text: # encoding: utf-8
  
  import collections
  import datetime
  from itertools import count
  import re
  import mimetypes
  
  import ckan.lib.navl.dictization_functions as df
  import ckan.logic as logic
  import ckan.lib.helpers as h
  from ckan.model import (MAX_TAG_LENGTH, MIN_TAG_LENGTH,
                          PACKAGE_NAME_MIN_LENGTH, PACKAGE_NAME_MAX_LENGTH,
                          PACKAGE_VERSION_MAX_LENGTH,
                          VOCABULARY_NAME_MAX_LENGTH,
                          VOCABULARY_NAME_MIN_LENGTH)
  import ckan.authz as authz
  from ckan.model.core import State
  
  from ckan.common import _
  
  Invalid = df.Invalid
  StopOnError = df.StopOnError
  Missing = df.Missing
  missing = df.missing
  
  def owner_org_validator(key, data, errors, context):
  
      value = data.get(key)
  
      if value is missing or value is None:
          if not authz.check_config_permission('create_unowned_dataset'):
              raise Invalid(_('An organization must be provided'))
          data.pop(key, None)
          raise df.StopOnError
  
      model = context['model']
      user = context['user']
      user = model.User.get(user)
      if value == '':
          if not authz.check_config_permission('create_unowned_dataset'):
              raise Invalid(_('An organization must be provided'))
          return
  
      group = model.Group.get(value)
      if not group:
          raise Invalid(_('Organization does not exist'))
      group_id = group.id
      if not context.get(u'ignore_auth', False) and not(user.sysadmin or
             authz.has_user_permission_for_group_or_org(
                 group_id, user.name, 'create_dataset')):
          raise Invalid(_('You cannot add a dataset to this organization'))
      data[key] = group_id
  
  
  def package_id_not_changed(value, context):
  
      package = context.get('package')
      if package and value != package.id:
          raise Invalid('Cannot change value of key from %s to %s. '
                        'This key is read-only' % (package.id, value))
      return value
  
  def int_validator(value, context):
      '''
      Return an integer for value, which may be a string in base 10 or
      a numeric type (e.g. int, long, float, Decimal, Fraction). Return
      None for None or empty/all-whitespace string values.
  
      :raises: ckan.lib.navl.dictization_functions.Invalid for other
          inputs or non-whole values
      '''
      if value is None:
          return None
      if hasattr(value, 'strip') and not value.strip():
          return None
  
      try:
          whole, part = divmod(value, 1)
      except TypeError:
          try:
              return int(value)
          except ValueError:
              pass
      else:
          if not part:
              try:
                  return int(whole)
              except TypeError:
                  pass  # complex number: fail like int(complex) does
  
      raise Invalid(_('Invalid integer'))
  
  def natural_number_validator(value, context):
      value = int_validator(value, context)
      if value < 0:
          raise Invalid(_('Must be a natural number'))
      return value
  
  def is_positive_integer(value, context):
      value = int_validator(value, context)
      if value < 1:
          raise Invalid(_('Must be a postive integer'))
      return value
  
  def boolean_validator(value, context):
      '''
      Return a boolean for value.
      Return value when value is a python bool type.
      Return True for strings 'true', 'yes', 't', 'y', and '1'.
      Return False in all other cases, including when value is an empty string or
      None
      '''
      if value is missing or value is None:
          return False
      if isinstance(value, bool):
          return value
      if value.lower() in ['true', 'yes', 't', 'y', '1']:
          return True
      return False
  
  def isodate(value, context):
      if isinstance(value, datetime.datetime):
          return value
      if value == '':
          return None
      try:
          date = h.date_str_to_datetime(value)
      except (TypeError, ValueError), e:
          raise Invalid(_('Date format incorrect'))
      return date
  
  def no_http(value, context):
  
      model = context['model']
      session = context['session']
  
      if 'http:' in value:
          raise Invalid(_('No links are allowed in the log_message.'))
      return value
  
  def package_id_exists(value, context):
  
      model = context['model']
      session = context['session']
  
      result = session.query(model.Package).get(value)
      if not result:
          raise Invalid('%s: %s' % (_('Not found'), _('Dataset')))
      return value
  
  def package_id_does_not_exist(value, context):
  
      model = context['model']
      session = context['session']
  
      result = session.query(model.Package).get(value)
      if result:
          raise Invalid(_('Dataset id already exists'))
      return value
  
  def package_name_exists(value, context):
  
      model = context['model']
      session = context['session']
  
      result = session.query(model.Package).filter_by(name=value).first()
  
      if not result:
          raise Invalid(_('Not found') + ': %s' % value)
      return value
  
  def package_id_or_name_exists(package_id_or_name, context):
      '''Return the given package_id_or_name if such a package exists.
  
