Tornado

r囧r小猫 2022-05-26 13:49 220阅读 0赞

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 epoll 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 C10K problem。）

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

## 一、快速上手 ##

#!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import tornado.ioloop
    import 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()

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][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

#### 异步非阻塞实例
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import tornado.ioloop
    import tornado.web
    from tornado import httpclient
    from tornado.web import asynchronous
    from tornado import gen
    
    import uimodules as md
    import uimethods as mt
    
    class 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.body
    
    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()

## 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.ioloop
    import 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()

## 三、模板 ##

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 template 模块 的代码文档中有着详细的描述。

<!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> <title>老男孩</title> <link href="{ {static_url("css/common.css")}}" rel="stylesheet" /> {% block CSS %}{% end %} </head> <body> <div class="pg-header"> </div> {% block RenderBody %}{% end %} <script src="{ {static_url("js/jquery-1.8.2.min.js")}}"></script> {% block JavaScript %}{% end %} </body> </html>

{% extends 'layout.html'%} {% block CSS %} <link href="{ {static_url("css/index.css")}}" rel="stylesheet" /> {% end %} {% block RenderBody %} <h1>Index</h1> <ul> {% for item in li %} <li>{ {item}}</li> {% end %} </ul> {% end %} {% block JavaScript %} {% end %}

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

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

Tornado默认提供的这些功能其实本质上就是 UIMethod 和 UIModule，我们也可以自定义从而实现类似于Django的simple\_tag的功能：  
1、定义

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

#!/usr/bin/env python
    # -*- coding:utf-8 -*-
    from tornado.web import UIModule
    from tornado import escape
    
    class custom(UIModule):
    
        def render(self, *args, **kwargs):
            return escape.xhtml_escape('<h1>wupeiqi</h1>')
            #return escape.xhtml_escape('<h1>wupeiqi</h1>')

2、注册

#!/usr/bin/env python
    # -*- coding:utf-8 -*-
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import tornado.ioloop
    import tornado.web
    from tornado.escape import linkify
    import uimodules as md
    import uimethods as mt
    
    class 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()
    
    main.py

3、使用

## 四、实用功能 ##

**1、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。  
main.py

#!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import tornado.ioloop
    import 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()

index.html

备注：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()
    
    静态文件缓存源码

**2、csrf**

Tornado中的夸张请求伪造和Django中的相似，跨站伪造请求(Cross-site request forgery)  
配置

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

普通表单使用

AJAX使用

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

**3、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。

a、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!")
    
    Code

b、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=")
    
    Code

内部算法

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())
    
    
    def _create_signature_v2(secret, s):
        hash = hmac.new(utf8(secret), digestmod=hashlib.sha256)
        hash.update(utf8(s))
        return utf8(hash.hexdigest())
    
    内部算法

内部算法加密

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)
    
    内部算法-加密

内部算法解密

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 None
    
    
    def _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_sig
    
    
    def _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 None
    
    
    def 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-解密

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。  
签名Cookie的本质是：

Demo-基于cookie进行用户验证

#!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import tornado.ioloop
    import 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()
    
    Demo-基于cookie进行用户验证

Demo-Toando内部提供基于cookie进行用户验证

#!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import tornado.ioloop
    import 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()
    
    Demo-Toando内部提供基于cookie进行用户验证

**4、Ajax上传文件**

<!DOCTYPE html>
    <html>
    <head lang="en">
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
        <input type="file" id="img" />
        <input type="button" onclick="UploadFile();" />
        <script> function UploadFile(){ var fileObj = document.getElementById("img").files[0]; var form = new FormData(); form.append("k1", "v1"); form.append("fff", fileObj); var xhr = new XMLHttpRequest(); xhr.open("post", '/index', true); xhr.send(form); } </script>
    </body>
    </html>

#!/usr/bin/env python
    # -*- coding:utf-8 -*-
    #!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import tornado.ioloop
    import tornado.web
    
    
    class 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

jQuery+AJAX

var fileObj = $("#img")[0].files[0];
    var form = new FormData();
    form.append("k1", "v1");
    form.append("fff", fileObj);
    
    $.ajax({
        type:'POST',
        url: '/index',
        data: form,
        processData: false,  // tell jQuery not to process the data
        contentType: false,  // tell jQuery not to set contentType
        success: function(arg){ 
            console.log(arg);
        }
    })

**五、扩展功能**

1、自定义Session

a.知识储备

#!/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']

b.session实现机制

#!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import tornado.ioloop
    import tornado.web
    from hashlib import sha1
    import os, time
    
    session_container = {}
    
    create_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):
            return session_container[self._id][key]
    
        def __setitem__(self, key, value):
            if session_container.has_key(self._id):
                session_container[self._id][key] = value
            else:
                session_container[self._id] = {key: value}
    
        def __delitem__(self, key):
            del session_container[self._id][key]
    
    
    class BaseHandler(tornado.web.RequestHandler):
    
        def initialize(self):
            # my_session['k1']访问 __getitem__ 方法
            self.my_session = Session(self)
    
    
    class MainHandler(BaseHandler):
    
        def get(self):
            print self.my_session['c_user']
            print self.my_session['c_card']
            self.write('index')
    
    class LoginHandler(BaseHandler):
    
        def get(self):
            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.my_session['c_user'] = 'wupeiqi'
                self.my_session['c_card'] = '12312312309823012'
    
                self.redirect('/index')
            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()

c. Session框架

#!/usr/bin/env python
    #coding:utf-8
    
    import sys
    import math
    from bisect import bisect
    
    
    if sys.version_info >= (2, 5):
        import hashlib
        md5_constructor = hashlib.md5
    else:
        import md5
        md5_constructor = md5.new
    
    
    class 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 """
    
    一致性哈希

from hashlib import sha1
    import os, time
    
    
    create_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

**2、自定义模型版定**

模型绑定有两个主要功能：

自动生成html表单  
用户输入验证  
在之前学习的Django中为程序员提供了非常便捷的模型绑定功能，但是在Tornado中，一切需要自己动手！！！

<!DOCTYPE html> <html> <head lang="en"> <meta charset="UTF-8"> <title></title> <link href="{ { static_url("commons.css")}}" rel="stylesheet" /> </head> <body> <h1>hello</h1> <form action="/index" method="post"> <p>hostname: <input type="text" name="host" /> </p> <p>ip: <input type="text" name="ip" /> </p> <p>port: <input type="text" name="port" /> </p> <p>phone: <input type="text" name="phone" /> </p> <input type="submit" /> </form> </body> </html> html

#!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import tornado.ioloop
    import tornado.web
    from hashlib import sha1
    import os, time
    import 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()

由于请求的验证时，需要考虑是否可以为空以及正则表达式的复用，所以：

#!/usr/bin/env python
    # -*- coding:utf-8 -*-
    
    import tornado.ioloop
    import tornado.web
    import re
    
    
    class 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" % name
    
    
    class 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" % name
    
    
    class 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 = False
    
    
    class 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 = False
    
    
    class 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()
    
    Form验证框架

[http_127.0.0.1_8888_index]: http://127.0.0.1:8888/index