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  • 【Python之路】第十六篇--Web框架之Tornado

    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 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。）

    下载安装：

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

    框架使用

    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()

    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 -*-

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()
    异步非阻塞事例

    注意: self.render('xx.html')  等, 仍然会执行完后面的语句再加载页面

    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.5poi.com$', [
    (r'/index',BuyHandler),
])
   
if __name__ == "__main__":
    application.listen(80)
    tornado.ioloop.IOLoop.instance().start()
    View Code

    Tornado中原生支持二级域名的路由，如：

    application = tornado.web.Application([
    (r"/index", MainHandler),
])
   
application.add_handlers('buy.5poi.com$', [
    (r'/index',BuyHandler),
])

    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 template 模块 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" : "views相应的文件夹"

    1、基本使用

    #!/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", 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
    <!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" />
</head>
<body>

    <div>
        <ul>
            {% for item in list_info %}
                <li>{{item}}</li>
            {% end %}
        </ul>
    </div>
    
    <script src="{{static_url("js/jquery-1.8.2.min.js")}}"></script>
    
</body>
</html>
    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  extends继承页面  常用于页面整体布局

    {% extends 'layout.html'%}   继承layout.html

{% block body1 %}      body1 替换到继承的 layout.html 中的body1 
<h1>Index</h1>
{% end %}  
    <!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>
    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

    3、导入 include  常用于导入小组件

    <div>
    <ul>
        <li>1024</li>
        <li>42区</li>
    </ul>
</div>
    导入
    <!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" />
</head>
<body>

    <div class="pg-header">
        {% include 'header.html' %}
    </div>
    
    <script src="{{static_url("js/jquery-1.8.2.min.js")}}"></script>
    
</body>
</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 UIModule
from tornado import escape

class custom(UIModule):

    def render(self, *args, **kwargs):
        return '<h1>alex</h1>'
        #return escape.xhtml_escape('<h1>alex</h1>')
    uimodules.py

    b. 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()
    View Code

    c. 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>
    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端使用时的前缀，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()
    app.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

    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

    注意:  想要静态文件自定义处理,不通过 static_url('xxx') 访问:

    application = tornado.web.Application([
    (r"/(upload/.*.jpg)", tornado.web.StaticFileHandler, dict(path=settings['static_path'])),
],**settings)

    五、cookie

    Tornado中可以对cookie进行操作，并且还可以对cookie进行签名以防止伪造。

    self.set_cookie(self, name, value, domain=None, expires=None, path="/", expires_days=None, **kwargs)
    name Cookie的Key
    value Cookie的value
    domain 生效的域名
    expires 以秒为过期时间，默认从 1970-01-01T00:00:10.000Z
    path 生效路径
    expires_days 以天数过期时间，如果设置为 None 则关闭浏览器Cookie就失效

    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!")

    补充:

    关闭浏览器,Cookie就失效, 设置 
expires_days=None

注意的是不要同时传递expires 和 expires_days
self.set_cookie('user_id', '1', expires_days=None, expires=某个时间)

expires_day=None, 或者expires_day=3, 即3天, 
都不会影响expires的, 因为expires比expires_days 的优先级高  

self.set_cookie('user_id', '1', expires=time.time()+15*60) 15分钟过期

path='/' 表示全局
self.set_cookie('user_id', '1', path='/',expires=time.time()+15*60)

    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!")

setting = {
　　'cookie_secret':'58ksjfSmxoi'
}
          
application = tornado.web.Application([
    (r"/", MainHandler),
],**setting)
    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 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

    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。

    import tornado.web
import tornado.ioloop


class IndexHandler(tornado.web.RequestHandler):
    def get(self):
        self.set_secure_cookie('username', 'ansheng')
        self.set_secure_cookie('password', 'hello')
        self.render('index.html')

    def post(self, *args, **kwargs):
        username = self.get_argument('username', None)
        password = self.get_argument('password', None)
        cooike_user = str(self.get_secure_cookie('username'), encoding='utf-8')
        cooike_pass = str(self.get_secure_cookie('password'), encoding='utf-8')
        if username == cooike_user and password == cooike_pass:
            self.write('Hello ' + cooike_user)
        else:
            self.write('用户名或密码错误')


settings = {
    'template_path': 'template',
}

application = tornado.web.Application([
    (r'/', IndexHandler),
], **settings,
    cookie_secret="508C934B83CC")

if __name__ == '__main__':
    application.listen(8000)
    tornado.ioloop.IOLoop.instance().start()
    基于Cookie用户登录验证

    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();
}

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

    六、CSRF

    Tornado中的跨站请求伪造和Django中的相似，跨站伪造请求(Cross-site request forgery)

    1.设置:

    settings = { "xsrf_cookies": True, }

    页面加载后,cookie里有一个为 _xsrf = 'xxxxxxxxxxxx' 的值.

