Laravel Quick Tip: Model Route Binding

Laravel routing component: Simplify and efficient routing management

This article discusses Laravel's powerful routing component, which provides simple and efficient routing management methods, and supports simple URLs, parameters, groups, naming, and event protection of routing groups. Its routing model binding function simplifies the processing of repetitive tasks by prompting the model name rather than ID parameters.

Core points:

• Laravel's routing component provides simple and efficient routing management methods, supporting simple URLs, parameters, groups, naming, and event protection routing groups. The routing model binding function simplifies repetitive task processing by prompting the model name rather than the ID parameters.
• Laravel's routing model binding will automatically parse the model using ID parameters, and throw an exception if the model does not exist. The App\Exceptions\Handler@render method is responsible for converting the exception to an HTTP response and can be used to process ModelNotFoundException and redirect to a 404 page.
• Laravel allows custom routing model binding, such as rewriting the getRouteKeyName method of the parent model class to use different attribute names, such as UUID. This helps avoid exposing internal IDs to the end user.

Example: Manage backend category

Suppose there are a series of categories in the database that administrators can manage in the background. The routing file is as follows:

<code class="language-php">Route::group(['namespace' => 'Admin', 'prefix' => 'admin', 'middleware' => 'admin'], function () {
    Route::resource('categories', 'CategoriesController');
});</code>

The

CategoriesController class contains seven resource methods. In the edit operation, you need to check whether the category to be edited exists in the database, otherwise an error message will be returned and redirected:

<code class="language-php">public function edit($id)
{
    $category = Category::find($id);
    if (!$category) {
        return redirect()->route('admin.categories.index')->withErrors([trans('errors.category_not_found')]);
    }

    // ...
}</code>

Routing model binding

This is a common practice, but Laravel provides a more optimized way - routing model binding. Just type prompts the model name, no ID parameters are required.

The available route list is as follows:

<code>+--------+-----------+------------------------------------+------------------------------------+----------------------------------------------------------------------+-----------------+
| Domain | Method    | URI                                | Name                               | Action                                                               | Middleware      |
+--------+-----------+------------------------------------+------------------------------------+----------------------------------------------------------------------+-----------------+
|        | GET|HEAD  | admin/categories                   | admin.categories.index             | App\Http\Controllers\Admin\CategoriesController@index                | web,admin       |
|        | POST      | admin/categories                   | admin.categories.store             | App\Http\Controllers\Admin\CategoriesController@store                | web,admin       |
|        | GET|HEAD  | admin/categories/create            | admin.categories.create            | App\Http\Controllers\Admin\CategoriesController@create               | web,admin       |
|        | GET|HEAD  | admin/categories/{categories}      | admin.categories.show              | App\Http\Controllers\Admin\CategoriesController@show                 | web,admin       |
|        | PUT|PATCH | admin/categories/{categories}      | admin.categories.update            | App\Http\Controllers\Admin\CategoriesController@update               | web,admin       |
|        | DELETE    | admin/categories/{categories}      | admin.categories.destroy           | App\Http\Controllers\Admin\CategoriesController@destroy              | web,admin       |
|        | GET|HEAD  | admin/categories/{categories}/edit | admin.categories.edit              | App\Http\Controllers\Admin\CategoriesController@edit                 | web,admin       |</code>

Routing parameters are {categories}, which can be modified as needed. Laravel provides an option to modify it:

<code class="language-php">Route::resource('categories', 'CategoriesController', [
    'parameters' => 'singular',
]);</code>

Modified route:

<code>+--------+-----------+------------------------------------+------------------------------------+----------------------------------------------------------------------+-----------------+
| Domain | Method    | URI                                | Name                               | Action                                                               | Middleware      |
+--------+-----------+------------------------------------+------------------------------------+----------------------------------------------------------------------+-----------------+
|        | GET|HEAD  | admin/categories                   | admin.categories.index             | App\Http\Controllers\Admin\CategoriesController@index                | web,admin       |
|        | POST      | admin/categories                   | admin.categories.store             | App\Http\Controllers\Admin\CategoriesController@store                | web,admin       |
|        | GET|HEAD  | admin/categories/create            | admin.categories.create            | App\Http\Controllers\Admin\CategoriesController@create               | web,admin       |
|        | GET|HEAD  | admin/categories/{category}        | admin.categories.show              | App\Http\Controllers\Admin\CategoriesController@show                 | web,admin       |
|        | PUT|PATCH | admin/categories/{category}        | admin.categories.update            | App\Http\Controllers\Admin\CategoriesController@update               | web,admin       |
|        | DELETE    | admin/categories/{category}        | admin.categories.destroy           | App\Http\Controllers\Admin\CategoriesController@destroy              | web,admin       |
|        | GET|HEAD  | admin/categories/{category}/edit   | admin.categories.edit              | App\Http\Controllers\Admin\CategoriesController@edit                 | web,admin       |</code>

Note: Laravel 5.3 uses the singular form by default.

<code class="language-php">public function edit(Category $category)
{
    return view('admin.categories.edit', [
        'category'      => $category
    ]);
}</code>

Laravel will now automatically parse the category with the ID parameter, throwing an exception if the model does not exist.

Note: Unless the parameter has a default value, it uses the findOrFail Eloquent method to parse the parameters.

Exception handling

The

App\Exceptions\Handler@render method is responsible for converting exceptions into HTTP responses. We will use it to handle ModelNotFoundException and redirect to the 404 page.

This method has the request and exception parameters, which can be used to determine the action to perform.

<code class="language-php">Route::group(['namespace' => 'Admin', 'prefix' => 'admin', 'middleware' => 'admin'], function () {
    Route::resource('categories', 'CategoriesController');
});</code>

We test whether the thrown exception is an instance of ModelNotFoundException. We can also test the model name to display the correct error message. To avoid adding multiple if tests to all models, we can create an array of indexed messages and use the model class name to extract the correct messages.

Parameter analysis

Laravel uses name and type hints to resolve routing parameters. If the parameter type is a model, it tries to look up records in the database using ID, and fails if the record cannot be found.

Custom routing key

To avoid exposing internal IDs to end users, UUIDs are usually used. But since Laravel uses table primary keys to parse bound parameters, an error is always thrown!

To do this, Laravel allows us to rewrite the getRouteKeyName method of the parent model class. This method should return the property name, in this case, UUID.

<code class="language-php">public function edit($id)
{
    $category = Category::find($id);
    if (!$category) {
        return redirect()->route('admin.categories.index')->withErrors([trans('errors.category_not_found')]);
    }

    // ...
}</code>

Now if we try to edit a specific category with UUID, it should work as expected, for example: https://www.php.cn/link/604541b9b9f266538ed001ea49fcc956.

FAQs on Laravel routing model binding (This part of the content has been answered in detail in the original text and will not be described here)

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