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2018년 2월 13일 화요일

CHAPTER 3 Routing and Controllers

The essential function of any web application framework is to take requests from a user and deliver responses, usually via HTTP(s). This means defining an application's routes is the first and most important project to tackle when learning a web framework; without routes, you have no ability to interact with the end user.

In this chapter we will examine routes in Laravel and show how to define them, how to point them to the code they should execute, and how to use Laravel's routing tools to handle a diverse array of routing needs.

Route Definitions
In a Laravel application, yhou will define your "web" routes in routes/web.php and your "API" routes in routes/api.php. Web routes are those hat will be visited by your end users; API routes are those for your API, if you have one, For now, we'll primaryly focus on the routes in routes/web.php.

In projects running versions of Laravel prior to 5.3, theere will be only one routes file, located at app/Http/routes.php

The simplest way to define a route is to match a path (e.g.,/)with a closure, as seen in Example 3-1.

Example 3-1. Basic route definition

//routes/web.php
Route::get('/', function(){
       return 'Hello, World!';
});


What's a Closuer?
Closures are PHP's version of anonymous functions. A closure is a function that you can pass around as an object, assign to a variable, pass as a parameter to other functions and methods, or even serialize.

You've now defined that, if anyone visits / (the root of your domain), Laravel's router should run the closure defined there and return the result. Not tat we return our content and don't echo or print it.

A quick introduction to middleware
You might be wondoering, "Why an I returning 'Hello, World!' instead of echoing it?"
There are quite a few answers, but the simplest is that there are a lot of wrappers around Laravel's request and response cycle, including something called middleware. When your route closure or controller method is done, it's not time to send the output to the browser yet; returning the content allows it to contnue flowing though the response stack and the middleware before it is returned back to the user.

Many simple websites could be defined entirely within the web routes file.With a few simple GET routes combined with some templates as illustrated in Example 3-2, you can serve a classic website easily.

Example 3-2. Sample website

Route::get('/', function(){
       return view('welcome');
});

Route::get('about', funciton(){
        return view('about');
});

Route::get('products', function(){
         return view('products');
});

Route::get('services', function (){
         return view('service');
});

Static calls
If you have much experience developing PHP, you might be surprised to see static calls on the Route class. This is not actually a static method per se, but rather service location using Laravel's facades, which we'll cover in Chapter 11.

If you perfer to avoid facades, you can accomplish thes same definitions like this:
$router->get('/', function (){
     return 'Hello, World!';
});

HTTP Methods
If you're not familiar with the idea of HTTP methods, read on in this chapter for more information, but for now, just know that every HTTP request has a "verb", or action, along with it. Laravel allows you to define your routes based on which verb was used; the most common are GET and POST, followed by PUT, DELETE, and PATCH.
Each mothod communicates a different thing to the server, and to yhour code, about the intentions of the caller.

 Route Verbs
You might've noticed that we've been using Route::get in our route definitions. This means we're telling Laravel to only match for these routes when the HTTP request use the GET action. But what if it's a form POST, or maybe some JavaScript sending PUT or DELETE requests? There are a few other options for methods to call on a route definition, as illustrated in Example 3-3.

Example 3-3. Route verbs

Route::get('/', function(){
      return 'Hello, World!';
});

Route::post('/', function () {});

Route::put('/', function (){});

Route::delete('/', function(){});

Route::any('/', function(){});

Route::match(['get','post'], '/', function(){});

Route Handling
As you've probably guessed, passing a closuer to the route definitiion is not the only way to teach it how to resolve a route. Closures are quick and simple, but the larger your application gets, the clumsier it becomes to put all of your routing logic in one file. Additionally, applications using route closures can't tacke advantage of Laravel's route caching (more on that later), which can shave up to hundreds of milliseconds off each request.

The other common option is to pass a controller name and method as a string in place of the closure, as in Example 3-4.

Example 3-4, Routes calling controller methods

Route:: get('/'. 'WelcomeController@index');

This is telling Laravel to pass requests to that path to the index() method of the App \Http\Controllers\WelcomeController controller. This metohd will be passed the same parameters and treated the same way as a closure you might've alternatively put in its place.

Route Parameters
If the route you're defining has parameters-segments in the URL structure that are variable-it's simple to define them in your route and pass them to your closure(see Example 3-5).

Example 3-5. Route parameters

Route::get('users/{id}/friends', function ($id){
//
});

The Naming Relationship Between Route  parameters and Closuer/Controller Method Prarameters

As you can see in Example 3-5, it's most common to use the same names for your route parameters ({id}) and the method parameters they inject into your route definition (function ($id)). But is this necessary?

Unless you're using route/model binding, no. The only thing that defines which route parameter matches with which method parameter is their order (left to right), as you can see here:

Route::get('users'/{userId}/comments/{commentId}', function (
              $thisIsActuallyTheUserId,
              $thisisReallyTheCommentId
             ){
          //
   });

That having been said, just because you can make them differnet doesn;t mean you should. I recommend keeping them the same for the sake of future developers, who could get tripperd up by inconsistent naming.

You can also make your route parameters optional by including a question mark(?) after the parameter name, as illustrated in Example 3-6. In this case, you should also provide a default value for the route's corresponding variable.

