diff --git a/mod/cal.php b/mod/cal.php
index 5779b0316a..2cc0b4a592 100644
--- a/mod/cal.php
+++ b/mod/cal.php
@@ -29,11 +29,11 @@ function cal_init(App $a)
 	}
 
 	if (Config::get('system', 'block_public') && !local_user() && !remote_user()) {
-		return;
+		System::httpExit(403, ['title' => L10n::t('Access denied.')]);
 	}
 
 	if ($a->argc < 2) {
-		System::httpExit(403, ["title" => L10n::t('Access denied.')]);
+		System::httpExit(403, ['title' => L10n::t('Access denied.')]);
 	}
 
 	Nav::setSelected('events');
@@ -41,7 +41,7 @@ function cal_init(App $a)
 	$nick = $a->argv[1];
 	$user = DBA::selectFirst('user', [], ['nickname' => $nick, 'blocked' => false]);
 	if (!DBA::isResult($user)) {
-		return;
+		System::httpExit(404, ['title' => L10n::t('Page not found.')]);
 	}
 
 	$a->data['user'] = $user;
diff --git a/mod/photos.php b/mod/photos.php
index 04d4138fc6..c2b00c7345 100644
--- a/mod/photos.php
+++ b/mod/photos.php
@@ -1260,6 +1260,8 @@ function photos_content(App $a)
 			);
 
 			if (DBA::isResult($prvnxt)) {
+				$prv = null;
+				$nxt = null;
 				foreach ($prvnxt as $z => $entry) {
 					if ($entry['resource-id'] == $ph[0]['resource-id']) {
 						$prv = $z - 1;
@@ -1274,8 +1276,12 @@ function photos_content(App $a)
 					}
 				}
 				$edit_suffix = ((($cmd === 'edit') && $can_post) ? '/edit' : '');
-				$prevlink = 'photos/' . $a->data['user']['nickname'] . '/image/' . $prvnxt[$prv]['resource-id'] . $edit_suffix . ($order_field === 'posted' ? '?f=&order=posted' : '');
-				$nextlink = 'photos/' . $a->data['user']['nickname'] . '/image/' . $prvnxt[$nxt]['resource-id'] . $edit_suffix . ($order_field === 'posted' ? '?f=&order=posted' : '');
+				if (!is_null($prv)) {
+					$prevlink = 'photos/' . $a->data['user']['nickname'] . '/image/' . $prvnxt[$prv]['resource-id'] . $edit_suffix . ($order_field === 'posted' ? '?f=&order=posted' : '');
+				}
+				if (!is_null($nxt)) {
+					$nextlink = 'photos/' . $a->data['user']['nickname'] . '/image/' . $prvnxt[$nxt]['resource-id'] . $edit_suffix . ($order_field === 'posted' ? '?f=&order=posted' : '');
+				}
  			}
 		}
 
diff --git a/src/App.php b/src/App.php
index f583f151a6..d02ea73ca4 100644
--- a/src/App.php
+++ b/src/App.php
@@ -1399,16 +1399,12 @@ class App
 			}
 		}
 
-		if (!empty($_SESSION)) {
-			$user_theme = defaults($_SESSION, 'theme', $system_theme);
-		} else {
-			$user_theme = $system_theme;
-		}
+		$user_theme = Core\Session::get('theme', $system_theme);
 
 		// Specific mobile theme override
-		if (($this->is_mobile || $this->is_tablet) && defaults($_SESSION, 'show-mobile', true)) {
+		if (($this->is_mobile || $this->is_tablet) && Core\Session::get('show-mobile', true)) {
 			$system_mobile_theme = Config::get('system', 'mobile-theme');
-			$user_mobile_theme = defaults($_SESSION, 'mobile-theme', $system_mobile_theme);
+			$user_mobile_theme = Core\Session::get('mobile-theme', $system_mobile_theme);
 
 			// --- means same mobile theme as desktop
 			if (!empty($user_mobile_theme) && $user_mobile_theme !== '---') {
diff --git a/src/Core/Session.php b/src/Core/Session.php
index b245c675b0..6d059eb4ef 100644
--- a/src/Core/Session.php
+++ b/src/Core/Session.php
@@ -45,9 +45,24 @@ class Session
 		return isset($_SESSION[$name]);
 	}
 
-	public static function get($name)
+	/**
+	 * Retrieves a key from the session super global or the defaults if the key is missing or the value is falsy.
+	 * 
+	 * Handle the case where session_start() hasn't been called and the super global isn't available.
+	 *
+	 * @param string $name
+	 * @param mixed $defaults
+	 * @return mixed
+	 */
+	public static function get($name, $defaults = null)
 	{
-		return defaults($_SESSION, $name, null);
+		if (isset($_SESSION)) {
+			$return = defaults($_SESSION, $name, $defaults);
+		} else {
+			$return = $defaults;
+		}
+
+		return $return;
 	}
 
 	public static function set($name, $value)
diff --git a/src/Model/Profile.php b/src/Model/Profile.php
index 29601ad32d..2e1af26c76 100644
--- a/src/Model/Profile.php
+++ b/src/Model/Profile.php
@@ -336,9 +336,11 @@ class Profile
 			$subscribe_feed = false;
 		}
 
+		$wallmessage = false;
+		$wallmessage_link = false;
+
 		if (remote_user() || (self::getMyURL() && x($profile, 'unkmail') && ($profile['uid'] != local_user()))) {
 			$wallmessage = L10n::t('Message');
-			$wallmessage_link = 'wallmessage/' . $profile['nickname'];
 
 			if (remote_user()) {
 				$r = q(
@@ -359,10 +361,9 @@ class Profile
 				$remote_url = $r[0]['url'];
 				$message_path = preg_replace('=(.*)/profile/(.*)=ism', '$1/message/new/', $remote_url);
 				$wallmessage_link = $message_path . base64_encode($profile['addr']);
+			} else if (!empty($profile['nickname'])) {
+				$wallmessage_link = 'wallmessage/' . $profile['nickname'];
 			}
-		} else {
-			$wallmessage = false;
-			$wallmessage_link = false;
 		}
 
 		// show edit profile to yourself
diff --git a/src/Util/Proxy.php b/src/Util/Proxy.php
index bb26185f46..3473e8d167 100644
--- a/src/Util/Proxy.php
+++ b/src/Util/Proxy.php
@@ -180,16 +180,8 @@ class Proxy
 	{
 		$query = parse_url($url, PHP_URL_QUERY);
 		$query = html_entity_decode($query);
-		$query_list = explode('&', $query);
 
-		$arr = [];
-
-		foreach ($query_list as $key_value) {
-			$key_value_list = explode('=', $key_value);
-			$arr[$key_value_list[0]] = $key_value_list[1];
-		}
-
-		unset($url, $query_list, $url);
+		parse_str($query, $arr);
 
 		return $arr;
 	}