mj-kiwi / php-coding-task

PHP coding task for web developer candidates

PHP Coding Tasks

PHP coding task for web developer candidates.

Candidates are free to use language features from any stable version of PHP.

Candidates may add code comments or provide any supporting documentation they wish.

Task 1: ActiveRecord-style ORM coding implementation and questions

Introduction

This task involves some questions and coding implementations with a mock ActiveRecord-style database ORM. The files for this task are contained are contained with the orm directory.

Assume that the ActiveRecord base class contains a working implementation of the type of features that you would expect of any database ORM.

The DownloadLog model represents a log entry denoting a user (identified by a user_id) downloading a file (identified by file_id).

Questions:

1. What does the final keyword mean the DownloadLog model? What are the implications in removing the final declaration?

Answer:

1. The DownloadLog class can not be extended.
2. After removing the final keyword, the DownloadLog class can be extended by the sub class

2. The current of implementation of DownloadLog contains a fatal error. What is it, and how would it be resolved?

Answer:

1. The isModified method in the ActiveRecordInterface is not implemented.
2. To fix the issue, just need to implement the isModified method in the ActiveRecord class or in the DownloadLog class.

Coding task 1:

Extend the current implementation so that the following code block provides the output as described:

Code block

$downloadLog = DownloadLog::create();
echo ($downloadLog->isModified() ? 'DownloadLog is modified' : 'DownloadLog is not modified');
$downloadLog->setFileId(1000)->setUserId(2000);
echo ($downloadLog->isModified() ? 'DownloadLog is modified' : 'DownloadLog is not modified');
echo ("UserId is: " . $downloadLog->getUserId());

Output

DownloadLog is not modified
DownloadLog is modified
UserId is: 2000
Destroying DownloadLog

Answer:

• Clone or download the code to your machine
• Make sure you have the latest version of PHP and composer installed on your machine
• Run composer install on the root directory of the project
• Run php test.php to see the output

Coding task 2:

Create a trait which validates that a value is numeric. Add this trait to DownloadLog and use it to validate that user_id and file_id values are numeric. If they are not, throw an exception.

Task 2: Web application controller implementation

Introduction

This task outlines some requirements for a one or more base classes that provide controller functionality as commonly found in MVC-style web application frameworks.

Assumptions:

There is an existing web application framework that:

• Bootstraps an incoming request via a router.
• The router dispatches the request to a controller via a defined entry point method called execute.
• The controller execute method expects request and response objects as parameters.
• The request object implements the Psr\Http\Message\ServerRequestInterface interface.
• The response object implements the Psr\Http\Message\ResponseInterface interface.
• The controller execute method returns a modified response object.

Requirements

The web application framework should provide functionality for handling HTTP requests that output both HTML web pages as well as JSON-encoded data responses (as commonly found in REST APIs, for example).

Coding task

Create one or more base classes that can be integrated into the existing web application framework and provide the following functionality as outlined below.

Functional requirements

• Functionality to return an HTML response body along with any valid HTTP response codes and/or response headers.
• Functionality to return a JSON response body along with any valid HTTP response codes and/or response headers.
• Generic functionality to validate input parameters for a PUT or POST request.

You need not provide a concrete implementation of the base class(es) but can do so if it helps describes the base implementation.

You do not need to create concrete implementations of the request and reponse objects. Assume that these have been created and conform to the relevant interfaces as mentioned above.

• My implement of the code is on Controller
• clone or download the code to your machine
• Make sure you have the latest version of PHP and composer installed on your machine
• Run composer install on the root directory of the project
• Run composer test to do the test
• You should see something similar to the following output

> ./vendor/bin/phpunit
PHPUnit 7.5.7 by Sebastian Bergmann and contributors.


MjLiang\PhpCodingTask\Tests\orm\DownloadLogTest
  ✓Destroying DownloadLog
 cannot assign string to file id [0.006s]
  ✓Destroying DownloadLog
 cannot assign string to user id [0.000s]
  ✓Destroying DownloadLog
 assign int to user id [0.001s]
  ✓Destroying DownloadLog
 assign int to file id [0.000s]
  ✓Destroying DownloadLog
 is not modified [0.000s]
  ✓Destroying DownloadLog
 is modified [0.000s]

MjLiang\PhpCodingTask\Tests\task2\ControllerTest
  ✓ json post [0.013s]
  ✓ form post [0.000s]
  ✓ get method [0.000s]
  ✓ delete method [0.001s]
  ✓ other content type handlers [0.001s]
  ✓ other method request [0.001s]
  ✓ bad request [0.001s]


Time: 65 ms, Memory: 4.00 MB

OK (13 tests, 28 assertions)