INNER CODE UNIT · JavaScript

writeError

sebastiancarlos/beachpatrol · beachpatrol.js:173

  const writeError = (message) => {
    // Log error to server console and to socket (with sentinel line)
    console.log(`Error: ${message}`);
    socket.write(`${ERROR_SENTINEL} ${message.replace(/\n/g, " ")}\n`);
    socket.end();
  };

  socket.on("data", async (data) => {
    const message = JSON.parse(data.toString());
    const [commandName, ...args] = message;

    // Sanitize commandName
    if (commandName.includes("..")) {
      writeError(`Invalid command name '${commandName}'. No path traversal allowed.`);
      return;
    }

    // A command may arrive before the browser is ready. Ask the client to retry.

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