.. reverse foreign key: pour le _set The poll webpage ================ The idea is a web page which offers the implementation of a weighted poll: participants might select *several* of the proposed choices, and voters can *stress their preference* of a choice over another. The poll webpage is twofold, first there is creation page at shmoodle.net, which when filled redirect to the newly created poll page (there is one address for each created poll) The creation page at http://shmoodle.net (why not!) offers this short description and a form with the following fields: - the **question**: for instance "Which theatre plays will we present to the public?" - the **list of choices**: it is a string composed of string separated by commas. For example: "Phedre,Romeo and Juliet" - if you want to administer it, you'll want to put your *name* and *password* to be able to modify later. The number of voting tokens to distribute might also be changed When the form is filled, the user is redirected to its, just created, poll page, for instance http://shmoodle.net/4lph4b3t. The page is composed of a table of the vote where each line is the vote of one participants and each column is one of the possible choices of the vote. The last line is the results: the number of participants so far and the respectives sums of the vote for each choices. The standard variation also shows to represent an indicator of the consensus as well as the list of choices sorted by order of preferences. the new's Web developer diary ----------------------------- There are good chances that applications get designed around the SQL models and the GET and POST HTTP paradigm instead of simple and clear interfaces. Applications tightly coupled with SQL and HTTP are difficult to reuse in other context: non interactive, API, command line oriented, no SQL. It is difficult to give a clear overview of user flow in urls, views and templates. Example: a view indirectly returns a string containing a tag *form*. Introspecting this tag, the action attributes indicates the next url to which the form is sent. At this point, urls.py indicates the views responsible for processing the form data. The view generally ends with a *redirection* to the next url displayed to the user. This is long... could this be simpler? Unhelpful 'app not found' on ``manager.py sqlall``. The app is indeed found but any exceptions or syntax error yields this misleading error I did not know a string instead of a class is acceptable for an argument of the foreignKey field. This is important if there is a need to declare a class after declaring the relation. SQL is not so much fun to represent a list (and multivalued fields). This impacts the design of many small models unneeded in any high level languages embedding dictionaries and list as first citizens. Note gor later: check the nosql new black. Reverse *one* to *many* relation generate an attribute many\ *_set* on the *one* object. It is surprising to use, in self's method an attribute of self which is not declared in the class itself but created by other classes. The form fields and model fields are not similar, too bad. There is no comma separated list. Errors in the template_dir, in the regexp expressions, in the patterns, in the template filename, are only caught at http get request time. How to test a web app? There is not much convention about where to put the templates in the filesystem. There are not .py files hence use a parallel import system. A hint would help he beginner: should it be in project/templates, in project/templates/app or in project/app/templates? There is not much convention about how to split yet encapsulate the code which sends a form and the code which process the form data. Can we use callbacks? deferred? yield? I would be lad to read some good hints on how to do The Right Thing concerning the back button in the various situation of post/get/authentication etc. I am sure people have gained experienced and I am sure I will re-invent the wheel instead. I confused the HttpRedirectResponse for a while. HttpRedirectResponse is for *changing URL* and does not really accept a context. Smart templates are not compliant html, they can't be used by pure web designer which are not programmers. What is left todo ================= - test test test, the configuration, the urls, the templates, the forms, the views, the models, the connection to the database. How to test a Django app any web app? - validate user input, - i18n, - memcache is no luxury: when a poll is created and when a when a ballot is casted, the user is redirected to a page which re-request the database about the exact same poll which would be better kept in memory for a short while instead of retrieved from the database, - an admin role, secured password and https - presentation: css from meyers is desirable, longer text fields or text area - going ajax might prove usefull and pave the way for xmpp interaction http://en.wikipedia.org/wiki/Condorcet_method http://en.wikipedia.org/wiki/Tactical_voting http://en.wikipedia.org/wiki/Arrow%27s_impossibility_theorem how to start a project? ======================= :: sudo aptitude install python-psycopg2 python-django{,-doc} postgresql sudo -s su postgres createuser jd exit # from being jd createdb shmoodle cd && django-admin startproject shmoodle cd shmoodle sed -i "s/# 'postgresql_psycopg2'/'postgresql_psycopg2' #/" settings.py # installed apps, template_dirs, template loaders and middleware classes python manage.py startapp poll mkdir poll/templates emacs poll/templates/{poll.html,vote.html} poll/forms.py emacs poll/views.py poll/models.py python manage.py sqlall | psql -d shmoodle # syncdb python manage.py sqlclear poll | psql -d shmoodle