# Concerns
Most of the export/import configuration is done by using Concerns.
# Contracts
Concerns are basically just simple interfaces. Implementing them will make the object adhere to a certain contract. This contract can request specific methods that e.g. data can be passed through.
For instance, the FromCollection requests the Export object to implement a collection method, that needs to return a Collection instance.
namespace App\Exports;
use App\User;
use Maatwebsite\Excel\Concerns\FromCollection;
class UsersExport implements FromCollection
{
public function collection()
{
return User::all();
}
}
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# Pointer interface
In other cases it might not ask for any methods to be implemented, but merely functions as a pointer interface.
For instance, the ShouldAutoSize concern doesn't pass on any specific information, but does tell the Export process that the columns need to be automatically sized.
namespace App\Exports;
use App\User;
use Maatwebsite\Excel\Concerns\ShouldAutoSize;
class UsersExport implements ShouldAutoSize
{
}
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