June 2015 – 一江春水向东流

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python升级到2.7.10及使用virtualenv搭建独立的Python环境

python升级到2.7.10及使用virtualenv搭建独立的Python环境 http://qicheng0211.blog.51cto.com/3958621/1561685 重新整理一下（2015-12-2更新）：先下载python2.7.10进行安装：

wget wget https://www.python.org/ftp/python/2.7.10/Python-2.7.10.tgz

tar -zxvf Python-2.7.10.tgz && cd Python-2.7.10 && ./configure --prefix=/usr/local/python2.7 && sudo make && sudo make install

wget wget https://www.python.org/ftp/python/2.7.10/Python-2.7.10.tgz

tar -zxvf Python-2.7.10.tgz && cd Python-2.7.10 && ./configure --prefix=/usr/local/python2.7 && sudo make && sudo make install

系统中在/usr/local/python2.7中安装了一个新版本的python后，再在新版本的python中安装ease_install-2.7, 再用新版本的ease_install-2.7安装pip2.7：

wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py

sudo /usr/local/python2.7/bin/python ez_setup.py 

easy_install-2.7 pip

wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py

sudo /usr/local/python2.7/bin/python ez_setup.py

easy_install-2.7 pip

用新安装的pip2.7安装虚拟环境：

pip2.7 install virtualenv && pip2.7 install virtualenvwrapper

1	pip2.7 install virtualenv && pip2.7 install virtualenvwrapper

在~/.bashrc中定义环境变量：

#PYTHON_HOME=/usr/local/python2.7/bin/
VIRTUALENVWRAPPER_PYTHON=/usr/local/python2.7/bin/python
WORKON_HOME=$HOME/.virtualenvs # 放所有虚拟环境的地方
PROJECT_HOME=$HOME/workspaces # 放所有项目的地方
export PATH=$PATH:$PYTHON_HOME:$WORKON_HOME:$PROJECT_HOME

#PYTHON_HOME=/usr/local/python2.7/bin/

VIRTUALENVWRAPPER_PYTHON=/usr/local/python2.7/bin/python

WORKON_HOME=$HOME/.virtualenvs # 放所有虚拟环境的地方

PROJECT_HOME=$HOME/workspaces # 放所有项目的地方

export PATH=$PATH:$PYTHON_HOME:$WORKON_HOME:$PROJECT_HOME

更新环境变量：

source  ~/.bashrc

source /usr/local/python2.7/bin/virtualenvwrapper.sh

source ~/.bashrc

source /usr/local/python2.7/bin/virtualenvwrapper.sh

指定使用python2.7创建虚拟环境：

mkvirtualenv venv --python=/usr/local/python2.7/bin/python

workon venv

mkvirtualenv venv --python=/usr/local/python2.7/bin/python

workon venv

========================================================= 经过试验，总结教训如下：系统自带的python，也就是/usr/bin/python，一定要使用系统自带的。可以在/usr/local/python2.7.10目录下新安装一个python, 然后使用这个python安装virtualenv和virtualenvwrapper, 然后安装ease_install, pip 然后在~/.bashrc里加入下面内容：

# virtualenv
#export PIP_REQUIRE_VIRTUALENV=true
export WORKON_HOME=$HOME/.virtualenvs
export PROJECT_HOME=/data/apps/opt/myprojects
export VIRTUALENVWRAPPER_PYTHON=/usr/local/python2.7/bin/python
export VIRTUALENVWRAPPER_VIRTUALENV=/usr/local/bin/virtualenv
export VIRTUALENVWRAPPER_VIRTUALENV_ARGS='--no-site-packages'

export tPIP_RESPECT_VIRTUALENV=true#这两句话的意思是pip安装东西的时候不安装到本地环境
source /usr/local/python2.7/bin/virtualenvwrapper.sh

