Web框架之Tornado-白红宇

Web框架之Tornado

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发布时间：2019-06-13

本文共 42247 字，大约阅读时间需要 140 分钟。

概述

Tornado 是 FriendFeed 使用的可扩展的非阻塞式 web 服务器及其相关工具的开源版本。这个 Web 框架看起来有些像web.py 或者 Google 的 webapp，不过为了能有效利用非阻塞式服务器环境，这个 Web 框架还包含了一些相关的有用工具和优化。

Tornado 和现在的主流 Web 服务器框架（包括大多数 Python 的框架）有着明显的区别：它是非阻塞式服务器，而且速度相当快。得利于其非阻塞的方式和对的运用，Tornado 每秒可以处理数以千计的连接，这意味着对于实时 Web 服务来说，Tornado 是一个理想的 Web 框架。我们开发这个 Web 服务器的主要目的就是为了处理 FriendFeed 的实时功能 ——在 FriendFeed 的应用里每一个活动用户都会保持着一个服务器连接。（关于如何扩容服务器，以处理数以千计的客户端的连接的问题，请参阅。）

下载安装：

pip3 install tornado源码安装https://pypi.python.org/packages/source/t/tornado/tornado-4.3.tar.gz

import tornadopirnt(tornado.version)

框架使用

一、快速上手

#!/usr/bin/env python# -*- coding:utf-8 -*-  import tornado.ioloopimport tornado.web    class MainHandler(tornado.web.RequestHandler):    def get(self):        self.write("Hello, world")  application = tornado.web.Application([    (r"/index", MainHandler),])    if __name__ == "__main__":    application.listen(8888)    tornado.ioloop.IOLoop.instance().start()

执行过程：

第一步：执行脚本，监听 8888 端口

第二步：浏览器客户端访问 /index --> http://127.0.0.1:8888/index

第三步：服务器接受请求，并交由对应的类处理该请求

第四步：类接受到请求之后，根据请求方式（post / get / delete ...）的不同调用并执行相应的方法

第五步：方法返回值的字符串内容发送浏览器

#!/usr/bin/env python# -*- coding:utf-8 -*-#!/usr/bin/env python# -*- coding:utf-8 -*-import tornado.ioloopimport tornado.webfrom tornado import httpclientfrom tornado.web import asynchronousfrom tornado import genimport uimodules as mdimport uimethods as mtclass MainHandler(tornado.web.RequestHandler):        @asynchronous        @gen.coroutine        def get(self):            print 'start get '            http = httpclient.AsyncHTTPClient()            http.fetch("http://127.0.0.1:8008/post/", self.callback)            self.write('end')        def callback(self, response):            print response.bodysettings = {    'template_path': 'template',    'static_path': 'static',    'static_url_prefix': '/static/',    'ui_methods': mt,    'ui_modules': md,}application = tornado.web.Application([    (r"/index", MainHandler),], **settings)if __name__ == "__main__":    application.listen(8009)    tornado.ioloop.IOLoop.instance().start()

异步非阻塞示例

二、路由系统

路由系统其实就是 url 和类的对应关系，这里不同于其他框架，其他很多框架均是 url 对应函数，Tornado中每个url对应的是一个类。

#!/usr/bin/env python# -*- coding:utf-8 -*-  import tornado.ioloopimport tornado.web    class MainHandler(tornado.web.RequestHandler):    def get(self):        self.write("Hello, world")  class StoryHandler(tornado.web.RequestHandler):    def get(self, story_id):        self.write("You requested the story " + story_id)  class BuyHandler(tornado.web.RequestHandler):    def get(self):        self.write("buy.wupeiqi.com/index")  application = tornado.web.Application([    (r"/index", MainHandler),    (r"/story/([0-9]+)", StoryHandler),])  application.add_handlers('buy.wupeiqi.com$', [    (r'/index',BuyHandler),])  if __name__ == "__main__":    application.listen(80)    tornado.ioloop.IOLoop.instance().start()

Tornado中原生支持二级域名的路由，如：

三、模板引擎

Tornao中的模板语言和django中类似，模板引擎将模板文件载入内存，然后将数据嵌入其中，最终获取到一个完整的字符串，再将字符串返回给请求者。

Tornado 的模板支持“控制语句”和“表达语句”，控制语句是使用 {% 和 %} 包起来的例如 {% if len(items) > 2 %}。表达语句是使用 {

和 }} 包起来的，例如

{ 
      { items[0] }}

。

控制语句和对应的 Python 语句的格式基本完全相同。我们支持 if、for、while 和 try，这些语句逻辑结束的位置需要用 {% end %} 做标记。还通过 extends 和 block 语句实现了模板继承。这些在的代码文档中有着详细的描述。

注：在使用模板前需要在setting中设置模板路径："template_path" : "tpl"

1、基本使用

#!/usr/bin/env python# -*- coding:utf-8 -*-  import tornado.ioloopimport tornado.web    class MainHandler(tornado.web.RequestHandler):    def get(self):        self.render("index.html", list_info = [11,22,33])  application = tornado.web.Application([    (r"/index", MainHandler),])    if __name__ == "__main__":    application.listen(8888)    tornado.ioloop.IOLoop.instance().start()

app.py

    
           老男孩    
           
               
        
