Laravel - Facade explanation and code example - laravel

whenever we call a Facade Method it involves Facade design pattern and it called for some hidden class by using Facade. for instance for File, if we call
File::get(public_path().'test.txt');
this will call the method in class
Illuminate\Filesystem\Filesystem
and in this class we will have get($path) method.
Now my question is how Facade Abstract Class is related to File and Filesystem and where Laravel is telling them to call get in Filesystem. is there some kind of register which i am missing ?? i want to find complete link.

If you go in your config/app.php, you will notice that there's an array called aliases which looks like this
'aliases' => [
//
//
//
//
'File' => Illuminate\Support\Facades\File::class,
];
So, basically whenever you call File, the Service Container will try to resolve an instance of Illuminate\Support\Facades\File::class which is just a Facade.
If you look into Illuminate\Support\Facades\File::class, you will see that it contains only one method:
class File extends Facade
{
/**
* Get the registered name of the component.
*
* #return string
*/
protected static function getFacadeAccessor()
{
return 'files';
}
}
As you can see, it extends the Facade class and whenever a Facade is being resolved, Laravel will try to find a key in the Service Container that is equal to whatever is returned by getFacadeAccessor().
If you check the source of Illuminate\Filesystem\FilesystemServiceProvider, you will see this:
$this->app->singleton('files', function () {
return new Filesystem;
});
As you can see, the key files is being bounded to a FileSystem implementation. So, that's how Laravel knows how to resolve the File facade.

Related

Laravel installation in sub-folder and horizon not working

I have installed the Laravel in sub-folder and is trying to install the horizon. After routing to "test.com/sub-folder/horizon", all the design in broken and also the internal links are pointing to main domain instead of main-domain-without-subfolder.
After the search, it seems to be the known issue which is already reported in github issue
Has there is any work around to make horizon work when Laravel is installed in sub-folder?
I have a solution that only involves PHP.
The issue, as pointed out by #Isaiahiroko, is the basePath defined for Horizon's interface. That code is in Laravel\Horizon\Http\Controllers\HomeController::index(). The idea is this: we are going to pass to Laravel's service container our own implementation of that controller that will override the basePath definition passed to Horizon's interface.
Create a new controller with code like this:
<?php
namespace App\Http\Controllers;
use Illuminate\Contracts\Foundation\Application;
use Illuminate\Contracts\View\Factory;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\App;
use Illuminate\Support\Str;
use Illuminate\View\View;
use Laravel\Horizon\Horizon;
use Laravel\Horizon\Http\Controllers\HomeController;
class HorizonHomeController extends HomeController
{
/**
* Overrides default horizon route to support subdirectory hosting.
*/
public function index ()
{
// We use a plain request to check for the base url.
$request = request();
// Set up our base path.
$base_path = Str::substr($request->getBasePath(), 1);
if (!empty($base_path)) {
$base_path .= '/';
}
// Patch default horizon variables with our own base path.
$variables = Horizon::scriptVariables();
$variables['path'] = $base_path . config('horizon.path');
// Render horizon's home view.
return view('horizon::layout', [
'assetsAreCurrent' => Horizon::assetsAreCurrent(),
'horizonScriptVariables' => $variables,
'cssFile' => Horizon::$useDarkTheme ? 'app-dark.css' : 'app.css',
'isDownForMaintenance' => App::isDownForMaintenance(),
]);
}
}
What's left is telling Laravel's service container that when Horizon's HomeController is requested, it should provide our HorizonHomeController class. In your AppServiceProvider, at the end of the register() method, set this up:
// [...]
class AppServiceProvider extends ServiceProvider
{
// [...]
/**
* Register any application services.
*
* #return void
* #throws InvalidConfiguration
*/
public function register()
{
// [...]
// Horizon's subdirectory hack
$this->app->bind(
Laravel\Horizon\Http\Controllers\HomeController::class,
App\Http\Controllers\HorizonHomeController::class
);
}
// [...]
}
After that, you should be able to browse to http(s)://<your-host>/<your-sub-dir>/horizon normally.
Considerations:
To me this feels cleaner that patching a compiled js, which also has the downside that needs to be re-applied every time Horizon is updated (this can be mitigated with a post-update script in composer, tho). Also, for additional points, this solution is only overriding the method that renders the view, but not the route, which means all of Horizon's authentication mechanisms (middlewares and gates) are working exactly as described in the documentation.
If you desperately need to do this, here is a hack:
In public\vendor\horizon\app.js, search for window.Horizon.basePath
replace window.Horizon.basePath="/"+window.Horizon.path; with window.Horizon.basePath="/[you sub-directoy]/"+window.Horizon.path;
It should work...until you run update one day and it mysteriously stop working.

