How to handle ETIMEDOUT error?

问题:

How to handle etimedout error on this call ?

 var remotePath = "myremoteurltocopy"
 var localStream = fs.createWriteStream("myfil");;
        var out = request({ uri: remotePath });
        out.on('response', function (resp) {
            if (resp.statusCode === 200) {
                out.pipe(localStream);
                localStream.on('close', function () {
                    copyconcurenceacces--;
                    console.log('aftercopy');
                    callback(null, localFile);
                });
            }
            else
                callback(new Error("No file found at given url."), null);
        })

There are a way to wait for longer? or to request the remote file again?

What exactly can cause this error? Timeout only?

回答1:

This is caused when your request response is not received in given time(by timeout request module option).

Basically to catch that error first, you need to register a handler on error, so the unhandled error won't be thrown anymore: out.on('error', function (err) { /* handle errors here */ }). Some more explanation here.

In the handler you can check if the error is ETIMEDOUT and apply your own logic: if (err.message.code === 'ETIMEDOUT') { /* apply logic */ }.

If you want to request for the file again, I suggest using node-retry or node-backoff modules. It makes things much simpler.

If you want to wait longer, you can set timeout option of request yourself. You can set it to 0 for no timeout.

回答2:

We could look at error object for a property code that mentions the possible system error and in cases of ETIMEDOUT where a network call fails, act accordingly.

if (err.code === 'ETIMEDOUT') {
    console.log('My dish error: ', util.inspect(err, { showHidden: true, depth: 2 }));
}