                     {
      % for item in list_info %}                
         {
     {item}}
            {
      % end %}

index.html

在模板中默认提供了一些函数、字段、类以供模板使用：escape: tornado.escape.xhtml_escape 的別名xhtml_escape: tornado.escape.xhtml_escape 的別名url_escape: tornado.escape.url_escape 的別名json_encode: tornado.escape.json_encode 的別名squeeze: tornado.escape.squeeze 的別名linkify: tornado.escape.linkify 的別名datetime: Python 的 datetime 模组handler: 当前的 RequestHandler 对象request: handler.request 的別名current_user: handler.current_user 的別名locale: handler.locale 的別名_: handler.locale.translate 的別名static_url: for handler.static_url 的別名xsrf_form_html: handler.xsrf_form_html 的別名

其他方法

2、母版

    
           老男孩    
           {% block CSS %}{% end %}    
           
       
        {% block RenderBody %}{% end %}               {% block JavaScript %}{% end %}

layout.html

{% extends 'layout.html'%}{% block CSS %}    
       {% end %}{% block RenderBody %}    Index
    
       
            {%  for item in li %}        
        {
     {item}}
    {% end %}    
       
{% end %}{% block JavaScript %}    {% end %}

index.html

3、导入

header.html

    
           老男孩    
           
       
                {% include 'header.html' %}

index.html

4、自定义UIMethod以UIModule

a. 定义

# uimethods.py def tab(self):    return 'UIMethod'

uimethods.py

#!/usr/bin/env python# -*- coding:utf-8 -*-from tornado.web import UIModulefrom tornado import escapeclass custom(UIModule):    def render(self, *args, **kwargs):        return escape.xhtml_escape('wupeiqi
')        #return escape.xhtml_escape('wupeiqi
')

uimodules.py

b. 注册

#!/usr/bin/env python# -*- coding:utf-8 -*-#!/usr/bin/env python# -*- coding:utf-8 -*-import tornado.ioloopimport tornado.webfrom tornado.escape import linkifyimport uimodules as mdimport uimethods as mtclass MainHandler(tornado.web.RequestHandler):    def get(self):        self.render('index.html')settings = {    'template_path': 'template',    'static_path': 'static',    'static_url_prefix': '/static/',    'ui_methods': mt,    'ui_modules': md,}application = tornado.web.Application([    (r"/index", MainHandler),], **settings)if __name__ == "__main__":    application.listen(8009)    tornado.ioloop.IOLoop.instance().start()

View Code

c. 使用

    
               
           hello
    {
      % module custom(123) %}    {
      { tab() }}

View Code

四、静态文件

对于静态文件，可以配置静态文件的目录和前段使用时的前缀，并且Tornaodo还支持静态文件缓存。

#!/usr/bin/env python# -*- coding:utf-8 -*- import tornado.ioloopimport tornado.web  class MainHandler(tornado.web.RequestHandler):    def get(self):        self.render('home/index.html') settings = {    'template_path': 'template',    'static_path': 'static',    'static_url_prefix': '/static/',} application = tornado.web.Application([    (r"/index", MainHandler),], **settings)  if __name__ == "__main__":    application.listen(80)    tornado.ioloop.IOLoop.instance().start()

app.py

    
               
           hello

index.html

注：静态文件缓存的实现

def get_content_version(cls, abspath):        """Returns a version string for the resource at the given path.        This class method may be overridden by subclasses.  The        default implementation is a hash of the file's contents.        .. versionadded:: 3.1        """        data = cls.get_content(abspath)        hasher = hashlib.md5()        if isinstance(data, bytes):            hasher.update(data)        else:            for chunk in data:                hasher.update(chunk)        return hasher.hexdigest()

View Code

五、cookie

Tornado中可以对cookie进行操作，并且还可以对cookie进行签名以放置伪造。

1、基本操作

class MainHandler(tornado.web.RequestHandler):    def get(self):        if not self.get_cookie("mycookie"):            self.set_cookie("mycookie", "myvalue")            self.write("Your cookie was not set yet!")        else:            self.write("Your cookie was set!")

View Code

2、加密cookie（签名）

Cookie 很容易被恶意的客户端伪造。加入你想在 cookie 中保存当前登陆用户的 id 之类的信息，你需要对 cookie 作签名以防止伪造。Tornado 通过 set_secure_cookie 和 get_secure_cookie 方法直接支持了这种功能。要使用这些方法，你需要在创建应用时提供一个密钥，名字为 cookie_secret。你可以把它作为一个关键词参数传入应用的设置中：

class MainHandler(tornado.web.RequestHandler):    def get(self):        if not self.get_secure_cookie("mycookie"):            self.set_secure_cookie("mycookie", "myvalue")            self.write("Your cookie was not set yet!")        else:            self.write("Your cookie was set!")             application = tornado.web.Application([    (r"/", MainHandler),], cookie_secret="61oETzKXQAGaYdkL5gEmGeJJFuYh7EQnp2XdTP1o/Vo=")

