Question

I just ran this simple code snippet provided by the wiki, because I couldn’t get sessions working:

import web
web.config.debug = False
urls = (
    "/count", "count",
    "/reset", "reset"
)
app = web.application(urls, locals())
session = web.session.Session(app, web.session.DiskStore('sessions'), initializer={'count': 0})

class count:
    def GET(self):
        session.count += 1
        return str(session.count)

class reset:
    def GET(self):
        session.kill()
        return ""

if __name__ == "__main__":
    app.run()

But it results in this error:

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/web/application.py", line 237, in process
    return self.handle()
  File "/usr/local/lib/python2.7/dist-packages/web/application.py", line 228, in handle
    return self._delegate(fn, self.fvars, args)
  File "/usr/local/lib/python2.7/dist-packages/web/application.py", line 411, in _delegate
    return handle_class(cls)
  File "/usr/local/lib/python2.7/dist-packages/web/application.py", line 387, in handle_class
    return tocall(*args)
  File "temp.py", line 12, in GET
    session.count += 1
  File "/usr/local/lib/python2.7/dist-packages/web/session.py", line 71, in __getattr__
    return getattr(self._data, name)
AttributeError: 'ThreadedDict' object has no attribute 'count'

Is webpy not compatible with 2.7.3? I’m running this on the internal webserver of webpy. I’m using Ubuntu 12.04.

Answer 1

session.count += 1 is equal to session.count = session.count + 1 so session.count must exist for this to work.

Add the following check to make it work:

if 'count' not in session:
    session.count = 0
session.count += 1

There is also another way which is even shown in the very simple session simple example of the docs:

try:
    s.click += 1
except AttributeError:
    s.click = 1