ShareX URL Shortener

.htaccess

RewriteEngine On
RewriteRule ^(?!.*\.php)(.*)$ go.php?jam=$1 [NC,L]

go.php

<?php
if(!isset($_GET['jam'])) {
    header("HTTP/1.0 400 Bad Request");
    die("HTTP/1.0 400 Bad Request");
}
if (!file_exists($_GET['jam'])) {
    header("HTTP/1.0 400 Bad Request");
    die("HTTP/1.0 400 Bad Request");
}
header("Location: ".file_get_contents($_GET['jam']));
die();
?>

Import this to ShareX

{
  "Name": "ScruffyRules.com_Shortener",
  "RequestType": "POST",
  "RequestURL": "http://scruffyrules.com/s/new.php",
  "FileFormName": "",
  "Arguments": {
    "url": "$input$"
  },
  "ResponseType": "Text",
  "RegexList": [],
  "URL": "",
  "ThumbnailURL": "",
  "DeletionURL": ""
}

new.php

<?php
//Number of characters to be shown when a random file name is generated
$url_length = 6;
//URL which will be displayed after upload (URL will have the file name appended)
$url = "http://scruffyrules.com/s/";

if(!isset($_POST['url'])) {
    header("HTTP/1.0 400 Bad Request");
    die("HTTP/1.0 400 Bad Request");
}

$name = generateRandomString();

file_put_contents($name, $_POST['url']);

echo $url.$name;

function generateRandomString() {
        global $url_length;
    $characters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    $randomString = '';
    for ($i = 0; $i < $url_length; $i++) {
        $randomString .= $characters[rand(0, strlen($characters) - 1)];
    }
    return $randomString;
}
?>

How do I use the PHP files(new.php, go.php) in ShareX?

you upload those files to your site.