没有回调的Node.js异步功能会阻塞主线程？

Question

So I noticed after making some recent changes to my Node.js app, the server stops responding after some requests. I think I've nailed down the culprit but want to confirm.

So I have a function which removes a file from the filesystem after use, I don't really care about the response from the file deletion so I just ignore it.

So lets say I have this function:

removeFileAtPath(filePath, callback) {
  fs.unlink(filePath, (err) => {
    if (callback) {
      return callback(err)
    }
  });
}

This gets called from a middleware function, so normally would be called like this:

uploadFile(req, res, next) {
  // Do something
  removeFileAtPath(path, (error) => {
     if (error) { /* handle error */ }
     res.send(someResponse)
  });
}

But since I don't care about the function response, I call the removeFileAtPath function like this:

uploadFile(req, res, next) {
  // Do something
  removeFileAtPath(path);    // No callback passed in here
  res.send(someResponse);
}

Will something like this block the main loop or is my issue likely somewhere else?

Answer 1

尝试在中间件结尾处调用next（）函数

Answer 2

No, it doesn't block - if you mean the main thread and the event loop - fs.unlinkSync would block in that sense.

But you still need to make sure that you return the response or call the next middleware - otherwise you will "block" the request from being served even though the thread and event loop will not be blocked in the usual sense and your server will still be able to handle other requests and events.