      :raises: ckan.lib.navl.dictization_functions.Invalid if there is no
          package with the given id or name
  
      '''
      model = context['model']
      session = context['session']
  
      result = session.query(model.Package).get(package_id_or_name)
      if result:
          return package_id_or_name
  
      result = session.query(model.Package).filter_by(
              name=package_id_or_name).first()
  
      if not result:
          raise Invalid('%s: %s' % (_('Not found'), _('Dataset')))
  
      return package_id_or_name
  
  
  def resource_id_exists(value, context):
      model = context['model']
      session = context['session']
      if not session.query(model.Resource).get(value):
          raise Invalid('%s: %s' % (_('Not found'), _('Resource')))
      return value
  
  
  def user_id_exists(user_id, context):
      '''Raises Invalid if the given user_id does not exist in the model given
      in the context, otherwise returns the given user_id.
  
      '''
      model = context['model']
      session = context['session']
  
      result = session.query(model.User).get(user_id)
      if not result:
          raise Invalid('%s: %s' % (_('Not found'), _('User')))
      return user_id
  
  def user_id_or_name_exists(user_id_or_name, context):
      '''Return the given user_id_or_name if such a user exists.
  
      :raises: ckan.lib.navl.dictization_functions.Invalid if no user can be
          found with the given id or user name
  
      '''
      model = context['model']
      session = context['session']
      result = session.query(model.User).get(user_id_or_name)
      if result:
          return user_id_or_name
      result = session.query(model.User).filter_by(name=user_id_or_name).first()
      if not result:
          raise Invalid('%s: %s' % (_('Not found'), _('User')))
      return user_id_or_name
  
  def group_id_exists(group_id, context):
      '''Raises Invalid if the given group_id does not exist in the model given
      in the context, otherwise returns the given group_id.
  
      '''
      model = context['model']
      session = context['session']
  
      result = session.query(model.Group).get(group_id)
      if not result:
          raise Invalid('%s: %s' % (_('Not found'), _('Group')))
      return group_id
  
  def group_id_or_name_exists(reference, context):
      '''
      Raises Invalid if a group identified by the name or id cannot be found.
      '''
      model = context['model']
      result = model.Group.get(reference)
      if not result:
          raise Invalid(_('That group name or ID does not exist.'))
      return reference
  
  def activity_type_exists(activity_type):
      '''Raises Invalid if there is no registered activity renderer for the
      given activity_type. Otherwise returns the given activity_type.
  
      This just uses object_id_validators as a lookup.
      very safe.
  
      '''
      if activity_type in object_id_validators:
          return activity_type
      else:
          raise Invalid('%s: %s' % (_('Not found'), _('Activity type')))
  
  
  # A dictionary mapping activity_type values from activity dicts to functions
  # for validating the object_id values from those same activity dicts.
  object_id_validators = {
      'new package' : package_id_exists,
      'changed package' : package_id_exists,
      'deleted package' : package_id_exists,
      'follow dataset' : package_id_exists,
      'new user' : user_id_exists,
      'changed user' : user_id_exists,
      'follow user' : user_id_exists,
      'new group' : group_id_exists,
      'changed group' : group_id_exists,
      'deleted group' : group_id_exists,
      'new organization' : group_id_exists,
      'changed organization' : group_id_exists,
      'deleted organization' : group_id_exists,
      'follow group' : group_id_exists,
      }
  
  def object_id_validator(key, activity_dict, errors, context):
      '''Validate the 'object_id' value of an activity_dict.
  
      Uses the object_id_validators dict (above) to find and call an 'object_id'
      validator function for the given activity_dict's 'activity_type' value.
  
      Raises Invalid if the model given in context contains no object of the
      correct type (according to the 'activity_type' value of the activity_dict)
      with the given ID.
  
      Raises Invalid if there is no object_id_validator for the activity_dict's
      'activity_type' value.
  
