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The 4-LOC µ (mu) PHP Microframework. Just cuz.
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The µ PHP Microframework

Code Climate

A "real" microframework that fits in just 4 lines of code.

The "microframeworks" out there weren't micro enough for me, so I brushed up on some of my code golfing skills to create µ.

Check out the code!


These 4 LOC come jam-packed with features!

Easy, regex-based routing system

Follows the well-established route-to-callable microframework pattern.

echo (new µ)
    ->get('/hello', function ($app) {
        return "<p>Hello, world!</p>";

Allows you to access parameters from the URL.

echo (new µ)
    ->get('/hello/(?<name>\w+)', function ($app, $params) {
        return "<p>Hello, {$params['name']}!</p>";

Supports all your favorite HTTP verbs.

echo (new µ)
    ->delete('/user/(?<id>\d+)', $fn)
    ->get('/user/(?<id>\d+)', $fn)
    ->head('/user/(?<id>\d+)', $fn)
    ->patch('/user/(?<id>\d+)', $fn)
    ->post('/users', $fn)
    ->put('/user/(?<id>\d+)', $fn)

Supports wildcard verbs too, because sometimes you are just making a web page and you really don't care about esoteric HTTP practices.

echo (new µ)
    ->any('/', $fn)

Simple, but powerful, dependency injection container

use Monolog\Logger;
use Monolog\Handler\StreamHandler;

echo (new µ)
    ->cfg('', 'your-app')
    ->cfg('log.handler', function ($app) {
        return new StreamHandler('path/to/your.log', Logger::WARNING);
    ->cfg('log', function ($app) {
        $log = new Logger($app->cfg(''));
        return $log;
    ->get('/hello/(?<name>\w+)', function ($app, $params) {
        $app->cfg('log')->addDebug("Said hello to {$params['name']}.");
        return "<p>Hello, {$params['name']}!</p>";

A truly elegant and fluent interface

See previous example (I'm lazy).

Built-in templating system, free of {}

Templates are just PHP files—no mustaches and no frills.

<!-- templates/hello.php -->
    <title>World Greeter</title>
    <p><?= ucfirst($greeting) ?>, <?= $name ?>!</p>
// index.php
echo (new µ)
    ->cfg('views', __DIR__ . '/templates')
    ->any('/hello/(?<name>\w+)', function ($app, $params) {
        return $app->view('hello', [
            'greeting' => 'howdy',
            'name'     => $params['name'],

No twigs, plates, or blades to cut you or poke you.

Design constraints

  • Must have at least a Router, Container, and Templating System as features.
  • Must attempt to incorporate usage patterns (e.g., chainable methods, closures as controllers) that resemble other contemporary microframeworks.
  • Must work with error_reporting set to -1 (all errors reported).
  • Must not exceed 4 lines of code (LOC), where each line is <= 120 characters.
  • Must not have dependencies on other packages.
  • May break traditional coding conventions for the sake of brevity.
  • Must be hand-written.

It works, but it's really just a joke.

Don't use this in production, or really anywhere. It's just for fun. 😄

If you want to use a production-quality microframework, try one of these:

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