Simple CORS bypass

index.php

<?php

$url = filter_input(INPUT_GET, 'url', FILTER_SANITIZE_URL) or exit;

// This allows for catching warnings eg. when offline, or `$url` resource missing
set_error_handler(
    function ($severity, $message, $file, $line) {
        if (error_reporting() & $severity) {
            throw new ErrorException($message, 0, $severity, $file, $line);
        }
    }
);

try {
    $content = file_get_contents($url, 0);

    if (false !== $content) {
        echo $content;
    }
} catch (Exception $e) {
    http_response_code(500);
}

// Back to normal
restore_error_handler();

server.rb

#!/usr/bin/env ruby

require 'open-uri'
require 'cgi'
require 'webrick'

server = WEBrick::HTTPServer.new(
  :Port => 9090,
)

server.mount_proc '/proxy' do |req, res|
  params = CGI.parse(req.query_string)
  target = params['url'].first

  # TODO: Wrap in try block?
  feed = URI.open(target)

  res.header["Access-Control-Allow-Origin"] = "*"
  res.header["Content-Type"] = feed.content_type
  res.body = feed.read
end

server.start