Node.JS function the returns http response value

Question

I need to call a function that makes an http request and have it return the value to me through callback. However, when I try I keep getting null response. Any help?

Here is my code:

var url = 'www.someurl.com'
makeCall(url, function(results){return results})

makeCall = function (url, results) {
          https.get(url,function (res) {
           res.on('data', function (d) {
                    resObj = JSON.parse(d);
                    results(resObj.value)

                });
            }).on('error', function (e) {
                     console.error(e);
                });
        }

mr.freeze · Accepted Answer · 2013-05-31 18:38:20Z

12

You need to restructure your code to use a callback instead of returning a value. Here is a modified example that gets your external IP address:

var http = require('http');

var url = 'http://ip-api.com/json';

function makeCall (url, callback) {
    http.get(url,function (res) {
        res.on('data', function (d) {
            callback(JSON.parse(d));
        });
        res.on('error', function (e) {
            console.error(e);
        });
    });
}

function handleResults(results){
    //do something with the results
}

makeCall(url, function(results){
    console.log('results:',results);
    handleResults(results);        
});

edited May 31, 2013 at 18:38

answered May 31, 2013 at 16:24

mr.freeze

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4 Comments

Rob Over a year ago

Thanks However, this function does exactly the same thing my sample does. My sample also works with console.log. I need to get a result RETURNED by calling the function. Take this for example hi = function(a, b) {c = "hi"return b(c)}; When I execute hi('string',function(bb){return bb}) I am returned "hi" as a result of calling the function. Hope this makes sense

mr.freeze Over a year ago

Your example is trying to return a value from an async callback. That won't work. You need to use the value in the callback instead of returning it.

Rob Over a year ago

Ok, I understand. Is there any way to get that value out of the callback function and use in another function executed at the same time? I know this is a bit wonky. Appreciate the help

mr.freeze Over a year ago

Sure, just call your target function and pass results as a parameter. I will update the example to reflect that.

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