1. use database
2. use redis
3. inport/export excel2007 version+
from flask import send_from_directory import openpyxl
# not xlwt or xlrd
4. how to debug
5. how to deploy
6. pylint rules 参见
http://pylint-messages.wikidot.com/messages:c0111
7. create a virtualenv
$ virtualenv venv $ source bin/activate venv]$ pip install -r requirements.txt venv]$ deactivate
8. flask-sqlalchemy paginate
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__) app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql+pymysql://user:password@host:port/database?charset=utf8mp4' app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False db_session = SQLAlchemy(app).session obj = db_session.quert(MODEL).filter(...).paginate(page=2, per_page=10) obj.total obj.pages obj.items
问题1：
ORM使用原生SQLAlchemy时报错。
官网参考地址 http://docs.sqlalchemy.org/en/latest/dialects/mysql.html#connection-timeouts
使用姿势如下：
from sqlalchemy import create_engine from sqlalchemy.orm import scoped_session, sessionmaker def create_app(conf_name=None): app = Flask(__name__) ...... db_session = scoped_session(sessionmaker( autocommit=False, autoflush=False, bind=create_engine('mysql+pymysql://{USER}:{PASSWORD}@{HOST}:{PORT}/{DATABASE}?charset=utf8mb4', convert_unicode=True)))
报错如下：
OperationalError: (pymysql.err.OperationalError) (2006, "MySQL server has gone away (error(32, 'Broken pipe'))") or OperationalError: (pymysql.err.OperationalError) (2013, 'Lost connection to MySQL server during query')
解决办法如下：
阅读源码 ./python2.7/site-packages/sqlalchemy/engine/__init__.py 发现
:param pool_recycle=-1: this setting causes the pool to recycle connections after the given number of seconds has passed. It defaults to -1, or no timeout. For example, setting to 3600 means connections will be recycled after one hour. Note that MySQL in particular will disconnect automatically if no activity is detected on a connection for eight hours (although this is configurable with the MySQLDB connection itself and the server configuration as well).
查看MySQL timeout 配置为默认值8小时
mysql> show variables like '%timeout%'; +-----------------------------+----------+ | Variable_name | Value | +-----------------------------+----------+ | connect_timeout | 10 | | delayed_insert_timeout | 300 | | have_statement_timeout | YES | | innodb_flush_log_at_timeout | 1 | | innodb_lock_wait_timeout | 50 | | innodb_rollback_on_timeout | OFF | | interactive_timeout | 28800 | | lock_wait_timeout | 31536000 | | net_read_timeout | 30 | | net_write_timeout | 60 | | rpl_stop_slave_timeout | 31536000 | | slave_net_timeout | 3600 | | thread_pool_idle_timeout | 60 | | wait_timeout | 28800 | +-----------------------------+----------+ 14 rows in set (0.00 sec)
所以在create_engine时新增参数 pool_recycle=3600。
至此 问题修复。