Python sqlalchemy.event方法代码示例

# 需要导入模块: import sqlalchemy [as 别名]
# 或者: from sqlalchemy import event [as 别名]
def register_table(table):
	"""
	Register a database table. This will populate the information provided in
	DATABASE_TABLES dictionary. This also forwards signals to the appropriate
	listeners within the :py:mod:`server.signal` module.

	:param cls table: The table to register.
	"""
	metatable = table.metatable()
	database_tables[metatable.name] = metatable

	sqlalchemy.event.listen(table, 'before_delete', forward_signal_delete)
	sqlalchemy.event.listen(table, 'before_insert', forward_signal_insert)
	sqlalchemy.event.listen(table, 'before_update', forward_signal_update)
	return table 

# 需要导入模块: import sqlalchemy [as 别名]
# 或者: from sqlalchemy import event [as 别名]
def _install_session_variables_setter(self):
        session_variables = collections.OrderedDict(self.constant_session_variables)
        session_variables.update(
            sorted(self.config[self.config_section_session_variables].iteritems()))

        setter_sql = 'SET ' + ' , '.join(
            'SESSION {} = {}'.format(name, value)
            for name, value in session_variables.iteritems())

        @sqlalchemy.event.listens_for(self.engine, 'connect')
        def set_session_variable(dbapi_connection, connection_record):
            """
            Execute "SET SESSION <var1> = <val1>, ..." to set the
            variables specified by the `constant_session_variables`
            attribute and in the appropriate configuration section.

            To be called automatically whenever a new low-level
            connection to the database is established.

            WARNING: for simplicity, the variable names and values are
            inserted "as is", *without* any escaping -- we assume we
            can treat config options (and, even more so, Python-level
            object attributes, of course) as a *trusted* source of
            data.
            """
            cursor = dbapi_connection.cursor()
            try:
                cursor.execute(setter_sql)
                cursor.execute('COMMIT')
            finally:
                cursor.close()

    # TODO after SQLAlchemy upgrade to 1.2+:
    # * add `pool_pre_ping = true :: bool` to config
    # * remove this method and the copyright note concerning this method... 

# 需要导入模块: import sqlalchemy [as 别名]
# 或者: from sqlalchemy import event [as 别名]
def _install_reconnector(self):
        # copied from:
        # http://docs.sqlalchemy.org/en/rel_0_9/core/pooling.html#disconnect-handling-pessimistic
        # and slightly adjusted
        @sqlalchemy.event.listens_for(sqlalchemy.pool.Pool, "checkout")
        def ping_connection(dbapi_connection, connection_record, connection_proxy):
            cursor = dbapi_connection.cursor()
            try:
                cursor.execute("SELECT 1")
            except Exception:
                # dispose the whole pool instead of invalidating one at a time
                connection_proxy._pool.dispose()
                # pool will try connecting again up to three times before giving up
                raise sqlalchemy.exc.DisconnectionError()
            cursor.close() 

# 需要导入模块: import sqlalchemy [as 别名]
# 或者: from sqlalchemy import event [as 别名]
def add_cors_headers_response_callback(event):
    def cors_headers(request, response):
        response.headers.update({
        'Access-Control-Allow-Origin': '*',
        'Access-Control-Allow-Methods': 'POST,GET,DELETE,PUT,OPTIONS',
        'Access-Control-Allow-Headers': 'Origin, Content-Type, Accept, Authorization',
        'Access-Control-Allow-Credentials': 'true',
        'Access-Control-Max-Age': '1728000',
        })
    event.request.add_response_callback(cors_headers)