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PHP7 Chain Of Responsibilities

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This commit is contained in:
Dominik Liebler
2016-09-22 12:17:22 +02:00
parent ea8c91ac68
commit 2b4b3beeff
10 changed files with 178 additions and 226 deletions
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67
Behavioral/ChainOfResponsibilities/Handler.php
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@@ -2,77 +2,42 @@
namespace DesignPatterns\Behavioral\ChainOfResponsibilities;
/**
* Handler is a generic handler in the chain of responsibilities.
*
* Yes you could have a lighter CoR with a simpler handler but if you want your CoR
* to be extendable and decoupled, it's a better idea to do things like that in real
* situations. Usually, a CoR is meant to be changed everytime and evolves, that's
* why we slice the workflow in little bits of code.
*/
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;
abstract class Handler
{
/**
* @var Handler
* @var Handler|null
*/
private $successor = null;
/**
* Append a responsibility to the end of chain.
*
* A prepend method could be done with the same spirit
*
* You could also send the successor in the constructor but in PHP that is a
* bad idea because you have to remove the type-hint of the parameter because
* the last handler has a null successor.
*
* And if you override the constructor, that Handler can no longer have a
* successor. One solution is to provide a NullObject (see pattern).
* It is more preferable to keep the constructor "free" to inject services
* you need with the DiC of symfony2 for example.
*
* @param Handler $handler
*/
final public function append(Handler $handler)
public function __construct(Handler $handler = null)
{
if (is_null($this->successor)) {
$this->successor = $handler;
} else {
$this->successor->append($handler);
}
$this->successor = $handler;
}
/**
* Handle the request.
*
* This approach by using a template method pattern ensures you that
* each subclass will not forget to call the successor. Besides, the returned
* boolean value indicates you if the request have been processed or not.
* each subclass will not forget to call the successor
*
* @param Request $req
* @param RequestInterface $request
*
* @return bool
* @return string|null
*/
final public function handle(Request $req)
final public function handle(RequestInterface $request)
{
$req->forDebugOnly = get_called_class();
$processed = $this->processing($req);
if (!$processed) {
$processed = $this->processing($request);
if ($processed === null) {
// the request has not been processed by this handler => see the next
if (!is_null($this->successor)) {
$processed = $this->successor->handle($req);
if ($this->successor !== null) {
$processed = $this->successor->handle($request);
}
}
return $processed;
}
/**
* Each concrete handler has to implement the processing of the request.
*
* @param Request $req
*
* @return bool true if the request has been processed
*/
abstract protected function processing(Request $req);
abstract protected function processing(RequestInterface $request);
}

6
Behavioral/ChainOfResponsibilities/README.rst
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@@ -33,12 +33,6 @@ Code
You can also find these code on `GitHub`_
Request.php
.. literalinclude:: Request.php
:language: php
:linenos:
Handler.php
.. literalinclude:: Handler.php

19
Behavioral/ChainOfResponsibilities/Request.php
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@@ -1,19 +0,0 @@
<?php
namespace DesignPatterns\Behavioral\ChainOfResponsibilities;
/**
* Request is a request which goes through the chain of responsibilities.
*
* About the request: Sometimes, you don't need an object, just an integer or
* an array. But in this case of a full example, I've made a class to illustrate
* this important idea in the CoR (Chain of Responsibilities). In the real world,
* I recommend to always use a class, even a \stdClass if you want, it proves
* to be more adaptive because a single handler doesn't know much about the
* outside world and it is more difficult if, one day, you want to add some
* criterion in a decision process.
*/
class Request
{
// getter and setter but I don't want to generate too much noise in handlers
}

37
Behavioral/ChainOfResponsibilities/Responsible/FastStorage.php
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@@ -1,37 +0,0 @@
<?php
namespace DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Handler;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Request;
class FastStorage extends Handler
{
/**
* @var array
*/
protected $data = array();
/**
* @param array $data
*/
public function __construct($data = array())
{
$this->data = $data;
}
protected function processing(Request $req)
{
if ('get' === $req->verb) {
if (array_key_exists($req->key, $this->data)) {
// the handler IS responsible and then processes the request
$req->response = $this->data[$req->key];
// instead of returning true, I could return the value but it proves
// to be a bad idea. What if the value IS "false" ?
return true;
}
}
return false;
}
}

