Fix for #2568

Slim/Router.php

@@ -130,20 +130,51 @@ public function getBasePath()
      */
     public function setCacheFile($cacheFile)
     {
+        $this->cacheFile = $cacheFile;
+
         if (!is_string($cacheFile) && $cacheFile !== false) {
-            throw new InvalidArgumentException('Router cacheFile must be a string or false');
+            throw new InvalidArgumentException('Router cache file must be a string or false');
         }
 
-        $this->cacheFile = $cacheFile;
-
-        if ($cacheFile !== false && !is_writable(dirname($cacheFile))) {
-            throw new RuntimeException('Router cacheFile directory must be writable');
+        if ($cacheFile && file_exists($cacheFile) && !$this->isCacheFileReadable($cacheFile)) {
+            throw new RuntimeException(
+                sprintf('Router cache file `%s` is not readable', $cacheFile)
+            );
         }
 
+        if ($cacheFile && !file_exists($cacheFile) && !$this->isCacheDirWritable(dirname($cacheFile))) {
+            throw new RuntimeException(
+                sprintf('Router cache file directory `%s` is not writable', dirname($cacheFile))
+            );
+        }
 
         return $this;
     }
 
+    /**
+     * This method is in place to facilitate unit tests
+     *
+     * @param $cacheFile
+     *
+     * @return bool
+     */
+    protected function isCacheFileReadable($cacheFile)
+    {
+        return is_readable($cacheFile);
+    }
+
+    /**
+     * This method is in place to facilitate unit tests
+     *
+     * @param $cacheDir
+     *
+     * @return bool
+     */
+    protected function isCacheDirWritable($cacheDir)
+    {
+        return is_writable($cacheDir);
+    }
+
     /**
      * @param ContainerInterface $container
      */

tests/RouterTest.php

@@ -6,21 +6,31 @@
  * @copyright Copyright (c) 2011-2017 Josh Lockhart
  * @license   https://github.com/slimphp/Slim/blob/3.x/LICENSE.md (MIT License)
  */
+
 namespace Slim\Tests;
 
-use Slim\Container;
 use Slim\Router;
 
 class RouterTest extends \PHPUnit_Framework_TestCase
 {
     /** @var Router */
     protected $router;
 
+    /** @var string */
+    protected $cacheFile;
+
     public function setUp()
     {
         $this->router = new Router;
     }
 
+    public function tearDown()
+    {
+        if (file_exists($this->cacheFile)) {
+            unlink($this->cacheFile);
+        }
+    }
+
     public function testMap()
     {
         $methods = ['GET'];
@@ -333,24 +343,62 @@ public function testSettingInvalidCacheFileValue()
     {
         $this->setExpectedException(
             '\InvalidArgumentException',
-            'Router cacheFile must be a string'
+            'Router cache file must be a string'
         );
         $this->router->setCacheFile(['invalid']);
     }
 
     /**
-     * Test if cacheFile is not a writable directory
+     * Test cache file exists but is not writable
      */
-    public function testSettingInvalidCacheFileNotExisting()
+    public function testCacheFileExistsAndIsNotReadable()
     {
+        $this->cacheFile = __DIR__ . '/' . time() . '.cache';
+        file_put_contents($this->cacheFile, '<?php return []; ?>');
+
         $this->setExpectedException(
             '\RuntimeException',
-            'Router cacheFile directory must be writable'
+            sprintf('Router cache file `%s` is not readable', $this->cacheFile)
         );
 
-        $this->router->setCacheFile(
-            dirname(__FILE__) . uniqid(microtime(true)) . '/' . uniqid(microtime(true))
+        $mock = $this
+            ->getMockBuilder(Router::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['isCacheFileReadable'])
+            ->getMock();
+
+        $mock->expects($this->any())
+            ->method('isCacheFileReadable')
+            ->will($this->returnValue(false));
+
+        /** @var Router $mock */
+        $mock->setCacheFile($this->cacheFile);
+    }
+
+    /**
+     * Test cache file does not exist and directory is not writable
+     */
+    public function testCacheFileDoesNotExistsAndDirectoryIsNotWritable()
+    {
+        $cacheFile = __DIR__ . '/NonWritableDirectory/WritableFile.php';
+
+        $this->setExpectedException(
+            '\RuntimeException',
+            sprintf('Router cache file directory `%s` is not writable', dirname($cacheFile))
         );
+
+        $mock = $this
+            ->getMockBuilder(Router::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['isCacheDirWritable'])
+            ->getMock();
+
+        $mock->expects($this->any())
+            ->method('isCacheDirWritable')
+            ->will($this->returnValue(false));
+
+        /** @var Router $mock */
+        $mock->setCacheFile($cacheFile);
     }
 
     /**