admin: fix warnings and status code in /load API

Author: amirdaraby

caddyconfig/load.go

@@ -91,37 +91,42 @@ func (adminLoad) handleLoad(w http.ResponseWriter, r *http.Request) error {
 	}
 	body := buf.Bytes()
 
-	// if the config is formatted other than Caddy's native
-	// JSON, we need to adapt it before loading it
+	var warnings []Warning
 	if ctHeader := r.Header.Get("Content-Type"); ctHeader != "" {
-		result, warnings, err := adaptByContentType(ctHeader, body)
+		result, wns, err := adaptByContentType(ctHeader, body)
 		if err != nil {
 			return caddy.APIError{
 				HTTPStatus: http.StatusBadRequest,
 				Err:        err,
 			}
 		}
-		if len(warnings) > 0 {
-			respBody, err := json.Marshal(warnings)
-			if err != nil {
-				caddy.Log().Named("admin.api.load").Error(err.Error())
-			}
-			_, _ = w.Write(respBody)
-		}
+		warnings = wns
 		body = result
 	}
 
 	forceReload := r.Header.Get("Cache-Control") == "must-revalidate"
 
-	err = caddy.Load(body, forceReload)
-	if err != nil {
-		return caddy.APIError{
-			HTTPStatus: http.StatusBadRequest,
-			Err:        fmt.Errorf("loading config: %v", err),
+	if err := caddy.Load(body, forceReload); err != nil {
+		errResp := struct {
+			Error    string    `json:"error"`
+			Warnings []Warning `json:"warnings,omitempty"`
+		}{
+			Error:    fmt.Sprintf("loading config: %v", err),
+			Warnings: warnings,
 		}
+		w.WriteHeader(http.StatusBadRequest)
+		return json.NewEncoder(w).Encode(errResp)
 	}
 
 	caddy.Log().Named("admin.api").Info("load complete")
+	if len(warnings) > 0 {
+		resp := struct {
+			Warnings []Warning `json:"warnings,omitempty"`
+		}{
+			Warnings: warnings,
+		}
+		return json.NewEncoder(w).Encode(resp)
+	}
 
 	return nil
 }