      '''
      activity_type = activity_dict[('activity_type',)]
      if object_id_validators.has_key(activity_type):
          object_id = activity_dict[('object_id',)]
          return object_id_validators[activity_type](object_id, context)
      else:
          raise Invalid('There is no object_id validator for '
              'activity type "%s"' % activity_type)
  
  name_match = re.compile('[a-z0-9_\-]*$')
  def name_validator(value, context):
      '''Return the given value if it's a valid name, otherwise raise Invalid.
  
      If it's a valid name, the given value will be returned unmodified.
  
      This function applies general validation rules for names of packages,
      groups, users, etc.
  
      Most schemas also have their own custom name validator function to apply
      custom validation rules after this function, for example a
      ``package_name_validator()`` to check that no package with the given name
      already exists.
  
      :raises ckan.lib.navl.dictization_functions.Invalid: if ``value`` is not
          a valid name
  
      '''
      if not isinstance(value, basestring):
          raise Invalid(_('Names must be strings'))
  
      # check basic textual rules
      if value in ['new', 'edit', 'search']:
          raise Invalid(_('That name cannot be used'))
  
      if len(value) < 2:
          raise Invalid(_('Must be at least %s characters long') % 2)
      if len(value) > PACKAGE_NAME_MAX_LENGTH:
          raise Invalid(_('Name must be a maximum of %i characters long') % \
                        PACKAGE_NAME_MAX_LENGTH)
      if not name_match.match(value):
          raise Invalid(_('Must be purely lowercase alphanumeric '
                          '(ascii) characters and these symbols: -_'))
      return value
  
  def package_name_validator(key, data, errors, context):
      model = context['model']
      session = context['session']
      package = context.get('package')
  
      query = session.query(model.Package.state).filter_by(name=data[key])
      if package:
          package_id = package.id
      else:
          package_id = data.get(key[:-1] + ('id',))
      if package_id and package_id is not missing:
          query = query.filter(model.Package.id <> package_id)
      result = query.first()
      if result and result.state != State.DELETED:
          errors[key].append(_('That URL is already in use.'))
  
      value = data[key]
      if len(value) < PACKAGE_NAME_MIN_LENGTH:
          raise Invalid(
              _('Name "%s" length is less than minimum %s') % (value, PACKAGE_NAME_MIN_LENGTH)
          )
      if len(value) > PACKAGE_NAME_MAX_LENGTH:
          raise Invalid(
              _('Name "%s" length is more than maximum %s') % (value, PACKAGE_NAME_MAX_LENGTH)
          )
  
  def package_version_validator(value, context):
  
      if len(value) > PACKAGE_VERSION_MAX_LENGTH:
          raise Invalid(_('Version must be a maximum of %i characters long') % \
                        PACKAGE_VERSION_MAX_LENGTH)
      return value
  
  def duplicate_extras_key(key, data, errors, context):
  
      unflattened = df.unflatten(data)
      extras = unflattened.get('extras', [])
      extras_keys = []
      for extra in extras:
          if not extra.get('deleted'):
              extras_keys.append(extra['key'])
  
      for extra_key in set(extras_keys):
          extras_keys.remove(extra_key)
      if extras_keys:
          key_ = ('extras_validation',)
          assert key_ not in errors
          errors[key_] = [_('Duplicate key "%s"') % extras_keys[0]]
  
  def group_name_validator(key, data, errors, context):
      model = context['model']
      session = context['session']
      group = context.get('group')
  
      query = session.query(model.Group.name).filter_by(name=data[key])
      if group:
          group_id = group.id
      else:
          group_id = data.get(key[:-1] + ('id',))
      if group_id and group_id is not missing:
          query = query.filter(model.Group.id <> group_id)
      result = query.first()
      if result:
          errors[key].append(_('Group name already exists in database'))
  
  def tag_length_validator(value, context):
  
      if len(value) < MIN_TAG_LENGTH:
          raise Invalid(
              _('Tag "%s" length is less than minimum %s') % (value, MIN_TAG_LENGTH)
          )
      if len(value) > MAX_TAG_LENGTH:
          raise Invalid(
              _('Tag "%s" length is more than maximum %i') % (value, MAX_TAG_LENGTH)
          )
      return value
  
  def tag_name_validator(value, context):
  
      tagname_match = re.compile('[\w \-.]*$', re.UNICODE)
      if not tagname_match.match(value):
          raise Invalid(_('Tag "%s" must be alphanumeric '
                          'characters or symbols: -_.') % (value))
      return value
  
  def tag_not_uppercase(value, context):
  
      tagname_uppercase = re.compile('[A-Z]')
      if tagname_uppercase.search(value):
          raise Invalid(_('Tag "%s" must not be uppercase' % (value)))
      return value
  
  def tag_string_convert(key, data, errors, context):
      '''Takes a list of tags that is a comma-separated string (in data[key])
      and parses tag names. These are added to the data dict, enumerated. They
      are also validated.'''
  