Example 3-6. Opptional route parameters

Route::get('users/{id?}, function ($id = 'fallbackId'){
//
});
And you can use regular expressions (regexes) to define that a route should only match if a parameter meets particular requirements, as in Example 3-7.

Example 3-7. Regular expression route constraints

Route::get('users/{id}', function($id){
 //
})-> where('id', '[0-9]+');

Route::get('users/{username}', function ($username){
  //
}) -> where('username', '[A=Za-z]+');

Route::get('posts/{id}/{slug}', function ($id, $slug){
//
})-> where(['id'=> '[0-9]+', 'slug'=>'[A-Za-z]+'])';

As you've probably guessed, if you visit a path that matches a route string, but the regex doesn't match the parameter, it woun't be matched.since routes are matched top to bottom, users/abc would skip the first closure in Example 3-7, but it would be matched by the secound closure, so it would get routed there. On the other hand, posts/abc/123 wouldn't match nay of the closures, so it would returna 404 Not Found error.

Route Names
The simplest way to refer to these routes elsewhere in your application is just by their path. There's a url() helper to simplify that linking in your views, if you need it; see Example 3-8 for an example. The helper will prefix your route with the full donain of your site.

Exmaple 3-8. URL helper
< a href = "">
//outputs

However, Laravel also allows you to name each route, which enables you to refer to it without explicityl referencing the URL. This is helpful because it means you can give simple nkcknames to complex routes, and also becuase linking them by name means you don't have to rewrite your frontend links if the paths change(see Example 3-9)

Example 3-9. Defining route names

//Defining a route with anme in routes/web.php
Route::get('members/{id}', 'MembersController@show')->name('members.show');

//Link the route in a view using the route() helper


This example illustrates a few new concepts. First, we're using fluent route definition to add the name, by chaining the name() method after the get() method. This method allows us to name the route, giving it a short alias to make it easier to reference elsewhere.

Defining custom roeutes in Laravel 5.1
Fluent route definitions don't exist in Laravel 5.1. You'll need to instead pass an array to the second parameter of your route definition; check the Laravel docs to see more about how this works.
Here's Example 3-9 in Laravel 5.1:

Route::get('members/{id}', [
       'as' => 'members.show',
       'user' => 'Memberscontroller@show'
  ]);

In our example, we've named this route members.show; resourcePlural.action is a common convention within Laravel for route and view names.

Route Naming Conventions
You can anme your route anything you'd like, but the common conventiion is to use the plural of the resource name, then a period, then the action. So, here are the routes most common for a resource named photo:

photos.index
photos.create
photos.store
photos.edit
photos.update
photos.destroy
To learn more about these conventions, see "Resource Controllers" on page 41.

We also introduced the route() helper. Just like url(), it's intended to be used in views to simplify linking to a named route. If the route has no parameters. You can simply pass the route name: (route('members.index')) and receive a route string http://myapp.com/members/index). If it has parameters, pass them in as an array as teh second parameter like we did in this example.

In general, I recommend using route names instead of paths to refer to your routes, and therefore using the route() helper instread of the url() helper. Somethimes it can get a bit clumsy-for exmapel, if your're working with multiple subdomanins- but it provides an incredible level of flexiblity to later change the application's routing structure without major penality.

Passing Route Parameters to the route() Helper
When your route has parameters(e.g., users/{id}), you need to define thosse parameters when you're using the route() helper to generate a link to the route.

There are a few different way to pass thers parameters. Let's imagine a route defined as users/{userId}/comments/{commentId}. If the user ID is 1 and the comment ID is 2, let's look at a few options we have available to us:

Option 1:
      route('users.comments.show', [1,2])
//http://mysqpp.com/users/1/comments/2

Option 2:
       route('users.comments.show', ['userId' => 1, 'commentId' =>2]
  //http://myapp.com/users/1/comments/2


Option 3:
       route('users.comments.show', ['commentId' => 2, 'userId' => 1]
 // http://myapp.com/users/1/comments/2

Option 4:
         route('users.comments.show', ['userId' => 1, 'commentsId' =>2, 'opt'=>'a'])
  //http://myapp.com/users/1/comments/2?opt=a

As you can see, nonkeyed array values are assigned in order; keyed array values are matched with the route parameters matching their keys, and anything left over is added as a query parameter.


Route Groups
Often a group of routes share a particular characteristic - a certain authentication requirement, a path prefix, or perhaps a controller namespace. Defining these shared characteristics again and again on each route not only seems tedious but also can muddy up the shape of your routes file and obscure some of the structures of your application

Route groups allow you to group serveral routes together, and apply any shared configuration settings once to the entire group, to reduce this duplication. Additionally, route groups are visual cues to future develpers ( and to your own brain) that these routes are grouped together.

To group two or more routes together, yo u"surround" the route definitions with a route group, as shwn in Example 3-10. Un reality, you're actually passing a closure to the group definition, and the grouped routes within that closure.

Example 3-10. Defining a route group

By default, a route group doesn't actually do anything. There's no difference between the group in Example 3-10 and separating a segment of your routes with code comments. The empty array that's the first parameter, however, allows you to pass a varierty of configuration settings that will apply to the entire route group.

Middleware
Probably the most common use for route groups is to apply middleware to a group of reoutes. We'll learn more about middleware in Chapter 10, but, among other things, they're what Laravel uses for authenticating users and restricting guest users from using certain parts of a site.

