i18n/loaders/loader.py
from .. import config
import io
class I18nFileLoadError(Exception):
def __init__(self, value):
self.value = value
def __str__(self):
return str(self.value)
class Loader(object):
"""Base class to load resources"""
def __init__(self):
super(Loader, self).__init__()
self.memoization_dict = {}
def _load_file_data(self, filename):
try:
with io.open(filename, 'r', encoding=config.get('encoding')) as f:
return f.read()
except IOError as e:
raise I18nFileLoadError("error loading file {0}: {1}".format(filename, e.strerror))
def load_file(self, filename):
enable_memoization = config.get('enable_memoization')
if enable_memoization:
if filename not in self.memoization_dict:
self.memoization_dict[filename] = self._load_file_data(filename)
return self.memoization_dict[filename]
else:
return self._load_file_data(filename)
def parse_file(self, file_content):
raise NotImplementedError("the method parse_file has not been implemented for class {0}".format(self.__class__.name__))
def check_data(self, data, root_data):
return True if root_data is None else root_data in data
def get_data(self, data, root_data):
return data if root_data is None else data[root_data]
def load_resource(self, filename, root_data):
file_content = self.load_file(filename)
data = self.parse_file(file_content)
if not self.check_data(data, root_data):
raise I18nFileLoadError("error getting data from {0}: {1} not defined".format(filename, root_data))
return self.get_data(data, root_data)