Good spyware?

| Comments (2) | Outstanding!
In a post titled "Is there a simple way to make a pdf call home?" and filed in the category "good code", Larry Lessig asks:
Let's say you release a draft of a paper using PDF. But when people open the paper to read it, you'd like the PDF to check whether there's a more recent version available. If there is, you'd like it to indicate as much — somewhere. Obviously, you could always include a link that says "For the most current version, go here." But is there a way to say, "A more recent version of this document is available here."?

I'm sure a feature like that would never be abused!


There is a way of doing this, it's called putting it on a web page.

Modern PDF includes Javascript as part of the spec, so abominations like this are indeed trivially possible. (Thank Adobe for making PDF Turing Complete. That's never a problem, right?)

I now only use PDF viewers that do not have or disable the Javascript functionality. I don't trust "active" documents.

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