Challenge - Mini API

PHP course · Intermediate · Lesson 115/115

Build a simple task tracking API with classes, JSON and DateTime.

Challenge - Mini API

In this last challenge you'll build a simple task tracking API. The Task class stores a title, a done flag and a creation time; its summarize() method turns them into a one-line report.

The creation time uses the DateTime class; format("Y-m-d H:i") produces a custom date string. A task is an object, a collection is an associative array. This combines your class, DateTime and array knowledge.

Task class skeleton

The Task class holds three private properties: private string $title, private bool $done = false, private DateTime $createdAt. The constructor takes the title and DateTime; $done defaults to false.

The markDone() method sets $this->done = true. The summarize(): string method returns the task in the form "[x] Title (2026-01-15 10:00)"; an unfinished task shows a space inside the brackets. The $this->createdAt->format("Y-m-d H:i") call formats the date.

Exercise Write the Task class and summarize method

Define a Task class with private string $title, private bool $done = false, private DateTime $createdAt. The constructor takes string $title and DateTime $createdAt. The markDone(): void method sets $this->done = true. The summarize(): string method starts with "[x] " when $this->done is true and "[ ] " otherwise; it then appends $this->title and " (" . $this->createdAt->format("Y-m-d H:i") . ")". Add the call $t = new Task("Fix login bug", new DateTime("2026-01-15 10:00")); $t->markDone(); echo $t->summarize() . "\n";.

Show example solution

i').
Example solution:
<?php
// Write the Task class and summarize method
class Task {
    private string $title;
    private bool $done = false;
    private DateTime $createdAt;

    public function __construct(string $title, DateTime $createdAt) {
        $this->title = $title;
        $this->createdAt = $createdAt;
    }

    public function markDone(): void {
        $this->done = true;
    }

    public function summarize(): string {
        $mark = $this->done ? "[x]" : "[ ]";
        return $mark . " " . $this->title . " (" . $this->createdAt->format("Y-m-d H:i") . ")";
    }
}

$t = new Task("Fix login bug", new DateTime("2026-01-15 10:00"));
$t->markDone();
echo $t->summarize() . "\n";

Test yourself

What does format('Y-m-d') return for new DateTime('2026-01-15 10:00')?
- 15-01-2026
- 2026-01-15
- 10:00
- 2026-01-15 10:00
Show answer

2026-01-15 — Correct. Y gives the year, m the zero-padded month, d the zero-padded day; the result is '2026-01-15'.

Complete the format call

$date = $this->createdAt->format(____);

Show answer

$date = $this->createdAt->format("Y-m-d H:i");

Match each function to its job

new DateTime

creates date object
format

formats date as string
markDone

marks task done
summarize

produces report

Challenge - Mini API