Add direct middleware mode

Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.25.1-alpine AS builder
+FROM golang:1.25.4-alpine AS builder
 RUN apk add --no-cache build-base vips-dev
 WORKDIR /app
 COPY go.mod go.sum ./

compose.dev.yaml

@@ -11,11 +11,12 @@ services:
       # - ALLOWED_DOMAINS=images.unsplash.com,static.pexels.com,*.example.com
       # - DEFAULT_IMAGE_QUALITY=100
       # - MAX_ALLOWED_SIZE=10485760
+      # - BASE_URL=cdn.example.com
     # deploy:
     #   resources:
     #     limits:
-    #       cpus: '0.5'      # Limit to 50% of a single CPU core
+    #       cpus: '0.5'
-    #       memory: '256M'   # Limit to 256 Megabytes of RAM
+    #       memory: '256M'
     #     reservations:
     #       cpus: '0.25'
     #       memory: '128M'

compose.yaml

@@ -7,6 +7,7 @@ services:
     restart: unless-stopped
     environment:
       - CACHE_TTL=30m
+      - BASE_URL=cdn.example.com
       - ALLOWED_DOMAINS=images.unsplash.com,static.pexels.com,*.example.com
       - DEFAULT_IMAGE_QUALITY=100
       - MAX_ALLOWED_SIZE=10485760

env.go

@@ -33,6 +33,13 @@ func getEnvDuration(key string, fallback time.Duration) time.Duration {
 	return fallback
 }
 
+func getEnvString(key string, fallback string) string {
+	if value, ok := os.LookupEnv(key); ok {
+		return value
+	}
+	return fallback
+}
+
 func getEnvStringSlice(key string, fallback []string) []string {
 	if value, ok := os.LookupEnv(key); ok {
 		if value == "" {

go.mod

@@ -1,10 +1,10 @@
 module mediaproxy
 
-go 1.25.1
+go 1.25.4
 
 require (
-	github.com/dgraph-io/ristretto v0.2.0
+	github.com/dgraph-io/ristretto v1.0.1
-	github.com/gabriel-vasile/mimetype v1.4.10
+	github.com/gabriel-vasile/mimetype v1.4.11
 	github.com/h2non/bimg v1.1.9
 )
 
@@ -13,5 +13,5 @@ require (
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/stretchr/testify v1.11.1 // indirect
-	golang.org/x/sys v0.36.0 // indirect
+	golang.org/x/sys v0.38.0 // indirect
 )

go.sum

@@ -2,14 +2,14 @@ github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UF
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/dgraph-io/ristretto v0.2.0 h1:XAfl+7cmoUDWW/2Lx8TGZQjjxIQ2Ley9DSf52dru4WE=
+github.com/dgraph-io/ristretto v1.0.1 h1:g3/HaHVSP+eC3kbryP9vjUY6IAW7jcGYRpj9wUVr0bU=
-github.com/dgraph-io/ristretto v0.2.0/go.mod h1:8uBHCU/PBV4Ag0CJrP47b9Ofby5dqWNh4FicAdoqFNU=
+github.com/dgraph-io/ristretto v1.0.1/go.mod h1:TrOB7p4tcGX5Un6ppslIxtZaH2JLAk5GITV3TX2fuU8=
 github.com/dgryski/go-farm v0.0.0-20200201041132-a6ae2369ad13 h1:fAjc9m62+UWV/WAFKLNi6ZS0675eEUC9y3AlwSbQu1Y=
 github.com/dgryski/go-farm v0.0.0-20200201041132-a6ae2369ad13/go.mod h1:SqUrOPUnsFjfmXRMNPybcSiG0BgUW2AuFH8PAnS2iTw=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
-github.com/gabriel-vasile/mimetype v1.4.10 h1:zyueNbySn/z8mJZHLt6IPw0KoZsiQNszIpU+bX4+ZK0=
+github.com/gabriel-vasile/mimetype v1.4.11 h1:AQvxbp830wPhHTqc1u7nzoLT+ZFxGY7emj5DR5DYFik=
-github.com/gabriel-vasile/mimetype v1.4.10/go.mod h1:d+9Oxyo1wTzWdyVUPMmXFvp4F9tea18J8ufA774AB3s=
+github.com/gabriel-vasile/mimetype v1.4.11/go.mod h1:d+9Oxyo1wTzWdyVUPMmXFvp4F9tea18J8ufA774AB3s=
 github.com/h2non/bimg v1.1.9 h1:WH20Nxko9l/HFm4kZCA3Phbgu2cbHvYzxwxn9YROEGg=
 github.com/h2non/bimg v1.1.9/go.mod h1:R3+UiYwkK4rQl6KVFTOFJHitgLbZXBZNFh2cv3AEbp8=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
@@ -18,7 +18,7 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
-golang.org/x/sys v0.36.0 h1:KVRy2GtZBrk1cBYA7MKu5bEZFxQk4NIDV6RLVcC8o0k=
+golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
-golang.org/x/sys v0.36.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -30,11 +30,12 @@ type Config struct {
 	DefaultImageQuality int
 	ClientTimeout       time.Duration
 	LogLevel            slog.Level
+	BaseURL             string
 }
 