    需要传递_xsrf的值请求才能通过.

    2.form 表单:

    <form action="/index" method="post">
    {% raw xsrf_form_html() %}    
    <input type="text" name="message"/>
    <input type="submit" value="Post"/>
</form>

    3.ajax 

    <!-- 一个获取cookie的方法 !-->
function getCookie(name) {
　　var r = document.cookie.match("\b" + name + "=([^;]*)\b");
　　return r ? r[1] : undefined;
}

<!-- ajax提交数据中,写上获取的cookie值  !-->
var cookie= getCookie("_xsrf");
$.post({
　　url:'/index',
　　data:{'content':'v1',  '_xsrf' :cookie},
　　success:function (callbakc) {
　　console.log(callbakc)
　　}
});

    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

    上传文件标签:   <input type="file" name="file" id="my_file" />

    后台获取:      file_metas = self.request.files['file']

    获取格式:
[{'body': b'xxxxxxxxx', 'content_type': 'text/plain', 'filename': '文件名.txt/...'},...多个文件]

    1、Form表单上传

    <!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
    <title>上传文件</title>
</head>
<body>
    <form id="my_form" name="form" action="/index" method="POST"  enctype="multipart/form-data" >
        <input name="fff" id="my_file"  type="file" />
        <input type="submit" value="提交"  />
    </form>
</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

    2、AJAX上传

    1.基于XMLHttpRequest

    <input type="file" id="img" />
<input type="button" onclick="UploadFile();" />
<script>
    function UploadFile(){
        var fileObj = document.getElementById("img")[0].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>

    2.基于Jquery

    function UploadFile() {
    var fileObj = $("#file1")[0].files[0];

    var form = new FormData();
    form.append("k1", "v1");
    form.append("fff", fileObj);

    $.ajax({
        type:'post',
        url:'/upload',
        data:form,
        processData: false,  // tell jQuery not to process the data
        contentType: false,  // tell jQuery not to set contentType
    });
}

    3.基于iframe

    <!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
    <form id="my_form" name="form" action="/index" method="POST"  enctype="multipart/form-data" >
        <div id="main">
            <input name="fff" id="my_file"  type="file" />
            <input type="button" name="action" value="Upload" onclick="redirect()"/>
            <iframe id='my_iframe' name='my_iframe' src=""  class="hide"></iframe>
        </div>
    </form>

    <script>
        function redirect(){
            document.getElementById('my_iframe').onload = Testt;
            document.getElementById('my_form').target = 'my_iframe';
            document.getElementById('my_form').submit();

        }
        
        function Testt(ths){
            var t = $("#my_iframe").contents().find("body").text();
            console.log(t);
        }
    </script>
</body>
</html>
    View Code
    <script type="text/javascript">
 
    $(document).ready(function () {
 
        $("#formsubmit").click(function () {
 
            var iframe = $('<iframe name="postiframe" id="postiframe" style="display: none"></iframe>');
 
            $("body").append(iframe);
 
            var form = $('#theuploadform');
            form.attr("action", "/upload.aspx");
            form.attr("method", "post");
 
            form.attr("encoding", "multipart/form-data");
            form.attr("enctype", "multipart/form-data");
 
            form.attr("target", "postiframe");
            form.attr("file", $('#userfile').val());
            form.submit();
 
            $("#postiframe").load(function () {
                iframeContents = this.contentWindow.document.body.innerHTML;
                $("#textarea").html(iframeContents);
            });
 
            return false;
 
        });
 
    });
 
</script>
 
 
<form id="theuploadform">
    <input id="userfile" name="userfile" size="50" type="file" />
    <input id="formsubmit" type="submit" value="Send File" />
</form>
 
<div id="textarea">
</div>
    扩展基于iframe实现ajax上传
    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：猛击这里

    class CheckcodeHandler(BaseHandler):
    def get(self, *args, **kwargs):
        import io
        import check_code
        mstream = io.BytesIO()
        img, code = check_code.create_validate_code()
        self.session['code'] = code   //生成验证码存放在session中
        img.save(mstream, "GIF")
        self.write(mstream.getvalue())


************************************************
<p>
    <input name='code' type="text" placeholder="验证码" />
    <img src="/check_code" onclick='ChangeCode();' id='imgCode'>
</p>

