Python自动化运维之31、Tornado框架

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Tornado

官网：http://www.tornadoweb.org/en/stable/

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。）

安装：

pip install tornado

源码安装

wget 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

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 -*-

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()

异步非阻塞实例

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.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>小男孩</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>

layout.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 %}

index.html

index.html

#!/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'

uimethods.py

#!/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>')

uimodules.py

2、注册

#!/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

<!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>

    {% module custom(123) %}

    {{ tab() }}

</body>

index.html

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。

#!/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()

main.py

<!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>

</body>

</html>

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()

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)

settings = {

    "xsrf_cookies": True,

}

application = tornado.web.Application([

    (r"/", MainHandler),

    (r"/login", LoginHandler),

], **settings)

配置

<form action="/new_message" method="post">

  {{ xsrf_form_html() }}

  <input type="text" name="message"/>

  <input type="submit" value="Post"/>

</form>

普通表单使用

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 + ")"));

    }});

};

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!")

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=")

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

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"",

            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

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""):

        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。

#!/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 == '':

            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 == '':

            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()

torando内部cookie实现用户验证

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>

HTML

#!/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

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);

    }

})

jQuery Ajax Upload

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 == '':

            self.my_session['c_user'] = 'wupeiqi'

            self.my_session['c_card'] = ''

            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hash算法

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

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()