View Code

def _create_signature_v1(secret, *parts):    hash = hmac.new(utf8(secret), digestmod=hashlib.sha1)    for part in parts:        hash.update(utf8(part))    return utf8(hash.hexdigest())# 加密def _create_signature_v2(secret, s):    hash = hmac.new(utf8(secret), digestmod=hashlib.sha256)    hash.update(utf8(s))    return utf8(hash.hexdigest())def create_signed_value(secret, name, value, version=None, clock=None,                        key_version=None):    if version is None:        version = DEFAULT_SIGNED_VALUE_VERSION    if clock is None:        clock = time.time    timestamp = utf8(str(int(clock())))    value = base64.b64encode(utf8(value))    if version == 1:        signature = _create_signature_v1(secret, name, value, timestamp)        value = b"|".join([value, timestamp, signature])        return value    elif version == 2:        # The v2 format consists of a version number and a series of        # length-prefixed fields "%d:%s", the last of which is a        # signature, all separated by pipes.  All numbers are in        # decimal format with no leading zeros.  The signature is an        # HMAC-SHA256 of the whole string up to that point, including        # the final pipe.        #        # The fields are:        # - format version (i.e. 2; no length prefix)        # - key version (integer, default is 0)        # - timestamp (integer seconds since epoch)        # - name (not encoded; assumed to be ~alphanumeric)        # - value (base64-encoded)        # - signature (hex-encoded; no length prefix)        def format_field(s):            return utf8("%d:" % len(s)) + utf8(s)        to_sign = b"|".join([            b"2",            format_field(str(key_version or 0)),            format_field(timestamp),            format_field(name),            format_field(value),            b''])        if isinstance(secret, dict):            assert key_version is not None, 'Key version must be set when sign key dict is used'            assert version >= 2, 'Version must be at least 2 for key version support'            secret = secret[key_version]        signature = _create_signature_v2(secret, to_sign)        return to_sign + signature    else:        raise ValueError("Unsupported version %d" % version)# 解密def _decode_signed_value_v1(secret, name, value, max_age_days, clock):    parts = utf8(value).split(b"|")    if len(parts) != 3:        return None    signature = _create_signature_v1(secret, name, parts[0], parts[1])    if not _time_independent_equals(parts[2], signature):        gen_log.warning("Invalid cookie signature %r", value)        return None    timestamp = int(parts[1])    if timestamp < clock() - max_age_days * 86400:        gen_log.warning("Expired cookie %r", value)        return None    if timestamp > clock() + 31 * 86400:        # _cookie_signature does not hash a delimiter between the        # parts of the cookie, so an attacker could transfer trailing        # digits from the payload to the timestamp without altering the        # signature.  For backwards compatibility, sanity-check timestamp        # here instead of modifying _cookie_signature.        gen_log.warning("Cookie timestamp in future; possible tampering %r",                        value)        return None    if parts[1].startswith(b"0"):        gen_log.warning("Tampered cookie %r", value)        return None    try:        return base64.b64decode(parts[0])    except Exception:        return Nonedef _decode_fields_v2(value):    def _consume_field(s):        length, _, rest = s.partition(b':')        n = int(length)        field_value = rest[:n]        # In python 3, indexing bytes returns small integers; we must        # use a slice to get a byte string as in python 2.        if rest[n:n + 1] != b'|':            raise ValueError("malformed v2 signed value field")        rest = rest[n + 1:]        return field_value, rest    rest = value[2:]  # remove version number    key_version, rest = _consume_field(rest)    timestamp, rest = _consume_field(rest)    name_field, rest = _consume_field(rest)    value_field, passed_sig = _consume_field(rest)    return int(key_version), timestamp, name_field, value_field, passed_sigdef _decode_signed_value_v2(secret, name, value, max_age_days, clock):    try:        key_version, timestamp, name_field, value_field, passed_sig = _decode_fields_v2(value)    except ValueError:        return None    signed_string = value[:-len(passed_sig)]    if isinstance(secret, dict):        try:            secret = secret[key_version]        except KeyError:            return None    expected_sig = _create_signature_v2(secret, signed_string)    if not _time_independent_equals(passed_sig, expected_sig):        return None    if name_field != utf8(name):        return None    timestamp = int(timestamp)    if timestamp < clock() - max_age_days * 86400:        # The signature has expired.        return None    try:        return base64.b64decode(value_field)    except Exception:        return Nonedef get_signature_key_version(value):    value = utf8(value)    version = _get_version(value)    if version < 2:        return None    try:        key_version, _, _, _, _ = _decode_fields_v2(value)    except ValueError:        return None    return key_version