45
Behavioral/ChainOfResponsibilities/Responsible/HttpInMemoryCacheHandler.php Normal file
View File

@@ -0,0 +1,45 @@
<?php
namespace DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Handler;
use Psr\Http\Message\RequestInterface;
class HttpInMemoryCacheHandler extends Handler
{
/**
* @var array
*/
private $data;
/**
* @param array $data
* @param Handler|null $successor
*/
public function __construct(array $data, Handler $successor = null)
{
parent::__construct($successor);
$this->data = $data;
}
/**
* @param RequestInterface $request
*
* @return string|null
*/
protected function processing(RequestInterface $request)
{
$key = sprintf(
'%s?%s',
$request->getUri()->getPath(),
$request->getUri()->getQuery()
);
if ($request->getMethod() == 'GET' && isset($this->data[$key])) {
return $this->data[$key];
}
return null;
}
}

21
Behavioral/ChainOfResponsibilities/Responsible/SlowDatabaseHandler.php Normal file
View File

@@ -0,0 +1,21 @@
<?php
namespace DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Handler;
use Psr\Http\Message\RequestInterface;
class SlowDatabaseHandler extends Handler
{
/**
* @param RequestInterface $request
*
* @return string|null
*/
protected function processing(RequestInterface $request)
{
// this is a mockup, in production code you would ask a slow (compared to in-memory) DB for the results
return 'Hello World!';
}
}

44
Behavioral/ChainOfResponsibilities/Responsible/SlowStorage.php
View File

@@ -1,44 +0,0 @@
<?php
namespace DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Handler;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Request;
/**
* This is mostly the same code as FastStorage but in fact, it may greatly differs.
*
* One important fact about CoR: each item in the chain MUST NOT assume its position
* in the chain. A CoR is not responsible if the request is not handled UNLESS
* you make an "ExceptionHandler" which throws exception if the request goes there.
*
* To be really extendable, each handler doesn't know if there is something after it.
*/
class SlowStorage extends Handler
{
/**
* @var array
*/
protected $data = array();
/**
* @param array $data
*/
public function __construct($data = array())
{
$this->data = $data;
}
protected function processing(Request $req)
{
if ('get' === $req->verb) {
if (array_key_exists($req->key, $this->data)) {
$req->response = $this->data[$req->key];
return true;
}
}
return false;
}
}

84
Behavioral/ChainOfResponsibilities/Tests/ChainTest.php
View File

@@ -2,80 +2,50 @@
namespace DesignPatterns\Behavioral\ChainOfResponsibilities\Tests;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Request;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible\FastStorage;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible\SlowStorage;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Handler;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible\HttpInMemoryCacheHandler;
use DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible\SlowDatabaseHandler;
/**
* ChainTest tests the CoR.
*/
class ChainTest extends \PHPUnit_Framework_TestCase
{
/**
* @var FastStorage
* @var Handler
*/
protected $chain;
private $chain;
protected function setUp()
{
$this->chain = new FastStorage(array('bar' => 'baz'));
$this->chain->append(new SlowStorage(array('bar' => 'baz', 'foo' => 'bar')));
}
public function makeRequest()
{
$request = new Request();
$request->verb = 'get';
return array(
array($request),
$this->chain = new HttpInMemoryCacheHandler(
['/foo/bar?index=1' => 'Hello In Memory!'],
new SlowDatabaseHandler()
);
}
/**
* @dataProvider makeRequest
*/
public function testFastStorage($request)
public function testCanRequestKeyInFastStorage()
{
$request->key = 'bar';
$ret = $this->chain->handle($request);
$uri = $this->createMock('Psr\Http\Message\UriInterface');
$uri->method('getPath')->willReturn('/foo/bar');
$uri->method('getQuery')->willReturn('index=1');
$this->assertTrue($ret);
$this->assertObjectHasAttribute('response', $request);
$this->assertEquals('baz', $request->response);
// despite both handle owns the 'bar' key, the FastStorage is responding first
$className = 'DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible\FastStorage';
$this->assertEquals($className, $request->forDebugOnly);
$request = $this->createMock('Psr\Http\Message\RequestInterface');
$request->method('getMethod')
->willReturn('GET');
$request->method('getUri')->willReturn($uri);
$this->assertEquals('Hello In Memory!', $this->chain->handle($request));
}
/**
* @dataProvider makeRequest
*/
public function testSlowStorage($request)
public function testCanRequestKeyInSlowStorage()
{
$request->key = 'foo';
$ret = $this->chain->handle($request);
$uri = $this->createMock('Psr\Http\Message\UriInterface');
$uri->method('getPath')->willReturn('/foo/baz');
$uri->method('getQuery')->willReturn('');
$this->assertTrue($ret);
$this->assertObjectHasAttribute('response', $request);
$this->assertEquals('bar', $request->response);
// FastStorage has no 'foo' key, the SlowStorage is responding
$className = 'DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible\SlowStorage';
$this->assertEquals($className, $request->forDebugOnly);
}
$request = $this->createMock('Psr\Http\Message\RequestInterface');
$request->method('getMethod')
->willReturn('GET');
$request->method('getUri')->willReturn($uri);
/**
* @dataProvider makeRequest
*/
public function testFailure($request)
{
$request->key = 'kurukuku';
$ret = $this->chain->handle($request);
$this->assertFalse($ret);
// the last responsible :
$className = 'DesignPatterns\Behavioral\ChainOfResponsibilities\Responsible\SlowStorage';
$this->assertEquals($className, $request->forDebugOnly);
$this->assertEquals('Hello World!', $this->chain->handle($request));
}
}