In Exmaple 3-11, we're createing a route group around the dashboard and account view and applying the auth middleware to both. In this example, it means users have to be logged in to the application to view the dashboard or the account page.

Example 3-11. Restricting a group of routes to logged-in users only

Route::group(['middleware' => 'auth'], function (){
    Route::get('dashboard', function () }
       return view('dashboard');
    });
    Route::get('account', function(){
       return view('account');
    });
 });

Applying middleware in controllers
Ofter it's clearer and more direct to attach middleware to your reoutes in the controller instead of at the route definition. You can do this by calling the middleware() method in the constructor of your controller. The string your pass to the middleware() method is the name of the middleware, and you can optionally chain modifier methods (only() and except()) to define which methods will receive that middleware:

class DashbardController extends Controller
{
        public function  __construct()
       {
            $this- > middleware('auth');
            $this -> middleware('admin-auth')
                   -> only('admin');
            $this -> middleware('team-member')
                   -> except('admin');
       }
  }
Note that, if you're doing a lot of "only" and "except" customizations, that's ofter a sign that you should break out a new controller for the exceptional routes.

Path Prefixes
If you have a group of routes ghat share a segment of their path-For example, if your site's API is prefixed with /api - you can use route groups to simplify this structure(see Example 3-13).

Example 3-12. Prefixing a group of routes

Route::group(['prefix' => 'api'], function (){
       Route::get('/', function(){
           //Handles the path / api
       });
       Route::get('users', function() {
         //Handles the path /api/users
      });
 });

Note that each prefixed group also has a /route that represents the root of the prefix - in Example 3-12 that's /api.

Subdomain Routing
Subdomain routing is the same as route prefixing, but it's scoped by subdomain instead of route prefix. There are two primary uses for this. First, you may want to present different sections of the application (or entirely different applications) to different subdomains. Example 3-13 show how you can achieve this.

Exampel 3-13. Subdomin routing

Route::group(['domain' => 'api.myapp.com'], function(){
        Route::get('/', function(){
           //
         });
 });

Second, you might want to set part of the subdomain as a parameter, as illustrated in Example 3-14. This is most often done in cases of multienancy (think Slack or Harverst, where each company gets its own subdomain, like tighten.slack.co).

Example 3-14. Parameterized subdomain routing

Route::grouop(['domain' => '{account}.myapp.com'], function (){
    Route::get('/', function($account) {
     //
    });
     Route::get('users/{id}', function ($account, $id){
       //
     });
  });

Note that any parameters for the group get passed into the grouped routes' methods as the first parameter(s).

Namespace Prefixed
When you're grouping routes by subdomain or route prefix, it's likely their controllers have a similar PHP namespace. In the API example, all of the API routes' controllers might be under an API  anmespace. By using the route group namespace prefix, as shown in Example 3-15, you can avoid long controller refeerences in groups like "API/ControllerA@index" and "API/ControllerB@index".

Example 3-15. Route group namespace prefixes

//App\Http\Controllers\ControllerA
Route::get('/', 'ControllerA@index');

Route::group(['namespace' => 'API']. function() {
     // App\Http\Controllers\API\ControllerB
     Route::get('api/', 'ControllerB@index');
 });

Name Prefixes
The prefixes don't stop ther. It's common that route names will reflect the inheritance chain of path elements, so users/commments/5 will be served by a route named user.comments.show. In this case, it's common to user a route group around all of the routes that are beneath the users.comments resource.

Just like we can prefix URL segments and controller namespaces, we can aslo prefix strings to the route name. With route group name prefixes, we can define that every route within this group should have a given string prefixed to its name. In this context, we're prefixing "users." to each route name, then "comments." (see Example 3-16).

Example 3-16. Route group name prefixes

Route::group(['as' => 'users.', 'prefix' => 'users'], function(){
    Route::group(['as' => 'comments.', 'prefix'=>comments'], function (){
      //Route name will be users.comments.show
      Route::get('{id};, fuinction (){
          //
       }) -> name('show');
    });
  });

Views
In a few of the route closures we've looked at so far, we've seen something along the lines of return view('account'). What's going on here?

If you're not familiar with the Model-View-Controller (MVC) pattern, views(or templates) are files that describe what some particular output should look like. You might have views for JSON or XML or emails, but the most common views in a web framework output HTML.

In Laravel, there are two formats of view you can use out of the box: plain PHP, or Blad templates (see Chapter 4). The difference is in the filename: about.php will be rendered with the PHP engine, and about.blade.php whill be rendered with the Blade engine.

Three ways to load a view()
There are three different ways to return a view. For now, just concern yourself with view(), but if you ever see View::make(), it's the same thisng, and you could also inject the Illuminate\View\ViewFactory if you prefer.

Once you've loaded a view, you have the option to simply return it (As in Example 3-17), which will work fine if the view doesn't rely on any variables from the controller.


Example 3-17. Simple view() usage

Route::get('/', function (){
       return view('home');
 });

This code looks for a view in resources/views/home/blade.php or resource/views/home/php, and loads its contents and parses any inline PHP or control structures until you have just the view's output. Once you return it, it's passed on to the rest of the response stack and eventualluy returned to the user.

