Socket hang up error with multiple http.get requests

Question

I'm using node.js to download a large number of files using http.get requests and the async.eachLimit method.

When i increase the concurrency of the async method above 5, this 'socket hang up' error is prone to appearing and I can't understand why.

Can anyone shine any light on why this is happening?

Here's the error received

events.js:72
        throw er; // Unhandled 'error' event
          ^
Error: socket hang up
    at createHangUpError (http.js:1472:15)
    at Socket.socketOnEnd [as onend] (http.js:1568:23)
    at Socket.g (events.js:180:16)
    at Socket.EventEmitter.emit (events.js:117:20)
    at _stream_readable.js:920:16
    at process._tickCallback (node.js:415:13)

and here's the function that is repeatedly called with the async.eachLimit method

        var urlPre = "http://api.steampowered.com/IEconItems_440/GetPlayerItems/v0001/?key=";
        var urlSidPre = "&steamid=";
        var urlInvSuf = "&inventory=yes";
        var URL = urlPre+steam_API+urlSidPre+sid+urlInvSuf;
        //log.info("Downloading "+ alias + "'s inventory");
        http.get(URL, function (res) {
            var body = '';
            res.on('data', function (data) {
                body+=data; 
                fs.appendFile(invLoc, data);
            });
            res.on('end', function() {
                try {
                    inventory = JSON.parse(body);
                    //log.info(alias + "'s inventory downloaded");
                } catch (e) {
                    fs.unlinkSync(invLoc);
                    log.error("parsing " + alias+"'s inventory");
                    loadInventory(sid, alias, invFolder, callback); 
                    return;
                }
                callback(inventory, alias);
            });
            res.on('error', function (e, socket) {
                log.error(alias + " inventory error")
            })
        })

Answer 1

I think your problems is the same of these people:

https://github.com/ether/etherpad-lite/issues/1541

Try adding a listener to the socket's error event

http.get(...)
.on('error', function(e) {
  console.log("Got error: " + e.message);
});