3
composer.json
View File

@@ -9,7 +9,8 @@
],
"minimum-stability": "stable",
"require": {
"php": ">=7.0"
"php": ">=7.0",
"psr/http-message": "^1.0"
},
"require-dev": {
"phpunit/phpunit": ">=5.5.4",

78
composer.lock generated
View File

@@ -4,9 +4,60 @@
"Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
"This file is @generated automatically"
],
"hash": "fc06bf31eb6cf4b21a7923e186abfb9d",
"content-hash": "c829a84cbe749d776139a3e9ebdd3094",
"packages": [],
"hash": "61109e150871360cd44739b2a6bea702",
"content-hash": "53848b7fc8e374b8e407799bb47d6917",
"packages": [
{
"name": "psr/http-message",
"version": "1.0.1",
"source": {
"type": "git",
"url": "https://github.com/php-fig/http-message.git",
"reference": "f6561bf28d520154e4b0ec72be95418abe6d9363"
},
"dist": {
"type": "zip",
"url": "https://api.github.com/repos/php-fig/http-message/zipball/f6561bf28d520154e4b0ec72be95418abe6d9363",
"reference": "f6561bf28d520154e4b0ec72be95418abe6d9363",
"shasum": ""
},
"require": {
"php": ">=5.3.0"
},
"type": "library",
"extra": {
"branch-alias": {
"dev-master": "1.0.x-dev"
}
},
"autoload": {
"psr-4": {
"Psr\\Http\\Message\\": "src/"
}
},
"notification-url": "https://packagist.org/downloads/",
"license": [
"MIT"
],
"authors": [
{
"name": "PHP-FIG",
"homepage": "http://www.php-fig.org/"
}
],
"description": "Common interface for HTTP messages",
"homepage": "https://github.com/php-fig/http-message",
"keywords": [
"http",
"http-message",
"psr",
"psr-7",
"request",
"response"
],
"time": "2016-08-06 14:39:51"
}
],
"packages-dev": [
{
"name": "doctrine/instantiator",
@@ -558,24 +609,24 @@
},
{
"name": "phpunit/phpunit",
"version": "5.5.4",
"version": "5.5.5",
"source": {
"type": "git",
"url": "https://github.com/sebastianbergmann/phpunit.git",
"reference": "3e6e88e56c912133de6e99b87728cca7ed70c5f5"
"reference": "a57126dc681b08289fef6ac96a48e30656f84350"
},
"dist": {
"type": "zip",
"url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/3e6e88e56c912133de6e99b87728cca7ed70c5f5",
"reference": "3e6e88e56c912133de6e99b87728cca7ed70c5f5",
"url": "https://api.github.com/repos/sebastianbergmann/phpunit/zipball/a57126dc681b08289fef6ac96a48e30656f84350",
"reference": "a57126dc681b08289fef6ac96a48e30656f84350",
"shasum": ""
},
"require": {
"ext-dom": "*",
"ext-json": "*",
"ext-pcre": "*",
"ext-reflection": "*",
"ext-spl": "*",
"ext-libxml": "*",
"ext-mbstring": "*",
"ext-xml": "*",
"myclabs/deep-copy": "~1.3",
"php": "^5.6 || ^7.0",
"phpspec/prophecy": "^1.3.1",
@@ -597,7 +648,12 @@
"conflict": {
"phpdocumentor/reflection-docblock": "3.0.2"
},
"require-dev": {
"ext-pdo": "*"
},
"suggest": {
"ext-tidy": "*",
"ext-xdebug": "*",
"phpunit/php-invoker": "~1.1"
},
"bin": [
@@ -632,7 +688,7 @@
"testing",
"xunit"
],
"time": "2016-08-26 07:11:44"
"time": "2016-09-21 14:40:13"
},
{
"name": "phpunit/phpunit-mock-objects",