pete-otaqui/dependency_injection.php

## dependency_injection.php
<?php


// this is the dependency injetion style stuff ...
class FlickrModel {

  // first off, have some internal store for the object:
  protected $_httpClient = null;

  // have a method to get the object:
  public function getHttpClient() {
    if ( !$this->_httpClient ) {
      $this->_httpClient = new HttpClient();
    }
    return $this->_httpClient;
  }

  // and a method to set it:
  public function setHttpClient($client) {
    $this->_httpClient = $client;
  }

  public function getSomeonesPictures($person) {
    return $this->_httpClient("http://flickr.com/" . $person);
  }
}

// here is the dependency we are setting up for injection
class HttpClient {
  public function request($url) {
    // this is crappy
    return file_get_contents($url);
  }
}


// this is an alternative that we want to inject
class MockHttpClient {
  protected $_fixtures = array();
  public function addFixture($url, $response) {
    $this->_fixtures[$url] = $response;
  }
  public function request($url) {
    if ( isset($this->_fixtures[$url]) ) {
      return $this->_fixtures[$url];
    } else {
      throw new Exception("Called a url without a fixture");
    }
  }
}


// and in a test you could then do this:
class FlickrModelTest {
  public function testFlickr() {
    $fixture = "<html><body><img /></body></html>";
    $fm = new FlickrModel();
    $mockhttp = new MockHttpClient();

    $mockhttp->addFixture("http://flickr.com/foo", $fixture);

    // now let's inject the dependency!
    $fm->setHttpClient($mockhttp);

    $response = $fm->getSomeonesPictures("foo");
    $this->assertEquals($fixture, $response);
  }
}
	<?php


	// this is the dependency injetion style stuff ...
	class FlickrModel {

	// first off, have some internal store for the object:
	protected $_httpClient = null;

	// have a method to get the object:
	public function getHttpClient() {
	if ( !$this->_httpClient ) {
	$this->_httpClient = new HttpClient();
	}
	return $this->_httpClient;
	}

	// and a method to set it:
	public function setHttpClient($client) {
	$this->_httpClient = $client;
	}

	public function getSomeonesPictures($person) {
	return $this->_httpClient("http://flickr.com/" . $person);
	}
	}

	// here is the dependency we are setting up for injection
	class HttpClient {
	public function request($url) {
	// this is crappy
	return file_get_contents($url);
	}
	}



	// this is an alternative that we want to inject
	class MockHttpClient {
	protected $_fixtures = array();
	public function addFixture($url, $response) {
	$this->_fixtures[$url] = $response;
	}
	public function request($url) {
	if ( isset($this->_fixtures[$url]) ) {
	return $this->_fixtures[$url];
	} else {
	throw new Exception("Called a url without a fixture");
	}
	}
	}


	// and in a test you could then do this:
	class FlickrModelTest {
	public function testFlickr() {
	$fixture = "<html><body><img /></body></html>";
	$fm = new FlickrModel();
	$mockhttp = new MockHttpClient();

	$mockhttp->addFixture("http://flickr.com/foo", $fixture);

	// now let's inject the dependency!
	$fm->setHttpClient($mockhttp);

	$response = $fm->getSomeonesPictures("foo");
	$this->assertEquals($fixture, $response);
	}
	}