Screencasts which introduce BFG and demonstrate BFG features.
Charlie Clark gives a high-level introduction to
repoze.bfg at Europython in 2010
In the first screencast in this series, we use BFG to begin building (with apologies to Armin Ronacher) a clone of the open source Flask "microframework" that we name Groundhog. At the end of the first video, we have built enough of Groundhog to allow users to map URLs to code in a way that will be familiar to Flask developers.
In the second screencast in this series, we give
Groundhog's users the ability to generate URLs based on
routing patterns associated with user-defined view
functions. At the end of the second video, a Groundhog user
can use the
url_for method of the application
to generate URLs which point into his application. We also
teach Groundhog how to redirect to slash-appended routes and
we show off the interactive exception debugger (WebError's
In the third screencast in this series, we allow
Groundhog users to render HTML using Jinja2 and Chameleon-ZPT templates. We
render_template method of the Groundhog
application object and we provide custom renderer
In the fourth Groundhog screencast, we give our microframework's users a way to store information in sessions by making use of Beaker middleware. We then implement flash messaging on top of this sessioning machinery.
In the fifth screencast in the Groundhog series, we equip
our microframework with a way to translate exceptions
raised by developers into HTTP responses. We then allow
our developers to use convenience APIs named
redirect to raise
exceptions. Finally, we allow them to customize the
appearance of exceptions they raise.
In the sixth and final screencast in the Groundhog series, we allow our microframework's users to subscribe to and receive events, which are objects broadcast by BFG at various well-known points during its processing cycle. We also allow our users to define and send their own custom event types. Once we've built up some event machinery, we use it to implement "importable locals" (aka "stacked object proxies" or "context locals").
We introduce the Deform form generation library by building an application using the Pylons web framework. Deform is a framework-independent form generation library written by the authors of BFG (and other Repoze projects). In the screencast, we build a small application using Deform in "real time".