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Yii3 - How to start

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Yii3 - How to start

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Tutorials

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3.0

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[...]
First of all, learn what [PHP Standards Recommendations](https://en.wikipedia.org/wiki/PHP_Standard_Recommendation) by [Framework Interoperability Group (FIG)](https://www.php-fig.org/psr) are. It will help you understand why so many "weird" PSR imports are in the Yii3 code. In short: These interfaces help authors of different frameworks to write compatible classes so they can be reused in any other framework following these principles.

## Dependency injection + container
Check [this YouTube video](https://www.youtube.com/watch?v=TqMXzEK0nsA) for explanation

## Construct vs Invoke
 
It may be confusing that some classes contain both methods. Note that "property promotion" should be only used in `__construct()`.
 
Magic method `__invoke()` is only used if you create an instance and then use it as a function. Example:invoke()
 
The `__invoke()` public method is called when you call the **instance** as a method. (Therefore the constructor was already executed) ```php $obj = new MyObj(); // Now the __construct() is executed. $obj(); // Now the __invoke() is executed
 
```
 
 
To be honest, I still do not fully understand the real purpose of this situation. (The instance is needed!)
 
```
 
 
I never used it, but prepared a following example that shows when invoking can be applied:
 
 
```php
 
class MyUpper
 
{
 
    public function __invoke($a) { return $this->go($a); }
 
    public function go($a) { return strtoupper($a); }
 
}
 
$instance = new MyUpper();
 
$array = ['a', 'B', 1, '1'];
 
 
// __invoke is used:
 
var_dump($instance($array[0])); 
 
var_dump(array_map($instance, $array));
 
 
// These do the same without invoking:
 
var_dump(array_map('strtoupper', $array));
 
var_dump(array_map([$instance, 'go'], $array));
 
var_dump(array_map(function($a) use ($instance) { return $instance->go($a); }, ['a','B',1,'1']));
 
```

## Hash annotations for class attributes
[...]
## Running the demo application

You may be surprised that docker-compose.yml is missing in the root. Instead the "make up" and "make down" commands are prepared.
If you run both basic commands as mentioned in the documentation:
[...]
If you want to modify the data that was returned by the endpoint, just open the action-class `src/Api/IndexAction.php` and add one more element to the returned array.

> You may be missing 'docker compose stop' or 'make stop', because 'make down' removes your containers and drops your DB. In that case you can add it to the Makefile in the root (see below). If you then type 'make help' you will see the new command. 
 
 
```sh
 
ifeq ($(PRIMARY_GOAL),stop)
 
stop: ## Stop the dev environment
 
$(DOCKER_COMPOSE_DEV) stop
 
endif
 
```
 
 
## Adding DB into your project

Your project now does not contain any DB. Let's add MariaDB and Adminer (DB browser) into file docker/dev/compose.yml:

In my case the resulting file looks like this:
[...]
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Version: 3.0
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Written by: rackycz rackycz
Last updated by: rackycz rackycz
Created on: Oct 8, 2025
Last updated: 2 months ago
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