Client read only server side source code

Lets assume a creator makes a web app and provides its sourcecode for reasons of transparency. Assuming that all data used is open to the public, How could a client know that the code being executed (prossesing of the data) on the remote server is the same as the one he is provided. Is there a way to compare and verify the provided script, with the executed script? Even better is there a way for a client to view all server side code but in read only mode without compromise in security? I'm Mostly interested in the plausibility of this with web oriented languages like php, ror, nodejs, python etc