Ticket #296: formencode_state.patch

pylons/decorators/__init__.py

@@ -9 +9 @@
 from decorator import decorator
 from formencode import htmlfill
 from paste.util.multidict import UnicodeMultiDict
+from pylons.i18n import _ as pylons_gettext
+from formencode.api import _stdtrans as formencode_gettext
 
 import pylons
 
@@ -16 +18 @@
 
 log = logging.getLogger(__name__)
 
+def pylons_formencode_gettext(value):
+    """Translates a string ``value`` using pylons gettext first
+    and if that fails, formencode gettext.
+    
+    This allows to "merge" localized error messages from built-in
+    FormEncode's validators with application-specific validators.
+    """
+    trans = pylons_gettext(value)
+    if trans == value: # translation failed, try formencode
+        trans = formencode_gettext(value)
+    return trans
+
+class PylonsFormEncodeState(object):
+    """A ``state`` for FormEncode validate API that includes
+    smart ``_`` hook.
+
+    The FormEncode library used by validate() decorator has some
+    provision for localizing error messages. In particular, it
+    looks for attribute ``_`` in the application-specific state
+    object that got passed to every ``.to_python()`` call. If it
+    is found, the ``_`` is assumed to be a gettext-like function
+    and is called to localize error messages.
+
+    One complication is that FormEncode ships with localized
+    error messages for standard validators so the user may want
+    to re-use them instead of gathering and translating
+    everything from scratch. To allow this, we pass as ``_`` a
+    function which looks up translation both in application and
+    formencode message catalogs.
+    """
+    _ = staticmethod(pylons_formencode_gettext)
+
 def jsonify(func, *args, **kwargs):
     """Action decorator that formats output for JSON
 
@@ -72 +106 @@
     """
     def wrapper(func, self, *args, **kwargs):
         """Decorator Wrapper function"""
+        state = PylonsFormEncodeState()
         request = pylons.request._current_obj()
         errors = {}
         if post_only:
@@ -90 +125 @@
         if schema:
             log.debug("Validating against a schema")
             try:
-                self.form_result = schema.to_python(decoded)
+                self.form_result = schema.to_python(decoded, state)
             except formencode.Invalid, e:
                 errors = e.unpack_errors(variable_decode, dict_char, list_char)
         if validators:
@@ -101 +136 @@
                 for field, validator in validators.iteritems():
                     try:
                         self.form_result[field] = \
-                            validator.to_python(decoded.get(field))
+                            validator.to_python(decoded.get(field), state)
                     except formencode.Invalid, error:
                         errors[field] = error
         if errors: