What is the best way to extract JSON data from a remote URL?

Question

What is the best way to extract JSON data from a remote URL?

Having recently started with JavaScript, I am looking to parse JSON from an external URL using pure JavaScript. Currently, I have the following code:

var getJSON = function(url, callback) {
var xhr = new XMLHttpRequest();
xhr.open('GET', url, true);
xhr.responseType = 'json';
xhr.onload = function() {
  var status = xhr.status;
  if (status === 200) {
    callback(null, xhr.response);
  } else {
    callback(status, xhr.response);
  }
};
xhr.send();
 };

 function statsget() {
 var uname = document.getElementById("nameget").value;
 var data = getJSON(`https://www.reddit.com/user/${uname}/circle.json`);
 var stats = JSON.parse(data);
 alert(data.is_betrayed);
 }

However, this implementation is not functioning as expected. Is there anyone who could assist me in resolving this issue? Thank you!

javascript json

Answer 1

Answer №1

Initially, it appears that you overlooked passing a callback function to getJSON as the second parameter, which should be executed when your request returns with the data. Additionally, there is no need to manually parse the data to JSON when requesting a JSON file from the server and setting the responseType to JSON; this process will be handled automatically for you.

var getJSON = function(url, callback) {
var xhr = new XMLHttpRequest();
xhr.open('GET', url, true);
xhr.responseType = 'json';
xhr.onload = function() {
  var status = xhr.status;
  if (status === 200) {
    callback(null, xhr.response);
  } else {
    callback(status, xhr.response);
  }
};
xhr.send();
 };


function yourCallBackFunction(err, data){
    if(err){
        //Handle the error 
    }else{
        //The data variable holds the JSON response received from the server
    }

}

 function statsget() {
 var uname = document.getElementById("nameget").value;
 var data = getJSON(`https://www.reddit.com/user/${uname}/circle.json`, yourCallBackFunction);

 }

If you require further clarification on any aspect, feel free to ask.

Answer 2

Initially, it appears that you overlooked passing a callback function to getJSON as the second parameter, which should be executed when your request returns with the data. Additionally, there is no need to manually parse the data to JSON when requesting a JSON file from the server and setting the responseType to JSON; this process will be handled automatically for you.

var getJSON = function(url, callback) {
var xhr = new XMLHttpRequest();
xhr.open('GET', url, true);
xhr.responseType = 'json';
xhr.onload = function() {
  var status = xhr.status;
  if (status === 200) {
    callback(null, xhr.response);
  } else {
    callback(status, xhr.response);
  }
};
xhr.send();
 };


function yourCallBackFunction(err, data){
    if(err){
        //Handle the error 
    }else{
        //The data variable holds the JSON response received from the server
    }

}

 function statsget() {
 var uname = document.getElementById("nameget").value;
 var data = getJSON(`https://www.reddit.com/user/${uname}/circle.json`, yourCallBackFunction);

 }

If you require further clarification on any aspect, feel free to ask.

Answer 3

Answer №2

If you're looking to utilize pure Javascript, there is a handy built-in method available that eliminates the need for creating your own function:

 function fetchData() {
   var username = 'CertainPerformance';
   fetch(`https://www.reddit.com/user/${username}/data.json`)
     .then(response => response.json())
     .then(jsonResponse => {
       // manipulate jsonResponse here
       console.log(jsonResponse);
     });
 }
 fetchData();

Promises offer a more streamlined approach compared to traditional callbacks.

Answer 4

If you're looking to utilize pure Javascript, there is a handy built-in method available that eliminates the need for creating your own function:

 function fetchData() {
   var username = 'CertainPerformance';
   fetch(`https://www.reddit.com/user/${username}/data.json`)
     .then(response => response.json())
     .then(jsonResponse => {
       // manipulate jsonResponse here
       console.log(jsonResponse);
     });
 }
 fetchData();

Promises offer a more streamlined approach compared to traditional callbacks.

Answer 5

Answer №3

Make sure to have a callback function specified within your statsget process. It should look something like this.

function statsget() {
 var username = document.getElementById("nameget").value;
 getJSON(`https://www.reddit.com/user/${username}/circle.json`, 
    function(data) {
      var statistics = JSON.parse(data);
      alert(data.is_betrayed);
    });
}

Answer 6

Make sure to have a callback function specified within your statsget process. It should look something like this.

function statsget() {
 var username = document.getElementById("nameget").value;
 getJSON(`https://www.reddit.com/user/${username}/circle.json`, 
    function(data) {
      var statistics = JSON.parse(data);
      alert(data.is_betrayed);
    });
}

Answer 7

Answer №4

The reason it's not working as expected is likely due to the fact that you are not utilizing the callback function, even though it is included as a parameter in your getJSON function.

In order for this function to be executed after receiving a response, you need to include something like the following:

var processData = function(status, data){
    console.log("Data received:\n", data);
    if(status == null) { 
       return data;
    }
}

function fetchData() {
     var username = document.getElementById("nameInput").value;
     var responseData = getJSON(`https://www.reddit.com/user/${username}/data.json`, processData);
     var parsedData = JSON.parse(responseData);
     alert(parsedData.is_betrayed);
}

Answer 8

The reason it's not working as expected is likely due to the fact that you are not utilizing the callback function, even though it is included as a parameter in your getJSON function.

In order for this function to be executed after receiving a response, you need to include something like the following:

var processData = function(status, data){
    console.log("Data received:\n", data);
    if(status == null) { 
       return data;
    }
}

function fetchData() {
     var username = document.getElementById("nameInput").value;
     var responseData = getJSON(`https://www.reddit.com/user/${username}/data.json`, processData);
     var parsedData = JSON.parse(responseData);
     alert(parsedData.is_betrayed);
}

What is the best way to extract JSON data from a remote URL?

Answer №1

Answer №2

Answer №3

Answer №4

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