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()

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()

Tornado中原生支持二级域名的路由，如：

三、模板引擎

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

Tornado 的模板支持“控制语句”和“表达语句”，控制语句是使用 {% 和 %} 包起来的例如 {% if len(items) > 2 %}。表达语句是使用 {{ 和 }} 包起来的，例如 {{ items[0] }}。

控制语句和对应的 Python 语句的格式基本完全相同。我们支持 if、for、while 和 try，这些语句逻辑结束的位置需要用 {% end %} 做标记。还通过 extends 和 block 语句实现了模板继承。这些在 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" : "tpl"

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

<!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

<div>
    <ul>
        <li>1024</li>
        <li>42区</li>
    </ul>
</div>

header.html

<!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 escape.xhtml_escape('<h1>wupeiqi</h1>')
        #return escape.xhtml_escape('<h1>wupeiqi</h1>')

uimodules.py

b. 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()

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()

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

五、cookie

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

1、基本操作

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

View Code

2、加密cookie（签名）

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

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

View Code

def _create_signature_v1(secret, *parts):
    hash = hmac.new(utf8(secret), digestmod=hashlib.sha1)
    for part in parts:
        hash.update(utf8(part))
    return utf8(hash.hexdigest())

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

def create_signed_value(secret, name, value, version=None, clock=None,
                        key_version=None):
    if version is None:
        version = DEFAULT_SIGNED_VALUE_VERSION
    if clock is None:
        clock = time.time

    timestamp = utf8(str(int(clock())))
    value = base64.b64encode(utf8(value))
    if version == 1:
        signature = _create_signature_v1(secret, name, value, timestamp)
        value = b"|".join([value, timestamp, signature])
        return value
    elif version == 2:
        # The v2 format consists of a version number and a series of
        # length-prefixed fields "%d:%s", the last of which is a
        # signature, all separated by pipes.  All numbers are in
        # decimal format with no leading zeros.  The signature is an
        # HMAC-SHA256 of the whole string up to that point, including
        # the final pipe.
        #
        # The fields are:
        # - format version (i.e. 2; no length prefix)
        # - key version (integer, default is 0)
        # - timestamp (integer seconds since epoch)
        # - name (not encoded; assumed to be ~alphanumeric)
        # - value (base64-encoded)
        # - signature (hex-encoded; no length prefix)
        def format_field(s):
            return utf8("%d:" % len(s)) + utf8(s)
        to_sign = b"|".join([
            b"2",
            format_field(str(key_version or 0)),
            format_field(timestamp),
            format_field(name),
            format_field(value),
            b''])

        if isinstance(secret, dict):
            assert key_version is not None, 'Key version must be set when sign key dict is used'
            assert version >= 2, 'Version must be at least 2 for key version support'
            secret = secret[key_version]

        signature = _create_signature_v2(secret, to_sign)
        return to_sign + signature
    else:
        raise ValueError("Unsupported version %d" % version)

# 解密
def _decode_signed_value_v1(secret, name, value, max_age_days, clock):
    parts = utf8(value).split(b"|")
    if len(parts) != 3:
        return None
    signature = _create_signature_v1(secret, name, parts[0], parts[1])
    if not _time_independent_equals(parts[2], signature):
        gen_log.warning("Invalid cookie signature %r", value)
        return None
    timestamp = int(parts[1])
    if timestamp < clock() - max_age_days * 86400:
        gen_log.warning("Expired cookie %r", value)
        return None
    if timestamp > clock() + 31 * 86400:
        # _cookie_signature does not hash a delimiter between the
        # parts of the cookie, so an attacker could transfer trailing
        # digits from the payload to the timestamp without altering the
        # signature.  For backwards compatibility, sanity-check timestamp
        # here instead of modifying _cookie_signature.
        gen_log.warning("Cookie timestamp in future; possible tampering %r",
                        value)
        return None
    if parts[1].startswith(b"0"):
        gen_log.warning("Tampered cookie %r", value)
        return None
    try:
        return base64.b64decode(parts[0])
    except Exception:
        return 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。

#!/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()

基于Cookie实现用户验证-Demo

#!/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()

基于签名Cookie实现用户验证-Demo

3、JavaScript操作Cookie

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

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

对于参数：

domain 指定域名下的cookie
path 域名下指定url中的cookie
secure https使用

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

六、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>

使用 - 普通表单

function getCookie(name) {
    var r = document.cookie.match("\b" + name + "=([^;]*)\b");
    return r ? r[1] : undefined;
}

jQuery.postJSON = function(url, args, callback) {
    args._xsrf = getCookie("_xsrf");
    $.ajax({url: url, data: $.param(args), dataType: "text", type: "POST",
        success: function(response) {
        callback(eval("(" + response + ")"));
    }});
};

