Add filters to forms

.gitignore

@@ -3,6 +3,7 @@
 *.pyo
 .*.swp
 .DS_Store
+.idea/*
 
 # Extra Files
 MANIFEST

tests/form.py

@@ -10,6 +10,11 @@
 
 
 class BaseFormTest(TestCase):
+    def strip_ws(self, s):
+        if isinstance(s, basestring):
+            s = s.strip()
+        return s
+
     def get_form(self, **kwargs):
         def validate_test(form, field):
             if field.data != 'foobar':
@@ -81,6 +86,17 @@ def test_formdata_wrapper_error(self):
         form = self.get_form()
         self.assertRaises(TypeError, form.process, [])
 
+    def test_form_filter(self):
+        form = self.get_form(form_filter=self.strip_ws)
+        form.process(test='  foo  ')
+        self.assertEqual(form.data, {'test': 'foo'})
+
+    def test_form_filter_field_add(self):
+        form = self.get_form(form_filter=self.strip_ws)
+        form['test2'] = TextField()
+        form.process(test='  foo  ', test2=' gappy text  ')
+        self.assertEqual(form.data, {'test': 'foo', 'test2': 'gappy text'})
+
 
 class FormMetaTest(TestCase):
     def test_monkeypatch(self):

wtforms/form.py

@@ -19,7 +19,7 @@ class BaseForm(object):
     validation, and data and error proxying.
     """
 
-    def __init__(self, fields, prefix='', meta=DefaultMeta()):
+    def __init__(self, fields, prefix='', meta=DefaultMeta(), form_filter=None):
         """
         :param fields:
             A dict or sequence of 2-tuples of partially-constructed fields.
@@ -37,10 +37,14 @@ def __init__(self, fields, prefix='', meta=DefaultMeta()):
         self._prefix = prefix
         self._errors = None
         self._fields = OrderedDict()
+        self.form_filter = form_filter
 
         if hasattr(fields, 'items'):
             fields = fields.items()
 
+        for field in fields:
+            self._apply_form_filter(field[1].kwargs)
+
         translations = self._get_translations()
         extra_fields = []
         if meta.csrf:
@@ -66,12 +70,20 @@ def __getitem__(self, name):
 
     def __setitem__(self, name, value):
         """ Bind a field to this form. """
+        value.kwargs = self._apply_form_filter(value.kwargs)
         self._fields[name] = value.bind(form=self, name=name, prefix=self._prefix)
 
     def __delitem__(self, name):
         """ Remove a field from this form. """
         del self._fields[name]
 
+    def _apply_form_filter(self, field_kwargs):
+        if self.form_filter and hasattr(self.form_filter, '__call__'):
+            if 'filters' not in field_kwargs:
+                field_kwargs['filters'] = []
+            field_kwargs['filters'].append(self.form_filter)
+        return field_kwargs
+
     def _get_translations(self):
         """
         .. deprecated:: 2.0
@@ -241,7 +253,8 @@ class Form(with_metaclass(FormMeta, BaseForm)):
     """
     Meta = DefaultMeta
 
-    def __init__(self, formdata=None, obj=None, prefix='', data=None, meta=None, **kwargs):
+    def __init__(self, formdata=None, obj=None, prefix='', data=None, meta=None,
+                 form_filter=None, **kwargs):
         """
         :param formdata:
             Used to pass data coming from the enduser, usually `request.POST` or
@@ -269,7 +282,8 @@ def __init__(self, formdata=None, obj=None, prefix='', data=None, meta=None, **k
         meta_obj = self._wtforms_meta()
         if meta is not None and isinstance(meta, dict):
             meta_obj.update_values(meta)
-        super(Form, self).__init__(self._unbound_fields, meta=meta_obj, prefix=prefix)
+        super(Form, self).__init__(self._unbound_fields, meta=meta_obj, prefix=prefix,
+                                   form_filter=form_filter)
 
         for name, field in iteritems(self._fields):
             # Set all the fields to attributes so that they obscure the class