Concerns

• Contracts
• Pointer interface

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(): Collection
    {
        return User::all();
    }
}

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
{

}