内部算法

签名Cookie的本质是：

写cookie过程：

将值进行base64加密

对除值以外的内容进行签名，哈希算法（无法逆向解析）

拼接签名 + 加密值

读cookie过程：

读取签名 + 加密值

对签名进行验证

base64解密，获取值内容

注：许多API验证机制和安全cookie的实现机制相同。

#!/usr/bin/env python# -*- coding:utf-8 -*- import tornado.ioloopimport tornado.web  class MainHandler(tornado.web.RequestHandler):     def get(self):        login_user = self.get_secure_cookie("login_user", None)        if login_user:            self.write(login_user)        else:            self.redirect('/login')  class LoginHandler(tornado.web.RequestHandler):    def get(self):        self.current_user()         self.render('login.html', **{
     'status': ''})     def post(self, *args, **kwargs):         username = self.get_argument('name')        password = self.get_argument('pwd')        if username == 'wupeiqi' and password == '123':            self.set_secure_cookie('login_user', '武沛齐')            self.redirect('/')        else:            self.render('login.html', **{
     'status': '用户名或密码错误'}) settings = {    'template_path': 'template',    'static_path': 'static',    'static_url_prefix': '/static/',    'cookie_secret': 'aiuasdhflashjdfoiuashdfiuh'} application = tornado.web.Application([    (r"/index", MainHandler),    (r"/login", LoginHandler),], **settings)  if __name__ == "__main__":    application.listen(8888)    tornado.ioloop.IOLoop.instance().start()

基于Cookie实现用户验证-Demo

#!/usr/bin/env python# -*- coding:utf-8 -*- import tornado.ioloopimport tornado.web class BaseHandler(tornado.web.RequestHandler):     def get_current_user(self):        return self.get_secure_cookie("login_user") class MainHandler(BaseHandler):     @tornado.web.authenticated    def get(self):        login_user = self.current_user        self.write(login_user)   class LoginHandler(tornado.web.RequestHandler):    def get(self):        self.current_user()         self.render('login.html', **{
     'status': ''})     def post(self, *args, **kwargs):         username = self.get_argument('name')        password = self.get_argument('pwd')        if username == 'wupeiqi' and password == '123':            self.set_secure_cookie('login_user', '武沛齐')            self.redirect('/')        else:            self.render('login.html', **{
     'status': '用户名或密码错误'}) settings = {    'template_path': 'template',    'static_path': 'static',    'static_url_prefix': '/static/',    'cookie_secret': 'aiuasdhflashjdfoiuashdfiuh',    'login_url': '/login'} application = tornado.web.Application([    (r"/index", MainHandler),    (r"/login", LoginHandler),], **settings)  if __name__ == "__main__":    application.listen(8888)    tornado.ioloop.IOLoop.instance().start()

基于签名Cookie实现用户验证-Demo

3、JavaScript操作Cookie

由于Cookie保存在浏览器端，所以在浏览器端也可以使用JavaScript来操作Cookie。

/*        设置cookie，指定秒数过期         */        function setCookie(name,value,expires){            var temp = [];            var current_date = new Date();            current_date.setSeconds(current_date.getSeconds() + 5);            document.cookie = name + "= "+ value +";expires=" + current_date.toUTCString();        }

对于参数：

domain 指定域名下的cookie

path 域名下指定url中的cookie

secure https使用

注：jQuery中也有指定的插件 jQuery Cookie 专门用于操作cookie，

六、CSRF

Tornado中的夸张请求伪造和Django中的相似，

settings = {    "xsrf_cookies": True,}application = tornado.web.Application([    (r"/", MainHandler),    (r"/login", LoginHandler),], **settings)

配置


       
          {
      { xsrf_form_html() }}

使用 - 普通表单

function getCookie(name) {    var r = document.cookie.match("\\b" + name + "=([^;]*)\\b");    return r ? r[1] : undefined;}jQuery.postJSON = function(url, args, callback) {    args._xsrf = getCookie("_xsrf");    $.ajax({url: url, data: $.param(args), dataType: "text", type: "POST",        success: function(response) {        callback(eval("(" + response + ")"));    }});};

使用 - AJAX

注：Ajax使用时，本质上就是去获取本地的cookie，携带cookie再来发送请求

七、上传文件

1、Form表单上传

    
           上传文件

HTML

#!/usr/bin/env python# -*- coding:utf-8 -*-import tornado.ioloopimport tornado.webclass MainHandler(tornado.web.RequestHandler):    def get(self):        self.render('index.html')    def post(self, *args, **kwargs):        file_metas = self.request.files["fff"]        # print(file_metas)        for meta in file_metas:            file_name = meta['filename']            with open(file_name,'wb') as up:                up.write(meta['body'])settings = {    'template_path': 'template',}application = tornado.web.Application([    (r"/index", MainHandler),], **settings)if __name__ == "__main__":    application.listen(8000)    tornado.ioloop.IOLoop.instance().start()

Python

2、AJAX上传

HTML - XMLHttpRequest

HTML - jQuery

HTML - iframe

#!/usr/bin/env python# -*- coding:utf-8 -*-import tornado.ioloopimport tornado.webclass MainHandler(tornado.web.RequestHandler):    def get(self):        self.render('index.html')    def post(self, *args, **kwargs):        file_metas = self.request.files["fff"]        # print(file_metas)        for meta in file_metas:            file_name = meta['filename']            with open(file_name,'wb') as up:                up.write(meta['body'])settings = {    'template_path': 'template',}application = tornado.web.Application([    (r"/index", MainHandler),], **settings)if __name__ == "__main__":    application.listen(8000)    tornado.ioloop.IOLoop.instance().start()

Python

扩展：基于iframe实现Ajax上传示例

$('#upload_iframe').load(function(){                    var iframeContents = this.contentWindow.document.body.innerText;                    iframeContents = JSON.parse(iframeContents);                                   })

