1 files changed, 32 insertions, 0 deletions
diff --git a/testing/web-platform/tests/common/custom-cors-response.js b/testing/web-platform/tests/common/custom-cors-response.js
new file mode 100644
index 0000000000..be9c7ce3bd
--- /dev/null
+++ b/testing/web-platform/tests/common/custom-cors-response.js
@@ -0,0 +1,32 @@
+const custom_cors_response = (payload, base_url) => {
+  base_url = base_url || new URL(location.href);
+
+  // Clone the given `payload` so that, as we modify it, we won't be mutating
+  // the caller's value in unexpected ways.
+  payload = Object.assign({}, payload);
+  payload.headers = payload.headers || {};
+  // Note that, in order to have out-of-the-box support for tests that don't
+  // call `setup({'allow_uncaught_exception': true})` we return a no-op JS
+  // payload. This approach will avoid hitting syntax errors if the resource is
+  // interpreted as script. Without this workaround, the SyntaxError would be
+  // caught by the test harness and trigger a test failure.
+  payload.content = payload.content || '/* custom-cors-response.js content */';
+  payload.status_code = payload.status_code || 200;
+
+  // Assume that we'll be doing a CORS-enabled fetch so we'll need to set ACAO.
+  const acao = "Access-Control-Allow-Origin";
+  if (!(acao in payload.headers)) {
+    payload.headers[acao] = '*';
+  }
+
+  if (!("Content-Type" in payload.headers)) {
+    payload.headers["Content-Type"] = "text/javascript";
+  }
+
+  let ret = new URL("/common/CustomCorsResponse.py", base_url);
+  for (const key in payload) {
+    ret.searchParams.append(key, JSON.stringify(payload[key]));
+  }
+
+  return ret;
+};