MIME Downloads

Trying to allow users to download database queries in various formats, such as pdf, excel, and csv. I have all the script created that take the query results and format the data for each of the formats, but the problem I'm having now is actually delivering the file when people want to download it. There is no physical file on the server they are downloading. The file is basically just stored in a variable. So, say I have the variable $results, which contains an encoded PDF file, and I want the person to download it... I'm assuming it would be something like header('Cache-Control: no-cache, must-revalidate'); header('Pragma: no-cache'); header("Content-type: application/pdf"); After this though, I'm stuck. How to I finish this part off here? Every example I've seen so far assumes the file exists on the server. Thanks!