PHP7 Dependency Injection

Structural/DependencyInjection/AbstractConfig.php

@@ -1,19 +0,0 @@
-<?php
-
-namespace DesignPatterns\Structural\DependencyInjection;
-
-/**
- * class AbstractConfig.
- */
-abstract class AbstractConfig
-{
-    /**
-     * @var Storage of data
-     */
-    protected $storage;
-
-    public function __construct($storage)
-    {
-        $this->storage = $storage;
-    }
-}

Structural/DependencyInjection/ArrayConfig.php

@@ -1,39 +0,0 @@
-<?php
-
-namespace DesignPatterns\Structural\DependencyInjection;
-
-/**
- * class ArrayConfig.
- *
- * uses array as data source
- */
-class ArrayConfig extends AbstractConfig implements Parameters
-{
-    /**
-     * Get parameter.
-     *
-     * @param string|int $key
-     * @param null       $default
-     *
-     * @return mixed
-     */
-    public function get($key, $default = null)
-    {
-        if (isset($this->storage[$key])) {
-            return $this->storage[$key];
-        }
-
-        return $default;
-    }
-
-    /**
-     * Set parameter.
-     *
-     * @param string|int $key
-     * @param mixed      $value
-     */
-    public function set($key, $value)
-    {
-        $this->storage[$key] = $value;
-    }
-}

Structural/DependencyInjection/Connection.php

@@ -1,47 +0,0 @@
-<?php
-
-namespace DesignPatterns\Structural\DependencyInjection;
-
-class Connection
-{
-    /**
-     * @var Configuration
-     */
-    protected $configuration;
-
-    /**
-     * @var Currently connected host
-     */
-    protected $host;
-
-    /**
-     * @param Parameters $config
-     */
-    public function __construct(Parameters $config)
-    {
-        $this->configuration = $config;
-    }
-
-    /**
-     * connection using the injected config.
-     */
-    public function connect()
-    {
-        $host = $this->configuration->get('host');
-        // connection to host, authentication etc...
-
-        //if connected
-        $this->host = $host;
-    }
-
-    /*
-     * Get currently connected host
-     *
-     * @return string
-     */
-
-    public function getHost()
-    {
-        return $this->host;
-    }
-}

Structural/DependencyInjection/DatabaseConfiguration.php

@@ -0,0 +1,54 @@
+<?php
+
+namespace DesignPatterns\Structural\DependencyInjection;
+
+class DatabaseConfiguration
+{
+    /**
+     * @var string
+     */
+    private $host;
+
+    /**
+     * @var int
+     */
+    private $port;
+
+    /**
+     * @var string
+     */
+    private $username;
+
+    /**
+     * @var string
+     */
+    private $password;
+
+    public function __construct(string $host, int $port, string $username, string $password)
+    {
+        $this->host = $host;
+        $this->port = $port;
+        $this->username = $username;
+        $this->password = $password;
+    }
+
+    public function getHost(): string
+    {
+        return $this->host;
+    }
+
+    public function getPort(): int
+    {
+        return $this->port;
+    }
+
+    public function getUsername(): string
+    {
+        return $this->username;
+    }
+
+    public function getPassword(): string
+    {
+        return $this->password;
+    }
+}

Structural/DependencyInjection/DatabaseConnection.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace DesignPatterns\Structural\DependencyInjection;
+
+class DatabaseConnection
+{
+    /**
+     * @var DatabaseConfiguration
+     */
+    private $configuration;
+
+    /**
+     * @param DatabaseConfiguration $config
+     */
+    public function __construct(DatabaseConfiguration $config)
+    {
+        $this->configuration = $config;
+    }
+
+    public function getDsn(): string
+    {
+        // this is just for the sake of demonstration, not a real DSN
+        // notice that only the injected config is used here, so there is
+        // a real separation of concerns here
+
+        return sprintf(
+            '%s:%s@%s:%d',
+            $this->configuration->getUsername(),
+            $this->configuration->getPassword(),
+            $this->configuration->getHost(),
+            $this->configuration->getPort()
+        );
+    }
+}

Structural/DependencyInjection/Parameters.php

@@ -1,26 +0,0 @@
-<?php
-
-namespace DesignPatterns\Structural\DependencyInjection;
-
-/**
- * Parameters interface.
- */
-interface Parameters
-{
-    /**
-     * Get parameter.
-     *
-     * @param string|int $key
-     *
-     * @return mixed
-     */
-    public function get($key);
-
-    /**
-     * Set parameter.
-     *
-     * @param string|int $key
-     * @param mixed      $value
-     */
-    public function set($key, $value);
-}

Structural/DependencyInjection/README.rst

@@ -10,17 +10,10 @@ testable, maintainable and extendable code.
 Usage
 -----
 
-Configuration gets injected and ``Connection`` will get all that it
+DatabaseConfiguration gets injected and ``DatabaseConnection`` will get all that it
 needs from ``$config``. Without DI, the configuration would be created
-directly in ``Connection``, which is not very good for testing and
-extending ``Connection``.
-
-Notice we are following Inversion of control principle in ``Connection``
-by asking ``$config`` to implement ``Parameters`` interface. This
-decouples our components. We don't care where the source of information
-comes from, we only care that ``$config`` has certain methods to
-retrieve that information. Read more about Inversion of control
-`here <http://en.wikipedia.org/wiki/Inversion_of_control>`__.
+directly in ``DatabaseConnection``, which is not very good for testing and
+extending it.
 
