Now that we’re familiar with dependency injection, what else can we do with the concept? Can we “inject” our models, like the User model, into our route and then utilize model properties without instantiating the User model? How would we even do that? Don’t we need to first “find” the specific user before we can use the properties associated with that user?

Believe it or not, Laravel has a way to get a user’s details without explicitly doing something like: User::find(24);.

Implicit Binding

We should understand that we do need to provide our model with an id at the very least, otherwise, how will it pull the information for our specific resource out of the database table? In the User example, we don’t want Laravel to return a random user, we want a specific user.

use App\Models\User;

Route::get('/implicit-binding/{user}', function (User $user) {
    return $user;
});

If we visit the route, you should get something like this.

{
  "id": 2,
  "name": "Maria Nitzsche",
  "email": "colt21@example.org",
  "email_verified_at": "2023-02-07T18:56:39.000000Z",
  "created_at": "2023-02-07T18:56:39.000000Z",
  "updated_at": "2023-02-07T18:56:39.000000Z"
}

What happened? Laravel implicitly bound {user} to $user. Since we type-hinted User $user, Laravel knew that we’re injecting a User model, so it automatically found our User with the specific id.

It doesn’t matter what your name your arguments, as long as they match. With implicit binding, the id will be the field that Laravel searches through, when the parameter is type-hinted.

So, in case you wanted to do something like this (name your URL parameter id), it won’t work:

use App\Models\User;

Route::get('/implicit-binding/{id}', function (User $user) {
    return $user;
});

You’ll just get [] as the response.

But what if we wanted to use another field, like name? We can do that, but it requires that the key is stated.

Changing the Key

If we wanted to instead look for a user based on their name or email, we have to state that that’s the column we want to look into. How do we do that? By stating the key in our route.

use App\Models\User;

Route::get('/implicit-binding/{user:name}', function (User $user) {
    return $user;
});

We can now visit a route like the following:

http://0.0.0.0/implicit-binding/Maria%20Nitzsche

Laravel will search the users table and will return that resource.

{
  "id": 2,
  "name": "Maria Nitzsche",
  "email": "colt21@example.org",
  "email_verified_at": "2023-02-07T18:56:39.000000Z",
  "created_at": "2023-02-07T18:56:39.000000Z",
  "updated_at": "2023-02-07T18:56:39.000000Z"
}

What if you wanted to show only a user if the email has been verified? This is the concept of explicit binding and will be covered next time.