fnpdjango/utils/models/translation.py

   1 """
   2 Utilities for creating multilingual fields in your apps.
   3 """
   4
   5 from copy import copy
   6 from django.conf import settings
   7 from django.db import models
   8 from django.utils.translation import get_language, string_concat
   9
  10
  11 def localize_field(name, lang=None):
  12     if lang is None:
  13         lang = get_language()
  14     if lang not in (x[0] for x in settings.LANGUAGES):
  15         lang = settings.LANGUAGE_CODE
  16     return "%s_%s" % (name, lang)
  17
  18 def field_getter(name):
  19     @property
  20     def getter(self):
  21         val = getattr(self, localize_field(name), None)
  22         if not val:
  23             val = getattr(self, localize_field(name, settings.LANGUAGE_CODE))
  24         return val
  25     return getter
  26
  27
  28 def add_translatable(model, fields, languages=None):
  29     """Adds some translatable fields to a model, and a getter."""
  30     if languages is None:
  31         languages = settings.LANGUAGES
  32     for name, field in fields.items():
  33         for lang_code, lang_name in languages:
  34             new_field = copy(field)
  35             if field.verbose_name:
  36                 new_field.verbose_name = string_concat(field.verbose_name, ' [%s]' % lang_code)
  37             new_field.contribute_to_class(model, localize_field(name, lang_code))
  38         setattr(model, name, field_getter(name))
  39         # add setter?
  40
  41
  42 def add_translatable_index(index_class, fields, languages=None):
  43     """Adds some translatable fields to a search index."""
  44     if languages is None:
  45         languages = settings.LANGUAGES
  46     for name, field in fields.items():
  47         for lang_code, lang_name in languages:
  48             new_field = copy(field)
  49             fname = localize_field(name, lang_code)
  50             new_field.index_fieldname = new_field.index_fieldname \
  51                 and localize_field(new_field.index_fieldname, lang_code) \
  52                 or fname
  53             new_field.model_attr = new_field.model_attr \
  54                 and localize_field(new_field.model_attr, lang_code) \
  55                 or fname
  56             setattr(index_class, fname, new_field)
  57             index_class.fields[fname] = new_field
  58
  59
  60 def translated_fields(field_names, languages=settings.LANGUAGES):
  61     """Generate a tuple of field names in translated versions."""
  62     return tuple(localize_field(field_name, lang_code)
  63                 for field_name in field_names
  64                 for lang_code, lang_name in languages
  65                 )
  66
  67 def tQ(**kwargs):
  68     """ Creates a query (Q) with lookups on translated fields. """
  69     trans_kwargs = {}
  70     for k, v in kwargs.items():
  71         trans_kwargs[localize_field(k)] = v
  72     return models.Q(**trans_kwargs)