Config: Update CORS header defaults and add /api/v1/echo endpoint #3931

Signed-off-by: Michael Mayer <michael@photoprism.app>

internal/api/echo.go

@@ -0,0 +1,49 @@
+package api
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+
+	"github.com/photoprism/photoprism/internal/get"
+)
+
+// Echo returns the request and response headers as JSON if debug mode is enabled.
+//
+// The supported request methods are:
+//
+//   - GET
+//   - POST
+//   - PUT
+//   - PATCH
+//   - HEAD
+//   - OPTIONS
+//   - DELETE
+//   - CONNECT
+//   - TRACE
+//
+// ANY /api/v1/echo
+func Echo(router *gin.RouterGroup) {
+	router.Any("/echo", func(c *gin.Context) {
+		// Abort if debug mode is disabled.
+		if !get.Config().Debug() {
+			AbortFeatureDisabled(c)
+			return
+		} else if c.Request == nil || c.Writer == nil {
+			AbortUnexpectedError(c)
+			return
+		}
+
+		// Return request information.
+		echoResponse := gin.H{
+			"url":    c.Request.URL.String(),
+			"method": c.Request.Method,
+			"headers": map[string]http.Header{
+				"request":  c.Request.Header,
+				"response": c.Writer.Header(),
+			},
+		}
+
+		c.JSON(http.StatusOK, echoResponse)
+	})
+}