Document upload and metadata input working

apps/common/wizard.py

@@ -0,0 +1,82 @@
+"""Common abstract classes for forms."""
+try:
+    import cPickle as pickle
+except ImportError:
+    import pickle
+
+from django import forms
+from django.conf import settings
+from django.contrib.formtools.wizard import FormWizard
+from django.forms.forms import BoundField
+from django.forms.formsets import BaseFormSet
+from django.utils.hashcompat import md5_constructor
+
+__all__ = ('security_hash', 'BoundFormWizard')
+
+def security_hash(request, form, exclude=None, *args):
+    """Calculates a security hash for the given Form/FormSet instance.
+
+    This creates a list of the form field names/values in a deterministic
+    order, pickles the result with the SECRET_KEY setting, then takes an md5
+    hash of that.
+    """
+
+    data = []
+    if exclude is None:
+        exclude = ()
+    if isinstance(form, BaseFormSet):
+        for _form in form.forms + [form.management_form]:
+            for bf in _form:
+                value = bf.field.clean(bf.data) or ''
+                if isinstance(value, basestring):
+                    value = value.strip()
+                data.append((bf.name, value))
+    else:
+        for bf in form:
+            if bf.name in exclude:
+                continue
+            value = bf.field.clean(bf.data) or ''
+            if isinstance(value, basestring):
+                value = value.strip()
+            data.append((bf.name, value))
+    data.extend(args)
+    data.append(settings.SECRET_KEY)
+
+    # Use HIGHEST_PROTOCOL because it's the most efficient. It requires
+    # Python 2.3, but Django requires 2.3 anyway, so that's OK.
+    pickled = pickle.dumps(data, pickle.HIGHEST_PROTOCOL)
+
+    return md5_constructor(pickled).hexdigest()
+
+class BoundFormWizard(FormWizard):
+    """Render prev_fields as a list of bound form fields in the template
+    context rather than raw html."""
+    def security_hash(self, request, form):
+        """Calculates the security hash for the given HttpRequest and
+        Form/FormSet instances.
+
+        Subclasses may want to take into account request-specific information,
+        such as the IP address.
+        """
+        return security_hash(request, form)
+
+    def render(self, form, request, step, context=None):
+        "Renders the given Form object, returning an HttpResponse."
+        old_data = request.POST
+        prev_fields = []
+        if old_data:
+            for i in range(step):
+                old_form = self.get_form(i, old_data)
+                hash_name = 'hash_%s' % i
+                if isinstance(old_form, BaseFormSet):
+                    for _form in old_form.forms + [old_form.management_form]:
+                        prev_fields.extend([bf for bf in _form])
+                else:
+                    prev_fields.extend([bf for bf in old_form])
+                hash_field = forms.Field(initial=old_data.get(hash_name,
+                    self.security_hash(request, old_form)))
+                bf = BoundField(forms.Form(), hash_field, hash_name)
+                prev_fields.append(bf)
+        return self.render_template(request, form, prev_fields, step, context)
+
+# vim: ai ts=4 sts=4 et sw=4