPFetcher(fetcherCfg)
 	}
 
 	signer := NewSigner(cfg.SigningKey)
@@ -74,14 +81,17 @@ func NewService(cfg *ServiceConfig) (*Service, error) {
 		allowHTTP = cfg.FetcherConfig.AllowHTTP
 	}
 
+	maxResponseSize := fetcherCfg.MaxResponseSize
+
 	return &Service{
 		cache:           cfg.Cache,
 		fetcher:         fetcher,
-		processor: NewImageProcessor(),
+		processor:       imageprocessor.New(imageprocessor.Params{MaxInputBytes: maxResponseSize}),
 		signer:          signer,
-		whitelist: NewHostWhitelist(cfg.Whitelist),
+		allowlist:       allowlist.New(cfg.Whitelist),
 		log:             log,
 		allowHTTP:       allowHTTP,
+		maxResponseSize: maxResponseSize,
 	}, nil
 }
 
@@ -104,7 +114,7 @@ func (s *Service) Get(ctx context.Context, req *ImageRequest) (*ImageResponse, e
 			"path", req.SourcePath,
 		)
 
-		return nil, fmt.Errorf("%w: %w", ErrUpstreamError, ErrNegativeCached)
+		return nil, fmt.Errorf("%w: %w", httpfetcher.ErrUpstreamError, ErrNegativeCached)
 	}
 
 	// Check variant cache first (disk only, no DB)
@@ -146,6 +156,40 @@ func (s *Service) Get(ctx context.Context, req *ImageRequest) (*ImageResponse, e
 	return response, nil
 }
 
+// loadCachedSource attempts to load source content from cache, returning nil
+// if the cached data is unavailable or exceeds maxResponseSize.
+func (s *Service) loadCachedSource(contentHash ContentHash) []byte {
+	reader, err := s.cache.GetSourceContent(contentHash)
+	if err != nil {
+		s.log.Warn("failed to load cached source, fetching", "error", err)
+
+		return nil
+	}
+
+	// Bound the read to maxResponseSize to prevent unbounded memory use
+	// from unexpectedly large cached files.
+	limited := io.LimitReader(reader, s.maxResponseSize+1)
+	data, err := io.ReadAll(limited)
+	_ = reader.Close()
+
+	if err != nil {
+		s.log.Warn("failed to read cached source, fetching", "error", err)
+
+		return nil
+	}
+
+	if int64(len(data)) > s.maxResponseSize {
+		s.log.Warn("cached source exceeds max response size, discarding",
+			"hash", contentHash,
+			"max_bytes", s.maxResponseSize,
+		)
+
+		return nil
+	}
+
+	return data
+}
+
 // processFromSourceOrFetch processes an image, using cached source content if available.
 func (s *Service) processFromSourceOrFetch(
 	ctx context.Context,
@@ -162,22 +206,8 @@ func (s *Service) processFromSourceOrFetch(
 	var fetchBytes int64
 
 	if contentHash != "" {
-		// We have cached source - load it
 		s.log.Debug("using cached source", "hash", contentHash)
-
+		sourceData = s.loadCachedSource(contentHash)
-		reader, err := s.cache.GetSourceContent(contentHash)
-		if err != nil {
-			s.log.Warn("failed to load cached source, fetching", "error", err)
-			// Fall through to fetch
-		} else {
-			sourceData, err = io.ReadAll(reader)
-			_ = reader.Close()
-
-			if err != nil {
-				s.log.Warn("failed to read cached source, fetching", "error", err)
-				// Fall through to fetch
-			}
-		}
 	}
 
 	// Fetch from upstream if we don't have source data or it's empty
@@ -249,7 +279,7 @@ func (s *Service) fetchAndProcess(
 	)
 
 	// Validate magic bytes match content type
-	if err := ValidateMagicBytes(sourceData, fetchResult.ContentType); err != nil {
+	if err := magic.ValidateMagicBytes(sourceData, fetchResult.ContentType); err != nil {
 		return nil, fmt.Errorf("content validation failed: %w", err)
 	}
 
@@ -274,7 +304,14 @@ func (s *Service) processAndStore(
 	// Process the image
 	processStart := time.Now()
 
-	processResult, err := s.processor.Process(ctx, bytes.NewReader(sourceData), req)
+	processReq := &imageprocessor.Request{
+		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)
 	}
@@ -347,7 +384,7 @@ func (s *Service) Stats(ctx context.Context) (*CacheStats, error) {
 
 // ValidateRequest validates the request signature if required.
 func (s *Service) ValidateRequest(req *ImageRequest) error {
-	// Check if host is whitelisted (no signature required)
+	// Check if host is allowed (no signature required)
 	sourceURL := req.SourceURL()
 
 	parsedURL, err := url.Parse(sourceURL)
@@ -355,11 +392,11 @@ func (s *Service) ValidateRequest(req *ImageRequest) error {
 		return fmt.Errorf("invalid source URL: %w", err)
 	}
 
-	if s.whitelist.IsWhitelisted(parsedURL) {
+	if s.allowlist.IsAllowed(parsedURL) {
 		return nil
 	}
 
-	// Signature required for non-whitelisted hosts
+	// Signature required for non-allowed hosts
 	return s.signer.Verify(req)
 }
 
@@ -382,13 +419,13 @@ const (
 
 // isNegativeCacheable returns true if the error should be cached.
 func isNegativeCacheable(err error) bool {
-	return errors.Is(err, ErrUpstreamError)
+	return errors.Is(err, httpfetcher.ErrUpstreamError)
 }
 
