Calling a POST function within PHP via URL

Question

I have a POST function contained in my page. I am trying to call it directly for my CURL Function, notice in the following code the url variable is set to http://dirtrif.loc/installs.php

//extract data from the post
//set POST variables

$cookie_name = "drcuserid";

if(isset($_COOKIE[$cookie_name]))
{
  $cookie = $_COOKIE[$cookie_name];
}
$url = 'http://dirtrif.loc/installs.php';
$fields['username'] = $vbulletin->userinfo[username];
$fields['webmasteremail'] = $vbulletin->options[webmasteremail];
$fields['cookie'] = $_COOKIE[$cookie_name];

//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);

//close connection
curl_close($ch);


echo $fields_string;

This is causing an issue when the CURL script is executed, by navigating to the actual page and not running the portion that it's supposed to.

I currently have the post portion set up as follows in my installs.php:

if (isset($_POST['username'])) {
  $vbulletin->db->query_write("
  INSERT INTO " . TABLE_PREFIX . "installs (
    username,
    webmasteremail,
    cookie
  ) VALUES (" .
    $_POST['username'] .", '" .
    $_POST['webmasteremail'] . ", '" .
    $_POST['cookie'] . "'
  )");
}

Is there a way I can change the URL in my CURL code to point directly to that part of the installs.php page?

the full contents of installs.php (note* I have made a few changes since posting this question)

<?php
// ####################### SET PHP ENVIRONMENT ###########################
error_reporting(E_ALL & ~E_NOTICE);

// #################### DEFINE IMPORTANT CONSTANTS #######################
define('THIS_SCRIPT', 'installs');
define('CSRF_PROTECTION', true);
define('CSRF_SKIP_LIST', '');

// ################### PRE-CACHE TEMPLATES AND DATA ######################

// pre-cache templates used by all actions
$globaltemplates = array(
  'installs'
);

// pre-cache templates used by specific actions
$actiontemplates = array();

// ######################### REQUIRE BACK-END ############################
require_once('./global.php');

// ######################### VARIABLES ############################

$username       = $_POST['username'];
$userid         = $_POST['userid'];
$email          = $_POST['email'];
$addontitle     = $_POST['addontitle'];
$addonversion   = $_POST['addonversion'];
$bburl          = $_POST['bburl'];
$bbtitle        = $_POST['bbtitle'];
$webmasteremail = $_POST['webmasteremail'];
$cookie         = $_POST['cookie'];

    if (isset($_POST['username'])) {
      $db->query_write("
      INSERT INTO " . TABLE_PREFIX . "installs (
        username,userid,email,addontitle,addonversion,bburl,bbtitle,webmasteremail,cookie,dateline
      ) VALUES (
        '$username',
        '$userid',
        '$email',
        '$addontitle',
        '$addonversion',
        '$bburl',
        '$bbtitle',
        '$webmasteremail',
        '$cookie',
        NOW()
      )");
    }

// #######################################################################
// ######################## START MAIN SCRIPT ############################
// #######################################################################

$navbits = array();
$navbits[$parent] = 'Installs Page';
$navbits = construct_navbits($navbits);

eval('$navbar = "' . fetch_template('navbar') . '";');
eval('print_output("' . fetch_template('installs') . '");');
?>

Answer 1

Is there a way I can change the URL in my CURL code to point directly to that part of the installs.php page?

As for standard HTTP features: no, there is no explicit way of calling parts of a script.

Let's start from the beginning. What we would usually do in this situation is that we set the path in the URL to the file, that contains parts we want to execute. Then, it is up us to decide, how we design our program to know, which part should be executed. We can use POST parameters for that like you were trying. So far, so good.

Now, how do we divide our script, installs.php in your case, into pieces?

One good way is the one RamRaider already mentioned: use a POST parameter action and in installs.php, put code into a big switch. Example:

// installs.php
<?php
switch ($_POST['action']) {
  case 'myfirstaction':
    if (isset($_POST['username'])) {
      $vbulletin->db->query_write("...");
    }
    break;
  case 'myotheraction':
    // code here
    break;
}
?>
To call specific actions, just extend you $fields array:
<?php
// script that "can be executed from anywhere":
$fields['action'] = 'myfirstaction';
?>

I would say this is the cleanest way to do it in your situation. However, if installs.php is a larger script you are adjusting, this might be way too much work. In that case you may want to exit the script after running your code (thus, running only the code you want). You can simply write exit; and no further code will be executed. See: https://www.php.net/exit.