cURL using a string to post multiple values

Question

Is there a way to post a string with multiple values following the code below? please consider the third postfield $multiple to output more than one value Thanks in advance

<?php

$ch = curl_init(); //http post to another server

curl_setopt($ch, CURLOPT_URL,"http://www.example.com");

curl_setopt($ch, CURLOPT_POST, 1);

curl_setopt($ch, CURLOPT_POSTFIELDS,"username=$username&password=$password&multiple=$ "); 

// receive server response

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

$server_output = curl_exec ($ch);

print_r($server_output);

curl_close ($ch);

Answer 1

Can we include your answer on the above code?

<?php

$ch = curl_init(); //http post to another server

curl_setopt($ch, CURLOPT_URL,"http://www.example.com");

curl_setopt($ch, CURLOPT_POST, 1);

  $username = 'user1';
  $password = 'strongpassword';

  $values = array(
    'username' => $username,
    'password' => $password,
    'multiple' => array(
        'value1',
        'value2',
        'value3',
    )
  );

$params = http_build_query($values);

curl_setopt($ch, CURLOPT_POSTFIELDS,$params); 

// receive server response

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

$server_output = curl_exec ($ch);

print_r($server_output);

curl_close ($ch);

For example

Answer 2

You can make this query string using http_build_query.

For example

<?php
  $username = 'user1';
  $password = 'strongpassword';

  $values = array(
    'username' => $username,
    'password' => $password,
    'multiple' => array(
        'value1',
        'value2',
        'value3',
    )
);

echo http_build_query($values);

Output:

username=user1&password=strongpassword&multiple%5B0%5D=value1&multiple%5B1%5D=value2&multiple%5B2%5D=value3

In other words multiple parameters should be multiple[]=value1&multiple[]=value2&multiple[]=value3