128 lines
4.9 KiB
Python
128 lines
4.9 KiB
Python
"""
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Formtools Preview application.
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"""
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import cPickle as pickle
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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.utils.hashcompat import md5_constructor
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from django.contrib.formtools.utils import security_hash
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AUTO_ID = 'formtools_%s' # Each form here uses this as its auto_id parameter.
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class FormPreview(object):
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preview_template = 'formtools/preview.html'
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form_template = 'formtools/form.html'
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# METHODS SUBCLASSES SHOULDN'T OVERRIDE ###################################
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def __init__(self, form):
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# form should be a Form class, not an instance.
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self.form, self.state = form, {}
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def __call__(self, request, *args, **kwargs):
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stage = {'1': 'preview', '2': 'post'}.get(request.POST.get(self.unused_name('stage')), 'preview')
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self.parse_params(*args, **kwargs)
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try:
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method = getattr(self, stage + '_' + request.method.lower())
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except AttributeError:
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raise Http404
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return method(request)
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def unused_name(self, name):
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"""
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Given a first-choice name, adds an underscore to the name until it
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reaches a name that isn't claimed by any field in the form.
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This is calculated rather than being hard-coded so that no field names
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are off-limits for use in the form.
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"""
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while 1:
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try:
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f = self.form.base_fields[name]
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except KeyError:
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break # This field name isn't being used by the form.
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name += '_'
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return name
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def preview_get(self, request):
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"Displays the form"
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f = self.form(auto_id=AUTO_ID)
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return render_to_response(self.form_template,
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{'form': f, 'stage_field': self.unused_name('stage'), 'state': self.state},
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context_instance=RequestContext(request))
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def preview_post(self, request):
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"Validates the POST data. If valid, displays the preview page. Else, redisplays form."
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f = self.form(request.POST, auto_id=AUTO_ID)
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context = {'form': f, 'stage_field': self.unused_name('stage'), 'state': self.state}
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if f.is_valid():
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self.process_preview(request, f, context)
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context['hash_field'] = self.unused_name('hash')
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context['hash_value'] = self.security_hash(request, f)
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return render_to_response(self.preview_template, context, context_instance=RequestContext(request))
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else:
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return render_to_response(self.form_template, context, context_instance=RequestContext(request))
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def post_post(self, request):
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"Validates the POST data. If valid, calls done(). Else, redisplays form."
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f = self.form(request.POST, auto_id=AUTO_ID)
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if f.is_valid():
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if self.security_hash(request, f) != request.POST.get(self.unused_name('hash')):
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return self.failed_hash(request) # Security hash failed.
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return self.done(request, f.cleaned_data)
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else:
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return render_to_response(self.form_template,
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{'form': f, 'stage_field': self.unused_name('stage'), 'state': self.state},
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context_instance=RequestContext(request))
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# METHODS SUBCLASSES MIGHT OVERRIDE IF APPROPRIATE ########################
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def parse_params(self, *args, **kwargs):
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"""
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Given captured args and kwargs from the URLconf, saves something in
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self.state and/or raises Http404 if necessary.
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For example, this URLconf captures a user_id variable:
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(r'^contact/(?P<user_id>\d{1,6})/$', MyFormPreview(MyForm)),
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In this case, the kwargs variable in parse_params would be
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{'user_id': 32} for a request to '/contact/32/'. You can use that
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user_id to make sure it's a valid user and/or save it for later, for
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use in done().
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"""
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pass
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def process_preview(self, request, form, context):
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"""
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Given a validated form, performs any extra processing before displaying
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the preview page, and saves any extra data in context.
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"""
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pass
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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 HttpRequest and Form instances.
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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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return security_hash(request, form)
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def failed_hash(self, request):
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"Returns an HttpResponse in the case of an invalid security hash."
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return self.preview_post(request)
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# METHODS SUBCLASSES MUST OVERRIDE ########################################
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def done(self, request, cleaned_data):
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"""
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Does something with the cleaned_data and returns an
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HttpResponseRedirect.
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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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