From 0d7f7dc543d6c15fbaaf86284e85c796d8f4de8c Mon Sep 17 00:00:00 2001
From: Nick Liu <deltik@gmx.com>
Date: Mon, 30 Apr 2018 06:24:20 -0500
Subject: [PATCH] Improved: Downloads >> Preferences >> Protection

- MOD: Refactored NGINX secure_link_md5 decorator into interface and
       class in Downloads plugin
- NEW: Downloads plugin: Admin preferences UX improvement:
       Preferences >> Protection now shows the user a list of
       supported NGINX variables pulled from
       NginxSecureLinkMd5Decorator
---
 .../handlers/NginxSecureLinkMd5Decorator.php  | 52 +++++++++++++++++++
 .../download/handlers/SecureLinkDecorator.php |  6 +++
 e107_plugins/download/includes/admin.php      | 14 +++++
 .../languages/English/English_admin.php       |  1 +
 e107_plugins/download/request.php             | 29 ++---------
 5 files changed, 76 insertions(+), 26 deletions(-)
 create mode 100644 e107_plugins/download/handlers/NginxSecureLinkMd5Decorator.php
 create mode 100644 e107_plugins/download/handlers/SecureLinkDecorator.php

diff --git a/e107_plugins/download/handlers/NginxSecureLinkMd5Decorator.php b/e107_plugins/download/handlers/NginxSecureLinkMd5Decorator.php
new file mode 100644
index 000000000..7ce9ffcca
--- /dev/null
+++ b/e107_plugins/download/handlers/NginxSecureLinkMd5Decorator.php
@@ -0,0 +1,52 @@
+<?php
+require_once('SecureLinkDecorator.php');
+
+class NginxSecureLinkMd5Decorator implements SecureLinkDecorator
+{
+	protected $url = null;
+	protected $prefs = array();
+
+	const SUPPORTED_VARIABLES = array(
+		'$secure_link_expires',
+		'$uri',
+		'$remote_addr'
+	);
+
+	static function supported_variables() {
+		return self::SUPPORTED_VARIABLES;
+	}
+
+	function __construct($url, $preferences)
+	{
+		$this->url = $url;
+		$this->prefs = $preferences;
+	}
+
+	public function decorate()
+	{
+		$prefs = $this->prefs;
+		$url = $this->url;
+		$expiry = intval($prefs['download_security_link_expiry']);
+		if ($expiry <= 0)
+			$expiry = PHP_INT_MAX;
+		else
+			$expiry = time() + $expiry;
+		$url_parts = parse_url($url);
+		$evaluation = str_replace(
+			self::supported_variables(),
+			array(
+				$expiry,
+				$url_parts['path'],
+				$_SERVER['REMOTE_ADDR']
+			),
+			$prefs['download_security_expression']
+		);
+		$query_string = $url_parts['query'];
+		parse_str($query_string, $query_args);
+		$query_args['md5'] = md5($evaluation);
+		if (strpos($prefs['download_security_expression'], '$secure_link_expires') !== false)
+			$query_args['expires'] = $expiry;
+		require_once(__DIR__.'/../includes/shim_http_build_url.php');
+		return http_build_url($url_parts, array('query' => http_build_query($query_args)));
+	}
+}
\ No newline at end of file
diff --git a/e107_plugins/download/handlers/SecureLinkDecorator.php b/e107_plugins/download/handlers/SecureLinkDecorator.php
new file mode 100644
index 000000000..0dd48ab93
--- /dev/null
+++ b/e107_plugins/download/handlers/SecureLinkDecorator.php
@@ -0,0 +1,6 @@
+<?php
+
+interface SecureLinkDecorator
+{
+	public function decorate();
+}
\ No newline at end of file
diff --git a/e107_plugins/download/includes/admin.php b/e107_plugins/download/includes/admin.php
index 8cf6abd51..54b0e2abc 100644
--- a/e107_plugins/download/includes/admin.php
+++ b/e107_plugins/download/includes/admin.php
@@ -2113,6 +2113,14 @@ $columnInfo = array(
 		function show_download_options()
 		{
 		   	global $pref, $ns;
+
+		   	require_once(__DIR__."/../handlers/NginxSecureLinkMd5Decorator.php");
+		   	$supported_secure_link_variables_html = "<ul>";
+		   	foreach(NginxSecureLinkMd5Decorator::supported_variables() as $variable)
+		    {
+		    	$supported_secure_link_variables_html .= "<li><code>$variable</code></li>";
+		    }
+		    $supported_secure_link_variables_html .= "</ul>";
 		