# virtualenv

#export PIP_REQUIRE_VIRTUALENV=true

export WORKON_HOME=$HOME/.virtualenvs

export PROJECT_HOME=/data/apps/opt/myprojects

export VIRTUALENVWRAPPER_PYTHON=/usr/local/python2.7/bin/python

export VIRTUALENVWRAPPER_VIRTUALENV=/usr/local/bin/virtualenv

export VIRTUALENVWRAPPER_VIRTUALENV_ARGS='--no-site-packages'

export tPIP_RESPECT_VIRTUALENV=true#这两句话的意思是pip安装东西的时候不安装到本地环境

source /usr/local/python2.7/bin/virtualenvwrapper.sh

pip安装python-rrdtool时依赖关系报错解决：

tar zxvf pip-1.5.6.tar.gz
cd pip-1.5.6
python setup.py install
yum install gcc cmake make python-devel cairo-devel libxml2 libxml2-devel pango-devel pango libpng-devel freetype freetype-devel libart_lgpl-devel -y
ln -s /usr/lib64/librrd.so.4 /usr/lib64/librrd.so
pip install python-rrdtool-1.4.7

tar zxvf pip-1.5.6.tar.gz

cd pip-1.5.6

python setup.py install

yum install gcc cmake make python-devel cairo-devel libxml2 libxml2-devel pango-devel pango libpng-devel freetype freetype-devel libart_lgpl-devel -y

ln -s /usr/lib64/librrd.so.4 /usr/lib64/librrd.so

pip install python-rrdtool-1.4.7

若报错：Failed building wheel for cryptography和Failed building wheel for cffi，则安装如下包：

sudo yum install gcc libffi-devel python-devel openssl-devel

1	sudo yum install gcc libffi-devel python-devel openssl-devel

以上为2015-10-18号备注。 ========================================================= 下载python2.7.10:

wget wget https://www.python.org/ftp/python/2.7.10/Python-2.7.10.tgz
tar -zxvf Python-2.7.10.tgz
cd Python-2.7.10/
./configure --prefix=/usr/local/python2.7
sudo make && make install

wget wget https://www.python.org/ftp/python/2.7.10/Python-2.7.10.tgz

tar -zxvf Python-2.7.10.tgz

cd Python-2.7.10/

./configure --prefix=/usr/local/python2.7

sudo make && make install

make时报错：Python build finished, but Read more…

By sean, 10 years06/09/2015 ago

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Flask SQLAlchemy 学习

Flask-SQLALchemy 是一个给你的应用添加 SQLALchemy 支持的 Flask 扩展。SQLALchemy 是Python语言的SQL工具包及对象关系映射（ORM）工具，使用MIT许可证发行，提供能兼容众多数据库（如 SQLite、MySQL、Postgres、Oracle、MS-SQL、SQLServer 和 Firebird）的企业级持久性模型。一、为你的Flask应用加载Flask-SqlAlchemy扩展 Code example:

from flask import Flask
from flask.ext.sqlalchemy import SQLAlchemy
 
app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/test.db'
db = SQLAlchemy(app)  #这个就是你以后操作数据库的对象实例了

from flask import Flask

from flask.ext.sqlalchemy import SQLAlchemy

app = Flask(__name__)

app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/test.db'

db = SQLAlchemy(app) #这个就是你以后操作数据库的对象实例了

SQLALCHEMY_DATABASE_URI格式实例：

postgresql://scott:tiger@localhost/mydatabase
mysql://scott:tiger@localhost/mydatabase
oracle://scott:tiger@127.0.0.1:1521/sidname
sqlite:////absolute/path/to/foo.db #注意：有3个斜杠+路径

postgresql://scott:tiger@localhost/mydatabase

mysql://scott:tiger@localhost/mydatabase

oracle://scott:tiger@127.0.0.1:1521/sidname

sqlite:////absolute/path/to/foo.db #注意：有3个斜杠+路径

二、建立数据库模型和初始化数据库建立数据库模型： Code example:

import hashlib
from app import db  #在数据库模型文件中导入上面建立的db对象
 
class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)  # id
    username = db.Column(db.String(80), unique=True)
    email = db.Column(db.String(320), unique=True)
    password = db.Column(db.String(32), nullable=False)
 