 Examples
 --------
@@ -45,27 +38,15 @@ Code
 
 You can also find these code on `GitHub`_
 
-AbstractConfig.php
+DatabaseConfiguration.php
 
-.. literalinclude:: AbstractConfig.php
+.. literalinclude:: DatabaseConfiguration.php
    :language: php
    :linenos:
 
-Parameters.php
+DatabaseConnection.php
 
-.. literalinclude:: Parameters.php
-   :language: php
-   :linenos:
-
-ArrayConfig.php
-
-.. literalinclude:: ArrayConfig.php
-   :language: php
-   :linenos:
-
-Connection.php
-
-.. literalinclude:: Connection.php
+.. literalinclude:: DatabaseConnection.php
    :language: php
    :linenos:
 
@@ -78,11 +59,5 @@ Tests/DependencyInjectionTest.php
    :language: php
    :linenos:
 
-Tests/config.php
-
-.. literalinclude:: Tests/config.php
-   :language: php
-   :linenos:
-
 .. _`GitHub`: https://github.com/domnikl/DesignPatternsPHP/tree/master/Structural/DependencyInjection
 .. __: http://en.wikipedia.org/wiki/Dependency_injection

Structural/DependencyInjection/Tests/DependencyInjectionTest.php

@@ -2,24 +2,16 @@
 
 namespace DesignPatterns\Structural\DependencyInjection\Tests;
 
-use DesignPatterns\Structural\DependencyInjection\ArrayConfig;
-use DesignPatterns\Structural\DependencyInjection\Connection;
+use DesignPatterns\Structural\DependencyInjection\DatabaseConfiguration;
+use DesignPatterns\Structural\DependencyInjection\DatabaseConnection;
 
 class DependencyInjectionTest extends \PHPUnit_Framework_TestCase
 {
-    protected $config;
-    protected $source;
-
-    public function setUp()
-    {
-        $this->source = include 'config.php';
-        $this->config = new ArrayConfig($this->source);
-    }
-
     public function testDependencyInjection()
     {
-        $connection = new Connection($this->config);
-        $connection->connect();
-        $this->assertEquals($this->source['host'], $connection->getHost());
+        $config = new DatabaseConfiguration('localhost', 3306, 'domnikl', '1234');
+        $connection = new DatabaseConnection($config);
+
+        $this->assertEquals('domnikl:1234@localhost:3306', $connection->getDsn());
     }
 }

Structural/DependencyInjection/Tests/config.php

@@ -1,3 +0,0 @@
-<?php
-
-return array('host' => 'github.com');

Structural/DependencyInjection/uml/DependencyInjection.uml

@@ -1,37 +1,19 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Diagram>
   <ID>PHP</ID>
-  <OriginalElement>\DesignPatterns\Structural\DependencyInjection\AbstractConfig</OriginalElement>
+  <OriginalElement>\DesignPatterns\Structural\DependencyInjection\DatabaseConfiguration</OriginalElement>
   <nodes>
-    <node x="0.0" y="230.0">\DesignPatterns\Structural\DependencyInjection\Connection</node>
-    <node x="51.0" y="118.0">\DesignPatterns\Structural\DependencyInjection\ArrayConfig</node>
-    <node x="0.0" y="0.5">\DesignPatterns\Structural\DependencyInjection\Parameters</node>
-    <node x="137.0" y="0.0">\DesignPatterns\Structural\DependencyInjection\AbstractConfig</node>
+    <node x="0.0" y="251.0">\DesignPatterns\Structural\DependencyInjection\DatabaseConnection</node>
+    <node x="0.0" y="0.0">\DesignPatterns\Structural\DependencyInjection\DatabaseConfiguration</node>
   </nodes>
   <notes />
-  <edges>
-    <edge source="\DesignPatterns\Structural\DependencyInjection\ArrayConfig" target="\DesignPatterns\Structural\DependencyInjection\AbstractConfig">
-      <point x="39.5" y="-33.5" />
-      <point x="169.5" y="93.0" />
-      <point x="201.5" y="93.0" />
-      <point x="0.0" y="34.0" />
-    </edge>
-    <edge source="\DesignPatterns\Structural\DependencyInjection\ArrayConfig" target="\DesignPatterns\Structural\DependencyInjection\Parameters">
-      <point x="-39.5" y="-33.5" />
-      <point x="90.5" y="93.0" />
-      <point x="58.5" y="93.0" />
-      <point x="0.0" y="33.5" />
-    </edge>
-  </edges>
-  <settings layout="Hierarchic Group" zoom="1.0" x="133.0" y="179.5" />
-  <SelectedNodes>
-    <node>\DesignPatterns\Structural\DependencyInjection\AbstractConfig</node>
-  </SelectedNodes>
+  <edges />
+  <settings layout="Hierarchic Group" zoom="1.0" x="88.5" y="51.5" />
+  <SelectedNodes />
   <Categories>
-    <Category>Fields</Category>
-    <Category>Constants</Category>
-    <Category>Constructors</Category>
     <Category>Methods</Category>
+    <Category>Constants</Category>
+    <Category>Fields</Category>
   </Categories>
   <VISIBILITY>private</VISIBILITY>
 </Diagram>