<script type="text/javascript">
    function ChangeCode() {
        var code = document.getElementById('imgCode');
        code.src += '?';    //点击一次图片,换一次激活码
    }
</script>

    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()

    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'] = 'alex'
#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 = "alex"
   
   
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 tornado.ioloop
import tornado.web

container = {}

class Session():

    def __init__(self,handler):
        self.handler = handler
        self.random_str = None

    def get_random_str(self):
        import hashlib
        import time
        hash = hashlib.md5()
        hash.update(bytes(str(time.time()), encoding='utf-8'))
        random_str = hash.hexdigest()
        return random_str

    def __setitem__(self, key, value):
        if not self.random_str:
            random_str = self.handler.get_cookie('_session', None)
            if not random_str:
                random_str = self.get_random_str()
                container[random_str] = {}
            else:
                if random_str not in container.keys():
                    random_str = self.get_random_str()
                    container[random_str] = {}
            self.random_str = random_str

        container[self.random_str][key] = value
        self.handler.set_cookie('_session', self.random_str)


    def __getitem__(self, key):

        random_str = self.handler.get_cookie('_session', None)
        if not random_str:
            return None
        user_info_dict = container.get(random_str, None)
        if not user_info_dict:
            return None
        value = user_info_dict.get(key,None)
        return value


class BaseHandler(tornado.web.RequestHandler):
    def initialize(self):
        self.session = Session(self)


class MainHandler(BaseHandler):
    def get(self):

        print(self.cookies)
        self.session['kkk'] = '123'
        
        self.write("Hello, world")


application = tornado.web.Application([
    (r"/index", MainHandler),
])

if __name__ == "__main__":
    application.listen(8888)
    tornado.ioloop.IOLoop.instance().start()
    demo

    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。

    例子1:

    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_value(self,handler):
        flag = True
        input_dict = {}
        for key,regular in self.__dict__.items():
            input_value = handler.get_argument(key)
            val = re.match(regular,input_value)
            if not val:
                flag = False
            input_dict[key] = input_value
            print(val,input_dict[key],regular)
        return flag,input_dict


class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.render("index.html")
    def post(self, *args, **kwargs):
        obj = MainForm()
        val,input_dict = obj.check_value(self)
        print(val,input_dict)

settings = {
    'template_path': 'views',    # 模版路径的配置
    'static_path' : 'static',       # 静态文件路径
    # 'static_url_prefix' : '/sss/',
}

application = tornado.web.Application([
    (r"/index", MainHandler),
],**settings)

if __name__ == "__main__":
    application.listen(8889)
    tornado.ioloop.IOLoop.instance().start()
    app.py
    <!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>

</head>
<body>
    <h1>hello</h1>
    <form action="/index" method="post">

        <p>hostname: <input type="text" name="host" placeholder="host"/> </p>
        <p>ip: <input type="text" name="ip" placeholder="ip"/> </p>
        <p>port: <input type="text" name="port" placeholder="port" /> </p>
        <p>phone: <input type="text" name="phone" placeholder="phone"/> </p>
        <input type="submit" />
    </form>
</body>
</html>
    index.html

    例子2:

    import tornado.ioloop
import tornado.web
from hashlib import sha1
import os, time
import re

class IPField():
    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,required=True,error_dict=None):

        self.error_dict = {}   #错误信息
        if error_dict:
            self.error_dict.update(error_dict)   #用户自定错误信息

        self.required = required
        self.value = None
        self.error = None
        self.is_valid = False

    def validate(self,name,input_value):

        if not self.required:       # 可以为空
            self.value = input_value
            self.is_valid = True
        else:
            #1.不能为空,用户输入为空
            #2.用户输入错误,
            #3.用户输入正确
            if not input_value:
                if self.error_dict.get('required',None):
                    self.error = self.error_dict['required']
                else:
                    self.error = '%s is requires '%(name)
            else:
                val = re.match(IPField.REGULAR,input_value)
                if not val:  #用户输入错误 , re返回None
                    if self.error_dict.get('valid', None):
                        self.error = self.error_dict['valid']
                    else:
                        self.error = '%s is valid ' % (name)
                else:
                    self.value = input_value
                    self.is_valid = True

class CheckBoxField():

    def __init__(self,required=True,error_dict=None):

        self.error_dict = {}
        if error_dict:
            self.error_dict.update(error_dict)
        self.required = required
        self.value = None
        self.error = None
        self.is_valid = False

