Publisher handler contains the code:
- we log a message if nothing was published, it helps with debugging
if (not published) and (req.bytes_sent==0) and (req.next is None):
req.log_error("mod_python.publisher: nothing to publish.")
The idea is that if the publisher didn't generate any output and simply returned None, that a warning would be generated which might be noticed by a developer and thus be helpful to debugging problems.
Problem is that "req.bytes_sent" is only actually non zero when data is flushed and actually written back to the client by Apache. It does not take into consideration any buffered data.
In other words, if "req.write()" is used but second optional argument is always being set to 0 indicating that data should not be flushed, then publisher will wrongly say nothing actually got published.
Because the PSP classes are no longer flushing data so that output filters like "CONTENT_LENGTH" will work, this will mean you will get this warning all the time when using code like:
from mod_python import apache, psp
page = psp.PSP(req, 'echo.psp')
Question is, is there a way to determine from Apache that there is buffered data. We don't really want to be adding another special flag in the mod_python request wrapper like req._content_type_set do we???