create cache functions (#37)

composer.json

@@ -11,7 +11,8 @@
     "require": {
         "php": ">=7.4",
         "ext-ldap": ">=7.4",
-        "phpmailer/phpmailer": "^6.5.0"
+        "phpmailer/phpmailer": "^6.5.0",
+        "symfony/cache": "v5.4.42"
     },
     "require-dev": {
         "phpunit/phpunit": ">=8",

src/Ltb/Cache.php

@@ -0,0 +1,66 @@
+<?php namespace Ltb;
+
+use Symfony\Component\Cache\Adapter\FilesystemAdapter;
+
+class Cache {
+
+    // symfony cache instance
+    public $sspCache = null;
+
+    public function __construct(
+                          $namespace = 'sspCache',
+                          $defaultLifetime = 0,
+                          $directory = null
+                      )
+    {
+
+        $this->sspCache = new FilesystemAdapter(
+            $namespace,
+            $defaultLifetime,
+            $directory
+        );
+
+        // Clean cache from expired entries
+        $this->sspCache->prune();
+
+    }
+
+    # Generate a cache entry containing a token,
+    # expiring after $cache_form_expiration seconds
+    function generate_form_token($cache_form_expiration)
+    {
+        $formtoken = hash('sha256', bin2hex(random_bytes(16)));
+        $cachedToken = $this->sspCache->getItem($formtoken);
+        $cachedToken->set($formtoken);
+        $cachedToken->expiresAfter($cache_form_expiration);
+        $this->sspCache->save($cachedToken);
+        error_log("generated form token: " .
+                  $formtoken .
+                  " valid for $cache_form_expiration s");
+        return $formtoken;
+    }
+
+    # Verify that give token exist in cache
+    # and if it exists, remove it from cache
+    function verify_form_token($formtoken)
+    {
+        $result = "";
+        $cachedToken = $this->sspCache->getItem($formtoken);
+        if( $cachedToken->isHit() && $cachedToken->get() == $formtoken )
+        {
+            # Remove token from cache entry
+            $this->sspCache->deleteItem($formtoken);
+        }
+        else
+        {
+            error_log("Invalid form token: sent: $formtoken, stored: " .
+                      $cachedToken->get());
+            $result = "invalidformtoken";
+        }
+        return $result;
+    }
+
+
+}
+
+?>

tests/Ltb/CacheTest.php

@@ -0,0 +1,133 @@
+<?php
+
+require __DIR__ . '/../../vendor/autoload.php';
+
+final class CacheTest extends \Mockery\Adapter\Phpunit\MockeryTestCase
+{
+
+    public function test_construct(): void
+    {
+        $cacheInstance = new \Ltb\Cache(
+                                           "testCache",
+                                           0,
+                                           null
+                                       );
+        $this->assertTrue($cacheInstance->sspCache instanceof Symfony\Component\Cache\Adapter\FilesystemAdapter, "Error while initializing sspCache object");
+    }
+
+
+    public function test_generate_form_token(): void
+    {
+
+        $cacheInstance = new \Ltb\Cache(
+                                           "testCache",
+                                           0,
+                                           null
+                                       );
+
+        $generated_token = "";
+
+        $cacheInstance->sspCache = Mockery::mock('FilesystemAdapter');
+        $cacheInstance->sspCache->shouldreceive('getItem')
+                      ->andReturnUsing(
+                          function($token) use (&$generated_token){
+                              $generated_token = $token;
+
+                              $cacheItem = Mockery::mock('CacheItem');
+
+                              $cacheItem->shouldreceive('set')
+                                            ->andReturnUsing(
+                                                function($formtoken) use (&$token) {
+                                                    $this->assertEquals($formtoken,
+                                                                        $token,
+                                                                        "Error: received token in set ($formtoken) is different from received token in getItem ($token)");
+                                                }
+                                            );
+
+                              $cacheItem->shouldreceive('expiresAfter')
+                                            ->with(120);
+
+                              return $cacheItem;
+                          }
+                      );
+
+        $cacheInstance->sspCache->shouldreceive('save');
+
+        $receivedToken = $cacheInstance->generate_form_token(120);
+        $this->assertEquals("$receivedToken",
+                            $generated_token,
+                            "Error: received token in generate_form_token ($receivedToken) is different from received token in getItem ($generated_token)");
+
+    }
+
+    public function test_verify_form_token_ok(): void
+    {
+
+        $generated_token = "e712b08e55f8977e2b9ecad35d5180ed24345e76607413411e90df66b9538fa1";
+
+        $cacheInstance = new \Ltb\Cache(
+                                           "testCache",
+                                           0,
+                                           null
+                                       );
+
+        $cacheInstance->sspCache = Mockery::mock('FilesystemAdapter');
+        $cacheInstance->sspCache->shouldreceive('getItem')
+                      ->andReturnUsing(
+                          function($token) use(&$generated_token) {
+                              $cacheItem = Mockery::mock('CacheItem');
+
+                              $cacheItem->shouldreceive('isHit')
+                                        ->andReturn(true);
+
+                              $cacheItem->shouldreceive('get')
+                                        ->andReturn($generated_token);
+
+                              return $cacheItem;
+                          }
+                      );
+
+        $cacheInstance->sspCache->shouldreceive('deleteItem')
+                                ->with($generated_token);
+
+        $result = $cacheInstance->verify_form_token($generated_token);
+        $this->assertEquals("",
+                            $result,
+                            "Error: invalid result: '$result' sent by verify_form_token");
+
+    }
+
+    public function test_verify_form_token_ko(): void
+    {
+
+        $generated_token = "e712b08e55f8977e2b9ecad35d5180ed24345e76607413411e90df66b9538fa1";
+
+        $cacheInstance = new \Ltb\Cache(
+                                           "testCache",
+                                           0,
+                                           null
+                                       );
+
+        $cacheInstance->sspCache = Mockery::mock('FilesystemAdapter');
+        $cacheInstance->sspCache->shouldreceive('getItem')
+                      ->andReturnUsing(
+                          function($token) use(&$generated_token) {
+                              $cacheItem = Mockery::mock('CacheItem');
+
+                              $cacheItem->shouldreceive('isHit')
+                                        ->andReturn(false);
+
+                              $cacheItem->shouldreceive('get')
+                                        ->andReturn(null);
+
+                              return $cacheItem;
+                          }
+                      );
+
+        $result = $cacheInstance->verify_form_token($generated_token);
+        $this->assertEquals("invalidformtoken",
+                            $result,
+                            "Error: expected 'invalidformtoken', but received result: '$result' in verify_form_token");
+
+    }
+}