使用 - AJAX

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

七、上传文件

1、Form表单上传

<!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

<!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 - XMLHttpRequest

<!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 = $("#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);
                }
            })
        }
    </script>
</body>
</html>

HTML - jQuery

<!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>

HTML - iframe

#!/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

<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上传示例

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

View Code

function bindChangeAvatar1() {
            $('#avatarImg').change(function () {
                var file_obj = $(this)[0].files[0];
                $('#prevViewImg')[0].src = window.URL.createObjectURL(file_obj)
            })
        }

        function bindChangeAvatar2() {
            $('#avatarImg').change(function () {
                var file_obj = $(this)[0].files[0];
                var reader = new FileReader();
                reader.readAsDataURL(file_obj);
                reader.onload = function (e) {
                    $('#previewImg')[0].src = this.result;
                };
            })
        }

        function bindChangeAvatar3() {
            $('#avatarImg').change(function () {
                var file_obj = $(this)[0].files[0];
                var form = new FormData();
                form.add('img_upload', file_obj);

                $.ajax({
                    url: '',
                    data: form,
                    processData: false,  // tell jQuery not to process the data
                    contentType: false,  // tell jQuery not to set contentType
                    success: function (arg) {

                    }
                })
            })
        }

        function bindChangeAvatar4() {
            $('#avatarImg').change(function () {
                $(this).parent().submit();

                $('#upload_iframe').load(function () {
                    var iframeContents = this.contentWindow.document.body.innerText;
                    iframeContents = JSON.parse(iframeContents);
                    if (iframeContents.status) {
                        $('#previewImg').attr('src', '/' + iframeContents.data);
                    }
                })

            })
        }

其他

八、验证码

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

安装图像处理模块：

1	`pip3 install pillow`

示例截图：

验证码Demo源码下载：猛击这里

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。

#!/usr/bin/env python
# -*- coding:utf-8 -*-
 
 
import tornado.web
from tornado import gen
from tornado import httpclient
 
# 方式一：
class AsyncHandler(tornado.web.RequestHandler):
    @gen.coroutine
    def get(self, *args, **kwargs):
        print('进入')
        http = httpclient.AsyncHTTPClient()
        data = yield http.fetch("http://www.google.com")
        print('完事',data)
        self.finish('6666')
 
# 方式二：
# class AsyncHandler(tornado.web.RequestHandler):
#     @gen.coroutine
#     def get(self):
#         print('进入')
#         http = httpclient.AsyncHTTPClient()
#         yield http.fetch("http://www.google.com", self.done)
# 
#     def done(self, response):
#         print('完事')
#         self.finish('666')
 
 
 
application = tornado.web.Application([
    (r"/async", AsyncHandler),
])
 
if __name__ == "__main__":
    application.listen(8888)
    tornado.ioloop.IOLoop.instance().start() 

#!/usr/bin/env python
# -*- coding:utf-8 -*-
"""
需要先安装支持异步操作Mysql的类库： 
    Tornado-MySQL： https://github.com/PyMySQL/Tornado-MySQL#installation
    
    pip3 install Tornado-MySQL

"""

import tornado.web
from tornado import gen

import tornado_mysql
from tornado_mysql import pools

POOL = pools.Pool(
    dict(host='127.0.0.1', port=3306, user='root', passwd='123', db='cmdb'),
    max_idle_connections=1,
    max_recycle_sec=3)


@gen.coroutine
def get_user_by_conn_pool(user):
    cur = yield POOL.execute("SELECT SLEEP(%s)", (user,))
    row = cur.fetchone()
    raise gen.Return(row)


@gen.coroutine
def get_user(user):
    conn = yield tornado_mysql.connect(host='127.0.0.1', port=3306, user='root', passwd='123', db='cmdb',
                                       charset='utf8')
    cur = conn.cursor()
    # yield cur.execute("SELECT name,email FROM web_models_userprofile where name=%s", (user,))
    yield cur.execute("select sleep(10)")
    row = cur.fetchone()
    cur.close()
    conn.close()
    raise gen.Return(row)


class LoginHandler(tornado.web.RequestHandler):
    def get(self, *args, **kwargs):
        self.render('login.html')

    @gen.coroutine
    def post(self, *args, **kwargs):
        user = self.get_argument('user')
        data = yield gen.Task(get_user, user)
        if data:
            print(data)
            self.redirect('http://www.oldboyedu.com')
        else:
            self.render('login.html')


application = tornado.web.Application([
    (r"/login", LoginHandler),
])

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

基于异步非阻塞和Tornado-MySQL实现用户登录示例

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原文地址：https://www.cnblogs.com/maple-shaw/p/8021720.html