因为 V2EX:Tornado 中好用的 mysql 的库有什么呢? 帖子,我才想起来我有一个一直在用的 Python 3+ 依赖 pymysql
的 torndb
的修改版,源码如下
#!/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 itertools import logging import os import time import pymysql version = "0.1" version_info = (0, 1, 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 = database.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 the character encoding to UTF-8 on all connections to avoid time zone and encoding errors. """ def __init__(self, host, database, user=None, password=None, max_idle_time=7 * 3600): self.host = host self.database = database self.max_idle_time = max_idle_time args = dict(use_unicode=True, charset="utf8", db=database, sql_mode="TRADITIONAL") 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_init_command = 'SET time_zone = "+0:00"' 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 = pymysql.connect(autocommit=True, **self._db_args) self.execute(self._db_init_command) def iter(self, query, *parameters): """Returns an iterator for the given query and parameters.""" self._ensure_connected() cursor = self._db.cursor(buffered=True) try: self._execute(cursor, query, parameters) 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): """Returns a row list for the given query and parameters.""" cursor = self._cursor() try: self._execute(cursor, query, parameters) 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): """Returns the first row returned for the given query.""" rows = self.query(query, *parameters) 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): """Executes the given query, returning the lastrowid from the query.""" return self.execute_lastrowid(query, *parameters) def execute_lastrowid(self, query, *parameters): """Executes the given query, returning the lastrowid from the query.""" cursor = self._cursor() try: self._execute(cursor, query, parameters) return cursor.lastrowid finally: cursor.close() def execute_rowcount(self, query, *parameters): """Executes the given query, returning the rowcount from the query.""" cursor = self._cursor() try: self._execute(cursor, query, parameters) 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() def _ensure_connected(self): # Mysql by default closes client connections that are idle for # 8 hours, but the client library does not report this fact until # you try to perform a query and it fails. Protect against this # case by preemptively closing and reopening the connection # if it has been idle for too long (7 hours by default). if (self._db is None or (time.time() - self._last_use_time > self.max_idle_time)): self._last_use_time = time.time() self.reconnect() def _cursor(self): self._ensure_connected() return self._db.cursor() def _execute(self, cursor, query, parameters): try: return cursor.execute(query, parameters) except pymysql.OperationalError: logging.error("Error connecting to MySQL on %s", self.host) self.close() raise update = delete = execute_rowcount updatemany = executemany_rowcount insert = execute_lastrowid insertmany = executemany_lastrowid class Row(dict): """A dict that allows for object-like property access syntax.""" def __getattr__(self, name): try: return self[name] except KeyError: raise AttributeError(name)
该修改版依赖 pymysql
,所以需要使用下面的语句安装
pip install pymysql
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