CODEWITHSUNDEEP
node.js
loneboat
loneboat

Reputation: 2945

Node.js - Could this miss some errors?

I'm reading Node.js in Action. There is an example for a simple static file server, as follows:

var server = http.createServer(function(req, res) {

    var url = parse(req.url);
    var path = join(root, url.pathname);

    var stream = fs.createReadStream(path);

    stream.pipe(res);
    stream.on('error', function(err) {
        res.statusCode=500;
        res.end('Internal Server Error');
    });
});

My question is, what happens if the stream.pipe() call hits an error BEFORE the 'error' handler is added to the stream? Could it "miss" this error?

Thanks!

Upvotes: 2

Views: 43

Answers (1)

robertklep
robertklep

Reputation: 203494

When you write stream.pipe(res), it doesn't mean that streaming will start right at that line, it will just be scheduled to run once the code in the request handler is done (Node runs code in a single thread, so it can do only one thing at a time).

After the request handler is done, control is yielded back to the internal Node event loop, which will check to see if there is any I/O to be performed, like handling your stream. At that time, the error handler is already in place to handle any errors.

Upvotes: 4

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