add simple admin service

local-admin/src/entities/asset/parseUploadPayload.mjs

@@ -0,0 +1,19 @@
+import { httpError } from '../../shared/http/httpError.mjs';
+
+export function parseUploadPayload(payload) {
+  if (typeof payload.dataUrl === 'string') {
+    const match = payload.dataUrl.match(/^data:[^;]+;base64,(.+)$/);
+
+    if (!match) {
+      throw httpError(400, '"dataUrl" must be a base64 data URL');
+    }
+
+    return Buffer.from(match[1], 'base64');
+  }
+
+  if (typeof payload.contentBase64 === 'string') {
+    return Buffer.from(payload.contentBase64, 'base64');
+  }
+
+  throw httpError(400, 'Upload payload must include "dataUrl" or "contentBase64"');
+}