View Code

function bindChangeAvatar1() {            $('#avatarImg').change(function () {                var file_obj = $(this)[0].files[0];                $('#prevViewImg')[0].src = window.URL.createObjectURL(file_obj)            })        }        function bindChangeAvatar2() {            $('#avatarImg').change(function () {                var file_obj = $(this)[0].files[0];                var reader = new FileReader();                reader.readAsDataURL(file_obj);                reader.onload = function (e) {                    $('#previewImg')[0].src = this.result;                };            })        }        function bindChangeAvatar3() {            $('#avatarImg').change(function () {                var file_obj = $(this)[0].files[0];                var form = new FormData();                form.add('img_upload', file_obj);                $.ajax({                    url: '',                    data: form,                    processData: false,  // tell jQuery not to process the data                    contentType: false,  // tell jQuery not to set contentType                    success: function (arg) {                    }                })            })        }        function bindChangeAvatar4() {            $('#avatarImg').change(function () {                $(this).parent().submit();                $('#upload_iframe').load(function () {                    var iframeContents = this.contentWindow.document.body.innerText;                    iframeContents = JSON.parse(iframeContents);                    if (iframeContents.status) {                        $('#previewImg').attr('src', '/' + iframeContents.data);                    }                })            })        }

其他

八、验证码

验证码原理在于后台自动创建一张带有随机内容的图片，然后将内容通过img标签输出到页面。

安装图像处理模块：

pip3 install pillow

示例截图：

验证码Demo源码下载：

九、异步非阻塞

1、基本使用

装饰器 + Future 从而实现Tornado的异步非阻塞

class AsyncHandler(tornado.web.RequestHandler):        @gen.coroutine        def get(self):            future = Future()            future.add_done_callback(self.doing)            yield future            # 或            # tornado.ioloop.IOLoop.current().add_future(future,self.doing)            # yield future        def doing(self,*args, **kwargs):            self.write('async')            self.finish()

当发送GET请求时，由于方法被@gen.coroutine装饰且yield 一个 Future对象，那么Tornado会等待，等待用户向future对象中放置数据或者发送信号，如果获取到数据或信号之后，就开始执行doing方法。

异步非阻塞体现在当在Tornaod等待用户向future对象中放置数据时，还可以处理其他请求。

注意：在等待用户向future对象中放置数据或信号时，此连接是不断开的。

2、同步阻塞和异步非阻塞对比

class SyncHandler(tornado.web.RequestHandler):    def get(self):        self.doing()        self.write('sync')    def doing(self):        time.sleep(10)

同步阻塞

class AsyncHandler(tornado.web.RequestHandler):    @gen.coroutine    def get(self):        future = Future()        tornado.ioloop.IOLoop.current().add_timeout(time.time() + 5, self.doing)        yield future    def doing(self, *args, **kwargs):        self.write('async')        self.finish()

异步非阻塞

3、httpclient类库

Tornado提供了httpclient类库用于发送Http请求，其配合Tornado的异步非阻塞使用。

class AsyncHandler(tornado.web.RequestHandler):    @gen.coroutine    def get(self):        from tornado import httpclient        http = httpclient.AsyncHTTPClient()        yield http.fetch("http://www.google.com", self.endding)    def endding(self, response):        print(len(response.body))        self.write('ok')        self.finish()

mysql：https://github.com/PyMySQL/Tornado-MySQL#installation

自定义Web组件

一、Session

1、面向对象基础

面向对象中通过索引的方式访问对象，需要内部实现 __getitem__ 、__delitem__、__setitem__方法

#!/usr/bin/env python# -*- coding:utf-8 -*-  class Foo(object):      def __getitem__(self, key):        print  '__getitem__',key      def __setitem__(self, key, value):        print '__setitem__',key,value      def __delitem__(self, key):        print '__delitem__',key      obj = Foo()result = obj['k1']#obj['k2'] = 'wupeiqi'#del obj['k1']

2、Tornado扩展

Tornado框架中，默认执行Handler的get/post等方法之前默认会执行 initialize方法，所以可以通过自定义的方式使得所有请求在处理前执行操作...

class BaseHandler(tornado.web.RequestHandler):      def initialize(self):        self.xxoo = "wupeiqi"    class MainHandler(BaseHandler):      def get(self):        print(self.xxoo)        self.write('index')class IndexHandler(BaseHandler):      def get(self):        print(self.xxoo)        self.write('index')

