Python版——博客网站<一>基础模块与框架搭建

原创
2017/06/25 20:35
阅读数 532

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__ = 'libingbin2015@aliyun.com'

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__ = 'libingbin2015@aliyun.com'

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__ = 'libingbin2015@aliyun.com'

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__ = '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_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)

本文为博主原创文章,转载请注明出处!

https://my.oschina.net/u/3375733/blog/

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