Introducing data stores

nemubot/datastore/__init__.py

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+# Nemubot is a smart and modulable IM bot.
+# Copyright (C) 2012-2015  Mercier Pierre-Olivier
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from nemubot.datastore.abstract import Abstract
+from nemubot.datastore.xml import XML

nemubot/datastore/abstract.py

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+# Nemubot is a smart and modulable IM bot.
+# Copyright (C) 2012-2015  Mercier Pierre-Olivier
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from nemubot.tools.xmlparser import module_state
+
+
+class Abstract:
+
+    """Abstract implementation of a module data store, that always return an
+    empty set"""
+
+    def open(self):
+        return
+
+    def close(self):
+        return
+
+    def load(self, module):
+        """Load data for the given module
+
+        Argument:
+        module -- the module name of data to load
+
+        Return:
+        The loaded data
+        """
+
+        return module_state.ModuleState("nemubotstate")
+
+    def save(self, module, data):
+        """Load data for the given module
+
+        Argument:
+        module -- the module name of data to load
+        data -- the new data to save
+
+        Return:
+        Saving status
+        """
+
+        return True
+
+    def __enter__(self):
+        self.open()
+        return self
+
+    def __exit__(self, type, value, traceback):
+        self.close()

nemubot/datastore/xml.py

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+# Nemubot is a smart and modulable IM bot.
+# Copyright (C) 2012-2015  Mercier Pierre-Olivier
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+
+from nemubot.datastore.abstract import Abstract
+from nemubot.tools.xmlparser import parse_file
+
+
+class XML(Abstract):
+
+    """A concrete implementation of a data store that relies on XML files"""
+
+    def __init__(self, basedir):
+        self.basedir = basedir
+
+    def open(self):
+        """Lock the directory"""
+
+        if os.path.isdir(self.basedir):
+            lock_file = os.path.join(self.basedir, ".used_by_nemubot")
+            if not os.path.exists(lock_file):
+                with open(lock_file, 'w') as lf:
+                    lf.write(str(os.getpid()))
+                return True
+
+            else:
+                with open(lock_file, 'r') as lf:
+                    pid = lf.readline()
+                raise Exception("Data dir already locked, by PID %s" % pid)
+        return False
+
+    def close(self):
+        """Release a locked path"""
+
+        lock_file = os.path.join(self.basedir, ".used_by_nemubot")
+        if os.path.isdir(self.basedir) and os.path.exists(lock_file):
+            os.unlink(lock_file)
+            return True
+        return False
+
+    def _get_data_file_path(self, module):
+        """Get the path to the module data file"""
+
+        return os.path.join(self.basedir, module + ".xml")
+
+    def load(self, module):
+        """Load data for the given module
+
+        Argument:
+        module -- the module name of data to load
+        """
+
+        data_file = self._get_data_file_path(module)
+        if os.path.isfile(data_file):
+            return parse_file(data_file)
+        else:
+            return Abstract.load(self, module)
+
+    def save(self, module, data):
+        """Load data for the given module
+
+        Argument:
+        module -- the module name of data to load
+        data -- the new data to save
+        """
+
+        return data.save(self._get_data_file_path(module))