    def __init__(self, username, email, password):
        self.username = username
        self.email = email
        self.password= hashlib.md5(password)  #呵呵，这样在插入数据自动给密码哈希了！
 
    def __repr__(self):
        return "<User '{:s}'>".format(self.username)

import hashlib

from app import db #在数据库模型文件中导入上面建立的db对象

class User(db.Model):

id = db.Column(db.Integer, primary_key=True) # id

username = db.Column(db.String(80), unique=True)

email = db.Column(db.String(320), unique=True)

password = db.Column(db.String(32), nullable=False)

def __init__(self, username, email, password):

self.username = username

self.email = email

self.password= hashlib.md5(password) #呵呵，这样在插入数据自动给密码哈希了！

def __repr__(self):

return "<User '{:s}'>".format(self.username)

初始化数据库也特别简单，只需要调用 db.create_all() 函数就可以了。 Code example:

if __name__ == '__main__':
    db.create_all()

1 2	if __name__ == '__main__': db.create_all()

三、插入数据 Code example:

u = User(username='peter', email='test@example.com<script cf-hash="f9e31" type="text/javascript">
/* <![CDATA[ */!function(){try{var t="currentScript"in document?document.currentScript:function(){for(var t=document.getElementsByTagName("script"),e=t.length;e--;)if(t[e].getAttribute("cf-hash"))return t[e]}();if(t&&t.previousSibling){var e,r,n,i,c=t.previousSibling,a=c.getAttribute("data-cfemail");if(a){for(e="",r=parseInt(a.substr(0,2),16),n=2;a.length-n;n+=2)i=parseInt(a.substr(n,2),16)^r,e+=String.fromCharCode(i);e=document.createTextNode(e),c.parentNode.replaceChild(e,c)}}}catch(u){}}();/* ]]> */</script>', password='123456')
db.session.add(u)  #插入数据
db.session.commit()  #只有提交事务了，才可以获取(u.id)数据的ID值。

u = User(username='peter', email='test@example.com<script cf-hash="f9e31" type="text/javascript">

/* <![CDATA[ */!function(){try{var t="currentScript"in document?document.currentScript:function(){for(var t=document.getElementsByTagName("script"),e=t.length;e--;)if(t[e].getAttribute("cf-hash"))return t[e]}();if(t&&t.previousSibling){var e,r,n,i,c=t.previousSibling,a=c.getAttribute("data-cfemail");if(a){for(e="",r=parseInt(a.substr(0,2),16),n=2;a.length-n;n+=2)i=parseInt(a.substr(n,2),16)^r,e+=String.fromCharCode(i);e=document.createTextNode(e),c.parentNode.replaceChild(e,c)}}}catch(u){}}();/* ]]> */</script>', password='123456')

db.session.add(u) #插入数据

db.session.commit() #只有提交事务了，才可以获取(u.id)数据的ID值。

四、查询数据用主键获取数据： Code example:

User.query.get(1)
<User u'admin'>

1 2	User.query.get(1) <User u'admin'>

通过一个精确参数进行反查： Code example:

peter = User.query.filter_by(username='peter').first()  #注意：精确查询函数query.filter_by()，是通过传递参数进行查询；其他增强型查询函数是query.filter()，通过传递表达式进行查询。
print(peter.id)  #如果数据不存在则返回None

1 2	peter = User.query.filter_by(username='peter').first() #注意：精确查询函数query.filter_by()，是通过传递参数进行查询；其他增强型查询函数是query.filter()，通过传递表达式进行查询。 print(peter.id) #如果数据不存在则返回None

模糊查询： Code example:

User.query.filter(User.email.endswith('@example.com')).all()
[<User u'admin'>, <User u'guest'>]

1 2	User.query.filter(User.email.endswith('@example.com')).all() [<User u'admin'>, <User u'guest'>]

逻辑非1： Code example:

peter = User.query.filter(User.username != 'peter').first()
print(peter.id)

1 2	peter = User.query.filter(User.username != 'peter').first() print(peter.id)

逻辑非2： Code Read more…

By sean, 10 years06/02/2015 ago

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