    def validate(self,name,input_value):
        if not self.required:
            self.value = input_value
            self.is_valid = True
        else:
            if not input_value:
                if self.error_dict.get('required',None):
                    self.error = self.error_dict['required']
                else:
                    self.error = '%s is requires '%(name)
            else:
                self.value = input_value
                self.is_valid = True

class FileField():
    REGULAR = "^(w+.pdf)|(w+.mp3)|(w+.py)$"

    def __init__(self, required=True, error_dict=None):

        self.error_dict = {}
        if error_dict:
            self.error_dict.update(error_dict)
        self.required = required
        self.value = []
        self.error = None
        self.is_valid = True
        self.success_file_name_list = []
        self.name = None

    def validate(self, name, all_file_name_list):
        self.name = name
        if not self.required:
            self.value = all_file_name_list
        else:
            if not all_file_name_list:
                self.is_valid = False
                if self.error_dict.get('required', None):
                    self.error = self.error_dict['required']
                else:
                    self.error = '%s is requires ' % (name)
            else:
                for file_name in all_file_name_list:
                    val = re.match(FileField.REGULAR, file_name)
                    if not val:
                        self.is_valid = False
                        if self.error_dict.get('valid', None):
                            self.error = self.error_dict['valid']
                        else:
                            self.error = '%s is valid ' % (name)
                        break
                    else:
                        self.value.append(file_name)

    def save(self,handler,path='upload'):
        file_list = handler.request.files.get(self.name)
        for file in file_list:
            file_name = file['filename']
            file_path = os.path.join(path,file_name)
            if file_name and file_name in self.value:
                with open(file_path,'wb') as up:
                    up.write(file['body'])


class BaseForm():
    def check_value(self,handler):
        flag = True
        success_value_dict = {}
        error_message_dict = {}
        for key,regular in self.__dict__.items():
            if type(regular) == CheckBoxField:
                input_value = handler.get_arguments(key)  # checkbox取值
            elif type(regular) == FileField:
                file_list = handler.request.files.get(key,[])  # 文件对象
                input_value = []
                for item in file_list:
                    input_value.append(item['filename'])
            else:
                input_value = handler.get_argument(key)

            regular.validate(key,input_value)
            if regular.is_valid:
                success_value_dict[key] = regular.value
            else:
                flag=False
                error_message_dict[key] = regular.error

        return flag,success_value_dict,error_message_dict


class HomeForm(BaseForm):
    def __init__(self):
        self.ip = IPField(required=True,error_dict={'required':'ip 不能为空!' , 'valid':'格式错误!!'})
        self.aihao = CheckBoxField(required=False,error_dict={'required':'checkbox 不能为空!' , 'valid':'格式错误!!'})
        self.fafafa = FileField(required=True)


class HomeHandler(tornado.web.RequestHandler):
    def get(self, *args, **kwargs):
        self.render('home.html',error_message = None)
    def post(self, *args, **kwargs):
        obj = HomeForm()
        val, success_value_dict , error_message_dict = obj.check_value(self)
        print(val, success_value_dict , error_message_dict)
        if val : #所有验证通过 文件上传
            obj.fafafa.save(self)
        self.render('home.html',error_message = None)

settings = {
    'template_path': 'views',    # 模版路径的配置
    'static_path' : 'static',       # 静态文件路径
    # 'static_url_prefix' : '/sss/',
}

application = tornado.web.Application([
    (r"/home", HomeHandler),
],**settings)

if __name__ == "__main__":
    application.listen(8889)
    tornado.ioloop.IOLoop.instance().start()
    app.py
    <!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>

</head>
<body>
    <h1>hello</h1>
    <form action="/home" method="post" enctype="multipart/form-data">

        <p>ip: <input type="text" name="ip" placeholder="ip"/> </p>
        <input type="checkbox" name='aihao' value="1">篮球
        <input type="checkbox" name='aihao' value="2">足球
        <input type="checkbox" name='aihao' value="3">乒乓球
        <input type="file" name="fafafa">
        <input type="file" name="fafafa">
        {% if error_message %}
        <span style="color: red">{{ error_message['ip'] }}</span>
        {% end %}
        <input type="submit" />
    </form>
</body>
</html>
    home.html

    三、分页

    核心: 后端生成标签，返回给前端显示。

    效果:

    首页 上一页  1 2 3 4 5 6 7 8 9 10 11 下一页 尾页

    首页 上一页  2 3 4 5 6 7 8 9 10 11 12 下一页 尾页

    首页 上一页  2 3 4 5 6 7 8 9 10 11 12 下一页 尾页

    设计思路:

