Introduce contrib/ to hold form wizard tool from django's trac.
Move form_decorator help function from utils.py to contrib/ - Legacy-Id: 121
This commit is contained in:
Bill Fenner
parent
73db42db56
commit
95209614b5
1
ietf/contrib/__init__.py
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1
ietf/contrib/__init__.py
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from form_decorator import *
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72
ietf/contrib/form_decorator.py
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72
ietf/contrib/form_decorator.py
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## formfield_callback generator
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## http://www.djangosnippets.org/snippets/59/
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def form_decorator(fields = {}, attrs = {}, widgets = {},
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labels = {}, choices = {}):
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"""
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This function helps to add overrides when creating forms from models/instances.
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Pass in dictionary of fields to override certain fields altogether, otherwise
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add widgets or labels as desired.
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For example:
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class Project(models.Model):
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name = models.CharField(maxlength = 100)
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description = models.TextField()
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owner = models.ForeignKey(User)
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project_fields = dict(
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owner = None
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)
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project_widgets = dict(
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name = forms.TextInput({"size":40}),
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description = forms.Textarea({"rows":5, "cols":40}))
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project_labels = dict(
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name = "Enter your project name here"
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)
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callback = form_decorator(project_fields, project_widgets, project_labels)
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project_form = forms.form_for_model(Project, formfield_callback = callback)
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This saves having to redefine whole fields for example just to change a widget
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setting or label.
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"""
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def formfields_callback(f, **kw):
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if f.name in fields:
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# replace field altogether
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field = fields[f.name]
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f.initial = kw.pop("initial", None)
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return field
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if f.name in widgets:
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kw["widget"] = widgets[f.name]
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if f.name in attrs:
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widget = kw.pop("widget", f.formfield().widget)
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if widget :
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widget.attrs.update(attrs[f.name])
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kw["widget"] = widget
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if f.name in labels:
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kw["label"] = labels[f.name]
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if f.name in choices:
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choice_set = choices[f.name]
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if callable(choice_set) : choice_set = choice_set()
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kw["choices"] = choice_set
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return f.formfield(**kw)
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return formfields_callback
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199
ietf/contrib/wizard.py
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199
ietf/contrib/wizard.py
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@ -0,0 +1,199 @@
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##
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## django form wizard
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## http://code.djangoproject.com/ticket/3218
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"""
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TODO:
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!!!! documentation !!!! including examples
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USAGE:
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urls: (replace wizard.Wizard with something that overrides its done() method,
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othervise it will complain at the end that __call__ does not return HttpResponse)
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( r'^$', MyWizard( [MyForm, MyForm, MyForm] ) ),
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template:
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<form action="." method="POST">
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FORM( {{ step }} ): {{ form }}
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step_info : <input type="hidden" name="{{ step_field }}" value="{{ step }}" />
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previous_fields: {{ previous_fields }}
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<input type="submit">
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</form>
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"""
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from django.conf import settings
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from django.http import Http404
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from django.shortcuts import render_to_response
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from django.template.context import RequestContext
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from django import newforms as forms
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import cPickle as pickle
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import md5
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class Wizard( object ):
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PREFIX="%d"
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STEP_FIELD="wizard_step"
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# METHODS SUBCLASSES SHOULDN'T OVERRIDE ###################################
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def __init__( self, form_list, initial=None ):
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" Pass list of Form classes (not instances !) "
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self.form_list = form_list[:]
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self.initial = initial or {}
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def __repr__( self ):
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return "step: %d\nform_list: %s\ninitial_data: %s" % ( self.step, self.form_list, self.initial )
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def get_form( self, step, data=None ):
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" Shortcut to return form instance. "
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return self.form_list[step]( data, prefix=self.PREFIX % step, initial=self.initial.get( step, None ) )
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def __call__( self, request, *args, **kwargs ):
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"""
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Main function that does all the hard work:
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- initializes the wizard object (via parse_params())
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- veryfies (using security_hash()) that noone has tempered with the data since we last saw them
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calls failed_hash() if it is so
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calls process_step() for every previously submitted form
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- validates current form and
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returns it again if errors were found
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returns done() if it was the last form
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returns next form otherwise
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"""
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# add extra_context, we don't care if somebody overrides it, as long as it remains a dict
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self.extra_context = kwargs.get( 'extra_context', {} )
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self.parse_params( request, *args, **kwargs )
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# we only accept POST method for form delivery no POST, no data
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if not request.POST:
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self.step = 0
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return self.render( self.get_form( 0 ), request )
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# verify old steps' hashes
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for i in range( self.step ):
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form = self.get_form( i, request.POST )
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# somebody is trying to corrupt our data
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if request.POST.get( "hash_%d" % i, '' ) != self.security_hash( request, form ):
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# revert to the corrupted step
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return self.failed_hash( request, i )
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self.process_step( request, form, i )
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# process current step
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form = self.get_form( self.step, request.POST )
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if form.is_valid():
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self.process_step( request, form, self.step )
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self.step += 1
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# this was the last step
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if self.step == len( self.form_list ):
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return self.done( request, [ self.get_form( i, request.POST ) for i in range( len( self.form_list ) ) ] )
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form = self.get_form( self.step )
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return self.render( form, request )
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def render( self, form, request ):
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"""
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Prepare the form and call the render_template() method to do tha actual rendering.