But what if you need to pass in variables? Take a look at Example 3-18.

Example 3-18. Passing variables to views

Route::get('task', function (){
    return view('tasks.index')
            ->with('task', Task::all());
  });
This closure laods the resources/views/tasks/index.blade.php or resources/views/tasks/index.php view and passes it a single variable named tasks, which contains the reuslt of the Task::all() method. Task::All() is an Eloquent database query we'll learn about in Chapter 8.

Using View Composers to Share Variables with Every View
Sometimes it can become a hassle to pass the same variables over and voer. There may be a variable that you want accessible to every view in the site, or to a certain class of views or a certain included subview - for example, allviews related to tasks, or the header partial.

It's possible to share certain variables with every template or jeust certain templates, like in the following code:
view() -> share('variableName", 'variableValue');

To learn more, check out "View composers and Service Injectio" on Page64.

Controllers
I've mentioned controllers a few times, but until now most of the exmaples have shown reute closures. If you're not familiar with the MVC pattern(Figure 3-1), controlelrs are essentially clases that organize the logic of one or more routes together in on place. Controllers tend to group similar routes together, especically if your application is structured along a traditionally CRUD-like foramt: in this case, a controller might handle all the actions that can be performed on a particular resource.

What is CRUD?
CRUD stands for create, read, update, delete, which are the four primary operations that web applications most commonly provide on a resource. For example, you can create a new blog post, you can read that post, you can update it, or you can delete it.

It may be tempting to cram all of the applicationn's logic into the controllers, but it's better to think of controllers as the traffic cops that route HTTP requests around your applications. Since there are other ways requests can come into your application - cron jobs, Artisan command-line calls, queue jobs, etc. - it's wise to not rely on controllers for much behavior. This means a controller's primary job is to capture the intent of an HTTP request and pass it on to the rest of the application.

So, let's create a controller. One easy way to do this is with an Artisan command, so from the command line run the following:

php artisan make:controller TasksController

Artisan adn Artisan generators
Laravel comes bundled with a command-line tool called Artisan.
Artisan can be used to run migrations, create users and other database records manual, onetime tasks.
Under the make namespace, Artisan provides tools for generating skeleton files for a variery of system files. That's what allows us to
run php artisan make:controller.
To learn more about theis and toehr Artisan features, see Chapter 7.

This will create a new file named TasksController.php in app/Http/Controllers, with the contents shown in Example 3-19.

Example 3-19. Default generated controller
namespace App\Http\Controllers;
use Illuminate\Http\Reqeust;
use App\Http\Requests;

class TasksController extends Controller
{

}

Modify this file as shown in Example 3-20, creating a new public method called home(). We'll just return some text there.

Example 3-20. Simple controller example
use App\Http\Controllers\Controller;
class TasksController extends Controller
{
       public function home()
       {
                 return 'Hello, World!';
     }
}

Then like we learned before, we'll hook up a route to it, as shown in Example 3-21.

Example 3-21. Route for the simple controller

// reoutes/web.php
Route::get('/', 'TasksController@home');

That's it. Visit the / route and you'll see the words "Hello, World!"

Controller Namespacing
In Example 3-21 we referenced a controller with the fully qualified class name of App \Http\Controllers\TasksController, but we only used the class name. This isn't because we can simply reference controllers by their class names. Rather, we can ignore the App\Http\Controllers\ when we refuerence controllers; by default, Laravel is configured to look for controllers within that namespace.

This means that if you have a controller with the fully qualified class name of App \Http\Controllers\API\ExercisesController, you'd reference it in a route definition as API\ExercisesController.

The most common use of a controller method, then, will be something like Example 3-22.

Example 3-22. Common controller method example.

//TasksController.php
....
public function index()
{
       return view('tasks.index')
             ->with('tasks', Task::all());
}

This controller method loads the resourcs/views/tasks/index.blade.php or resources/views/tasks/index.php view and passe it  a single variable named tasks, which contains the result of the Task::all() Eloquent method.


Generating resource controllers
If you ever use php artisan make:controller in Laravel prior to 5.3, you might be expecting it to autogenerate methods for all of the basic resource routes like create() and update(). You can bring this behavior back in Laravel 5.3 by passing the -- resource flag when you create the controller:
php artisan make:controller TasksController --resource

Getting User Input
The second most common action to perform in a controller method is to take input from the user and act on it. That introduces a few new concepts, so let's take a look at a bit of sample code and walk through the new pieces.

First. let's bind it quickly; see Example 3-23.

Example 3-23. Binding basic form actions

//routes/web.php
Route::get('tasks/create', 'TasksController@create');
Route::post('tasks', 'TasksController@store');

Notice that we're binding the GET action of tasks/create (which shows the form) and the POST action of tasks/ (which is where we POST when we're createing a new task). We can assume the create() method in our controller just shows a form, so let's look at the store() mtthod in Example 3-24.

Example 3.24. Common from input contrller method

// TaskController.php
....
public function store()
{
        $task = new   Task();
        $task -> title = Input::get('title');
        $task -> description = Input::get('description');
        $task -> save();
   
        return redirect('tasks');
}
This example makes use of Eloquent models and the redirect() functionality, and we'll talk agbout them more later, but you can see what we're doing here: we create a new Task, pull data out of the user input and set it on the task, save it, and then redirect back to the page that shows all task.

