revert: revert deletion of validation.ts

- Restore original file content
- Partial reversion of 721fd6f.

Author: Genyus

template/app/src/server/validation.ts

@@ -0,0 +1,15 @@
+import { HttpError } from 'wasp/server';
+import * as z from 'zod';
+
+export function ensureArgsSchemaOrThrowHttpError<Schema extends z.ZodType>(
+  schema: Schema,
+  rawArgs: unknown
+): z.infer<Schema> {
+  const parseResult = schema.safeParse(rawArgs);
+  if (!parseResult.success) {
+    console.error(parseResult.error);
+    throw new HttpError(400, 'Operation arguments validation failed', { errors: parseResult.error.errors });
+  } else {
+    return parseResult.data;
+  }
+}