I got a lot of content behind the wall and i want them to indexed. How can i fix this without a lot of effort? But also i dont have any link to this content behind the wall i dont want anyone to see it except my users. Can I do it with php code with if useragent googlebot bla bla bla? Or robots.txt ?
if they indexed, anyone can see them! better if you share link to the file personally to your users unless you use cms. some cms like Joomla can handle this problem automatically.