How do I call a JSON web service from PHP with parameters and callback?

Question

I call a webservice from a JQuery $.getJSON function, it works fine.

 var p = {
 'field1': 'value1',
 'field2': 'value2',
 'field3': 'value3'
 };
 $.getJSON('https://service:[email protected]/service/search?callback=?', p, function(data) {
 if (data[0]) { 
 // print results
 } else {
 // no results found
 }
});

I am trying to connect from PHP and CURL, however it does not work, it always return false.

//FIRST TRY

$params = array( 'field1' => 'value1', 'field2' => 'value2', 'field3'=> 'value3');
$ch = curl_init();
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_URL, 'https://service:[email protected]/service/search?callback=?');
curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
$result = curl_exec($ch); // return false instead of my JSON

// SECOND TRY

 $data_string = json_encode($params); 
 $ch = curl_init('https://https://service:[email protected]/service/search?callback=?'); 
 curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST"); 
 curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string); 
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); 
 curl_setopt($ch, CURLOPT_HTTPHEADER, array( 
 'Content-Type: application/json', 
 'Content-Length: ' . strlen($data_string)) 
); 
 $result2 = curl_exec($ch); //return false instead of my JSON

What I am doing wrong?

many thanks,

• Landon: is the request jsonp or json? The format of what's returned is different in both cases
• Codeguy007: .getJSON is a get request. In PHP you are using a post request. Also in POSTFIELDS takes an associative array but in your second try you only gave it a string.

Answer 1

Try changing your code to this:

$params = array( 'field1' => 'value1', 'field2' => 'value2', 'field3'=> 'value3');
$data_string = implode('&',$params);
//NB: you may need to urlencode the each of your params
$ch = curl_init('https://service:[email protected]/service/search? callback=?&' .$data_string); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); 
$result2 = curl_exec($ch);

Untested code, hope it helps.

Answer 2

The jquery request is using GET. The curl code you wrote appears to be sending a post request (i'm not an expert in curl). Obviously the receiving server handles different types of requests differently, so make sure you send a get via curl and that should help.

Answer 3

getJSON sends a GET request, so you need to convert params array to a string with http_build_query and append it to query. As you're requesting the data with HTTPS you need to point CURL to valid cerficate with CURLOPT_CAINFO / CURLOPT_CAPATH, i'll just ignore the validation in the code.

$params = array( 'field1' => 'value1', 'field2' => 'value2', 'field3'=> 'value3');
$url = 'https://service:[email protected]/service/search?callback=?' . http_build_query($params);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch , CURLOPT_SSL_VERIFYPEER , false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$result = curl_exec($ch);
if($result === FALSE) {
 echo curl_error($ch);
}