getting data from callbacks using node "request" library

Question

I'm struggling with working out how to get the return data from this code example. If I try to get the cert data from the callback function its always empty. Is there something I'm missing here?

 var Request = require('request');

     function callhttp(host) {

     var cert = " ";

     var options = {
         url: 'https://' + host
     };

     function callback(error, response, body) {
         if (!error && response.statusCode == 200) {
             var cert = response.connection.getPeerCertificate();
         }
     }
     Request(options, callback);
     return cert
 }
 console.log(callhttp("www.google.com"));

Best Regards.

Ben Diamant · Accepted Answer · 2015-02-10 19:03:28Z

2

By returning 'cert' you refer to the operation as a sync one, which is not.

The correct pattern is to pass a callback function and handle the data whitin:

 var Request = require('request');

 function callhttp(host, cb) {

     var cert = " ";

     var options = {
         url: 'https://' + host
     };

     function callback(error, response, body) {
         if (!error && response.statusCode == 200) {
             var cert = response.connection.getPeerCertificate();
             cb(cert);
         }
     }
     Request(options, callback);
}

callhttp("www.google.com", function(_cert) {
    console.log(_cert);
});

answered Feb 10, 2015 at 19:03

Ben Diamant

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2 Comments

user1513388 Over a year ago

Wow - OK. Thanks very much for this. It now works properly. Just out of interest what do the _ mean?

Ben Diamant Over a year ago

Nothing, just semantics for you to display the difference with the one inside the callhttp function

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