开源地址：

 

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/mysqlsudo rm -rf /usr/local/mysql*sudo rm -rf /Library/StartupItems/MySQLCOMsudo 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__ = 'libingbin2015@aliyun.com'import asyncio, loggingimport aiomysqldef 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Rasync 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 affecteddef 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__ = 'libingbin2015@aliyun.com'import time, uuidfrom orm import Model, StringField, BooleanField, FloatField, TextFielddef 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__ = 'libingbin2015@aliyun.com'import asyncio, os, inspect, logging, functoolsfrom urllib import parsefrom aiohttp import webfrom apis import APIErrordef 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 decoratordef 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 decoratordef 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 Truedef has_var_kw_arg(fn):    params = inspect.signature(fn).parameters    for name, param in params.items():        if param.kind == inspect.Parameter.VAR_KEYWORD:            return Truedef 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 foundclass 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__ = 'libingbin2015@aliyun.com''''    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': 'libingbin2015@aliyun.com'    }}

    编写配置文件config_override.py ：

#!/usr/bin/env python3# -*- coding: utf-8 -*-__author__ = 'libingbin2015@aliyun.com''''    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__ = 'libingbin2015@aliyun.com''''    Configuration'''import config_defaultclass 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] = valuedef 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 rdef toDict(d):    D = Dict()    for k, v in d.items():        D[k] = toDict(v) if isinstance(v, dict) else v    return Dconfigs = config_default.configstry:    import config_override    configs = merge(configs, config_override.configs)except ImportError:    passconfigs = toDict(configs)

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