 // extractStatusCode extracts HTTP status code from error message.
 func extractStatusCode(err error) int {
 	// Default to 502 Bad Gateway for upstream errors
-	if errors.Is(err, ErrUpstreamError) {
+	if errors.Is(err, httpfetcher.ErrUpstreamError) {
 		return httpStatusBadGateway
 	}
 

internal/imgcache/service_test.go

@@ -5,6 +5,8 @@ import (
 	"io"
 	"testing"
 	"time"
+
+	"sneak.berlin/go/pixa/internal/magic"
 )
 
 func TestService_Get_WhitelistedHost(t *testing.T) {
@@ -151,6 +153,74 @@ 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()
@@ -247,17 +317,17 @@ func TestService_Get_FormatConversion(t *testing.T) {
 				t.Fatalf("failed to read response: %v", err)
 			}
 
-			detectedMIME, err := DetectFormat(data)
+			detectedMIME, err := magic.DetectFormat(data)
 			if err != nil {
 				t.Fatalf("failed to detect format: %v", err)
 			}
 
-			expectedFormat, ok := MIMEToImageFormat(tt.wantMIME)
+			expectedFormat, ok := magic.MIMEToImageFormat(tt.wantMIME)
 			if !ok {
 				t.Fatalf("unknown format for MIME type: %s", tt.wantMIME)
 			}
 
-			detectedFormat, ok := MIMEToImageFormat(string(detectedMIME))
+			detectedFormat, ok := magic.MIMEToImageFormat(string(detectedMIME))
 			if !ok {
 				t.Fatalf("unknown format for detected MIME type: %s", detectedMIME)
 			}

internal/imgcache/signature.go

@@ -43,6 +43,11 @@ 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() {
@@ -66,6 +71,8 @@ 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

@@ -152,6 +152,178 @@ 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")

internal/imgcache/stats_test.go

@@ -16,7 +16,7 @@ func setupStatsTestDB(t *testing.T) *sql.DB {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if err := database.ApplyMigrations(db); err != nil {
+	if err := database.ApplyMigrations(context.Background(), db, nil); err != nil {
 		t.Fatal(err)
 	}
 	t.Cleanup(func() { db.Close() })

internal/imgcache/testutil_test.go

@@ -2,6 +2,7 @@ package imgcache
 
 import (
 	"bytes"
+	"context"
 	"database/sql"
 	"image"
 	"image/color"
@@ -14,6 +15,7 @@ import (
 	"time"
 
 	"sneak.berlin/go/pixa/internal/database"
+	"sneak.berlin/go/pixa/internal/httpfetcher"
 )
 
 // TestFixtures contains paths to test files in the mock filesystem.
@@ -171,7 +173,7 @@ func SetupTestService(t *testing.T, opts ...TestServiceOption) (*Service, *TestF
 
 	svc, err := NewService(&ServiceConfig{
 		Cache:      cache,
-		Fetcher:    NewMockFetcher(mockFS),
+		Fetcher:    httpfetcher.NewMock(mockFS),
 		SigningKey: cfg.signingKey,
 		Whitelist:  cfg.whitelist,
 	})
@@ -193,7 +195,7 @@ func setupServiceTestDB(t *testing.T) *sql.DB {
 	}
 
 	// Use the real production schema via migrations
-	if err := database.ApplyMigrations(db); err != nil {
+	if err := database.ApplyMigrations(context.Background(), db, nil); err != nil {
 		t.Fatalf("failed to apply migrations: %v", err)
 	}
 

internal/magic/magic.go

@@ -1,4 +1,6 @@
-package imgcache
+// Package magic detects image formats from magic bytes and validates
+// content against declared MIME types.
+package magic
 
 import (
 	"bytes"
@@ -27,6 +29,20 @@ const (
 	MIMETypeSVG  = MIMEType("image/svg+xml")
 )
 
+// ImageFormat represents supported output image formats.
+// This mirrors the type in imgcache to avoid circular imports.
+type ImageFormat string
+
+// Supported image output formats.
+const (
+	FormatOriginal ImageFormat = "orig"
+	FormatJPEG     ImageFormat = "jpeg"
+	FormatPNG      ImageFormat = "png"
+	FormatWebP     ImageFormat = "webp"
+	FormatAVIF     ImageFormat = "avif"
+	FormatGIF      ImageFormat = "gif"
+)
+
 // MinMagicBytes is the minimum number of bytes needed to detect format.
 const MinMagicBytes = 12
 
@@ -189,7 +205,7 @@ func PeekAndValidate(r io.Reader, declaredType string) (io.Reader, error) {
 	return io.MultiReader(bytes.NewReader(buf), r), nil
 }
 
-// MIMEToImageFormat converts a MIME type to our ImageFormat type.
+// MIMEToImageFormat converts a MIME type to an ImageFormat.
 func MIMEToImageFormat(mimeType string) (ImageFormat, bool) {
 	normalized := normalizeMIMEType(mimeType)
 	switch MIMEType(normalized) {
@@ -208,7 +224,7 @@ func MIMEToImageFormat(mimeType string) (ImageFormat, bool) {
 	}
 }
 
-// ImageFormatToMIME converts our ImageFormat to a MIME type string.
+// ImageFormatToMIME converts an ImageFormat to a MIME type string.
 func ImageFormatToMIME(format ImageFormat) string {
 	switch format {
 	case FormatJPEG:

internal/magic/magic_test.go

@@ -1,4 +1,4 @@
-package imgcache
+package magic
 
 import (
 	"bytes"