Function parseMessage

src/rpc.ts:38–88

(line: string)

/** Parse a JSON-RPC message from a line. Returns null if unparseable or not a valid protocol message. */
export function parseMessage(line: string): JsonRpcMessage | null {
  try {
    const raw = JSON.parse(line);
    if (typeof raw !== "object" || raw === null) return null;

    const hasMethod = "method" in raw && typeof raw.method === "string";
    const hasId = "id" in raw && (typeof raw.id === "string" || typeof raw.id === "number");
    const hasResult = "result" in raw;
    const hasError = "error" in raw;

    if (!hasMethod && !hasId) {
      console.error(`[codex] Warning: ignoring non-protocol message: ${line.slice(0, 200)}`);
      return null;
    }

    if (hasId && !hasMethod) {
      if (hasResult === hasError) {
        console.error(`[codex] Warning: ignoring malformed response: ${line.slice(0, 200)}`);
        return null;
      }
      if (hasError) {
        const error = (raw as { error?: unknown }).error;
        if (
          typeof error !== "object" ||
          error === null ||
          typeof (error as { code?: unknown }).code !== "number" ||
          typeof (error as { message?: unknown }).message !== "string"
        ) {
          console.error(`[codex] Warning: ignoring malformed error response: ${line.slice(0, 200)}`);
          return null;
        }
      }
      return raw as JsonRpcMessage;
    }

    if (hasMethod && hasId && (hasResult || hasError)) {
      console.error(`[codex] Warning: ignoring malformed request/response hybrid: ${line.slice(0, 200)}`);
      return null;
    }

    if (hasMethod && !hasId && (hasResult || hasError)) {
      console.error(`[codex] Warning: ignoring malformed notification/response hybrid: ${line.slice(0, 200)}`);
      return null;
    }

    return raw as JsonRpcMessage;
  } catch {
    console.error(`[codex] Warning: unparseable message from app server: ${line.slice(0, 200)}`);
    return null;
  }
}

/** Type guard: message is a response (has id + result). */
export function isResponse(msg: JsonRpcMessage): msg is JsonRpcResponse {