    1.当总页数 all_page 小于11时，

    　　=> 是，( 直接生成全部页码 ) 设置 起始页s = 1 , 结束页t = all_page

    　　=> 否，当当前页current_page 小于6时，(页码不发生改变)

    　　　　　　=> 是,  s = 1 , t = 11

    　　　　　　=> 否, 当current_page + 5 < all_page 时,

    　　　　　　　　　　=> 是 , s = current_page - 5 , t = current_page + 5

                                => 否 , ( 此时当前页为最后5页 ,不再往后生成页码 ,保持原来不变)  s = all_page - 10 , t = all_page

    2.当前页为1时,点击上一页,首页不跳转，当前页为最后一页时,点击下一页,尾页不跳转。href='javascript:void(0)'

    3.字典存储生成的a标签, join()连接列表每项,生成字符串标签返回前端

    4.前端显示,输出原始标签字符串  {%raw str_page %}

    def page_str(self,base_url):
    if self.all_page < 11:
        s = 1
        t = self.all_page
    else:
        if self.current_page < 6:
            s = 1
            t = 11
        else:
            if (self.current_page + 5) < self.all_page:
                s = self.current_page - 5
                t = self.current_page + 5
            else:
                s = self.all_page - 10
                t = self.all_page
    list_page = []

    # 首页
    first_page = "<a href='%s1'>首页</a>" % (base_url)
    list_page.append(first_page)

    # 上一页
    if self.current_page == 1:
        pre_page = "<a href='javascript:void(0)'>上一页</a>"
    else:
        pre_page = "<a href='%s%s'>上一页</a>" % (base_url, self.current_page -1 ,)
    list_page.append(pre_page)

    # 页码生成
    for i in range(s, t + 1):
        if i == self.current_page:
            temp = "<a class='active-paper' href='%s%s'>%s</a>" % (base_url,i, i)
        else:
            temp = "<a href='%s%s'>%s</a>" % (base_url , i, i)
        list_page.append(temp)

    # 下一页
    if self.current_page >= self.all_page:
        next_page = "<a href='javascript:void(0)'>下一页</a>"
    else:
        next_page = "<a href='%s%s'>下一页</a>" % (base_url, self.current_page + 1,)
    list_page.append(next_page)

    # 尾页
    end_page = "<a href='%s%s'>尾页</a>" % (base_url,self.all_page)
    list_page.append(end_page)

    # 页面跳转
    pagejump_input = """<input type="text"><a onclick="pageNumjump(this,'%s')">Go</a>"""%(base_url)
    pagejump_script = """
    <script>
    function pageNumjump(ths,base_url){
        var pagenum = ths.previousElementSibling.value;
        if (pagenum.trim().length > 0){
            location.href = base_url+pagenum
        }
    }
    </script>
    """
    list_page.append(pagejump_input)
    list_page.append(pagejump_script)

    # 数据拼接 返回
    str_page = ''.join(list_page)   # 列表连接成为字符串
    return str_page
    View Code

    仿:chouti.com分页显示:

    上一页  1 ... 4 5 6 7 8 9 10  下一页

    def page_str(self,base_url):
    if self.all_page < 10:
        s = 1
        t = self.all_page
    else:
        if self.current_page < 7:
            s = 1
            t = 10
        else:
            if self.all_page - self.current_page >= 4 :
                s = self.current_page - 3
                t = self.current_page + 4
            else:
                s = self.all_page - 6
                t = self.all_page
    list_page = []


    # 上一页
    if self.current_page != 1:
        pre_page = "<a href='%s%s' class='pageedg'>上一页</a>" % (base_url, self.current_page - 1,)
        list_page.append(pre_page)

    # 页码生成
    # 生成 1 , ... ,
    if( self.current_page >= 7 ):
        temp = "<a class='pageNum' href='%s%s'>%s</a>" % (base_url, 1, 1)
        list_page.append(temp)
        temp = "<span class='ignore' >...</span>"
        list_page.append(temp)


    for i in range(s, t + 1):
        if i == self.current_page:
            temp = "<span class='active-page' href='%s%s'>%s</span>" % (base_url,i, i)
        else:
            temp = "<a href='%s%s' class='pageNum'>%s</a>" % (base_url , i, i)
        list_page.append(temp)

    # 下一页
    if self.current_page < self.all_page:
        next_page = "<a href='%s%s' class='pageedg'>下一页</a>" % (base_url, self.current_page + 1,)
        list_page.append(next_page)

    str_page = ''.join(list_page)   # 列表连接成为字符串
    return str_page
    View Code
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  • 原文地址：https://www.cnblogs.com/5poi/p/6414299.html
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