Python库 | torndb3-0.3.tar.gz

#!/usr/bin/env python # # Copyright 2009 Facebook # # Licensed under the Apache License, Version 2.0 (the "License"); you may # not use this file except in compliance with the License. You may obtain # a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the # License for the specific language governing permissions and limitations # under the License. """A lightweight wrapper around MySQLdb. Originally part of the Tornado framework. The tornado.database module is slated for removal in Tornado 3.0, and it is now available separately as torndb. """ from __future__ import absolute_import, division, with_statement import copy import logging import os import time try: import MySQLdb.constants import MySQLdb.converters import MySQLdb.cursors except ImportError: try: import pymysql as MySQLdb except ImportError: # If MySQLdb isn't available this module won't actually be useable, # but we want it to at least be importable on readthedocs.org, # which has limitations on third-party modules. if 'READTHEDOCS' in os.environ: MySQLdb = None else: raise version = "0.3" version_info = (0, 3, 0, 0) class Connection(object): """A lightweight wrapper around MySQLdb DB-API connections. The main value we provide is wrapping rows in a dict/object so that columns can be accessed by name. Typical usage:: db = torndb.Connection("localhost", "mydatabase") for article in db.query("SELECT * FROM articles"): print article.title Cursors are hidden by the implementation, but other than that, the methods are very similar to the DB-API. We explicitly set the timezone to UTC and assume the character encoding to UTF-8 (can be changed) on all connections to avoid time zone and encoding errors. The sql_mode parameter is set by default to "traditional", which "gives an error instead of a warning" (http://dev.mysql.com/doc/refman/5.0/en/server-sql-mode.html). However, it can be set to any other mode including blank (None) thereby explicitly clearing the SQL mode. Arguments read_timeout and write_timeout can be passed using kwargs, if MySQLdb version >= 1.2.5 and MySQL version > 5.1.12. """ def __init__(self, host, database, user=None, password=None, max_idle_time=7 * 3600, connect_timeout=0, time_zone="+0:00", charset="utf8", sql_mode="TRADITIONAL", **kwargs): self.host = host self.database = database self.max_idle_time = float(max_idle_time) args = dict(conv=CONVERSIONS, use_unicode=True, charset=charset, db=database, init_command=('SET time_zone = "%s"' % time_zone), connect_timeout=connect_timeout, sql_mode=sql_mode, **kwargs) if user is not None: args["user"] = user if password is not None: args["passwd"] = password # We accept a path to a MySQL socket file or a host(:port) string if "/" in host: args["unix_socket"] = host else: self.socket = None pair = host.split(":") if len(pair) == 2: args["host"] = pair[0] args["port"] = int(pair[1]) else: args["host"] = host args["port"] = 3306 self._db = None self._db_args = args self._last_use_time = time.time() try: self.reconnect() except Exception: logging.error("Cannot connect to MySQL on %s", self.host, exc_info=True) def __del__(self): self.close() def close(self): """Closes this database connection.""" if getattr(self, "_db", None) is not None: self._db.close() self._db = None def reconnect(self): """Closes the existing database connection and re-opens it.""" self.close() self._db = MySQLdb.connect(**self._db_args) self._db.autocommit(True) def iter(self, query, *parameters, **kwparameters): """Returns an iterator for the given query and parameters.""" self._ensure_connected() cursor = MySQLdb.cursors.SSCursor(self._db) try: self._execute(cursor, query, parameters, kwparameters) column_names = [d[0] for d in cursor.description] for row in cursor: yield Row(zip(column_names, row)) finally: cursor.close() def query(self, query, *parameters, **kwparameters): """Returns a row list for the given query and parameters.""" cursor = self._cursor() try: self._execute(cursor, query, parameters, kwparameters) column_names = [d[0] for d in cursor.description] return [Row(zip(column_names, row)) for row in cursor] finally: cursor.close() def get(self, query, *parameters, **kwparameters): """Returns the (singular) row returned by the given query. If the query has no results, returns None. If it has more than one result, raises an exception. """ rows = self.query(query, *parameters, **kwparameters) if not rows: return None elif len(rows) > 1: raise Exception("Multiple rows returned for Database.get() query") else: return rows[0] # rowcount is a more reasonable default return value than lastrowid, # but for historical compatibility execute() must return lastrowid. def execute(self, query, *parameters, **kwparameters): """Executes the given query, returning the lastrowid from the query.""" return self.execute_lastrowid(query, *parameters, **kwparameters) def execute_lastrowid(self, query, *parameters, **kwparameters): """Executes the given query, returning the lastrowid from the query.""" cursor = self._cursor() try: self._execute(cursor, query, parameters, kwparameters) return cursor.lastrowid finally: cursor.close() def execute_rowcount(self, query, *parameters, **kwparameters): """Executes the given query, returning the rowcount from the query.""" cursor = self._cursor() try: self._execute(cursor, query, parameters, kwparameters) return cursor.rowcount finally: cursor.close() def executemany(self, query, parameters): """Executes the given query against all the given param sequences. We return the lastrowid from the query. """ return self.executemany_lastrowid(query, parameters) def executemany_lastrowid(self, query, parameters): """Executes the given query against all the given param sequences. We return the lastrowid from the query. """ cursor = self._cursor() try: cursor.executemany(query, parameters) return cursor.lastrowid finally: cursor.close() def executemany_rowcount(self, query, parameters): """Executes the given query against all the given param sequences. We return the rowcount from the query. """ cursor = self._cursor() try: cursor.executemany(query, parameters) return cursor.rowcount finally: cursor.close() update = delete = execute_rowcount updatemany = executemany_rowcount insert = execute_lastrowid insertmany = executemany_lastrowid def _ensure_connected(self): # Mysql by default closes client connections tha