      if isinstance(data[key], basestring):
          tags = [tag.strip() \
                  for tag in data[key].split(',') \
                  if tag.strip()]
      else:
          tags = data[key]
  
      current_index = max( [int(k[1]) for k in data.keys() if len(k) == 3 and k[0] == 'tags'] + [-1] )
  
      for num, tag in zip(count(current_index+1), tags):
          data[('tags', num, 'name')] = tag
  
      for tag in tags:
          tag_length_validator(tag, context)
          tag_name_validator(tag, context)
  
  def ignore_not_admin(key, data, errors, context):
      # Deprecated in favour of ignore_not_package_admin
      return ignore_not_package_admin(key, data, errors, context)
  
  def ignore_not_package_admin(key, data, errors, context):
      '''Ignore if the user is not allowed to administer the package specified.'''
  
      model = context['model']
      user = context.get('user')
  
      if 'ignore_auth' in context:
          return
  
      if user and authz.is_sysadmin(user):
          return
  
      authorized = False
      pkg = context.get('package')
      if pkg:
          try:
              logic.check_access('package_change_state',context)
              authorized = True
          except logic.NotAuthorized:
              authorized = False
  
      if (user and pkg and authorized):
          return
  
      # allow_state_change in the context will allow the state to be changed
      # FIXME is this the best way to cjeck for state only?
      if key == ('state',) and context.get('allow_state_change'):
          return
      data.pop(key)
  
  
  def ignore_not_sysadmin(key, data, errors, context):
      '''Ignore the field if user not sysadmin or ignore_auth in context.'''
  
      user = context.get('user')
      ignore_auth = context.get('ignore_auth')
  
      if ignore_auth or (user and authz.is_sysadmin(user)):
          return
  
      data.pop(key)
  
  
  def ignore_not_group_admin(key, data, errors, context):
      '''Ignore if the user is not allowed to administer for the group specified.'''
  
      model = context['model']
      user = context.get('user')
  
      if user and authz.is_sysadmin(user):
          return
  
      authorized = False
      group = context.get('group')
      if group:
          try:
              logic.check_access('group_change_state',context)
              authorized = True
          except logic.NotAuthorized:
              authorized = False
  
      if (user and group and authorized):
          return
  
      data.pop(key)
  
  def user_name_validator(key, data, errors, context):
      '''Validate a new user name.
  
      Append an error message to ``errors[key]`` if a user named ``data[key]``
      already exists. Otherwise, do nothing.
  
      :raises ckan.lib.navl.dictization_functions.Invalid: if ``data[key]`` is
          not a string
      :rtype: None
  
      '''
      model = context['model']
      new_user_name = data[key]
  
      if not isinstance(new_user_name, basestring):
          raise Invalid(_('User names must be strings'))
  
      user = model.User.get(new_user_name)
      if user is not None:
          # A user with new_user_name already exists in the database.
  
          user_obj_from_context = context.get('user_obj')
          if user_obj_from_context and user_obj_from_context.id == user.id:
              # If there's a user_obj in context with the same id as the user
              # found in the db, then we must be doing a user_update and not
              # updating the user name, so don't return an error.
              return
          else:
              # Otherwise return an error: there's already another user with that
              # name, so you can create a new user with that name or update an
              # existing user's name to that name.
              errors[key].append(_('That login name is not available.'))
  
  def user_both_passwords_entered(key, data, errors, context):
  
      password1 = data.get(('password1',),None)
      password2 = data.get(('password2',),None)
  
      if password1 is None or password1 == '' or \
         password2 is None or password2 == '':
          errors[('password',)].append(_('Please enter both passwords'))
  
  def user_password_validator(key, data, errors, context):
      value = data[key]
  
      if isinstance(value, Missing):
          pass
      elif not isinstance(value, basestring):
          errors[('password',)].append(_('Passwords must be strings'))
      elif value == '':
          pass
      elif len(value) < 4:
          errors[('password',)].append(_('Your password must be 4 characters or longer'))
  
  def user_passwords_match(key, data, errors, context):
  
      password1 = data.get(('password1',),None)
      password2 = data.get(('password2',),None)
  
      if not password1 == password2:
          errors[key].append(_('The passwords you entered do not match'))
      else:
          #Set correct password
          data[('password',)] = password1
  
  def user_password_not_empty(key, data, errors, context):
      '''Only check if password is present if the user is created via action API.
         If not, user_both_passwords_entered will handle the validation'''
  
