开源地址：https://github.com/leebingbin/Python3.WebAPP.Blog
一、搭建开发环境
首先，确认系统安装的Python版本是否为3.6.x：
在Mac上安装Python。如果你正在使用Mac，系统是OS X 10.8~10.10，那么系统自带的Python版本是2.7。要安装最新的Python 3.6，有两个方法：
方法一：从Python官网下载Python 3.6的安装程序，双击运行并安装；
方法二：如果安装了Homebrew，直接通过命令brew install python3安装即可。
然后，用pip安装开发Web App需要的第三方库：
异步框架aiohttp：
前端模板引擎jinja2：
MySQL 5.x数据库，从官方网站下载并安装，安装完毕后，请务必牢记root口令。
MySQL的Python异步驱动程序aiomysql：
项目结构
选择一个工作目录，然后，我们建立如下的目录结构：
blog-python3-webapp/ <-- 根目录
|
+- backup/ <-- 备份目录
|
+- conf/ <-- 配置文件
|
+- dist/ <-- 打包目录
|
+- www/ <-- Web目录，存放.py文件
| |
| +- static/ <-- 存放静态文件
| |
| +- templates/ <-- 存放模板文件
|
+- ios/ <-- 存放iOS App工程
|
+- android/ <-- 存放Android App工程
|
+- LICENSE <-- 代码LICENSE创建好项目的目录结构后，同时建立git仓库并同步至GitHub （地址：https://github.com/leebingbin/Python3.WebAPP.Blog）。
由于我们的blog-python3-webapp建立在asyncio的基础上，因此用aiohttp写一个基本的app.py测试异步web服务环境等是否正常。
在测试之前，需要先安装第三方模块asyncio。asyncio是Python 3.4版本引入的标准库，直接内置了对异步IO的支持。python 3.4开始就支持异步IO编程，提供了asyncio库，但是3.4中采用的是@asyncio.coroutine和yield from这和原来的generator关键字yield不好区分，在3.5以后，采用了async(表示协程)和await关键字，这样就好区分多了。由于Web框架使用了基于asyncio的aiohttp，这是基于协程的异步模型。在协程中，不能调用普通的同步IO操作，因为所有用户都是由一个线程服务的，协程的执行速度必须非常快，才能处理大量用户的请求。而耗时的IO操作不能在协程中以同步的方式调用，否则，等待一个IO操作时，系统无法响应任何其他用户。
异步编程的一个原则：一旦决定使用异步，则系统每一层都必须是异步。幸运的是aiomysql为MySQL数据库提供了异步IO的驱动。
但在这之前，需要先安装MySQL；毕竟Web App里面有很多地方都要访问数据库。采用dmg的方式安装
1、下载完成后，双击打开
2、右键，选打开，紧接着按照提示，傻瓜式安装即可；但是当弹出一个MYSQL Installer提示框的时候一定打开备忘录复制粘贴记下弹出框的密码（这是你MySQL的root账户的密码）
3、 打开MySQL服务
4、配置路径
用文本编辑器打开.bash_profile，加入PATH=$PATH:/usr/local/mysql/bin并保存。我习惯用 Atom 作为文本编辑器，或者直接用自带的 vim 编辑。在命令行输入source ~/.bash_profile路径就配置好了。
5、登陆并修改密码
登录——mysql -u root -p登陆，输入之前保存的密码
修改密码——用SET PASSWORD FOR 'root'@'localhost' = PASSWORD('root') ;
修改密码。如果你的版本比较新的话（比如我安装的是5.7.x的版本），就会出现如下提示，这个时候已经更新了密码，但是会有 warning。如果想查看warning，可以用SHOW WARNINGS。
6、Mac下MySQL卸载方法 （如果安装错或忘了密码，还不如卸载重装）
mac下mysql的DMG格式安装内有安装文件，却没有卸载文件……很郁闷的事。
先停止所有mysql有关进程。
sudo rm /usr/local/mysql
sudo rm -rf /usr/local/mysql*
sudo rm -rf /Library/StartupItems/MySQLCOM
sudo rm -rf /Library/PreferencePanes/My*
#如果电脑上没有这个文件，跳过这步骤就好
#如果有打开文件，去掉MYSQLCOM=-YES-保存即可
vim /etc/hostconfig (and removed the line MYSQLCOM=-YES-)
rm -rf ~/Library/PreferencePanes/My*
sudo rm -rf /Library/Receipts/mysql*
sudo rm -rf /Library/Receipts/MySQL*
sudo rm -rf /var/db/receipts/com.mysql.*二、用Python写一个ORM
搭建好环境之后，那就让我们用用Python写一个ORM吧！
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
__author__ = '[email protected]'
import asyncio, logging
import aiomysql
def log(sql, args=()):
logging.info('SQL: %s ' % sql)
#创建连接池
async def create_pool(loop, **kw):
logging.info('create database connection pool...')
