Function parseMirroredUpstreamJson

client/src/lib/proxyFetch.ts:41–81

* Validates the JSON shape the proxy returns when it successfully forwarded * a request and is mirroring the upstream response.

(data: unknown)

 * a request and is mirroring the upstream response.
 */
function parseMirroredUpstreamJson(data: unknown): ProxyFetchResponse | null {
  if (!isJsonObject(data)) {
    return null;
  }
  const rec = data;

  if (typeof rec.status !== "number") {
    return null;
  }
  if (typeof rec.body !== "string") {
    return null;
  }
  if (typeof rec.statusText !== "string") {
    return null;
  }
  if (typeof rec.ok !== "boolean") {
    return null;
  }
  if (rec.headers === null || typeof rec.headers !== "object") {
    return null;
  }
  if (Array.isArray(rec.headers)) {
    return null;
  }

  const headers: Record<string, string> = {};
  for (const [key, val] of Object.entries(rec.headers)) {
    if (typeof val !== "string") {
      return null;
    }
    headers[key] = val;
  }

  return {
    ok: rec.ok,
    status: rec.status,
    statusText: rec.statusText,
    headers,
    body: rec.body,
  };
}

/**
 * Creates a fetch function that routes requests through the proxy server