3、session

session其实就是定义在服务器端用于保存用户回话的容器，其必须依赖cookie才能实现。

#!/usr/bin/env python# -*- coding:utf-8 -*-import configfrom hashlib import sha1import osimport timecreate_session_id = lambda: sha1(bytes('%s%s' % (os.urandom(16), time.time()), encoding='utf-8')).hexdigest()class SessionFactory:    @staticmethod    def get_session_obj(handler):        obj = None        if config.SESSION_TYPE == "cache":            obj = CacheSession(handler)        elif config.SESSION_TYPE == "memcached":            obj = MemcachedSession(handler)        elif config.SESSION_TYPE == "redis":            obj = RedisSession(handler)        return objclass CacheSession:    session_container = {}    session_id = "__sessionId__"    def __init__(self, handler):        self.handler = handler        client_random_str = handler.get_cookie(CacheSession.session_id, None)        if client_random_str and client_random_str in CacheSession.session_container:            self.random_str = client_random_str        else:            self.random_str = create_session_id()            CacheSession.session_container[self.random_str] = {}        expires_time = time.time() + config.SESSION_EXPIRES        handler.set_cookie(CacheSession.session_id, self.random_str, expires=expires_time)    def __getitem__(self, key):        ret = CacheSession.session_container[self.random_str].get(key, None)        return ret    def __setitem__(self, key, value):        CacheSession.session_container[self.random_str][key] = value    def __delitem__(self, key):        if key in CacheSession.session_container[self.random_str]:            del CacheSession.session_container[self.random_str][key]class RedisSession:    def __init__(self, handler):        passclass MemcachedSession:    def __init__(self, handler):        pass

自定义Session

4、分布式Session

#!/usr/bin/env python#coding:utf-8import sysimport mathfrom bisect import bisectif sys.version_info >= (2, 5):    import hashlib    md5_constructor = hashlib.md5else:    import md5    md5_constructor = md5.newclass HashRing(object):    """一致性哈希"""        def __init__(self,nodes):        '''初始化        nodes : 初始化的节点，其中包含节点已经节点对应的权重                默认每一个节点有32个虚拟节点                对于权重，通过多创建虚拟节点来实现                如：nodes = [                        {'host':'127.0.0.1:8000','weight':1},                        {'host':'127.0.0.1:8001','weight':2},                        {'host':'127.0.0.1:8002','weight':1},                    ]        '''                self.ring = dict()        self._sorted_keys = []        self.total_weight = 0                self.__generate_circle(nodes)                                    def __generate_circle(self,nodes):        for node_info in nodes:            self.total_weight += node_info.get('weight',1)                    for node_info in nodes:            weight = node_info.get('weight',1)            node = node_info.get('host',None)                            virtual_node_count = math.floor((32*len(nodes)*weight) / self.total_weight)            for i in xrange(0,int(virtual_node_count)):                key = self.gen_key_thirty_two( '%s-%s' % (node, i) )                if self._sorted_keys.__contains__(key):                    raise Exception('该节点已经存在.')                self.ring[key] = node                self._sorted_keys.append(key)                def add_node(self,node):        ''' 新建节点        node : 要添加的节点，格式为：{'host':'127.0.0.1:8002','weight':1}，其中第一个元素表示节点，第二个元素表示该节点的权重。        '''        node = node.get('host',None)        if not node:                raise Exception('节点的地址不能为空.')                        weight = node.get('weight',1)                self.total_weight += weight        nodes_count = len(self._sorted_keys) + 1                virtual_node_count = math.floor((32 * nodes_count * weight) / self.total_weight)        for i in xrange(0,int(virtual_node_count)):            key = self.gen_key_thirty_two( '%s-%s' % (node, i) )            if self._sorted_keys.__contains__(key):                raise Exception('该节点已经存在.')            self.ring[key] = node            self._sorted_keys.append(key)            def remove_node(self,node):        ''' 移除节点        node : 要移除的节点 '127.0.0.1:8000'        '''        for key,value in self.ring.items():            if value == node:                del self.ring[key]                self._sorted_keys.remove(key)        def get_node(self,string_key):        '''获取 string_key 所在的节点'''        pos = self.get_node_pos(string_key)        if pos is None:            return None        return self.ring[ self._sorted_keys[pos]].split(':')        def get_node_pos(self,string_key):        '''获取 string_key 所在的节点的索引'''        if not self.ring:            return None                    key = self.gen_key_thirty_two(string_key)        nodes = self._sorted_keys        pos = bisect(nodes, key)        return pos        def gen_key_thirty_two(self, key):                m = md5_constructor()        m.update(key)        return long(m.hexdigest(), 16)            def gen_key_sixteen(self,key):                b_key = self.__hash_digest(key)        return self.__hash_val(b_key, lambda x: x)    def __hash_val(self, b_key, entry_fn):        return (( b_key[entry_fn(3)] << 24)|(b_key[entry_fn(2)] << 16)|(b_key[entry_fn(1)] << 8)| b_key[entry_fn(0)] )    def __hash_digest(self, key):        m = md5_constructor()        m.update(key)        return map(ord, m.digest())"""nodes = [    {'host':'127.0.0.1:8000','weight':1},    {'host':'127.0.0.1:8001','weight':2},    {'host':'127.0.0.1:8002','weight':1},]ring = HashRing(nodes)result = ring.get_node('98708798709870987098709879087')print result"""

