rxnlabs

<?php
$url = 'https://insert-domain-here.com/api-endpoint';
// The file is stored on your system/host
$path_to_uploaded_file = '/full-path-to-file/picture.jpg';
$form_fields = [ 'first_name' => 'Foo', 'last_name' => 'Bar' ];
if ( file_exists( $path_to_uploaded_file ) ) {
	$form_fields['profile_picture'] = new CurlFile( $path_to_uploaded_file );
}

/*

sirbrillig

<?php

$local_file = 'file_path'; //path to a local file on your server
$post_fields = array(
	'name' => 'value',
);
$boundary = wp_generate_password( 24 );
$headers  = array(
	'content-type' => 'multipart/form-data; boundary=' . $boundary,
);

iandunn

/**
 * Programmatically logs a user in
 * 
 * @param string $username
 * @return bool True if the login was successful; false if it wasn't
 */
function programmatic_login( $username ) {
	
	if ( is_user_logged_in() ) {
		wp_logout();