There are two main ways to get user input from  a POST: the Input facade, which we used here, and the Request object, which we'll talk about next.

Importing facades
If you follow any of these examples, whether in controllers or any other PHP class that is namespaced, you might find errors showing that the facade cannot be found. This is because they're not present in every namespace, but rather they're made available the root namespace.

So, in Example 3-24, we'd need to import the Input facade at the top of the file, There are two ways to do that: either we can import \Input, or we can import Illuminate\Suppert\Facades\Input.
For example:
namespace App\Http\Controllers;
use Illuminate\Support\facades\Input;

class TaskController
{
     public function store()
     {
        $task = new   Task();
        $task -> title = Input::get('title');
        $task -> description = Input::get('description');
        $task -> save();
   
        return redirect('tasks');
      }
As you can see, we can get the value of any user-provided information, whether from a query parameter or a POST value, using input::get('filedName'). So our user filled out two fields on the "add task" page:"title" and "description." We retrieve both using the Input facade, save them to the database, and then return.

Injecting Dependencies into Controllers
Laravel's facades paresent a simple interface to the most useful classes in Laravel's codebase. You can get information about the current request and user input, the session, caches, and much more.

But if you prefer to inject your dependencies, or if you want to use a service that doesn't have a facade, you'll need to find some way to bring instances of these classes into your controller.

This is our first exposure to Laravel's service container. For now, if this is unfamiliar you can think about it as a little bit of Laravel magic; or, if you want to know more about how it's actually functioning, you can skip ahead to Chapter 11.

All controller methods (including the constructors) are resolved out of Laravel's container, which means anything you typehint that the container knows how to resolve will be automatically injected.

As a nice example, what if you'd refer having an instance of the Request object instead of using the facade? Jest typehint Illuminate\Http\Request in your method parameters, like in Example 3-25.

Example 3-25. Controller method injecting via typehinting
//TasksController.php
.....
public function store(\Illuminate\Http\Request $request)
{
        $task = new   Task();
        $task -> title = $request->input('title');
        $task -> description = $request->input('description');
        $task -> save();
   
        return redirect('tasks');
}

So, you've defined a parameter that must be passed into the store() method. And since you typehinted it, and since Laravel knows how to resolve that class name, you're going to have the Reqeust object ready for  you to use in your method with no work on your parkt. No explicit binding, no anything else-it's just there are the $reqeust variable.

By the way, this is actually how I and many other Laravel developers prefer to get the user input: inject an instance of the Reqeusedt and read the user input from there, instread of relying on the Input facade.


Resource Controllers
Sometimes naming the methods in your controllers can be the hardest part of writing a controller. Thankfully, Laravel has some conventions for all of the routes of a traditional REST/CRUD controller ( called a "resource controller" in Laravel); additionally, it ocmes with a generator out of the box and a convenience route definition that allows you to bind an entire resource controller at once.

To see the mothods that Laravel expects for a resouce controller, let's generate a new controller from the command line:
php aratisan make:controller MySampleResourceController --resource

Now open app/Http/Controllers/MysampleResourceController.php. You'll see it comes prefilled with quite a few methods. Let's walk over what each represents. We'll use a Task as an example.

The methods of Laravel's resource controllers

For each, you can see the HTTP verb, the URL, the controller method name, and the "name". Table 3-1 shows the HTTP verb, the URL, the controller method name, and the "name" for each of these default methods.

Table 3-1. The methods of Laravel's resource controllers

Verb     URL            Controller method Name             Description
GET      tasks           index()                tasks.index       Show all tasks
GET      tasks/create  create()               tasks.create      Show the create task form
POST    tasks           store()                tasks.store       Accept form submission
                                                                        from the create task form
GET      tasks/{task}    show()                tasks.show      Show one task
GET      tasks/          edit()                  tasks.edit        Edit one task
          {task}/edit

PUT/PATCH tasks/{task} update()            tasks.update    Accept form submission from
                                                                       the edit task form
DELETE   tasks/{task}   destroy()             tasks.destroy    Delete one task

Binding a resource controller
So, we've seen that these are the conventional route names to sue in Laravel, and also that it's easy to generate a resource controller with methods for each of these controller methods by hand, if you don't want to. Instead, there's a trick for that, and it's called "resource controller binding." Task a look at Example 3-26.

Example 3-26. Resource controller binding

//routes/web.php
Route::resource('tasks', 'TasksController');

This will automatically bind all of the routes for this resource to the appropriate method names on the specified controller. It'll also name these routes appropriately; for example, the index() method on the tasks resource controller will be named tasks.index.

artisan route:list
If you ever find yourself in a situation where you're wondering what routes your current application has available, there's  a tool for that: from the command line, run php artisan route:list and you'll get listing of all of the available routes.

Route Model Binding
One of the most common routing patterns is that the first line of any controller method tries to find the resource with the given ID, like in Example 3-27.

Example 3-27. Getting a resource for each route
Route::get('conferences/{id}', function ($id) {
      $conference = Conference::findOrFail($id);
 });
Laravel provides a feature that simplifies this pattern called "route model binding."
This allows you to define that a particular parameter name (e.g., {conference}) will indicate to the route resolver that it should look up an Eloquent record with that ID and then pass it in as the parameter instead of just passing the ID.

