Merge pull request #102 from akoryak/closures

Add filter for Closure functions

Author: chadicus

.github/workflows/php.yml

@@ -14,7 +14,7 @@ jobs:
         php-versions: ['7.3', '7.4', '8.0', '8.1', '8.2', '8.3']
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
     - name: Install PHP
       uses: shivammathur/setup-php@v2
       with:

README.md

@@ -644,6 +644,17 @@ The following checks that `$value` is a URL.
 \TraderInteractive\Filter\Url::filter($value);
 ```
 
+#### Closures::filter
+Aliased in the filterer as `closure`, this filter verifies that the argument is a closure function.
+
+The following checks that `$closureMethod` is a closure.
+```php
+$closureMethod = function () {
+    doSomething();
+};
+\TraderInteractive\Filter\Closures::filter($closureMethod);
+```
+
 #### Email::filter
 Aliased in the filterer as `email`, this filter verifies that the argument is an email.
 

src/Filter/Closures.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace TraderInteractive\Filter;
+
+use TraderInteractive\Exceptions\FilterException;
+
+/**
+ * A collection of filters for Closures.
+ */
+class Closures
+{
+    /**
+     * Filters $value to a Closure strictly.
+     * The return value is \Closure, as expected by the \TraderInteractive\Filterer class.
+     *
+     * @param mixed $value       the value to filter to a closure function
+     * @param bool  $allowNull   Set to true if NULL values are allowed. The filtered result of a NULL value is NULL
+     *
+     * @return \Closure|null the filtered $value
+     *
+     * @throws FilterException
+     */
+    public static function filter($value, bool $allowNull = false)
+    {
+        if ($allowNull === true && $value === null) {
+            return null;
+        }
+
+        if ($value instanceof \Closure) {
+            return $value;
+        }
+
+        if (is_callable($value)) {
+            return \Closure::fromCallable($value);
+        }
+
+        throw new FilterException('Value "' . var_export($value, true) . '" is not Closure or $allowNull is not set');
+    }
+}

src/Filterer.php

@@ -28,6 +28,7 @@ final class Filterer implements FiltererInterface
         'arrayize' => '\\TraderInteractive\\Filter\\Arrays::arrayize',
         'bool' => '\\TraderInteractive\\Filter\\Booleans::filter',
         'bool-convert' => '\\TraderInteractive\\Filter\\Booleans::convert',
+        'closure' => Filter\Closures::class . '::filter',
         'compress-string' => '\\TraderInteractive\\Filter\\Strings::compress',
         'concat' => '\\TraderInteractive\\Filter\\Strings::concat',
         'date' => '\\TraderInteractive\\Filter\\DateTime::filter',

tests/Filter/ClosuresTest.php

@@ -0,0 +1,81 @@
+<?php
+
+namespace TraderInteractive\Filter;
+
+use PHPUnit\Framework\TestCase;
+use TraderInteractive\Exceptions\FilterException;
+
+/**
+ * @coversDefaultClass \TraderInteractive\Filter\Closures
+ * @covers ::<private>
+ */
+final class ClosuresTest extends TestCase
+{
+    /**
+     * @test
+     * @covers ::filter
+     */
+    public function filterAllowNullAndNullValue()
+    {
+        $result = Closures::filter(null, true);
+        $this->assertSame(null, $result);
+    }
+
+    /**
+     * @test
+     * @covers ::filter
+     */
+    public function filterAllowNullIsFalseAndNullValue()
+    {
+        $this->expectException(FilterException::class);
+        Closures::filter(null, false);
+    }
+
+    /**
+     * @test
+     * @covers ::filter
+     */
+    public function filterClosure()
+    {
+        $closureFunction = function () {
+            return 'do nothing';
+        };
+        $result = Closures::filter($closureFunction);
+        $this->assertTrue($result instanceof \Closure);
+    }
+
+    public static function myCallableFunction()
+    {
+        return 'do nothing';
+    }
+
+    /**
+     * @test
+     * @covers ::filter
+     */
+    public function filterCallable()
+    {
+        $result = Closures::filter(['\\TraderInteractive\\Filter\\ClosuresTest', 'myCallableFunction']);
+        $this->assertTrue($result instanceof \Closure);
+    }
+
+    /**
+     * @test
+     * @covers ::filter
+     */
+    public function filterNotCallableString()
+    {
+        $this->expectException(FilterException::class);
+        Closures::filter('string');
+    }
+
+    /**
+     * @test
+     * @covers ::filter
+     */
+    public function filterNotCallableInt()
+    {
+        $this->expectException(FilterException::class);
+        Closures::filter(123);
+    }
+}