Saving an object into the session or cookie

I'm using Instagram API library to connect user to Instagram profile and then do smth with it. So, as Instagram API wiki says:
Once you have initialized the InstagramAPI class, you must login to an account.
$ig = new \InstagramAPI\Instagram();
$ig->login($username, $password); // Will resume if a previous session exists.
I have initialized InstagramAPI class and then I called $ig->login('username', 'password');. But I have to call it in every function where I need to work with Instagram.
So how could I save this object $ig for using it in the future in other controllers without calling login() any more? Can I save $ig object into the session or cookie file?
P.S. I think saving into the session is not safe way to solve the issue.
UPD: I was trying to save $ig object into the session, however the size is large and session become stop working as well.
Regarding the register method you asked in the comments section, all you need to create a new service provider class in your app\providers directory and declare the register method in there for example:
namespace App\Providers;
use InstagramAPI\Instagram;
use Illuminate\Support\ServiceProvider;
class InstagramServiceProvider extends ServiceProvider
{
public function register()
{
// Use singleton because, always you need the same instance
$this->app->singleton(Instagram::class, function ($app) {
return new Instagram();
});
}
}
Then, add your newly created InstagramServiceProvider class in providers array inside the config/app.php file for example:
'providers' => [
// Other ...
App\Providers\InstagramServiceProvider::class,
]
Now on, in any controller class, whenever you need the Instagram instance, all you need to call the App::make('InstagramAPI\Instagram') or simply call the global function app('InstagramAPI\Instagram') or even you can typehint the class in any method/constructor etc. Some examples:
$ig = App::make('InstagramAPI\Instagram');
$ig = App::make(Instagram::class); // if has use statement at the top fo the class
$ig = app('...');
In a class method as a dependency:
public function someMethod(Instagram $ig)
{
// You can use $ig here
}
Hope this helps but read the documentation properly, there will get everything documented.

Laravel - How do I inject automatically in Validation Rule Construct?

I'm not able to inject these variables through Laravel:
//...class AllowedUsername implements Rule...
public function __construct(Router $router, Filesystem $files, Repository $config)
{
$this->router = $router;
$this->files = $files;
$this->config = $config;
}
I get the error:
Type error: Too few arguments to function ... 0 passed in.
Why is Laravel not doing it automatically?
$request->validate([
'username' => ['required', new AllowedUsername],
]);
In order to leverage Laravel's injection magic you need to use Laravel's API which essentially is:
resolve($class) which is wrapper around app($class)
app($class, $params = []) which is wrapper around:
Note: I've changed $abstract for $class
if (is_null($class)) {
return Container::getInstance();
}
return Container::getInstance()->make($class, $parameters);
Classes that you want to resolve out of container (as seen in your code sample):
public function __construct(Router $router, Filesystem $files, Repository $config)
can be resolved only because Laravel maintainers already defined binding for Router::class, Filesystem:class (example: FilesystemServiceProvider).
Repository::class seems to be simple class that does not require parameters (or require parameters that container already knows how to resolve) while "newing up" - thus Laravel can resolve it without problem.
There is no need to bind classes into the container if they do not depend on any interfaces. The container does not need to be instructed on how to build these objects, since it can automatically resolve these objects using reflection.
Thats why resolve(AllowedUser::class) or resolve(Router::class)... work.
In order to let Laravel know what constructor's parameters should be sent during "newing up" you use bindings mentioned in documentation.

Why won't this Laravel 5.4 service provider register?

