tt-rss/plugins/auth_proxy/init.php

<?php
class Auth_Proxy extends Plugin implements IAuthModule {

	private $host;
	/* @var Auth_Base $base */
	private $base;

	function about() {
		return array(1.0,
			"Trust proxy X-Forwarded-User. May be dangerous, see doc",
			"boyska",
			true);
	}

	/* @var PluginHost $host */
	function init($host ) {
		$this->host = $host;
		$this->base = new Auth_Base();

		$host->add_hook($host::HOOK_AUTH_USER, $this);
	}

	/**
	 * @SuppressWarnings(PHPMD.UnusedFormalParameter)
	 */
	function authenticate($login, $password) {
		// TODO: check source ip!
		if(!array_key_exists("HTTP_X_FORWARDED_USER", $_SERVER)) {
			return false;
		}
		$try_login = $_SERVER["HTTP_X_FORWARDED_USER"];

		if ($try_login) {
			$user_id = $this->base->auto_create_user($try_login, $password);

			if ($user_id) {
				$_SESSION["fake_login"] = $try_login;
				$_SESSION["fake_password"] = "******";
				$_SESSION["hide_hello"] = true;
				$_SESSION["hide_logout"] = true;

				return $user_id;
			}
		}

		return false;
	}

	function api_version() {
		return 2;
	}

}