There are two kinkds of route model binding:implicit and custom(or explicit).

Implicit Route Model Binding
The simplest way to use route model binding is to name your route parameter something unique to that model (e.g., name it $conference instead of $id), then typehint that parameter in the closure/controller method and use the same variable name there. It's easier to show than to describe, so take a look at Example 3-28.

Example 3-28. Using an explicit route model binding
Route::get('conferences/{conference}', function(Conference $conference){
    return view('conferences.show') ->with('conference', $conference);
});

Because the route parameter ({conference}) is the same as the method parameter ($conference), and the method parameter is typehited with a Conference model (Conference $conference), Laravel sees this as a route model binding. Every time this route is visited, the application will assume that whatever is passes into the URL in place of {conference} is an ID that should be  used to look up a Conference, and then that resulting model instance will be passed into your closure or controller method.

Customizing the route key for an Eloquent model
Any time an Eloquent model is looked up via a URL segment (usually because of route model binding), the default column Eloquent will because of route model binding), the default column Eloquent will look it up is its primary key(ID).

To change the column your Eloquent model uses for URL lookups add a method to your model named getRouteKeyName*():

public function getRouteKeyName()

              return 'slug';
}

Now, a URL like conferences/{conference{ will expect to get the slug instread of the ID, and will perform its lookupas accordingly.

5.2 Implicit route model binding was added in Laravel 5.2, so you won't have access to it in 5.1

Custom Route Model Binding
To manually configure route model bindings, add a line like the one in Example 3-29 to the boot() method in App\Providers\RoutesServiceProvider.

Example 3-29. Adding a route model binding

public function boot(Router $router)
{
    // just allows the parent's boot() method to still run
    parent::boot($router);

   // perform the binding
    $router -> model('event', Conference::class);
}

You've now defined that whenever a route has a parameter in its definition named {event}, as demonstrated in Example 3-30, the route resolver will return an instance of the Conference class with the ID of that URL parameter.

Example 3-3-. Using an explicit route model binding

Route::get('events/{event}', function(Conference $event){
   return view('events.show') ->with('event', $event);
});

Route Caching
If you're looking to squeeze every millisecond out of your load time, you may wantto take a look at route caching. One of the pieces of Laravel's bootstrap that can take anywhere from a few dozen to a few hundred milliseconds is parsing the routes/* files, and route caching speeds up this process dramatically.

To cache your routes file, you need to be using all controller and resource routes (no routes closures). If you r app isn't using any route closures, you can run php artisan route:cache, Laravel will serialize the results of your routes/* files. If you want to delete the cache, run php artisan route:clear.

Here's the drawback: Laravel will now match routes against that cached file instread of your actual routes/* files. You can make endless changes to those files, and they won't take effect until you run route:cache again. This means you'll have to recache every time you make a change, which introduces a lot of potential for confusion.

Here's what I would recommend instead: since Git ignores the route cache file by default anyway, consider only using route caching on your production server, and run the php artisan route:cache command every time you deploy new code (whether via a Git post-deploy hook, a Forge deploy command, or as a part of whatever other deploy system you use). This way you won't have confusing local development issues, but your remeote environment will still benefit from route caching.

Form Method Soofing
Sometimes, you need to manually define which HTTP verb a from should send as. HTML forms only allow for GET or POST, so if you want any other sort of verb,  you'll need to specify that yourself.

An Introduction to HTTP Verbs
We've talked about the GET and POST HTTP verbs already. If  you're not familiar with HTTP verbs, the other two most common ones are PUT and DELETE, but rhere's also HEAD, OPTIONS, PATCH, and two others that are pretty much never used in normal web development, TRACE and CONNECT.

Here's the quick rundown: GET requests a resource and HEAD asks for a headers-only version of the GET, POST creates a resource, PUT overwrites a resource and PATCH modifies a resource, DELETE deletes a resource, and OPTIONS asks the server which verbs are allowed at this URL.

HTTP Verbs in Laravel
As we've shown already, you can define which verbs a route will match in the route definition using Route::get(), Route::post(), Route::any(), or Route::match().
You can also match with Route::patch(), Route::put(), and Route::delete().

But how does one send a request other than GET with a web browser? First, the method attribute in an HTML form determines its HTTP verb: if your form has a method of "GET", it will submit via query parameters and a GET method; if the form has a method of "POST", it will submit via the post body and a POST method.

JavaScript frameworks make it easy to send other requests, like DELETE and PATCH. But if you find yourself needing to submit HTML forms in Laravel with verbs other than GET or POST, you'll need to sue form method spoofing, which is spoofing the

HTTP method in an HTML form.
To inform Laravel that the form you're currently submitting should be treated as something other than POST, add a hidden variable named _method with the value of either "PUT", "PATCH", or "DELETE", and Laravel will match and route that form submission as if it were actually a request with that verb.

The form in Example 3-31, since it's passing Laravel the method of "DELETE", will match routes defined with Route::delete() but not those with Route::post().

Example 3-31. Form method spoofing

   


CSRFJ Protection
If you've tried to create and submit a form in a Laravel application already - including the form in Example 3-31 - you've likely run into the dreaded TokenMismatchException.

