How to return object to client when https request is fired in another file?

Question

I'm trying to have the user be able to click a button, which sends a request to my node server and then with the data sent, it fires a function thats in another file. My problem isn't with the code, I'm just new to javascript so I'm not quite sure how i should be returning this object back to the client, i'm quite lost i'll explain more in the code below. I'm not sure if I should be doing something as simple as

return obj;

or If i should be using async/await, i've tried doing this but couldn't quite understand it.

http.createServer(function (req, res) {
    res.setHeader('Content-Type', 'application/json');
    res.setHeader("Access-Control-Allow-Origin", "*");
    res.setHeader("Access-Control-Allow-Headers", "X-Requested-With")
    //res.writeHead(200, { 'Content-Type': 'text/plain' });
    var data = []
    if (req.method == "POST") {
        res.writeHead(200, { 'Content-Type': 'text/plain' });
        req.on('data', function (dat) {
            data.push(dat)
        })
        req.on('end', function () {
            var gamedata = Buffer.concat(data).toString();
            var game = JSON.parse(gamedata)

            games.getPing(game.placeId, 0)<--This is the function that gets fired in the other file


            res.end(/*some how get games.gameservers here to send back to client*/)

        })
    }


}).listen(9999)

This is my node server that is in a file called server.js.

Now here is the function that gets fired. This function is in a file called api.js

games = {
gameservers: [],

getPing: function (id,index,callback) {
    var keepAliveAgent = new https.Agent({ keepAlive: true })

    var r = https.request(options, function (res) {
        var data = []
        res.on('data', function (d) {
            data.push(d)
        }).on('end', function () {
            var buf = Buffer.concat(data)
            var encodingheader = res.headers['content-encoding']
            if (encodingheader == 'gzip') {
                zlib.gunzip(buf, function (err, buffer) {
                    var o = JSON.parse(buffer.toString())
                    // o is what is returned
                    if (index < o.TotalCollectionSize) {
                        index = index + 10;
                        //console.log(index, o.TotalCollectionSize)
                        try {
                            let lowest = o.c.reduce((lowest, item) => item.x < lowest.x ? item : lowest)
                            if (lowest.q != lowest.p) {
                               // console.log(lowest)
                                games.gameservers.push(lowest)

                            }
                            games.getPing(id, index)
                        } catch (e) {
                            if (e) {
                                console.log(games.gameservers)
                               /*
                                This is where my function ends, I need to be able to send the games.gameservers array, back to the client in cloud.js

                               */ 
                            }
                        }
                    }
                })
            }
        })
    })
    r.end()
}
}

Inside the error of the try/catch, is where the function ends. Basically, the res.end() in server.js needs to have the games.gameservers object in it to go back to the client.

I'm pretty new to javascript as a whole, so i'm not sure if I should be using return, async/await, callbacks. I've been at this for awhile and cant seem to get it.

score -1 · Answer 1 · answered May 30 '19 at 22:38

In Javascript, if you use function without "return" the function will return undefined. You can't do anything with that value. Inside your method getPing. Use return to return your games.gameservers. Inside your http.createServer . This part , you can write like this.

const result = [...games.getPing(game.placeId, 0)] (as you have return so this function will return your games.gameservers and assign it to result)

res.end(/some how get games.gameservers here to send back to client/) Hope this help.

That won't work: https://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call — Quentin, May 30 '19 at 22:42

How to return object to client when https request is fired in another file?

1 Answers1