global __pool
__pool = await aiomysql.create_pool(
host = kw.get('host', 'localhost'),
port = kw.get('port', 3306),
user = kw['root'],
password = kw['toor'],
db = kw['db'],
charset = kw.get('charset', 'utf8mb4'), #utf8mb4是utf8的超集,完全兼容utf8,支持emoji直接插入存储
autocommit = kw.get('autocommit', True),
maxsize = kw.get('maxsizze', 10),
minsize = kw.get('minsize', 1),
loop = loop
)
#CRUD之R
async def select(sql, args, size=None):
log(sql, args)
global __pool
async with __pool.get() as conn:
async with conn.cursor(aiomysql.DictCursor) as cur:
await cur.execute(sql.replace('?', '%s'), args or ()) #SQL语句的占位符是?，而MySQL的占位符是%s，select()函数在内部自动替换。防止SQL注入攻击:注意要始终坚持使用带参数的SQL，而不是自己拼接SQL字符串
if size:
rs = await cur.fetchmany(size) #获取最多指定数量的记录
else:
rs = await cur.fetchall() #获取所有记录
logging.info('rows returned: %s' % len(rs))
return rs
#定义通用的execute()函数,用于执行CRUD方法
async def execute(sql, args, autocommit=True):
log(sql)
async with __pool.get() as conn:
if not autocommit:
await conn.begin()
try:
async with conn.cursor(aiomysql.DictCursor) as cur:
await cur.execute(sql.replace('?', '%s'), args)
affected = cur.rowcount
if not autocommit:
await conn.commit()
except BaseException as e:
if not autocommit:
await conn.rollback()
raise
return affected
def create_args_string(num):
L = []
for n in range(num):
L.append('?')
return ','.join(L)
class Field(object):
def __init__(self, name, column_type, primary_key, default):
self.name = name
self.colum_type = column_type
self.primary_key = primary_key
self.default = default
def __str__(self):
return '<%s , $s:%s>' % (self.__class__.__name__, self.colum_type, self.name)
class StringField(Field):
def __init__(self, name=None, primary_key=False, default=None, ddl='varchar(100)'):
super().__init__(name, ddl, primary_key, default)
class BooleanField(Field):
def __init__(self, name=None, default=False):
super().__init__(name, 'boolean', False, default)
class IntegerField(Field):
def __init__(self, name=None, primary_key=False, default=0):
super().__init__(name, 'bigint', primary_key, default)
class FloatField(Field):
def __init__(self, name=None, primary_key=False, default=0.0):
super().__init__(name, 'real', primary_key, default)
class TextField(Field):
def __init__(self, name=None, default=None):
super().__init__(name, 'text', False, default)
class ModeMetaclass(type):
def __new__(cls, name, bases, attrs):
if name == 'Model':
return type.__new__(cls, name, bases, attrs)
tableName = attrs.get('__table__', None) or name
logging.info('found model: %s (table: %s)' % (name, tableName))
mappings = dict()
fields = []
primaryKey = None
for k, v in attrs.items():
if isinstance(v, Field):
logging.info(' found mapping: %s ==> %s' % (k, v))
mappings[k] = v
if v.primary_key:
# 找到主键
if primaryKey:
raise StandardErroe('Duplicate primary key for field: %s' % k)
primaryKey = k
else:
fields.append(k)
if not primaryKey:
raise StandardError('Primary key not found.')
