Callable parameter injection

This is like what we have to DI and classes, but for callables.

The motivating factor is to get rid of *service locators* in the `boot`
method of apps as a new pattern is about to emerge where we have lots of
`query` calls on the app or server container in order to fetch some
services.

With this little helper it's possible to call another (public) method
and magically have everything injected.

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index 9d1ebf2815b7d7866f67e08f088e982698a8a9f4..1fa17bab000bd7ca6866c352bf4df0990f775054 100644 (file)
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -548,6 +548,7 @@ return array(
     'OC\\AppFramework\\App' => $baseDir . '/lib/private/AppFramework/App.php',
     'OC\\AppFramework\\Bootstrap\\BootContext' => $baseDir . '/lib/private/AppFramework/Bootstrap/BootContext.php',
     'OC\\AppFramework\\Bootstrap\\Coordinator' => $baseDir . '/lib/private/AppFramework/Bootstrap/Coordinator.php',
+    'OC\\AppFramework\\Bootstrap\\FunctionInjector' => $baseDir . '/lib/private/AppFramework/Bootstrap/FunctionInjector.php',
     'OC\\AppFramework\\Bootstrap\\RegistrationContext' => $baseDir . '/lib/private/AppFramework/Bootstrap/RegistrationContext.php',
     'OC\\AppFramework\\DependencyInjection\\DIContainer' => $baseDir . '/lib/private/AppFramework/DependencyInjection/DIContainer.php',
     'OC\\AppFramework\\Http' => $baseDir . '/lib/private/AppFramework/Http.php',

diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index 1b7cf1fa13aba1f4a2a71bf3aab203914799f03f..82ebb9eef05c89acd9869c2eac94983750c66ad8 100644 (file)
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -577,6 +577,7 @@ class ComposerStaticInit53792487c5a8370acc0b06b1a864ff4c
         'OC\\AppFramework\\App' => __DIR__ . '/../../..' . '/lib/private/AppFramework/App.php',
         'OC\\AppFramework\\Bootstrap\\BootContext' => __DIR__ . '/../../..' . '/lib/private/AppFramework/Bootstrap/BootContext.php',
         'OC\\AppFramework\\Bootstrap\\Coordinator' => __DIR__ . '/../../..' . '/lib/private/AppFramework/Bootstrap/Coordinator.php',
+        'OC\\AppFramework\\Bootstrap\\FunctionInjector' => __DIR__ . '/../../..' . '/lib/private/AppFramework/Bootstrap/FunctionInjector.php',
         'OC\\AppFramework\\Bootstrap\\RegistrationContext' => __DIR__ . '/../../..' . '/lib/private/AppFramework/Bootstrap/RegistrationContext.php',
         'OC\\AppFramework\\DependencyInjection\\DIContainer' => __DIR__ . '/../../..' . '/lib/private/AppFramework/DependencyInjection/DIContainer.php',
         'OC\\AppFramework\\Http' => __DIR__ . '/../../..' . '/lib/private/AppFramework/Http.php',

diff --git a/lib/private/AppFramework/Bootstrap/BootContext.php b/lib/private/AppFramework/Bootstrap/BootContext.php
index 3831fe4e396e9a82e9b8621f158aa2103981f064..d206884c0b7fe20a9a6ed57306e66f427413b227 100644 (file)
--- a/lib/private/AppFramework/Bootstrap/BootContext.php
+++ b/lib/private/AppFramework/Bootstrap/BootContext.php
@@ -45,4 +45,8 @@ class BootContext implements IBootContext {
        public function getServerContainer(): IServerContainer {
                return $this->appContainer->getServer();
        }
+
+       public function injectFn(callable $fn) {
+               return (new FunctionInjector($this->appContainer))->injectFn($fn);
+       }
 }

diff --git a/lib/private/AppFramework/Bootstrap/FunctionInjector.php b/lib/private/AppFramework/Bootstrap/FunctionInjector.php
new file mode 100644 (file)
index 0000000..cb1dc7d
--- /dev/null
+++ b/lib/private/AppFramework/Bootstrap/FunctionInjector.php
@@ -0,0 +1,69 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OC\AppFramework\Bootstrap;
+
+use Closure;
+use OCP\AppFramework\QueryException;
+use OCP\IContainer;
+use ReflectionFunction;
+use ReflectionParameter;
+use function array_map;
+
+class FunctionInjector {
+
+       /** @var IContainer */
+       private $container;
+
+       public function __construct(IContainer $container) {
+               $this->container = $container;
+       }
+
+       public function injectFn(callable $fn) {
+               $reflected = new ReflectionFunction(Closure::fromCallable($fn));
+               return $fn(...array_map(function (ReflectionParameter $param) {
+                       // First we try by type (more likely these days)
+                       if (($type = $param->getType()) !== null) {
+                               try {
+                                       return $this->container->query($type->getName());
+                               } catch (QueryException $ex) {
+                                       // Ignore and try name as well
+                               }
+                       }
+                       // Second we try by name (mostly for primitives)
+                       try {
+                               return $this->container->query($param->getName());
+                       } catch (QueryException $ex) {
+                               // As a last resort we pass `null` if allowed
+                               if ($type !== null && $type->allowsNull()) {
+                                       return null;
+                               }
+
+                               // Nothing worked, time to bail out
+                               throw $ex;
+                       }
+               }, $reflected->getParameters()));
+       }
+}

diff --git a/lib/public/AppFramework/Bootstrap/IBootContext.php b/lib/public/AppFramework/Bootstrap/IBootContext.php
index 6ceec5d2fcbf14f250afa945f46ff63004211efa..47b26528c6617ceba002af6e4dc8aefa344a8860 100644 (file)
--- a/lib/public/AppFramework/Bootstrap/IBootContext.php
+++ b/lib/public/AppFramework/Bootstrap/IBootContext.php
@@ -26,7 +26,9 @@ declare(strict_types=1);
 namespace OCP\AppFramework\Bootstrap;
 
 use OCP\AppFramework\IAppContainer;
+use OCP\AppFramework\QueryException;
 use OCP\IServerContainer;
+use Throwable;
 
