backend move to tools

weboob/tools/backend.py

@@ -0,0 +1,167 @@
+# -*- coding: utf-8 -*-
+
+# Copyright(C) 2010  Romain Bignon
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, version 3 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+
+import re
+import os
+from threading import RLock
+
+
+__all__ = ['BaseBackend']
+
+
+class BackendStorage(object):
+    def __init__(self, name, storage):
+        self.name = name
+        self.storage = storage
+
+    def set(self, *args):
+        if self.storage:
+            return self.storage.set('backends', self.name, *args)
+
+    def get(self, *args, **kwargs):
+        if self.storage:
+            return self.storage.get('backends', self.name, *args, **kwargs)
+        else:
+            return kwargs.get('default', None)
+
+    def load(self, default):
+        if self.storage:
+            return self.storage.load('backends', self.name, default)
+
+    def save(self):
+        if self.storage:
+            return self.storage.save('backends', self.name)
+
+
+class BaseBackend(object):
+    # Backend name.
+    NAME = None
+    # Name of the maintainer of this backend.
+    MAINTAINER = '<unspecified>'
+    # Email address of the maintainer.
+    EMAIL = '<unspecified>'
+    # Version of backend (for information only).
+    VERSION = '<unspecified>'
+    # Description
+    DESCRIPTION = '<unspecified>'
+    # License of this backend.
+    LICENSE = '<unspecified>'
+    # Icon file path
+    ICON = ''
+    # Configuration required for this backend.
+    # Values must be ConfigField objects.
+    CONFIG = {}
+    # Storage
+    STORAGE = {}
+    # Browser class
+    BROWSER = None
+    # Test class
+    TEST = None
+
+    class ConfigField(object):
+        def __init__(self, default=None, is_masked=False, regexp=None, description=None):
+            self.default = default
+            self.is_masked = is_masked
+            self.regexp = regexp
+            self.description = description
+
+    class ConfigError(Exception): pass
+
+    def __enter__(self):
+        self.lock.acquire()
+
+    def __exit__(self, t, v, tb):
+        self.lock.release()
+
+    def __repr__(self):
+        return u"<Backend '%s'>" % self.name
+
+    def __init__(self, weboob, name, config, storage):
+        self.weboob = weboob
+        self.name = name
+        self.lock = RLock()
+
+        # Private fields (which start with '_')
+        self._private_config = dict([(key, value) for key, value in config.iteritems() if key.startswith('_')])
+
+        # Configuration of backend
+        self.config = {}
+        for name, field in self.CONFIG.iteritems():
+            value = config.get(name, field.default)
+
+            if value is None:
+                raise BaseBackend.ConfigError('Missing parameter "%s" (%s)' % (name, field.description))
+
+            if field.regexp and not re.match(field.regexp, str(value)):
+                raise BaseBackend.ConfigError('Value of "%s" does not match regexp "%s"' % (name, field.regexp))
+
+            if not field.default is None:
+                if isinstance(field.default, bool) and not isinstance(value, bool):
+                    value = value.lower() in ('1', 'true', 'on', 'yes')
+                elif isinstance(field.default, int) and not isinstance(value, int):
+                    value = int(value)
+                elif isinstance(field.default, float) and not isinstance(value, float):
+                    value = float(value)
+            self.config[name] = value
+        self.storage = BackendStorage(self.name, storage)
+        self.storage.load(self.STORAGE)
+
+    @property
+    def browser(self):
+        """
+        Attribute 'browser'. The browser is created at the first call
+        of this attribute, to avoid useless pages access.
+
+        Note that the 'default_browser' method is called to create it.
+        """
+        if not hasattr(self, '_browser'):
+            self._browser = self.default_browser()
+        return self._browser
+
+    def default_browser(self):
+        """
+        Method to overload to build the default browser in
+        attribute 'browser'.
+        """
+        return self.build_browser()
+
+    def build_browser(self, *args, **kwargs):
+        """
+        Build a browser from the BROWSER class attribute and the
+        given arguments.
+        """
+        if not self.BROWSER:
+            return None
+
+        if '_proxy' in self._private_config:
+            kwargs['proxy'] = self._private_config['_proxy']
+        elif 'HTTP_PROXY' in os.environ:
+            kwargs['proxy'] = os.environ['HTTP_PROXY']
+
+        return self.BROWSER(*args, **kwargs)
+
+    def has_caps(self, *caps):
+        for c in caps:
+            if isinstance(self, c):
+                return True
+        return False
+
+    def get_test(self):
+        if not self.TEST:
+            return None
+        return self.TEST(self)