78 lines
2.5 KiB
Python
78 lines
2.5 KiB
Python
# coding: utf-8
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"""
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This module contains a Bottle plugin to pass the database argument to any route
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which needs it.
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This module is heavily based on code from
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[Bottle-SQLAlchemy](https://github.com/iurisilvio/bottle-sqlalchemy) which is
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licensed under MIT license.
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"""
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from __future__ import absolute_import, division, print_function, unicode_literals
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import inspect
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import bottle
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class DatabasePlugin(object):
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"""
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A Bottle plugin to automatically pass an SQLAlchemy database session object
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to the routes specifying they need it.
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"""
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name = "database"
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api = 2
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KEYWORD = "db"
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def __init__(self, get_session):
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"""
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:param create_session: SQLAlchemy session maker created with the
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'sessionmaker' function. Will create its own if undefined.
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"""
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self.get_session = get_session
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def setup(self, app): # pylint: disable=locally-disabled,no-self-use
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"""
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Make sure that other installed plugins don't affect the same
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keyword argument and check if metadata is available.
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"""
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for other in app.plugins:
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if not isinstance(other, DatabasePlugin):
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continue
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else:
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raise bottle.PluginError("Found another conflicting Database plugin.")
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def apply(self, callback, route):
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"""
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Method called on route invocation. Should apply some transformations to
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the route prior to returing it.
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We check the presence of ``self.KEYWORD`` in the route signature and
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replace the route callback by a partial invocation where we replaced
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this argument by a valid SQLAlchemy session.
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"""
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# Check whether the route needs a valid db session or not.
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try:
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callback_args = inspect.signature(route.callback).parameters
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except AttributeError:
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# inspect.signature does not exist on older Python
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callback_args = inspect.getargspec(route.callback).args
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if self.KEYWORD not in callback_args:
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# If no need for a db session, call the route callback
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return callback
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def wrapper(*args, **kwargs):
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"""
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Wrap the callback in a call to get_session.
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"""
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with self.get_session() as session:
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# Get a db session and pass it to the callback
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kwargs[self.KEYWORD] = session
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return callback(*args, **kwargs)
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return wrapper
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Plugin = DatabasePlugin
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