How do I use arrays in cURL POST requests - php

Question

I am wondering how do I make this code support arrays? At the moment the images array only seems to send the first value.
Here is my code:
<?php
//extract data from the post
extract($_POST);
//set POST variables
$url = 'http://api.example.com/api';
$fields = array(
'username' => "annonymous",
'api_key' => urlencode("1234"),
'images[]' => urlencode(base64_encode('image1')),
'images[]' => urlencode(base64_encode('image2'))
);
//url-ify the data for the POST
foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&'; }
rtrim($fields_string, '&');
//open connection
$ch = curl_init();
//set the url, number of POST vars, POST data
curl_setopt($ch,CURLOPT_URL, $url);
curl_setopt($ch,CURLOPT_POST, count($fields));
curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);
//execute post
$result = curl_exec($ch);
echo $result;
//close connection
curl_close($ch);
?>
and this is what is received at the api
VAR: username = annonymous
VAR: api_key = 1234
VAR: images = Array
array(3) {
["username"]=> string(10) "annonymous"
["api_key"]=> string(4) "1234"
["images"]=> array(1) { // this should contain 2 strings :( what is happening?
[0]=> string(8) "aW1hZ2Uy"
}
}
What is happening to the second value in images[]?

Answer 1

You are just creating your array incorrectly. You could use http_build_query:
$fields = array(
'username' => "annonymous",
'api_key' => urlencode("1234"),
'images' => array(
urlencode(base64_encode('image1')),
urlencode(base64_encode('image2'))
)
);
$fields_string = http_build_query($fields);
So, the entire code that you could use would be:
<?php
//extract data from the post
extract($_POST);
//set POST variables
$url = 'http://api.example.com/api';
$fields = array(
'username' => "annonymous",
'api_key' => urlencode("1234"),
'images' => array(
urlencode(base64_encode('image1')),
urlencode(base64_encode('image2'))
)
);
//url-ify the data for the POST
$fields_string = http_build_query($fields);
//open connection
$ch = curl_init();
//set the url, number of POST vars, POST data
curl_setopt($ch,CURLOPT_URL, $url);
curl_setopt($ch,CURLOPT_POST, 1);
curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);
//execute post
$result = curl_exec($ch);
echo $result;
//close connection
curl_close($ch);
?>

Answer 2

$ch = curl_init();
$data = array(
'client_id' => 'xx',
'client_secret' => 'xx',
'redirect_uri' => $x,
'grant_type' => 'xxx',
'code' => $xx,
);
$data = http_build_query($data);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
curl_setopt($ch, CURLOPT_URL, "https://example.com");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_POST, 1);
$output = curl_exec($ch);