for k in mappings.keys():
attrs.pop(k)
escaped_fields = list(map(lambda f: '`%s`' % f, fields))
attrs['__mappings__'] = mappings # 保存属性和列的映射关系
attrs['__table__'] = tableName
attrs['__primary_key__'] = primaryKey # 主键属性名
attrs['__fields__'] = fields # 除主键外的属性名
attrs['__select__'] = 'select `%s`, %s from `%s`' % (primaryKey, ', '.join(escaped_fields), tableName)
attrs['__insert__'] = 'insert into `%s` (%s, `%s`) values (%s)' % (tableName, ', '.join(escaped_fields), primaryKey, create_args_string(len(escaped_fields) + 1))
attrs['__update__'] = 'update `%s` set %s where `%s` = ?' % (tableName, ', '.join(map(lambda f: '`%s` = ?' % (mappings.get(f).name or f), fields)), primaryKey)
attrs['__delete__'] = 'delete from `%s` where `%s` = ?' % (tableName, primaryKey)
return type.__new__(cls, name, bases, attrs)
class Model(dict, metaclass=ModelMetaclass):
def __init__(self, **kw):
super(Model, self).__init__(**kw)
def __getattr__(self, key):
try:
return self[key]
except KeyError:
raise AttributeError(r"'Model' object has no attribute '%s'" % key)
def __setattr__(self, key, value):
self[key] = value
def getValue(self, key):
return getattr(self, key, None)
def getValueOrDefault(self, key):
value = getattr(self, key, None)
if value is None:
field = self.__mappings__[key]
if field.default is not None:
value = field.default() if callable(field.default) else field.default
logging.debug('using default value for %s : %s' % (key, str(value)))
setattr(self, key, value)
return value
@classmethod
async def findall(cls, where=None, args=None, **kw):
' find objects by where clause.'
sql = [cls.__slect__]
if where:
sql.append('where')
sql.append(where)
if args is None:
args = []
orderBy = kw.get('orderBy', None)
if orderBy:
sql.append('order by')
sql.append(orderBy)
limit = kw.get('limit', None)
if limit is not None:
sql.append('limit')
if isinstance(limit, int):
sql.append('?')
args.append(limit)
elif isinstance(limit, tuple) and len(limit) == 2:
sql.append('?, ?')
args.extend(limit)
else:
raise ValueError('Invalid limit value: %s' % str(limit))
rs = await select(' '.join(sql), args)
return [cls(**r) for r in rs]
@classmethod
async def findNumber(cls, selectField, where=None, args=None):
' find number by select and where. '
sql = ['select %s _num_ from `%s`' % (selectField, cls.__table__)]
if where:
sql.append('where')
sql.append(where)
rs = await select(' '.join(sql), args, 1)
if len(rs) == 0:
return None
return rs[0]['_num_']
@classmethod
async def find(cls, pk):
' find object by primary key. '
rs = await select('%s where `%s`=?' % (cls.__select__, cls.__primary_key__), [pk], 1)
if len(rs) == 0:
return None
return cls(**rs[0])
async def save(self):
args = list(map(self.getValueOrDefault, self.__fields__))
args.append(self.getValueOrDefault(self.__primary_key__))
rows = await execute(self.__inset__, args)
if rows != 1:
logging.warning('failed to update by primary key: affected rows: %s' % rows)
async def remove(self):
args = [self.getValue(self.__primary_key__)]
rows = await execute(self.__delete__, args)
if rows != 1:
logging.warning('failed to remove by primary key: affected rows: %s' % rows)
有了ORM，我们就可以把Python3.WebAPP.Blog需要的3个表用Model表示出来：
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
'''
Models for user, blog, comment.
