From 938117afb5b15e268ee8811fdaec929671d1346b Mon Sep 17 00:00:00 2001
From: Ian Ward <ian@excess.org>
Date: Mon, 14 Jul 2014 14:26:47 -0400
Subject: [PATCH] [#1841] add IValidators, IConverters plugin interfaces

---
 ckan/logic/__init__.py     | 18 ++++++++++++++++++
 ckan/plugins/interfaces.py | 23 +++++++++++++++++++++++
 ckan/plugins/toolkit.py    |  4 ++--
 3 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/ckan/logic/__init__.py b/ckan/logic/__init__.py
index 49fbc0d7beb..2e2da720a10 100644
--- a/ckan/logic/__init__.py
+++ b/ckan/logic/__init__.py
@@ -624,6 +624,15 @@ def get_validator(validator):
         validators = _import_module_functions('ckan.logic.validators')
         _validators_cache.update(validators)
         _validators_cache.update({'OneOf': formencode.validators.OneOf})
+
+        for plugin in p.PluginImplementations(p.IValidators):
+            for name, validator in plugin.get_validators().items():
+                if name in _validators_cache:
+                    raise Exception(
+                        'The validator %r is already defined' % (name,)
+                    )
+                log.debug('Validator function {0} from plugin {1} was inserted'.format(name, plugin.name))
+                _validators_cache[name] = validator
     try:
         return _validators_cache[validator]
     except KeyError:
@@ -662,6 +671,15 @@ def get_converter(converter):
     if not _converters_cache:
         converters = _import_module_functions('ckan.logic.converters')
         _converters_cache.update(converters)
+
+        for plugin in p.PluginImplementations(p.IConverters):
+            for name, converter in plugin.get_converters().items():
+                if name in _converters_cache:
+                    raise Exception(
+                        'The converter %r is already defined' % (name,)
+                    )
+                log.debug('Converter function {0} from plugin {1} was inserted'.format(name, plugin.name))
+                _converters_cache[name] = validator
     try:
         return _converters_cache[converter]
     except KeyError:
diff --git a/ckan/plugins/interfaces.py b/ckan/plugins/interfaces.py
index 50380bdf471..607bc41ebbb 100644
--- a/ckan/plugins/interfaces.py
+++ b/ckan/plugins/interfaces.py
@@ -13,6 +13,7 @@
     'IPackageController', 'IPluginObserver',
     'IConfigurable', 'IConfigurer',
     'IActions', 'IResourceUrlChange', 'IDatasetForm',
+    'IValidators', 'IConverters',
     'IResourcePreview',
     'IResourceController',
     'IGroupForm',
@@ -523,6 +524,28 @@ def get_actions(self):
         """
 
 
+class IValidators(Interface):
+    """
+    Allow adding of validators to be returned by ``get_validator()``.
+    """
+    def get_validators(self):
+        """
+        Should return a dict, the keys being the name of the validator
+        function and the values being the functions themselves.
+        """
+
+
+class IConverters(Interface):
+    """
+    Allow adding of converters to be returned by ``get_converter()``.
+    """
+    def get_converters(self):
+        """
+        Should return a dict, the keys being the name of the converter
+        function and the values being the functions themselves.
+        """
+
+
 class IAuthFunctions(Interface):
     '''Override CKAN's authorization functions, or add new auth functions.'''
 
diff --git a/ckan/plugins/toolkit.py b/ckan/plugins/toolkit.py
index 5c45b21a70b..d8ad2723e64 100644
--- a/ckan/plugins/toolkit.py
+++ b/ckan/plugins/toolkit.py
@@ -44,8 +44,8 @@ class _Toolkit(object):
         'aslist',               # converts an object to a list
         'literal',              # stop tags in a string being escaped
         'get_action',           # get logic action function
-        'get_converter',        # get validator function
-        'get_validator',        # get convertor action function
+        'get_converter',        # get navl schema converter
+        'get_validator',        # get navl schema validator
         'check_access',         # check logic function authorisation
         'navl_validate',        # implements validate method with navl schema
         'ObjectNotFound',       # action not found exception