1 files changed, 55 insertions, 0 deletions
diff --git a/utils/forms.py b/utils/forms.py
new file mode 100644
index 0000000..a6ff4de
--- /dev/null
+++ b/utils/forms.py
@@ -0,0 +1,55 @@
+from flask import request, url_for, redirect
+from urlparse import urlparse, urljoin
+from wtforms import Field, HiddenField, ValidationError
+
+from widgets import Static
+
+
+class Unique(object):
+    """ validator that checks field uniqueness """
+    def __init__(self, model, field, message=None):
+        self.model = model
+        self.field = field
+        if not message:
+            message = u'This element already exists.'
+        self.message = message
+
+    def __call__(self, form, field):
+        if self.model.query.filter(self.field == field.data).count() > 0:
+            raise ValidationError(self.message)
+
+
+class ReadonlyField(Field):
+    widget = Static()
+
+    def process_formdata(self, _):
+        pass
+
+
+class RedirectMixin(object):
+    next = HiddenField()
+
+    def __init__(self, *args, **kwargs):
+        super(RedirectMixin, self).__init__(*args, **kwargs)
+        if not self.next.data:
+            self.next.data = self._get_redirect_target() or ''
+    
+    def _get_redirect_target(self):
+        for target in request.args.get('next'), request.referrer:
+            if not target:
+                continue
+            if self._is_safe_url(target):
+                return target
+
+    def _is_safe_url(self, target):
+        ref_url = urlparse(request.host_url)
+        test_url = urlparse(urljoin(request.host_url, target))
+        return test_url.scheme in ('http', 'https') and \
+            ref_url.netloc == test_url.netloc
+    
+    def redirect(self, endpoint='index', **values):
+        if self._is_safe_url(self.next.data):
+            return redirect(self.next.data)
+
+        target = self._get_redirect_target()
+        return redirect(target or url_for(endpoint, **values))