tweeper: allow to run tweeper either with or without composer

diff --git a/autoload.php b/autoload.php
new file mode 100644 (file)
index 0000000..1e11adf
--- /dev/null
+++ b/autoload.php
@@ -0,0 +1,82 @@
+<?php
+/**
+ * @file
+ * Tweeper - some logic to allow tweeper to run with or without composer.
+ *
+ * Copyright (C) 2016  Antonio Ospite <ao2@ao2.it>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+$package_name = 'ao2/tweeper';
+
+if (file_exists(__DIR__ . '/vendor/autoload.php')) {
+  /*
+   * If "composer install" has been executed, use the composer autoloader.
+   *
+   * Using __DIR__ is OK as long as this file is on the same level of the
+   * project "vendor/" directory (usually the project root directory).
+   */
+  require __DIR__ . '/vendor/autoload.php';
+}
+elseif (preg_match('/' . preg_quote('/vendor/' . $package_name, '/') . '$/', __DIR__)) {
+  /*
+   * If running from a "vendor/" directory of another project use the
+   * autoloader of the parent project.
+   *
+   * This covers the case of running from a symlink in ./vendor/bin/ because
+   * __DIR__ contains the *real path* of this file.
+   *
+   * Note that using __DIR__ here and going back two levels is OK under the
+   * assumptions that this file is in the project root directory, and that the
+   * package name has the structure VENDOR/PROJECT_NAME.
+   */
+  require __DIR__ . '/../../autoload.php';
+}
+else {
+  /*
+   * Otherwise, run without composer:
+   *
+   *  1. register our own autoloader function for the Tweeper class
+   *
+   * The implementation follows the one suggested in:
+   * http://www.php-fig.org/psr/psr-4/
+   */
+  spl_autoload_register(function ($fully_qualified_class_name) {
+    /* This matches the data defined for the PSR-4 autoloader in composer.json */
+    $namespace_prefix = 'Tweeper\\';
+    $base_directory = 'src/';
+
+    $len = strlen($namespace_prefix);
+    if (strncmp($namespace_prefix, $fully_qualified_class_name, $len) !== 0) {
+      return;
+    }
+
+    $class_relative = substr($fully_qualified_class_name, $len);
+
+    $file_path = $base_directory . str_replace('\\', '/', $class_relative) . '.php';
+
+    require_once $file_path;
+  });
+
+  /*
+   *  2. load the system-wide autoloader from php-symphony-serializer
+   *
+   * This allows to run tweeper without composer, provided that the
+   * dependencies are available system-wide.
+   *
+   * For example, the Debian package takes care of that.
+   */
+  require_once 'Symfony/Component/Serializer/autoload.php';
+}

diff --git a/src/Tweeper.php b/src/Tweeper.php
index 73cbe81..944b37c 100644 (file)
--- a/src/Tweeper.php
+++ b/src/Tweeper.php
@@ -25,8 +25,6 @@ namespace Tweeper;
 use DOMDocument;
 use XSLTProcessor;
 
-require_once 'Symfony/Component/Serializer/autoload.php';
-
 use Symfony\Component\Serializer\Serializer;
 use Symfony\Component\Serializer\Encoder\XmlEncoder;
 use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;

diff --git a/tweeper.php b/tweeper.php
index ba8b1d7..c9040b0 100644 (file)
--- a/tweeper.php
+++ b/tweeper.php
@@ -19,7 +19,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-require_once 'src/Tweeper.php';
+require_once 'autoload.php';
 
 use Tweeper\Tweeper;