      # sysadmin may provide password_hash directly for importing users
      if (data.get(('password_hash',), missing) is not missing and
              authz.is_sysadmin(context.get('user'))):
          return
  
      if not ('password1',) in data and not ('password2',) in data:
          password = data.get(('password',),None)
          if not password:
              errors[key].append(_('Missing value'))
  
  def user_about_validator(value,context):
      if 'http://' in value or 'https://' in value:
          raise Invalid(_('Edit not allowed as it looks like spam. Please avoid links in your description.'))
  
      return value
  
  def vocabulary_name_validator(name, context):
      model = context['model']
      session = context['session']
  
      if len(name) < VOCABULARY_NAME_MIN_LENGTH:
          raise Invalid(_('Name must be at least %s characters long') %
              VOCABULARY_NAME_MIN_LENGTH)
      if len(name) > VOCABULARY_NAME_MAX_LENGTH:
          raise Invalid(_('Name must be a maximum of %i characters long') %
                        VOCABULARY_NAME_MAX_LENGTH)
      query = session.query(model.Vocabulary.name).filter_by(name=name)
      result = query.first()
      if result:
          raise Invalid(_('That vocabulary name is already in use.'))
      return name
  
  def vocabulary_id_not_changed(value, context):
      vocabulary = context.get('vocabulary')
      if vocabulary and value != vocabulary.id:
          raise Invalid(_('Cannot change value of key from %s to %s. '
                          'This key is read-only') % (vocabulary.id, value))
      return value
  
  def vocabulary_id_exists(value, context):
      model = context['model']
      session = context['session']
      result = session.query(model.Vocabulary).get(value)
      if not result:
          raise Invalid(_('Tag vocabulary was not found.'))
      return value
  
  def tag_in_vocabulary_validator(value, context):
      model = context['model']
      session = context['session']
      vocabulary = context.get('vocabulary')
      if vocabulary:
          query = session.query(model.Tag)\
              .filter(model.Tag.vocabulary_id==vocabulary.id)\
              .filter(model.Tag.name==value)\
              .count()
          if not query:
              raise Invalid(_('Tag %s does not belong to vocabulary %s') % (value, vocabulary.name))
      return value
  
  def tag_not_in_vocabulary(key, tag_dict, errors, context):
      tag_name = tag_dict[('name',)]
      if not tag_name:
          raise Invalid(_('No tag name'))
      if tag_dict.has_key(('vocabulary_id',)):
          vocabulary_id = tag_dict[('vocabulary_id',)]
      else:
          vocabulary_id = None
      model = context['model']
      session = context['session']
  
      query = session.query(model.Tag)
      query = query.filter(model.Tag.vocabulary_id==vocabulary_id)
      query = query.filter(model.Tag.name==tag_name)
      count = query.count()
      if count > 0:
          raise Invalid(_('Tag %s already belongs to vocabulary %s') %
                  (tag_name, vocabulary_id))
      else:
          return
  
  def url_validator(key, data, errors, context):
      ''' Checks that the provided value (if it is present) is a valid URL '''
      import urlparse
      import string
  
      model = context['model']
      session = context['session']
  
      url = data.get(key, None)
      if not url:
          return
  
      pieces = urlparse.urlparse(url)
      if all([pieces.scheme, pieces.netloc]) and \
         set(pieces.netloc) <= set(string.letters + string.digits + '-.') and \
         pieces.scheme in ['http', 'https']:
         return
  
      errors[key].append(_('Please provide a valid URL'))
  
  
  def user_name_exists(user_name, context):
      model = context['model']
      session = context['session']
      result = session.query(model.User).filter_by(name=user_name).first()
      if not result:
          raise Invalid('%s: %s' % (_('Not found'), _('User')))
      return result.name
  
  
  def role_exists(role, context):
      if role not in authz.ROLE_PERMISSIONS:
          raise Invalid(_('role does not exist.'))
      return role
  
  
  def datasets_with_no_organization_cannot_be_private(key, data, errors,
          context):
  
