fix: add toNormalizedJson to match github output

api/webhook_manager.go

@@ -10,6 +10,8 @@ import (
 	"gorm.io/gorm"
 	"io"
 	"net/http"
+	"regexp"
+	"strings"
 )
 
 type WebhookManager struct {
@@ -63,6 +65,8 @@ func (whm *WebhookManager) sendWebhooks(request interface{}, r *http.Request) {
 			}
 
 			payload := getWebhookData(r, whm.logger)
+			payload = toNormalizedJson(payload)
+
 			signature := generatePayloadSignature(payload, app.WebhookSecret)
 			req.Header.Add("X-Hub-Signature-256", signature)
 
@@ -86,5 +90,27 @@ func (whm *WebhookManager) sendWebhooks(request interface{}, r *http.Request) {
 			}
 		}(app)
 	}
-
+}
+
+/*
+* Ported from https://github.com/octokit/webhooks.js/blob/984f3f51e077dbc7637aa55406c3bb114dbb7f82/src/to-normalized-json-string.ts
+ */
+
+func toNormalizedJson(payload []byte) []byte {
+	jsonString := string(payload)
+
+	// Regex to find Unicode escape sequences
+	re := regexp.MustCompile(`\\u([\da-fA-F]{4})`)
+
+	// Function to convert found sequences to uppercase
+	replaceFunc := func(match string) string {
+		parts := strings.Split(match, "\\u")
+		// Convert the Unicode sequence part to uppercase
+		return parts[0] + "\\u" + strings.ToUpper(parts[1])
+	}
+
+	// Replace the matches in the jsonString
+	normalizedString := re.ReplaceAllStringFunc(jsonString, replaceFunc)
+
+	return []byte(normalizedString)
 }