By default, all routes in Laravel except "read-only" routes (those using GET, HEAD, or OPTIONS) are protected against cross-site request forgery (CSRF) attacks by requiring a token, in  the form of an input named _token, to be passed along with each request.
This token is generated at the start of every session, and every non-read-only route
What is CSFR?
A cross-site request forgery is when one website pretends to be anoher. The goal is for someone to hijack your users' access to your website, by submitting forms from their website to your website via the logged-in user's browser.
The best way around CSRF attacks is to protect all inbound routes -POST, DELETE, etc. -with a token, which Laravel does out of the box.

You have two options for getting around this. The first, and preferred, method is to add the _token input to each of your submissions. In HTML  froms, that's simple;
look at Example 3-32.

Example 3-32. CSRF token

     
     
     


In JavaScript applications, it's a bit mroe work, but not much. The most common solution for sites using JavaScript fraeworks is to stre the token on every page in a tag like this one:
 

Storing the toekn is a tag makes it easy to bind it to the correct HTTP header, shich you can do once globally for all requests from your JavaScript framework, like in Example 3-33.

Example 3-33. Globally binding a header for CSRF

//in jQuery:
$.ajaxSetup({
      headers: {
           'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
     }
});

//in vue:
Vue.http.interceptors.push((request, next) => {
     request.headers['X-CSRF-TOKEN'] =
           document.querySelector('#token').getAttribute('content');

    next();
});

Laravel will check the X-CSRF-TOKEN on every request, and valid tokens passed these will mark the CSRF protection as satisfied.

Note that the Vue syntax for CSRF in this example is not necessary if you're working with the 5.3 Vue bootstrap; it already does  this work for you.

Redirects
So far the only tings we've returned from a controoler method or route definition have been views. But there are a few other structures we can return to give the browser instructions on how to behave.

First, let's cover the redirect. There are two common ways to generate a redirect; we'll use the redirect global helper here, but you may prefer the facade. Both create an instance of Illuminate\Http\RedirectResponse, perform some convenience methods on it, and then return it. You can also do this manualluy, but you'll have to do a little more work yourself. Take a look at Example 3-34 to see a few ways you can return a redirect.

Example 3-34. Different ways to return a redirect

// Using the global helper to generate a redirect response
Route::get('redirect-with-helper', function(){
    return redirect()->to('login');
});

// Using the global helper shortcut
Route::get('redirect-with-helper-shortcut', function(){
      return redirect('login')
});

// Using the facade to generate a redirect response
 Route::get('redirect-with-facade', function(){
       return Redirect::to('login');
 });

Note that the redirect() helper exposes the same methods as the Redirect facade, but it also has a shortcut; if you pass parameters directly to the helper, instead of chaining methods after it, it's shortcut to the to() redirect method.

redirect() -> to()
The method signature for the to() method for redirects looks like this:
    function to($to = null, $status = 302, $headers = [], #secure = null)
$to is a valid internal path; $status is the HTTP status (defaulting to 302 FOUND); $headers allows you to define which HTTP headers to send along with yhour redirect; and $secure allows you to override the default choice of http versus https(which is normally set based on your current request URL). Example 3-35 shows another example of its use.

Example 3-35. redirect()->to()
Route::get('redirect', function(){
    return redirect()->to('home')'

   // or sam, useing the shortcut
    return redirect('home');
});

redirect()->route()
The route() method is the same as the to() method, but rather than pointing to a particular path, it points to particular route name (see Example 3-36).

Example 3-36. redirect()->route()
Route::get('redirect', function (){
   return redirect()->route('conferences.index');
});
Note that, since some route names require paramters, its parameter order is a little dirrerent.route() has an optional second parameter for the route parameters:
    function route($to = null, $parameters = [], $status = 302, $headers = [])
So, using it might look a little like Example 3- 37.

Example 3-37. redirect()->route() with parameters
Route::get('redirect', function(){
     return redirect()->route('conferences.show', ['conference' => 99]);
});

redirect()->back()
Because of some of the built-in conveniences of Laravel's session implementation, your application will always have knowledge of what the user's previously visited page was. That open up the opportunity for a redirect()->() redirect, which simply reidrects the user to whatever page she came from. there's also a global shortcut for this:back().

Other Redirect Methods
The redirect service provides other methods ghat are less commonly used, but still available:

- home() redirects to a route named home.
- refresh() redirects to the same page the user is currently on.
- away() allows for redirecting to an external URL without the default URL validation.
- secure() is like to() with the secure parameter set to "true"
- action() allows you to link to a controller and method like this: redirect()->action('MyController@myMethod').
- getst() is used internally by the auth system (discussed in Chapter 9); when a user visits a route he's not authenticated for, this captures the "intended" route and then redirects the user (usually to  a login page).
- intended() is also used internally by the auth system; after a successful authentication, this grabs the "intended" URL stored by the guest() method and redirects the user there.

redirect()->with()
When you're redirecting users to different pages, you ofter want to pass certain data along with them. You could manually flash the data to the session, but Laravel has some convenience methods to help you with that.

Most commonly, you can pass along either an array of keys and valeus or a single key and value using with(), like in Example 3-38.

