Local file storage (#5763)

Co-authored-by: Tom Moor <tom.moor@gmail.com>

server/models/validators/IsUrlOrRelativePath.ts

@@ -0,0 +1,23 @@
+import { isURL } from "class-validator";
+import { addAttributeOptions } from "sequelize-typescript";
+
+/**
+ * A decorator that validates that a string is a url or relative path.
+ */
+export default function IsUrlOrRelativePath(target: any, propertyName: string) {
+  return addAttributeOptions(target, propertyName, {
+    validate: {
+      validUrlOrPath(value: string) {
+        if (
+          value &&
+          !isURL(value, {
+            require_host: false,
+            require_protocol: false,
+          })
+        ) {
+          throw new Error("Must be a URL or relative path");
+        }
+      },
+    },
+  });
+}