一致性哈西

from hashlib import sha1import os, timecreate_session_id = lambda: sha1('%s%s' % (os.urandom(16), time.time())).hexdigest()class Session(object):    session_id = "__sessionId__"    def __init__(self, request):        session_value = request.get_cookie(Session.session_id)        if not session_value:            self._id = create_session_id()        else:            self._id = session_value        request.set_cookie(Session.session_id, self._id)    def __getitem__(self, key):        # 根据 self._id ，在一致性哈西中找到其对应的服务器IP        # 找到相对应的redis服务器，如： r = redis.StrictRedis(host='localhost', port=6379, db=0)        # 使用python redis api 链接        # 获取数据，即：        # return self._redis.hget(self._id, name)    def __setitem__(self, key, value):        # 根据 self._id ，在一致性哈西中找到其对应的服务器IP        # 使用python redis api 链接        # 设置session        # self._redis.hset(self._id, name, value)    def __delitem__(self, key):        # 根据 self._id 找到相对应的redis服务器        # 使用python redis api 链接        # 删除，即：        return self._redis.hdel(self._id, name)

session

二、表单验证

在Web程序中往往包含大量的表单验证的工作，如：判断输入是否为空，是否符合规则。

HTML

#!/usr/bin/env python# -*- coding:utf-8 -*-  import tornado.ioloopimport tornado.webfrom hashlib import sha1import os, timeimport re    class MainForm(object):    def __init__(self):        self.host = "(.*)"        self.ip = "^(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}$"        self.port = '(\d+)'        self.phone = '^1[3|4|5|8][0-9]\d{8}$'      def check_valid(self, request):        form_dict = self.__dict__        for key, regular in form_dict.items():            post_value = request.get_argument(key)            # 让提交的数据 和 定义的正则表达式进行匹配            ret = re.match(regular, post_value)            print key,ret,post_value    class MainHandler(tornado.web.RequestHandler):    def get(self):        self.render('index.html')    def post(self, *args, **kwargs):        obj = MainForm()        result = obj.check_valid(self)        self.write('ok')      settings = {    'template_path': 'template',    'static_path': 'static',    'static_url_prefix': '/static/',    'cookie_secret': 'aiuasdhflashjdfoiuashdfiuh',    'login_url': '/login'}  application = tornado.web.Application([    (r"/index", MainHandler),], **settings)    if __name__ == "__main__":    application.listen(8888)    tornado.ioloop.IOLoop.instance().start()

