How to send HTTP requests in phonegap?

Question

I'm using phonegap to develop an inventory management mobile application and I can't figure out how to send http request without running into the CORS policy problem. I installed the cordova advanced http plugin but when I preview the app on chrome, the cordova object doesn't exist because the cordova.js script isn't added until later so I haven't really been able to tinker with the plugin. I simply want to send an http request and read back a JSON. I have a URL. There is no username or password. Please help! I'm stuck!

Update:

I used this code:

    $.ajax({

    url: 'https://api.barcodelookup.com/v2/products?barcode=075500000010&formatted=y&key=8f5uvzskkmjnptt43bz7yjzgwehscl',
    data: null,
    type: 'GET',
    crossDomain: true,
    dataType: 'jsonp',
    success: function() { alert("Success"); },
    error: function() { alert('Failed!'); },
});

And the request went through, now, but the response is being blocked. I tried whitelisting by putting this in my xml:

allow-intent href="https://api.barcodelookup.com/*"
access origin="https://api.barcodelookup.com/*"

But I still get this error saying that the response was blocked:

jquery-1.11.1.min.js:4 Cross-Origin Read Blocking (CORB) blocked cross-origin response https://api.barcodelookup.com/v2/products?barcode=075500000010&formatted=y&key=8f5uvzskkmjnptt43bz7yjzgwehscl&callback=jQuery111107483149196833481_1568855081600&_=1568855081601 with MIME type application/json. See https://www.chromestatus.com/feature/5629709824032768 for more details.

Answer 1

Well, you could simply add jQuery to your app and do

$.ajax({
        url: "http://localhost/",
        type: "POST",
        crossDomain: true,
        data: JSON.stringify(somejson),
        dataType: "json",
        success: function (response) {
            var resp = JSON.parse(response)
            alert(resp.status);
        },
        error: function (xhr, status) {
            alert("error");
        }
    });

You could also try this depending on your backend (and post your data as a JSON string)

$.ajax({
        method:'POST',
        url:url,
        data:json_string,
        async:true,
        processData:false,
        contentType:'application/x-www-form-urlencoded',
        dataType:'json',            
        ...
   );

Answer 2

u can use this in your API php

header('Access-Control-Allow-Origin: *'); header("Content-Type: application/json; charset=UTF-8");

Answer 3

Okay. I finally got it: I had to use the cordova advanced http plugin. I used the following code:

const options = {
  method: 'get',
  headers: { Authorization: 'OAuth2: token' }
};

cordova.plugin.http.sendRequest('https://api.upcitemdb.com/prod/trial/lookup?upc=075500000010', options, function(response) {
  // prints 200
  alert(response.status);
  var obj = JSON.parse(response.data); // This is the resultant JSON in useful form
}, function(response) {
  // prints 403
  alert(response.status);

  //prints Permission denied
  alert(response.error);
});