Refactor session token management

Relates to https://github.com/shaarli/Shaarli/issues/324

Added:
- `SessionManager` class to group session-related features
- unit tests

Changed:
- `getToken()` -> `SessionManager->generateToken()`
- `tokenOk()` -> `SessionManager->checkToken()`
- inject a `$token` parameter to `PageBuilder`'s constructor

Signed-off-by: VirtualTam <virtualtam@flibidi.net>

1 files changed, 53 insertions, 0 deletions

diff --git a/application/SessionManager.php b/application/SessionManager.php
new file mode 100644
index 00000000..2083df42
--- /dev/null
+++ b/application/SessionManager.php
@@ -0,0 +1,53 @@
+<?php
+namespace Shaarli;
+
+/**
+ * Manages the server-side session
+ */
+class SessionManager
+{
+    protected $session = [];
+
+    /**
+     * Constructor
+     *
+     * @param array         $session The $_SESSION array (reference)
+     * @param ConfigManager $conf    ConfigManager instance (reference)
+     */
+    public function __construct(& $session, & $conf)
+    {
+        $this->session = &$session;
+        $this->conf = &$conf;
+    }
+
+    /**
+     * Generates a session token
+     *
+     * @return string token
+     */
+    public function generateToken()
+    {
+        $token = sha1(uniqid('', true) .'_'. mt_rand() . $this->conf->get('credentials.salt'));
+        $this->session['tokens'][$token] = 1;
+        return $token;
+    }
+
+    /**
+     * Checks the validity of a session token, and destroys it afterwards
+     *
+     * @param string $token The token to check
+     *
+     * @return bool true if the token is valid, else false
+     */
+    public function checkToken($token)
+    {
+        if (! isset($this->session['tokens'][$token])) {
+            // the token is wrong, or has already been used
+            return false;
+        }
+
+        // destroy the token to prevent future use
+        unset($this->session['tokens'][$token]);
+        return true;
+    }
+}