Python

由于验证规则可以代码重用，所以可以如此定义：

#!/usr/bin/env python# -*- coding:utf-8 -*-import tornado.ioloopimport tornado.webimport reclass Field(object):    def __init__(self, error_msg_dict, required):        self.id_valid = False        self.value = None        self.error = None        self.name = None        self.error_msg = error_msg_dict        self.required = required    def match(self, name, value):        self.name = name        if not self.required:            self.id_valid = True            self.value = value        else:            if not value:                if self.error_msg.get('required', None):                    self.error = self.error_msg['required']                else:                    self.error = "%s is required" % name            else:                ret = re.match(self.REGULAR, value)                if ret:                    self.id_valid = True                    self.value = ret.group()                else:                    if self.error_msg.get('valid', None):                        self.error = self.error_msg['valid']                    else:                        self.error = "%s is invalid" % nameclass IPField(Field):    REGULAR = "^(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}$"    def __init__(self, error_msg_dict=None, required=True):        error_msg = {}  # {'required': 'IP不能为空', 'valid': 'IP格式错误'}        if error_msg_dict:            error_msg.update(error_msg_dict)        super(IPField, self).__init__(error_msg_dict=error_msg, required=required)class IntegerField(Field):    REGULAR = "^\d+$"    def __init__(self, error_msg_dict=None, required=True):        error_msg = {
     'required': '数字不能为空', 'valid': '数字格式错误'}        if error_msg_dict:            error_msg.update(error_msg_dict)        super(IntegerField, self).__init__(error_msg_dict=error_msg, required=required)class CheckBoxField(Field):    def __init__(self, error_msg_dict=None, required=True):        error_msg = {}  # {'required': 'IP不能为空', 'valid': 'IP格式错误'}        if error_msg_dict:            error_msg.update(error_msg_dict)        super(CheckBoxField, self).__init__(error_msg_dict=error_msg, required=required)    def match(self, name, value):        self.name = name        if not self.required:            self.id_valid = True            self.value = value        else:            if not value:                if self.error_msg.get('required', None):                    self.error = self.error_msg['required']                else:                    self.error = "%s is required" % name            else:                if isinstance(name, list):                    self.id_valid = True                    self.value = value                else:                    if self.error_msg.get('valid', None):                        self.error = self.error_msg['valid']                    else:                        self.error = "%s is invalid" % nameclass FileField(Field):    REGULAR = "^(\w+\.pdf)|(\w+\.mp3)|(\w+\.py)$"    def __init__(self, error_msg_dict=None, required=True):        error_msg = {}  # {'required': '数字不能为空', 'valid': '数字格式错误'}        if error_msg_dict:            error_msg.update(error_msg_dict)        super(FileField, self).__init__(error_msg_dict=error_msg, required=required)    def match(self, name, value):        self.name = name        self.value = []        if not self.required:            self.id_valid = True            self.value = value        else:            if not value:                if self.error_msg.get('required', None):                    self.error = self.error_msg['required']                else:                    self.error = "%s is required" % name            else:                m = re.compile(self.REGULAR)                if isinstance(value, list):                    for file_name in value:                        r = m.match(file_name)                        if r:                            self.value.append(r.group())                            self.id_valid = True                        else:                            self.id_valid = False                            if self.error_msg.get('valid', None):                                self.error = self.error_msg['valid']                            else:                                self.error = "%s is invalid" % name                            break                else:                    if self.error_msg.get('valid', None):                        self.error = self.error_msg['valid']                    else:                        self.error = "%s is invalid" % name    def save(self, request, upload_path=""):        file_metas = request.files[self.name]        for meta in file_metas:            file_name = meta['filename']            with open(file_name,'wb') as up:                up.write(meta['body'])class Form(object):    def __init__(self):        self.value_dict = {}        self.error_dict = {}        self.valid_status = True    def validate(self, request, depth=10, pre_key=""):        self.initialize()        self.__valid(self, request, depth, pre_key)    def initialize(self):        pass    def __valid(self, form_obj, request, depth, pre_key):        """        验证用户表单请求的数据        :param form_obj: Form对象（Form派生类的对象）        :param request: Http请求上下文（用于从请求中获取用户提交的值）        :param depth: 对Form内容的深度的支持        :param pre_key: Html中name属性值的前缀（多层Form时，内部递归时设置，无需理会）        :return: 是否验证通过，True：验证成功；False：验证失败        """        depth -= 1        if depth < 0:            return None        form_field_dict = form_obj.__dict__        for key, field_obj in form_field_dict.items():            print key,field_obj            if isinstance(field_obj, Form) or isinstance(field_obj, Field):                if isinstance(field_obj, Form):                    # 获取以key开头的所有的值，以参数的形式传至                    self.__valid(field_obj, request, depth, key)                    continue                if pre_key:                    key = "%s.%s" % (pre_key, key)                if isinstance(field_obj, CheckBoxField):                    post_value = request.get_arguments(key, None)                elif isinstance(field_obj, FileField):                    post_value = []                    file_list = request.request.files.get(key, None)                    for file_item in file_list:                        post_value.append(file_item['filename'])                else:                    post_value = request.get_argument(key, None)                print post_value                # 让提交的数据 和 定义的正则表达式进行匹配                field_obj.match(key, post_value)                if field_obj.id_valid:                    self.value_dict[key] = field_obj.value                else:                    self.error_dict[key] = field_obj.error                    self.valid_status = Falseclass ListForm(object):    def __init__(self, form_type):        self.form_type = form_type        self.valid_status = True        self.value_dict = {}        self.error_dict = {}    def validate(self, request):        name_list = request.request.arguments.keys() + request.request.files.keys()        index = 0        flag = False        while True:            pre_key = "[%d]" % index            for name in name_list:                if name.startswith(pre_key):                    flag = True                    break            if flag:                form_obj = self.form_type()                form_obj.validate(request, depth=10, pre_key="[%d]" % index)                if form_obj.valid_status:                    self.value_dict[index] = form_obj.value_dict                else:                    self.error_dict[index] = form_obj.error_dict                    self.valid_status = False            else:                break            index += 1            flag = Falseclass MainForm(Form):    def __init__(self):        # self.ip = IPField(required=True)        # self.port = IntegerField(required=True)        # self.new_ip = IPField(required=True)        # self.second = SecondForm()        self.fff = FileField(required=True)        super(MainForm, self).__init__()## class SecondForm(Form):##     def __init__(self):#         self.ip = IPField(required=True)#         self.new_ip = IPField(required=True)##         super(SecondForm, self).__init__()class MainHandler(tornado.web.RequestHandler):    def get(self):        self.render('index.html')    def post(self, *args, **kwargs):        # for i in  dir(self.request):        #     print i        # print self.request.arguments        # print self.request.files        # print self.request.query        # name_list = self.request.arguments.keys() + self.request.files.keys()        # print name_list        # list_form = ListForm(MainForm)        # list_form.validate(self)        #        # print list_form.valid_status        # print list_form.value_dict        # print list_form.error_dict        # obj = MainForm()        # obj.validate(self)        #        # print "验证结果：", obj.valid_status        # print "符合验证结果：", obj.value_dict        # print "错误信息:"        # for key, item in obj.error_dict.items():        #     print key,item        # print self.get_arguments('favor'),type(self.get_arguments('favor'))        # print self.get_argument('favor'),type(self.get_argument('favor'))        # print type(self.get_argument('fff')),self.get_argument('fff')        # print self.request.files        # obj = MainForm()        # obj.validate(self)        # print obj.valid_status        # print obj.value_dict        # print obj.error_dict        # print self.request,type(self.request)        # obj.fff.save(self.request)        # from tornado.httputil import HTTPServerRequest        # name_list = self.request.arguments.keys() + self.request.files.keys()        # print name_list        # print self.request.files,type(self.request.files)        # print len(self.request.files.get('fff'))                # obj = MainForm()        # obj.validate(self)        # print obj.valid_status        # print obj.value_dict        # print obj.error_dict        # obj.fff.save(self.request)        self.write('ok')settings = {    'template_path': 'template',    'static_path': 'static',    'static_url_prefix': '/static/',    'cookie_secret': 'aiuasdhflashjdfoiuashdfiuh',    'login_url': '/login'}application = tornado.web.Application([    (r"/index", MainHandler),], **settings)if __name__ == "__main__":    application.listen(8888)    tornado.ioloop.IOLoop.instance().start()

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