 /**
  * @since 20.0.0
@@ -52,4 +54,24 @@ interface IBootContext {
         * @since 20.0.0
         */
        public function getServerContainer(): IServerContainer;
+
+       /**
+        * Invoke the given callable and inject all parameters based on their types
+        * and names
+        *
+        * Note: when used with methods, make sure they are public or use \Closure::fromCallable
+        * to wrap the private method call, e.g.
+        *  * `$context->injectFn([$obj, 'publicMethod'])`
+        *  * `$context->injectFn([$this, 'publicMethod'])`
+        *  * `$context->injectFn(\Closure::fromCallable([$this, 'privateMethod']))`
+        *
+        * Note: the app container will be queried
+        *
+        * @param callable $fn
+        * @throws QueryException if at least one of the parameter can't be resolved
+        * @throws Throwable any error the function invocation might cause
+        * @return mixed|null the return value of the invoked function, if any
+        * @since 20.0.0
+        */
+       public function injectFn(callable $fn);
 }

diff --git a/tests/lib/AppFramework/Bootstrap/FunctionInjectorTest.php b/tests/lib/AppFramework/Bootstrap/FunctionInjectorTest.php
new file mode 100644 (file)
index 0000000..cd2332b
--- /dev/null
+++ b/tests/lib/AppFramework/Bootstrap/FunctionInjectorTest.php
@@ -0,0 +1,84 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * @copyright 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2020 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace lib\AppFramework\Bootstrap;
+
+use OC\AppFramework\Bootstrap\FunctionInjector;
+use OC\AppFramework\Utility\SimpleContainer;
+use Test\TestCase;
+
+interface Foo {
+}
+
+class FunctionInjectorTest extends TestCase {
+
+       /** @var SimpleContainer */
+       private $container;
+
+       protected function setUp(): void {
+               parent::setUp();
+
+               $this->container = new SimpleContainer();
+       }
+
+       public function testInjectFnNotRegistered(): void {
+               $this->expectException(\OCP\AppFramework\QueryException::class);
+
+               (new FunctionInjector($this->container))->injectFn(static function (Foo $p1): void {
+               });
+       }
+
+       public function testInjectFnNotRegisteredButNullable(): void {
+               (new FunctionInjector($this->container))->injectFn(static function (?Foo $p1): void {
+               });
+
+               // Nothing to assert. No errors means everything is fine.
+               $this->addToAssertionCount(1);
+       }
+
+       public function testInjectFnByType(): void {
+               $this->container->registerService(Foo::class, function () {
+                       $this->addToAssertionCount(1);
+                       return new class implements Foo {
+                       };
+               });
+
+               (new FunctionInjector($this->container))->injectFn(static function (Foo $p1): void {
+               });
+
+               // Nothing to assert. No errors means everything is fine.
+               $this->addToAssertionCount(1);
+       }
+
+       public function testInjectFnByName(): void {
+               $this->container->registerParameter('test', 'abc');
+
+               (new FunctionInjector($this->container))->injectFn(static function ($test): void {
+               });
+
+               // Nothing to assert. No errors means everything is fine.
+               $this->addToAssertionCount(1);
+       }
+}

diff --git a/tests/lib/AppFramework/Utility/SimpleContainerTest.php b/tests/lib/AppFramework/Utility/SimpleContainerTest.php
index f8a430583055909a1ac3ad966da0f1c91cf3be46..36fa1febfcf77e0048215a8d0bd5f97796ddcfee 100644 (file)
--- a/tests/lib/AppFramework/Utility/SimpleContainerTest.php
+++ b/tests/lib/AppFramework/Utility/SimpleContainerTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /**
  * ownCloud - App Framework
  *
@@ -67,13 +69,14 @@ class SimpleContainerTest extends \Test\TestCase {
        }
 
 
+
        public function testRegister() {
                $this->container->registerParameter('test', 'abc');
                $this->assertEquals('abc', $this->container->query('test'));
        }
 
 
-       
+
        public function testNothingRegistered() {
                $this->expectException(\OCP\AppFramework\QueryException::class);
 
@@ -81,7 +84,7 @@ class SimpleContainerTest extends \Test\TestCase {
        }
 
 
-       
+
        public function testNotAClass() {
                $this->expectException(\OCP\AppFramework\QueryException::class);
 
@@ -190,7 +193,7 @@ class SimpleContainerTest extends \Test\TestCase {
                $this->assertEquals('abc', $this->container->query($query));
        }
 
-       
+
        public function testConstructorComplexNoTestParameterFound() {
                $this->expectException(\OCP\AppFramework\QueryException::class);