Example 3-38. Redirect with data
Route::get('redirect-with-key-value', function(){
     return redirect('dashboard')
              ->with('error', true);
});

Route::get('redirect-with-array', function(){
      return redirect('dashbard')
              ->with(['error' => true, 'message' => 'Whoops!']);
});

Chaining methods on redirects
As with many other facades, most calls to the Redirect facade can accept fluent method chains, like the with() calls in Example 3-38. Learn more about fluency in "What Is a Fluent Interface?" on page 146.

You can also use withInput(), as in Example 3-39, to redirect with the user's form input flashed; this is most common in the case of a validation error, where you want to send the user back to the form she just came from.

Example 3-39. Redirect with form input

Route::get('form', function(){
   return view('form');
});

Route::post('form', function(){
    return redirect('form')
            ->withInput()
            ->with(['error' => true, 'message' => 'Whoops!']);
});
The easiest way to get the flashed input that was passed with withInput() is using the old() helper, which can be used to get all old input (old()) or just the value for a particular key (old('username'), with the second parameter as the default if ehre is no old value). You'll commonly see this in views, which allows this HTML to be used both on the "create" and the "edit" view for this form:



Speaking of validation, there is also a useful method for passing errors along with a redirect response:withErrors(). You can pass it any "provider" of errors, which may be an error string, an array of errors, or, most commonly, an instance of the Illuminate Validator, which we'll cover in Chapter 10. Example 3-40 shows an example of its use.

Example 3-40. Redirect with errors
Route::post('form', function (){
      $validator = Validator::make($request->all()), $this->validationRules);

      if($validator->fails()){
            return redirect('form')
                    ->withErrors($validator)
                    ->withInput();
      }
});

withErrors() automatically shares an $errors variable with the views of the page it's redirecting to, for you to handle however you'd liek.

The validate() shortcut in controller methods
Like how Example 3-40 looks? If you're defining your routes in a controller, there's a simple and powerful tool that cleans up that code. Read more in "validate() in the controller Using VlidatesRequests" on page 103.

Aborting the Request
Aside from returning views and redirects, the most common way to exit a route is to about. There are a few globally available methods (abort(), abort_if(), and abort_unless()), which optionally take HTTP status codes, a message, and a headers array as parameters.

As Example 3-41 shows, abort_if() and abort_unless() take a first parameter that is evaluated for its truthiness, and perform the abort depending on the result.

Exampel 3-41. 403 Forbidden aborts
Route::post('something-you-cant-do', function(Illuminate\Http\Request){
    abort(403, 'You cannot do that!');
    abort_unless($request->has('magicToken'), 403);
    abort_if($reqeust->user()->isBannerd, 403);
});

Custom Responses
There are a few other options available for us to return, so let's go over the most common responses after views, redirects, and aborts. Just like with redirects, you can either use the response() helper or the Response facade to run these methods on.

response()->make()
If you want to create an HTTP response manually, just pass your data into the first parameter of response()->make(): e.g., return response()->make('Hello, World!'). Once again, the second parameter is the HTTP status code and the third is your headers.

response()->json()and->jsonp()
To create a JSON-encoded HTTP response manaually, pass your JSON-able content (arrays, collections, or whatever else) to the json() method: e.g., return response()->json(User::all());. It's just liek make(), except it json_encodes your content and sets the appropriate headers.

response()->download() and ->file()
To send a file for the end user to download, pass either an SplFileInfo instance of a string filename to download(), with an optional second parameter of the filename: e.g., return response()->download('file501751.pdf', 'myFile.pdf').
To display the same file in the browser (if it's a PDF or an image or something else the browser cna handle), use response()->file() instead, which takes the same parameters.

Testing
In some other communities, the idea of unit testing controller methods is common, but within Laravel (and most of the PHP community), it't most common to rely on application testing to test the functionality of routes.

For example, to verify that a POST route works correctly, we can write a test liek Example 3-42.

Example 3-42. Writing a simple POST route test
// AssignmentTest.php
public function test_post_creates_new _assignment()
{
        $this->post('/assigments', [
              'title'=> 'My great assignment'
         ]);
        $this->seeInDatabase('assignments', [
              'title'=> 'My great assigment'
         ]);
}

Did we directly call the controller methods? No. But we ensured that the goal of this route-to receive a POST and save its importnt information to the database-was met.
You can also use similar syntax to visit a route and verify that certain text shows up on the page, or that clicking certain buttons does certain things (see Example 3-43).

Example 3-43. Writing a simple GET route test

// AssignmentTest.php
public function test_list_page_shows_all_assignments()
{
       $assigment = Assignment::create([
             'title' => 'My great assignmnet'
       ]);

        $this->visit('assignments')
                -> see)['My great assignment']);

  }

TL;DR
Laravel;s routes are defined in routes/web.php and routes/api.php, where you can define the expected path for each route, which segments are static and which are parameters, which HTTP verbs can access the route, and how to resolve it. You can also attach middleware to reoutes, group them, and give them names.

What is returned from theroute closue or controller method dictates how Laravel responds to the user. If it's a string ro a view, it's presented to the user; if it's other sorts of data, it's converted to JSON and presented to the user; and if it's a redirect, it forces a redirect.

Laravel provides a series of tools and conveniences to simplify common routing-related tasks and structures. These include resource controllers, route model binding and form method spoofing.










   




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