Wire up image handler endpoint with service orchestration

- Add image proxy config options (signing_key, whitelist_hosts, allow_http)
- Create Service to orchestrate cache, fetcher, and processor
- Initialize image service in handlers OnStart hook
- Implement HandleImage with URL parsing, signature validation, cache
- Implement HandleRobotsTxt for search engine prevention
- Parse query params for signature, quality, and fit mode

internal/handlers/handlers.go

@@ -6,9 +6,13 @@ import (
 	"encoding/json"
 	"log/slog"
 	"net/http"
+	"time"
 
 	"go.uber.org/fx"
+	"sneak.berlin/go/pixa/internal/config"
+	"sneak.berlin/go/pixa/internal/database"
 	"sneak.berlin/go/pixa/internal/healthcheck"
+	"sneak.berlin/go/pixa/internal/imgcache"
 	"sneak.berlin/go/pixa/internal/logger"
 )
 
@@ -17,30 +21,76 @@ type Params struct {
 	fx.In
 	Logger      *logger.Logger
 	Healthcheck *healthcheck.Healthcheck
+	Database    *database.Database
+	Config      *config.Config
 }
 
 // Handlers provides HTTP request handlers.
 type Handlers struct {
-	log *slog.Logger
-	hc  *healthcheck.Healthcheck
+	log      *slog.Logger
+	hc       *healthcheck.Healthcheck
+	db       *database.Database
+	config   *config.Config
+	imgSvc   *imgcache.Service
+	imgCache *imgcache.Cache
 }
 
 // New creates a new Handlers instance.
 func New(lc fx.Lifecycle, params Params) (*Handlers, error) {
 	s := &Handlers{
-		log: params.Logger.Get(),
-		hc:  params.Healthcheck,
+		log:    params.Logger.Get(),
+		hc:     params.Healthcheck,
+		db:     params.Database,
+		config: params.Config,
 	}
 
 	lc.Append(fx.Hook{
 		OnStart: func(_ context.Context) error {
-			return nil
+			return s.initImageService()
 		},
 	})
 
 	return s, nil
 }
 
+// initImageService initializes the image cache and service.
+func (s *Handlers) initImageService() error {
+	// Create the cache
+	cache, err := imgcache.NewCache(s.db.DB(), imgcache.CacheConfig{
+		StateDir:        s.config.StateDir,
+		CacheTTL:        imgcache.DefaultCacheTTL,
+		NegativeTTL:     imgcache.DefaultNegativeTTL,
+		HotCacheSize:    imgcache.DefaultHotCacheSize,
+		HotCacheEnabled: true,
+	})
+	if err != nil {
+		return err
+	}
+
+	s.imgCache = cache
+
+	// Create the fetcher config
+	fetcherCfg := imgcache.DefaultFetcherConfig()
+	fetcherCfg.AllowHTTP = s.config.AllowHTTP
+
+	// Create the service
+	svc, err := imgcache.NewService(&imgcache.ServiceConfig{
+		Cache:         cache,
+		FetcherConfig: fetcherCfg,
+		SigningKey:    s.config.SigningKey,
+		Whitelist:     s.config.WhitelistHosts,
+		Logger:        s.log,
+	})
+	if err != nil {
+		return err
+	}
+
+	s.imgSvc = svc
+	s.log.Info("image service initialized")
+
+	return nil
+}
+
 func (s *Handlers) respondJSON(w http.ResponseWriter, data interface{}, status int) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(status)
@@ -51,3 +101,11 @@ func (s *Handlers) respondJSON(w http.ResponseWriter, data interface{}, status i
 		}
 	}
 }
+
+func (s *Handlers) respondError(w http.ResponseWriter, message string, status int) {
+	s.respondJSON(w, map[string]interface{}{
+		"error":     message,
+		"status":    status,
+		"timestamp": time.Now().UTC().Format(time.RFC3339),
+	}, status)
+}