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"""
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if self.step >= len( self.form_list ):
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raise Http404
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old_data = request.POST
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prev_fields = ''
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if old_data:
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# old data
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prev_fields = '\n'.join(
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bf.as_hidden() for i in range(self.step) for bf in self.get_form( i, old_data )
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)
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# hashes for old forms
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hidden = forms.widgets.HiddenInput()
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prev_fields += '\n'.join(
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hidden.render( "hash_%d" % i, old_data.get( "hash_%d" % i, self.security_hash( request, self.get_form( i, old_data ) ) ) )
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for i in range( self.step)
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)
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return self.render_template( request, form, prev_fields )
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# METHODS SUBCLASSES MIGHT OVERRIDE IF APPROPRIATE ########################
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def failed_hash( self, request, i ):
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"""
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One of the hashes verifying old data doesn't match.
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"""
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self.step = i
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return self.render( self.get_form(self.step), request )
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def security_hash(self, request, form):
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"""
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Calculates the security hash for the given Form instance.
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This creates a list of the form field names/values in a deterministic
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order, pickles the result with the SECRET_KEY setting and takes an md5
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hash of that.
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Subclasses may want to take into account request-specific information
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such as the IP address.
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"""
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data = [(bf.name, bf.data) for bf in form] + [settings.SECRET_KEY]
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# Use HIGHEST_PROTOCOL because it's the most efficient. It requires
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# Python 2.3, but Django requires 2.3 anyway, so that's OK.
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pickled = pickle.dumps(data, protocol=pickle.HIGHEST_PROTOCOL)
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return md5.new(pickled).hexdigest()
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def parse_params( self, request, *args, **kwargs ):
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"""
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Set self.step, process any additional info from parameters and/or form data
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"""
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if request.POST:
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self.step = int( request.POST.get( self.STEP_FIELD, 0 ) )
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else:
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self.step = 0
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def get_template( self ):
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"""
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Return name of the template to be rendered, use self.step to get the step number.
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"""
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return "wizard.html"
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def render_template( self, request, form, previous_fields ):
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"""
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Render template for current step, override this method if you wish to add custom context, return a different mimetype etc.
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If you only wish to override the template name, use get_template
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Some additional items are added to the context:
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'step_field' is the name of the hidden field containing step
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'step' holds the current step
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'form' containing the current form to be processed (either empty or with errors)
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'previous_data' contains all the addtitional information, including
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hashes for finished forms and old data in form of hidden fields
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any additional data stored in self.extra_context
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"""
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return render_to_response( self.get_template(), dict(
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step_field=self.STEP_FIELD,
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step=self.step,
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form=form,
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previous_fields=previous_fields,
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** self.extra_context
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), context_instance=RequestContext( request ) )
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def process_step( self, request, form, step ):
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"""
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This should not modify any data, it is only a hook to modify wizard's internal state
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(such as dynamically generating form_list based on previously submited forms).
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It can also be used to add items to self.extra_context base on the contents of previously submitted forms.
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Note that this method is called every time a page is rendered for ALL submitted steps.
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Only valid data enter here.
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"""
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pass
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# METHODS SUBCLASSES MUST OVERRIDE ########################################
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def done( self, request, form_list ):
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"""
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this method must be overriden, it is responsible for the end processing - it will be called with instances of all form_list with their data
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"""
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raise NotImplementedError('You must define a done() method on your %s subclass.' % self.__class__.__name__)
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@ -3,77 +3,6 @@ import syslog
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from django.utils.html import escape
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# look at snippets 59, 148, 99 for newforms helpers
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# http://www.djangosnippets.org/snippets/59/
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def form_decorator(fields = {}, attrs = {}, widgets = {},
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labels = {}, choices = {}):
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"""
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This function helps to add overrides when creating forms from models/instances.
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Pass in dictionary of fields to override certain fields altogether, otherwise
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add widgets or labels as desired.
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For example:
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class Project(models.Model):
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name = models.CharField(maxlength = 100)
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description = models.TextField()
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owner = models.ForeignKey(User)
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project_fields = dict(
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owner = None
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)
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project_widgets = dict(
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name = forms.TextInput({"size":40}),
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description = forms.Textarea({"rows":5, "cols":40}))
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project_labels = dict(
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name = "Enter your project name here"
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)
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callback = form_decorator(project_fields, project_widgets, project_labels)
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project_form = forms.form_for_model(Project, formfield_callback = callback)
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This saves having to redefine whole fields for example just to change a widget
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setting or label.
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"""
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def formfields_callback(f, **kw):
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if f.name in fields:
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# replace field altogether
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field = fields[f.name]
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f.initial = kw.pop("initial", None)
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return field
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if f.name in widgets:
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kw["widget"] = widgets[f.name]
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if f.name in attrs:
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widget = kw.pop("widget", f.formfield().widget)
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if widget :
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widget.attrs.update(attrs[f.name])
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kw["widget"] = widget
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if f.name in labels:
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kw["label"] = labels[f.name]
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if f.name in choices:
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choice_set = choices[f.name]
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if callable(choice_set) : choice_set = choice_set()
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kw["choices"] = choice_set
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return f.formfield(**kw)
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return formfields_callback
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# Caching accessor for the reverse of a ForeignKey relatinoship
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# Started by axiak on #django
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