 type App struct {
 	Config *Config
-	Cache  *ristretto.Cache
+	Cache  *ristretto.Cache[string, CacheEntry]
 	Client *http.Client
 	Logger *slog.Logger
 }
@@ -50,10 +51,11 @@ func main() {
 		MaxAllowedSize:      getEnvInt64("MAX_ALLOWED_SIZE", 1024*1024*50),
 		DefaultImageQuality: getEnvInt("DEFAULT_IMAGE_QUALITY", 80),
 		ClientTimeout:       getEnvDuration("CLIENT_TIMEOUT", 2*time.Minute),
+		BaseURL:             getEnvString("BASE_URL", ""),
 		LogLevel:            logLevel,
 	}
 
-	cache, err := ristretto.NewCache(&ristretto.Config{
+	cache, err := ristretto.NewCache(&ristretto.Config[string, CacheEntry]{
 		NumCounters: 1e7,     // Number of keys to track frequency of (10M).
 		MaxCost:     1 << 30, // Maximum cost of cache (1GB).
 		BufferItems: 64,      // Number of keys per Get buffer.
@@ -111,13 +113,19 @@ func main() {
 func (app *App) handleProxy(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
 	logger := ctx.Value(loggerKey).(*slog.Logger)
-	mediaURL := r.URL.Path[1:]
 
-	if strings.HasPrefix(mediaURL, "https:/") && !strings.HasPrefix(mediaURL, "https://") {
+	var mediaURL string
-		mediaURL = "https://" + mediaURL[6:]
+	if app.Config.BaseURL != "" {
-	}
+		baseURL := strings.TrimSuffix(app.Config.BaseURL, "/")
-	if strings.HasPrefix(mediaURL, "http:/") && !strings.HasPrefix(mediaURL, "http://") {
+		mediaURL = "https://" + baseURL + r.URL.Path
-		mediaURL = "http://" + mediaURL[5:]
+	} else {
+		mediaURL = r.URL.Path[1:]
+		if strings.HasPrefix(mediaURL, "https:/") && !strings.HasPrefix(mediaURL, "https://") {
+			mediaURL = "https://" + mediaURL[6:]
+		}
+		if strings.HasPrefix(mediaURL, "http:/") && !strings.HasPrefix(mediaURL, "http://") {
+			mediaURL = "http://" + mediaURL[5:]
+		}
 	}
 
 	logger = logger.With("media_url", mediaURL)
@@ -134,19 +142,17 @@ func (app *App) handleProxy(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if !isAllowedDomain(parsedURL.Host, app.Config.AllowedDomains) {
+	if app.Config.BaseURL == "" && !isAllowedDomain(parsedURL.Host, app.Config.AllowedDomains) {
 		logger.Warn("Domain not allowed", "domain", parsedURL.Host)
 		http.Error(w, "Domain not allowed", http.StatusForbidden)
 		return
 	}
 
-	if value, found := app.Cache.Get(mediaURL); found {
+	if cachedEntry, found := app.Cache.Get(mediaURL); found {
-		if cachedEntry, ok := value.(CacheEntry); ok {
+		logger.Debug("Serving from cache")
-			logger.Debug("Serving image from cache")
+		w.Header().Set("Content-Type", cachedEntry.ContentType)
-			w.Header().Set("Content-Type", cachedEntry.ContentType)
+		w.Write(cachedEntry.Data)
-			w.Write(cachedEntry.Data)
+		return
-			return
-		}
 	}
 