'''
__author__ = '[email protected]'
import time, uuid
from orm import Model, StringField, BooleanField, FloatField, TextField
def next_id():
return '%015%s000' % (int(time.time() * 1000), uuid.uuid4().hex)
class User(Model):
__table__ = 'users'
id = StringField(primary_key=True, default=next_id(), ddl='varchar(50)')
email = StringField(ddl='varchar(50)')
passwd = StringField(ddl='varchar(50)')
admin = BooleanField()
name = StringField(ddl='varchar(50)')
image = StringField(ddl='varchar(500)')
created_at = FloatField(default=time.time)
class Blog(Model):
__table__ = 'blogs'
id = StringField(primary_key=True, default=next_id, ddl='varchar(50)')
user_id = StringField(ddl='varchar(50)')
user_name = StringField(ddl='varchar(50)')
user_image = StringField(ddl='varchar(500)')
name = StringField(ddl='varchar(50)')
summary = StringField(ddl='varchar(200)')
content = TextField()
created_at = FloatField(default=time.time)
class Comment(Model):
__table__ = 'comments'
id = StringField(primary_key=True, default=next_id, ddl='varchar(50)')
blog_id = StringField(ddl='varchar(50)')
user_id = StringField(ddl='varchar(50)')
user_name = StringField(ddl='varchar(50)')
user_image = StringField(ddl='varchar(500)')
content = TextField()
created_at = FloatField(default=time.time)
三、编写Web框架
开始Web开发前，我们需要编写一个Web框架。
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
__author__ = '[email protected]'
import asyncio, os, inspect, logging, functools
from urllib import parse
from aiohttp import web
from apis import APIError
def get(path):
'''
Define decorator @get('/path')
'''
def decorator(func):
@functools.wraps(func)
def wrapper(*args, **kw):
return func(*args, **kw)
wrapper.__method__ = 'GET'
wrapper.__route__ = path
return wrapper
return decorator
def post(path):
'''
Define decorator @post('/path')
'''
def decorator(func):
@functools.wraps(func)
def wrapper(*args, **kw):
return func(*args, **kw)
wrapper.__method__ = 'POST'
wrapper.__route__ = path
return wrapper
return decorator
def get_required_kw_args(fn):
args = []
params = inspect.signature(fn).parameters
for name, param in params.items():
if param.kind == inspect.Parameter.KEYWORD_ONLY and param.default == inspect.Parameter.empty:
args.append(name)
return tuple(args)
def get_named_kw_args(fn):
args = []
params = inspect.signature(fn).parameters
for name, param in params.items():
if param.kind == inspect.Parameter.KEYWORD_ONLY:
args.append(name)
return tuple(args)
def has_named_kw_args(fn):
params = inspect.signature(fn).parameters
for name, param in params.items():
if param.kind == inspect.Parameter.KEYWORD_ONLY:
return True
def has_var_kw_arg(fn):
params = inspect.signature(fn).parameters
for name, param in params.items():
if param.kind == inspect.Parameter.VAR_KEYWORD:
return True
def has_request_arg(fn):
sig = inspect.signature(fn)
params = sig.parameters
found = False
for name, param in params.items():
if name == 'request':
found = True
continue
if found and (param.kind != inspect.Parameter.VAR_POSITIONAL and param.kind != inspect.Parameter.KEYWORD_ONLY and param.kind != inspect.Parameter.VAR_KEYWORD):
raise ValueError('request parameter must be the last named parameter in function: %s%s' % (fn.__name__, str(sig)))
return found
class RequestHandler(object):
def __init__(self, app, fn):
self._app = app
self._func = fn
self._has_request_arg = has_request_arg(fn)
self._has_var_kw_arg = has_var_kw_arg(fn)
self._has_named_kw_args = has_named_kw_args(fn)
self._named_kw_args = get_named_kw_args(fn)
self._required_kw_args = get_required_kw_args(fn)
async def __call__(self, request):
kw = None
if self._has_var_kw_arg or self._has_named_kw_args or self._required_kw_args:
if request.method == 'POST':
if not request.content_type:
return web.HTTPBadRequest('Missing Content-Type.')
ct = request.content_type.lower()
if ct.startswith('application/json'):
params = await request.json()
if not isinstance(params, dict):
return web.HTTPBadRequest('JSON body must be object.')
