node.js - Writing a chucksum to pdf changes a checksum of the pdf. How to chalange this

Question

It is common to print a checksum on pdf file to check if the file is the one I want tu use.

I'm buiding a node/puppeteer app to generate a pdf submition - a set of according data save to a database as well. Then an operater gets the pdf file and imports to the app and app is suppoused to validate the checksum.

But, I try, as many apps do, to print a checksum on a pdf that user don't send an old file. But I got stuck. To calculate a checksum of a file (md5) I need the file, then I print this checksum on a file ... it chandes the checksum...

How to overcome?

标签： node.jspdfchecksum