public function getInputFilterSpecification(): array
    {
        return [
            'api_key' => [
                'required' => false,
                'filters' => [
                    ['name' => StripTags::class],
                    ['name' => StringTrim::class],
                ],
                'validators' => [
                    ['name' => StringLength::class, 'options' => [
                        'encoding' => 'UTF-8',
                        'min'      => 10,
                        'max'      => 20,
                    ]],
                    ['name' => Alnum::class],
                ],
            ],
            'blog' => [
                'required' => false,
                'filters' => [
                    ['name' => StripTags::class],
                    ['name' => StringTrim::class],
                ],
                'validators' => [
                    ['name' => StringLength::class, 'options' => [
                        'encoding' => 'UTF-8',
                        'min'      => 10,
                        'max'      => 255,
                    ]],
                    ['name' => Uri::class, 'options' => [
                        'uriHandler'    => Http::class,
                        'allowRelative' => false,
                    ]],
                ],
            ],
        ];
    }