 				require_once(e_HANDLER."form_handler.php");
 				$frm = new e_form(true); //enable inner tabindex counter
@@ -2263,6 +2271,12 @@ $columnInfo = array(
 		            		     	 	<td>
 		            		     	 		".$frm->text('download_security_expression', $pref['download_security_expression'], 1024)."
 		            		     	 		<div class='field-help'>".LAN_DL_SECURITY_NGINX_SECURELINKMD5_EXPRESSION_HELP."</div>
+		            		     	 		<small><a href='#' onclick='event.preventDefault();$(\"#supported-nginx-variables\").toggle();this.blur()'>
+		            		     	 			".LAN_DL_SECURITY_NGINX_SUPPORTED_VARIABLES_TOGGLE."
+		            		     	 		</a></small>
+		            		     	 		<div id='supported-nginx-variables' style='display:none'>
+		            	   						".$supported_secure_link_variables_html."
+		            		     	 		</div>
 		            		     	 	</td>
 		            		      	</tr>
 		            		      	<tr>
diff --git a/e107_plugins/download/languages/English/English_admin.php b/e107_plugins/download/languages/English/English_admin.php
index 0a63c15ea..d3a6d1d33 100644
--- a/e107_plugins/download/languages/English/English_admin.php
+++ b/e107_plugins/download/languages/English/English_admin.php
@@ -235,6 +235,7 @@ define("LAN_DL_SECURITY_DESCRIPTION", "Downloads can make use of server-side URL
 define("LAN_DL_SECURITY_MODE", "URL protection mode");
 define("LAN_DL_SECURITY_MODE_NONE", "None (Default)");
 define("LAN_DL_SECURITY_MODE_NGINX_SECURELINKMD5", "NGINX secure_link_md5");
+define("LAN_DL_SECURITY_NGINX_SUPPORTED_VARIABLES_TOGGLE", "Click to toggle list of supported NGINX variables");
 define("LAN_DL_SECURITY_NGINX_SECURELINKMD5_EXPRESSION",
 	"<a target='_blank' href='https://nginx.org/en/docs/http/ngx_http_secure_link_module.html#secure_link_md5'>NGINX secure_link_md5 expression</a>");
 define("LAN_DL_SECURITY_NGINX_SECURELINKMD5_EXPRESSION_HELP", "Same expression as configured on the server");
diff --git a/e107_plugins/download/request.php b/e107_plugins/download/request.php
index 346eae424..afe4de188 100644
--- a/e107_plugins/download/request.php
+++ b/e107_plugins/download/request.php
@@ -440,30 +440,7 @@ function decorate_download_location($url)
 	$pref = e107::getPref();
 	if ($pref['download_security_mode'] !== 'nginx-secure_link_md5')
 		return $url;
-	$expiry = intval($pref['download_security_link_expiry']);
-	if ($expiry <= 0)
-		$expiry = PHP_INT_MAX;
-	else
-		$expiry = time() + $expiry;
-	$url_parts = parse_url($url);
-	$evaluation = str_replace(
-		array(
-			'$secure_link_expires',
-			'$uri',
-			'$remote_addr'
-		),
-		array(
-			$expiry,
-			$url_parts['path'],
-			$_SERVER['REMOTE_ADDR']
-		),
-		$pref['download_security_expression']
-	);
-	$query_string = $url_parts['query'];
-	parse_str($query_string, $query_args);
-	$query_args['md5'] = md5($evaluation);
-	if (strpos($pref['download_security_expression'], '$secure_link_expires') !== false)
-		$query_args['expires'] = $expiry;
-	require_once(__DIR__.'/includes/shim_http_build_url.php');
-	return http_build_url($url_parts, array('query' => http_build_query($query_args)));
+	require_once(__DIR__."/handlers/NginxSecureLinkMd5Decorator.php");
+	$decorator = new NginxSecureLinkMd5Decorator($url, $pref);
+	return $decorator->decorate();
 }
\ No newline at end of file