kw = params
elif ct.startswith('application/x-www-form-urlencoded') or ct.startswith('multipart/form-data'):
params = await request.post()
kw = dict(**params)
else:
return web.HTTPBadRequest('Unsupported Content-Type: %s' % request.content_type)
if request.method == 'GET':
qs = request.query_string
if qs:
kw = dict()
for k, v in parse.parse_qs(qs, True).items():
kw[k] = v[0]
if kw is None:
kw = dict(**request.match_info)
else:
if not self._has_var_kw_arg and self._named_kw_args:
# remove all unamed kw:
copy = dict()
for name in self._named_kw_args:
if name in kw:
copy[name] = kw[name]
kw = copy
# check named arg:
for k, v in request.match_info.items():
if k in kw:
logging.warning('Duplicate arg name in named arg and kw args: %s' % k)
kw[k] = v
if self._has_request_arg:
kw['request'] = request
# check required kw:
if self._required_kw_args:
for name in self._required_kw_args:
if not name in kw:
return web.HTTPBadRequest('Missing argument: %s' % name)
logging.info('call with args: %s' % str(kw))
try:
r = await self._func(**kw)
return r
except APIError as e:
return dict(error=e.error, data=e.data, message=e.message)
def add_static(app):
path = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'static')
app.router.add_static('/static/', path)
logging.info('add static %s => %s' % ('/static/', path))
def add_route(app, fn):
method = getattr(fn, '__method__', None)
path = getattr(fn, '__route__', None)
if path is None or method is None:
raise ValueError('@get or @post not defined in %s.' % str(fn))
if not asyncio.iscoroutinefunction(fn) and not inspect.isgeneratorfunction(fn):
fn = asyncio.coroutine(fn)
logging.info('add route %s %s => %s(%s)' % (method, path, fn.__name__, ', '.join(inspect.signature(fn).parameters.keys())))
app.router.add_route(method, path, RequestHandler(app, fn))
def add_routes(app, module_name):
n = module_name.rfind('.')
if n == (-1):
mod = __import__(module_name, globals(), locals())
else:
name = module_name[n+1:]
mod = getattr(__import__(module_name[:n], globals(), locals(), [name]), name)
for attr in dir(mod):
if attr.startswith('_'):
continue
fn = getattr(mod, attr)
if callable(fn):
method = getattr(fn, '__method__', None)
path = getattr(fn, '__route__', None)
if method and path:
add_route(app, fn)
编写配置文件config_default.py ：
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
__author__ = '[email protected]'
'''
Default configurations.
'''
# 'secret': secret 是必需的选项，这是用于签名会话ID cookie的密钥。这可以是单个密钥的字符串或多个秘密的数组(只有第一个元素将用于签名会话ID cookie)而在验证请求中的签名时，将考虑所有元素
# 另外, 考虑到安全性, 这个密钥是不建议存储在的程序中的. 最好的方法是存储在你的系统环境变量中, 通过 os.getenv(key, default=None) 获得
configs = {
'debug': True,
'db': {
'host': '127.0.0.1',
'port': 3306,
'user': 'root',
'password': 'toor',
'db': 'db'
},
'session': {
'secret': '[email protected]'
}
}
编写配置文件config_override.py ：
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
__author__ = '[email protected]'
'''
Override configurations.
'''
configs = {
'db': {
'host': '127.0.0.1'
}
}
把 config_default.py 作为开发环境的标准配置，把 config_override.py 作为生产环境的标准配置，我们就可以既方便地在本地开发，又可以随时把应用部署到服务器上。应用程序读取配置文件需要优先从config_override.py 读取。为了简化读取配置文件，可以把所有配置读取到统一的 config.py 中：
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
__author__ = '[email protected]'
'''
Configuration
'''
import config_default
class Dict(dict):
'''
Simple dict but support access as x.y style.
'''
def __init__(self, names=(), values=(), **kw):
super(Dict, self).__init__(**kw)
for k, v in zip(names, values):
self[k] = v
def __getattr__(self, key):
try:
return self[key]
except KeyError:
raise AttributeError(r"'Dict' object has no attribute '%s'" % key)
def __setattr__(self, key, value):
self[key] = value
def merge(defaults, override):
r = {}
for k, v in defaults.items():
if k in override:
if isinstance(v, dict):
r[k] = merge(v, override[k])
else:
r[k] = override[k]
else:
r[k] = v
return r
def toDict(d):
D = Dict()
for k, v in d.items():
D[k] = toDict(v) if isinstance(v, dict) else v
return D
configs = config_default.configs
try:
import config_override
configs = merge(configs, config_override.configs)
except ImportError:
pass
configs = toDict(configs)
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