1 files changed, 23 insertions, 9 deletions
diff --git a/modules/caddyhttp/encode/encode.go b/modules/caddyhttp/encode/encode.go
index b2c1327..4e5f743 100644
--- a/modules/caddyhttp/encode/encode.go
+++ b/modules/caddyhttp/encode/encode.go
@@ -52,19 +52,15 @@ type Encode struct {
 
 // Provision provisions enc.
 func (enc *Encode) Provision(ctx caddy.Context) error {
-	enc.writerPools = make(map[string]*sync.Pool)
-
 	for modName, rawMsg := range enc.EncodingsRaw {
 		val, err := ctx.LoadModule("http.encoders."+modName, rawMsg)
 		if err != nil {
 			return fmt.Errorf("loading encoder module '%s': %v", modName, err)
 		}
-		encoder := val.(Encoding)
-
-		enc.writerPools[encoder.AcceptEncoding()] = &sync.Pool{
-			New: func() interface{} {
-				return encoder.NewEncoder()
-			},
+		encoding := val.(Encoding)
+		err = enc.addEncoding(encoding)
+		if err != nil {
+			return err
 		}
 	}
 	enc.EncodingsRaw = nil // allow GC to deallocate - TODO: Does this help?
@@ -85,10 +81,28 @@ func (enc *Encode) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyh
 		defer w.(*responseWriter).Close()
 		break
 	}
-
 	return next.ServeHTTP(w, r)
 }
 
+func (enc *Encode) addEncoding(e Encoding) error {
+	ae := e.AcceptEncoding()
+	if ae == "" {
+		return fmt.Errorf("encoder does not specify an Accept-Encoding value")
+	}
+	if _, ok := enc.writerPools[ae]; ok {
+		return fmt.Errorf("encoder already added: %s", ae)
+	}
+	if enc.writerPools == nil {
+		enc.writerPools = make(map[string]*sync.Pool)
+	}
+	enc.writerPools[ae] = &sync.Pool{
+		New: func() interface{} {
+			return e.NewEncoder()
+		},
+	}
+	return nil
+}
+
 // openResponseWriter creates a new response writer that may (or may not)
 // encode the response with encodingName. The returned response writer MUST
 // be closed after the handler completes.