laravel-custom-relation maintained by johnnyfreeman
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This repo was a bit of a science experiment to find a solution to this issue. I now believe a better to handle custom relations is to create a new class possibly extending one of the existing classes.
Laravel Custom Relation
A custom relation for when stock relations aren't enough.
Use this if...
- None of the stock Relations fit the bill. (BelongsToManyThrough, etc)
Installation
The recommended way to install is with composer:
composer require johnnyfreeman/laravel-custom-relationExample
Let's say we have 3 models:
UserRolePermission
Let's also say User has a many-to-many relation with Role, and Role has a many-to-many relation with Permission.
So their models might look something like this. (I kept them brief on purpose.)
class User
{
public function roles() {
return $this->belongsToMany(Role::class);
}
}class Role
{
public function users() {
return $this->belongsToMany(User::class);
}
public function permissions() {
return $this->belongsToMany(Permission::class);
}
}class Permission
{
public function roles() {
return $this->belongsToMany(Role::class);
}
}What if you wanted to get all the Permissions for a User, or all the Users with a particular Permission? There no stock Relation in Laravel to descibe this. What we need is a BelongsToManyThrough but no such thing exists in stock Laravel.
Solution
First, make sure your models are using the HasCustomRelations trait. Then, define custom relations like this.
use LaravelCustomRelation\HasCustomRelations;
class User
{
use HasCustomRelations;
/**
* Get the related permissions
*
* @return Illuminate\Database\Eloquent\Relations\Relation
*/
public function permissions()
{
return $this->custom(
Permission::class,
// add constraints
function ($relation) {
$relation->getQuery()
// join the pivot table for permission and roles
->join('permission_role', 'permission_role.permission_id', '=', 'permissions.id')
// join the pivot table for users and roles
->join('role_user', 'role_user.role_id', '=', 'permission_role.role_id')
// for this user
->where('role_user.user_id', $this->id);
},
// add eager constraints
function ($relation, $models) {
$relation->getQuery()->whereIn('role_user.user_id', $relation->getKeys($models));
}
);
}
}use LaravelCustomRelation\HasCustomRelations;
class Permission
{
use HasCustomRelations;
/**
* Get the related users
*
* @return Illuminate\Database\Eloquent\Relations\Relation
*/
public function users()
{
return $this->custom(
User::class,
// constraints
function ($relation) {
$relation->getQuery()
// join the pivot table for users and roles
->join('role_user', 'role_user.user_id', '=', 'users.id')
// join the pivot table for permission and roles
->join('permission_role', 'permission_role.role_id', '=', 'role_user.role_id')
// for this permission
->where('permission_role.permission_id', $this->id);
},
// eager constraints
function ($relation, $models) {
$relation->getQuery()->whereIn('permission_role.permission_id', $relation->getKeys($models));
}
);
}
}You could now do all the normal stuff for relations without having to query in-between relations first.