 	logger.Debug("Cache miss, performing HEAD request to origin")
@@ -156,12 +162,13 @@ func (app *App) handleProxy(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "Could not fetch media metadata", http.StatusInternalServerError)
 		return
 	}
+	defer headResp.Body.Close()
+
 	if headResp.StatusCode != http.StatusOK {
 		logger.Warn("Origin server returned non-200 status for HEAD request", "status", headResp.StatusCode)
 		http.Error(w, fmt.Sprintf("Media source returned status: %d", headResp.StatusCode), headResp.StatusCode)
 		return
 	}
-	defer headResp.Body.Close()
 
 	headerContentType := headResp.Header.Get("Content-Type")
 	if !isAllowedType(headerContentType, true) {
@@ -174,19 +181,18 @@ func (app *App) handleProxy(w http.ResponseWriter, r *http.Request) {
 	switch mediaTypeCategory {
 	case "image":
 		logger.Debug("Delegating to image handler")
-		app.handleImage(w, r)
+		app.handleImage(w, r, mediaURL)
 	case "video", "audio":
 		logger.Debug("Delegating to stream handler")
-		app.handleStream(w, r)
+		app.handleStream(w, r, mediaURL)
 	default:
 		logger.Warn("Media type passed initial checks but is not an image, video, or audio", "category", mediaTypeCategory)
 		http.Error(w, "Unsupported media type", http.StatusUnsupportedMediaType)
 	}
 }
 
-func (app *App) handleImage(w http.ResponseWriter, r *http.Request) {
+func (app *App) handleImage(w http.ResponseWriter, r *http.Request, mediaURL string) {
 	logger := r.Context().Value(loggerKey).(*slog.Logger)
-	mediaURL := r.URL.Path[1:]
 
 	resp, err := app.Client.Get(mediaURL)
 	if err != nil {
@@ -196,11 +202,16 @@ func (app *App) handleImage(w http.ResponseWriter, r *http.Request) {
 	}
 	defer resp.Body.Close()
 
-	r.Body = http.MaxBytesReader(w, r.Body, app.Config.MaxAllowedSize)
+	limitedReader := &io.LimitedReader{R: resp.Body, N: app.Config.MaxAllowedSize}
-	mediaData, err := io.ReadAll(resp.Body)
+	mediaData, err := io.ReadAll(limitedReader)
 	if err != nil {
 		logger.Error("Could not read image data", "error", err)
-		http.Error(w, "Could not read image data", http.StatusRequestEntityTooLarge)
+		http.Error(w, "Could not read image data", http.StatusInternalServerError)
+		return
+	}
+	if limitedReader.N == 0 {
+		logger.Error("Image exceeds max allowed size", "limit", app.Config.MaxAllowedSize)
+		http.Error(w, "Image exceeds max allowed size", http.StatusRequestEntityTooLarge)
 		return
 	}
 
@@ -233,25 +244,32 @@ func (app *App) handleImage(w http.ResponseWriter, r *http.Request) {
 		entryToCache = CacheEntry{ContentType: "image/webp", Data: optimizedImage}
 	}
 
-	app.Cache.SetWithTTL(mediaURL, entryToCache, 1, app.Config.CacheTTL)
+	app.Cache.SetWithTTL(mediaURL, entryToCache, int64(len(entryToCache.Data)), app.Config.CacheTTL)
 	app.Cache.Wait()
 
 	w.Header().Set("Content-Type", entryToCache.ContentType)
 	w.Write(entryToCache.Data)
 }
 
-func (app *App) handleStream(w http.ResponseWriter, r *http.Request) {
+func (app *App) handleStream(w http.ResponseWriter, r *http.Request, mediaURL string) {
 	logger := r.Context().Value(loggerKey).(*slog.Logger)
-	mediaURL := r.URL.Path[1:]
 
-	originReq, err := http.NewRequestWithContext(r.Context(), r.Method, mediaURL, r.Body)
+	originReq, err := http.NewRequestWithContext(r.Context(), r.Method, mediaURL, nil)
 	if err != nil {
 		logger.Error("Failed to create origin request", "error", err)
 		http.Error(w, "Internal server error", http.StatusInternalServerError)
 		return
 	}
 
