Source code for flatisfy.web.dbplugin

# coding: utf-8
This module contains a Bottle plugin to pass the database argument to any route
which needs it.

This module is heavily based on code from
[Bottle-SQLAlchemy]( which is
licensed under MIT license.
from __future__ import (
    absolute_import, division, print_function, unicode_literals

import inspect

import bottle

[docs]class DatabasePlugin(object): """ A Bottle plugin to automatically pass an SQLAlchemy database session object to the routes specifying they need it. """ name = 'database' api = 2 KEYWORD = "db" def __init__(self, get_session): """ :param create_session: SQLAlchemy session maker created with the 'sessionmaker' function. Will create its own if undefined. """ self.get_session = get_session
[docs] def setup(self, app): # pylint: disable=locally-disabled,no-self-use """ Make sure that other installed plugins don't affect the same keyword argument and check if metadata is available. """ for other in app.plugins: if not isinstance(other, DatabasePlugin): continue else: raise bottle.PluginError( "Found another conflicting Database plugin." )
[docs] def apply(self, callback, route): """ Method called on route invocation. Should apply some transformations to the route prior to returing it. We check the presence of ``self.KEYWORD`` in the route signature and replace the route callback by a partial invocation where we replaced this argument by a valid SQLAlchemy session. """ # Check whether the route needs a valid db session or not. try: callback_args = inspect.signature(route.callback).parameters except AttributeError: # inspect.signature does not exist on older Python callback_args = inspect.getargspec(route.callback).args if self.KEYWORD not in callback_args: # If no need for a db session, call the route callback return callback def wrapper(*args, **kwargs): """ Wrap the callback in a call to get_session. """ with self.get_session() as session: # Get a db session and pass it to the callback kwargs[self.KEYWORD] = session return callback(*args, **kwargs) return wrapper
Plugin = DatabasePlugin