I am trying to do a hello world service provider with the new Laravel 5.4.
I have created the following service provider file:
//File: app/TestProvider/TestServiceProvider.php
namespace App\TestProvider;
use Illuminate\Support\ServiceProvider;
class TestServiceProvider extends ServiceProvider
{
/**
* Register bindings in the container.
*
* #return void
*/
public function register()
{
$this->app->bind('Test', function ($app) {
return new Test();
});
}
}
I have created a simple class under the same namespace:
//File: app/TestProvider/Test.php
namespace App\TestProvider;
class Test
{
/**
* Register bindings in the container.
*
* #return void
*/
public function helloWorld()
{
echo "hello world";
}
}
The problem is, this is not registering. The register method is executing as when I put a breaker before the 'bind' method, it executes:
public function register()
{
dd("BREAKER");
$this->app->bind('Test', function ($app) {
return new Test();
});
}
So this outputs "BREAKER" as expected. However if I put the breaker in the closure, nothing happens which suggests for some reason, that 'bind' method isn't being executed??
Any ideas?
EDIT:
Just some further info: I know that the Test class is registered and in the correct namespace as I can do:
dd(new Test());
in the registration method, and it outputs the resource id as expected.
Explanation
The closure provided only runs when the binding is being resolved. That's why it's a closure, it can be saved in the service container and resolved at any time while the program runs.
Solution
To see the resolved binding, create a controller and resolve the class in that controller:
// File: app/Http/Controllers/TestController.php
namespace App\Http\Controllers;
// This isn't the best way, but it works. See the best way below
class TestController extends Controller {
public function index()
{
return \App::make('Test')->helloWorld();
}
}
Of course, don't forget to register the route:
// File: routes/web.php
Route::get('/', 'TestController#index');
The binding will resolve when you hit the homepage.
However, as I said, it's not the best way, so here I prepared a better way. Change the way you register the binding:
// File: app/Providers/TestProvider.php
namespace App\TestProvider;
use Illuminate\Support\ServiceProvider;
use App\TestProvider\Test;
// Better way
class TestServiceProvider extends ServiceProvider
{
/**
* Register bindings in the container.
*
* #return void
*/
public function register()
{
// Note: we bind the exact complete class name!
$this->app->bind(Test::class, function ($app) {
return new Test();
});
}
}
After this change the controller so that it looks like this:
namespace App\Http\Controllers;
use App\TestProvider\Test;
class TestController extends Controller {
/**
* #var Test $test
*/
private $test;
// Let Laravel resolve the dependency on constructing the class
public function __construct(Test $test)
{
$this->test = $test;
}
public function index()
{
return $this->test->helloWorld();
}
}
You will see that the exact same thing happens, but it looks more elegant and avoids conflicts.
Details
Laravel gives only a high level overview of the service container, which doesn't help to learn how it works on the inside. The best way to see that is to go down the call stack.
When you do that, you find that Laravel registers every class in the project in the service container. That means that whether you create a service provider or not, the class will be in the container. How exactly?
When you run php artisan optimize, Laravel creates files that have array with all the classes of the project. When you run the app, after registering everything from the service providers, Laravel registers the rest of the classes from that file.
That means that in your case, if you don't specifically register the Test class, it will still be resolvable. Basically, you only need to register classes that need some specific instructions to be resolved.
So how does Laravel resolve the dependencies?
When you run \App::make(Test::class) or inject dependency via type hinting in the constructor (the "better way" from my solution), Laravel looks for that dependency among the bindings.
When it finds the dependency, it resolves either the closure associated to it or the constructor of the class directly.
When it resolves the constructor directly, it looks for type hints among the constructor parameters and recursively resolves all of them until there's nothing else to resolve.
After that it returns the resolved class.
Of course, bear in mind that for Laravel to analyze the contructor of a class, it needs to be resolved via the service container in the first place. You can't just call $test = new Test(); and expect Laravel to do all the magic :)
Conclusion
This is a rather quick overview of Laravel's service container. The best way for you to learn it is, of course, studying the sources for yourself. It's truly elegant and it uses PHP's functionality to the fullest.
I really hope this shed some light on the service container for you and can help you in the future :)
The closure passed to the bind() method is not executed until you actually attempt to resolve the alias you are binding.
So, if you dd('breaker') inside the closure, this won't actually get executed until Test is resolved (whatever your preferred resolution method is):
Service provider:
// bind the closure to the 'Test' alias
public function register()
{
$this->app->bind('Test', function ($app) {
dd("BREAKER");
return new Test();
});
}
Code that resolve Test alias:
// different ways of resolving the alias out of the container.
// any of these will execute the bound closure.
$test = resolve('Test');
$test = app('Test');
$test = app()->make('Test');
$test = \App::make('Test');
try:
$this->app->bind(Test::class, function ($app) {
return new Test();
});

Trying to create my first package, but getting undefined method callAction() exception

I'm trying to develop a package, so I've followed this tutorial until Creating a Facade section because I don't need a facade.
The problem is:
/app/routes.php
Route::get('test', 'Aristona\Installer\Installer#install');
throws an exception: Call to undefined method Aristona\Installer\Installer::callAction()
My Installer.php is like this:
workbench/aristona/installer/src/Aristona/Installer/Installer.php
<?php namespace Aristona\Installer;
class Installer
{
public static function install()
{
return "Hello";
}
}
The class is loading. I've added it to my service providers list. Also I can confirm it is loading by adding one more install method, because PHP throws a fatal error about redeclaring same method twice.
I've tried different combinations on my method prefixes (e.g without static) Doesn't solve.
Anyone know what am I doing wrong?
Your getting an error because you're trying to use routing to controller where none exists. To be more specific, Laravel is trying to perform this method from it's core Controller class:
/**
* Execute an action on the controller.
*
* #param string $method
* #param array $parameters
* #return \Symfony\Component\HttpFoundation\Response
*/
public function callAction($method, $parameters)
{
$this->setupLayout();
$response = call_user_func_array(array($this, $method), $parameters);
// If no response is returned from the controller action and a layout is being
// used we will assume we want to just return the layout view as any nested
// views were probably bound on this view during this controller actions.
if (is_null($response) && ! is_null($this->layout))
{
$response = $this->layout;
}
return $response;
}
So unless the class you're specifying in Route::get() is extending either BaseController or Controller, this exception will be thrown. If you tested the same method inside a closure, it would work.
More about Laravel controller routing can be found here.
To fix this, you should either add a controller to your package or use the Installer class inside another controller.

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