-	originReq.Header = r.Header.Clone()
+	if rangeHeader := r.Header.Get("Range"); rangeHeader != "" {
+		originReq.Header.Set("Range", rangeHeader)
+	}
+	if acceptHeader := r.Header.Get("Accept"); acceptHeader != "" {
+		originReq.Header.Set("Accept", acceptHeader)
+	}
+	if userAgentHeader := r.Header.Get("User-Agent"); userAgentHeader != "" {
+		originReq.Header.Set("User-Agent", userAgentHeader)
+	}
 
 	originResp, err := app.Client.Do(originReq)
 	if err != nil {

readme.md

@@ -7,25 +7,47 @@
 - **Intelligent**: Optimizes static images to WebP, preserves GIF animations, and streams video/audio.
 - **High-Performance**: Uses an in-memory cache (ristretto) for instant delivery of hot assets.
 - **Low Usage**: Built with Go and `libvips` for minimal CPU and memory footprint.
-- **Whitelisting**: Optionally restrict proxying to a specific list of allowed domains.
+- **Flexible Modes**: Can be used as a standard proxy requiring the full media URL or as a direct middleware with a pre-configured base URL.
+- **Whitelisting**: In standard mode, you can restrict proxying to a specific list of allowed domains.
 - **Configurable**: All settings are managed via environment variables for easy deployment.
 
 ## Example Usage
 
+`mediaproxy` can run in two modes:
+
+### Standard Mode
+
+In this mode, you pass the full URL of the media asset in the path.
+
 The service endpoint is `https://<your-domain>/<full_media_url>`.
 
+**Example:** `https://cdn.example.com/https://images.pexels.com/photos/1314550/pexels-photo-1314550.jpeg`
+
+### Middleware Mode
+
+This mode is activated by setting the `BASE_URL` environment variable. It allows you to use the service as a direct proxy without passing the full URL.
+
+**Example:**
+
+1. Set the environment variable `BASE_URL=cdn.example.com`.
+2. Request `https://media.example.com/object/image.jpg`.
+3. The service will proxy the request to `https://cdn.albert.lol/object/image.jpg`.
+
+This is useful for cleaner URLs and when proxying to a single, trusted domain.
+
 ## Configuration
 
 The service is configured using environment variables:
 
-| Variable              | Description                                                  | Default          |
+| Variable | Description | Default |
-| --------------------- | ------------------------------------------------------------ | ---------------- |
+| :--- | :--- | :--- |
-| `LOG_LEVEL`           | The logging level (`DEBUG`, `INFO`, `WARN`, `ERROR`).        | `INFO`           |
+| `LOG_LEVEL` | The logging level (`DEBUG`, `INFO`, `WARN`, `ERROR`). | `INFO` |
-| `CACHE_TTL`           | The duration for which images are cached.                    | `10m`            |
+| `BASE_URL` | If set, activates middleware mode. The service will prepend `https://<BASE_URL>/` to all incoming request paths. When active, `ALLOWED_DOMAINS` is ignored. | (empty, disabled) |
-| `ALLOWED_DOMAINS`     | Comma-separated list of domains to whitelist.                | (empty, all allowed) |
+| `CACHE_TTL` | The duration for which images are cached. | `10m` |
-| `MAX_ALLOWED_SIZE`    | Maximum media file size in bytes.                            | `52428800` (50MB)|
+| `ALLOWED_DOMAINS` | Comma-separated list of domains to whitelist. Ignored if `BASE_URL` is set. | (empty, all allowed) |
-| `DEFAULT_IMAGE_QUALITY` | Quality for optimized WebP images (1-100).                 | `80`             |
+| `MAX_ALLOWED_SIZE` | Maximum media file size in bytes. | `52428800` (50MB)|
-| `CLIENT_TIMEOUT`      | Timeout for fetching media from the origin.                  | `2m`             |
+| `DEFAULT_IMAGE_QUALITY` | Quality for optimized WebP images (1-100). | `80` |
+| `CLIENT_TIMEOUT` | Timeout for fetching media from the origin. | `2m` |
 
 ## Running Locally
 
@@ -57,7 +79,9 @@ go run .
 
 ### Docker Compose
 
-Create a `compose.yaml` file with the following content:
+Create a `compose.yaml` file with your desired configuration.
+
+**Standard Mode Example:**
 
 ```yaml
 services:
@@ -73,6 +97,22 @@ services:
       ALLOWED_DOMAINS: images.pexels.com,media.giphy.com,videos.pexels.com
 ```
 
+**Middleware Mode Example:**
+
+```yaml
+services:
+  mediaproxy:
+    image: ghcr.io/skidoodle/mediaproxy:main
+    container_name: mediaproxy
+    restart: unless-stopped
+    ports:
+      - "8080:8080"
+    environment:
+      LOG_LEVEL: INFO
+      CACHE_TTL: 1h
+      BASE_URL: cdn.example.com
+```
+
 ## License
 
 [GPL-3.0](https://github.com/skidoodle/mediaproxy/blob/main/license)