      dataset_id = data.get(('id',))
      owner_org = data.get(('owner_org',))
      private = data[key] is True
  
      check_passed = True
  
      if not dataset_id and private and not owner_org:
          # When creating a dataset, enforce it directly
          check_passed = False
      elif dataset_id and private and not owner_org:
          # Check if the dataset actually has an owner_org, even if not provided
          try:
              dataset_dict = logic.get_action('package_show')({},
                              {'id': dataset_id})
              if not dataset_dict.get('owner_org'):
                  check_passed = False
  
          except logic.NotFound:
              check_passed = False
  
      if not check_passed:
          errors[key].append(
                  _("Datasets with no organization can't be private."))
  
  
  def list_of_strings(key, data, errors, context):
      value = data.get(key)
      if not isinstance(value, list):
          raise Invalid(_('Not a list'))
      for x in value:
          if not isinstance(x, basestring):
              raise Invalid('%s: %s' % (_('Not a string'), x))
  
  def if_empty_guess_format(key, data, errors, context):
      value = data[key]
      resource_id = data.get(key[:-1] + ('id',))
  
      # if resource_id then an update
      if (not value or value is Missing) and not resource_id:
          url = data.get(key[:-1] + ('url',), '')
          mimetype, encoding = mimetypes.guess_type(url)
          if mimetype:
              data[key] = mimetype
  
  def clean_format(format):
      return h.unified_resource_format(format)
  
  def no_loops_in_hierarchy(key, data, errors, context):
      '''Checks that the parent groups specified in the data would not cause
      a loop in the group hierarchy, and therefore cause the recursion up/down
      the hierarchy to get into an infinite loop.
      '''
      if not 'id' in data:
          # Must be a new group - has no children, so no chance of loops
          return
      group = context['model'].Group.get(data['id'])
      allowable_parents = group.\
                          groups_allowed_to_be_its_parent(type=group.type)
      for parent in data['groups']:
          parent_name = parent['name']
          # a blank name signifies top level, which is always allowed
          if parent_name and context['model'].Group.get(parent_name) \
                  not in allowable_parents:
              raise Invalid(_('This parent would create a loop in the '
                              'hierarchy'))
  
  
  def filter_fields_and_values_should_have_same_length(key, data, errors, context):
      convert_to_list_if_string = logic.converters.convert_to_list_if_string
      fields = convert_to_list_if_string(data.get(('filter_fields',), []))
      values = convert_to_list_if_string(data.get(('filter_values',), []))
  
      if len(fields) != len(values):
          msg = _('"filter_fields" and "filter_values" should have the same length')
          errors[('filter_fields',)].append(msg)
          errors[('filter_values',)].append(msg)
  
  
  def filter_fields_and_values_exist_and_are_valid(key, data, errors, context):
      convert_to_list_if_string = logic.converters.convert_to_list_if_string
      fields = convert_to_list_if_string(data.get(('filter_fields',)))
      values = convert_to_list_if_string(data.get(('filter_values',)))
  
      if not fields:
          errors[('filter_fields',)].append(_('"filter_fields" is required when '
                                              '"filter_values" is filled'))
      if not values:
          errors[('filter_values',)].append(_('"filter_values" is required when '
                                              '"filter_fields" is filled'))
  
      filters = collections.defaultdict(list)
      for field, value in zip(fields, values):
          filters[field].append(value)
  
      data[('filters',)] = dict(filters)
  
  
  def extra_key_not_in_root_schema(key, data, errors, context):
  
      for schema_key in context.get('schema_keys', []):
          if schema_key == data[key]:
              raise Invalid(_('There is a schema field with the same name'))
  
  
  def empty_if_not_sysadmin(key, data, errors, context):
      '''Only sysadmins may pass this value'''
      from ckan.lib.navl.validators import empty
  
      user = context.get('user')
  
      ignore_auth = context.get('ignore_auth')
      if ignore_auth or (user and authz.is_sysadmin(user)):
          return
  
      empty(key, data, errors, context)
  
  #pattern from https://html.spec.whatwg.org/#e-mail-state-(type=email)
  email_pattern = re.compile(r"^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~-]+@[a-zA-Z0-9]"\
                         "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9]"\
                         "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$")
  
  
  def email_validator(value, context):
      '''Validate email input '''
  
      if value:
          if not email_pattern.match(value):
              raise Invalid(_('Email {email} is not a valid format').format(email=value))
      return value
  