Does anyone know of a PHP PDF library (like FPDF) that has a function to set an expiry date on the generated file? I am selling subscriptions to an online service that has a download as PDF component. I would like to semi-secure the PDFs by having them expire after the subscription period.
Actually - PDF supports JavaScript embedding, so maybe there's something like an annoying popup you could display whenever the time is right.
Link to Adobe site: Adobe JavaScript embedding
There are servies which essentially add this as a wrapper around a PDF but nothing in the actual spec.