Python Tornado簡介

時間 2019-11-12

原文原文鏈接

簡介javascript

Tornado 是 FriendFeed 使用的可擴展的非阻塞式 web 服務器及其相關工具的開源版本。這個 Web 框架看起來有些像web.py 或者 Google 的 webapp，不過爲了能有效利用非阻塞式服務器環境，這個 Web 框架還包含了一些相關的有用工具和優化。css

Tornado 和如今的主流 Web 服務器框架（包括大多數 Python 的框架）有着明顯的區別：它是非阻塞式服務器，並且速度至關快。得利於其非阻塞的方式和對epoll的運用，Tornado 每秒能夠處理數以千計的鏈接，這意味着對於實時 Web 服務來講，Tornado 是一個理想的 Web 框架。咱們開發這個 Web 服務器的主要目的就是爲了處理 FriendFeed 的實時功能 ——在 FriendFeed 的應用裏每個活動用戶都會保持着一個服務器鏈接。html

Tornado安裝java

pip3 install tornado

初識Tornadopython

首先打開pycharm，新建一個乾淨的projectjquery

新建一個py文件：git

import tornado.ioloop
import tornado.web


class MainHandler(tornado.web.RequestHandler):  # 相似於Django裏面的CBV
    def get(self):  # get方法
        self.write("Hello, world")


application = tornado.web.Application([  # 相似於Django裏面的路由系統
    (r"/index", MainHandler),
])

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

app.py

運行文件並打開瀏覽器訪問網址：web

運行該腳本，依次執行：ajax

建立一個Application對象，並把一個正則表達式'/'和類名MainHandler傳入構造函數：tornado.web.Application(...)　　
執行Application對象的listen(...)方法，即：application.listen(8888)
執行IOLoop類的類的 start() 方法，即：tornado.ioloop.IOLoop.instance().start()

整個過程其實就是在建立一個socket服務端並監聽8888端口，當請求到來時，根據請求中的url和請求方式（post、get或put等）來指定相應的類中的方法來處理本次請求，在上述demo中只爲url爲http://127.0.0.1:8888/index的請求指定了處理類MainHandler（具體如何尋找見下文）。因此，在瀏覽器上訪問：http://127.0.0.1:8888/index，則服務器給瀏覽器就會返回 Hello,world ，不然返回 404: Not Found（tornado內部定義的值），即完成一次http請求和響應。正則表達式

由上述分析，咱們將整個Web框架分爲兩大部分：

待請求階段，即：建立服務端socket並監聽端口
處理請求階段，即：當有客戶端鏈接時，接受請求，並根據請求的不一樣作出相應的相應

經典的Login案例

首先，建立模版文件夾和模版文件：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form method="POST" action="/login">
        <input type="text" name="username" />
        <input type="submit" value="提交" />
    </form>
</body>
</html>

新建一個路由：

    (r"/login", LoginHandler),

新建CBV：

class LoginHandler(tornado.web.RequestHandler):
    def get(self):
        self.render("login.html")

    def post(self, *args, **kwargs):
        # 獲取url中以GET形式傳遞的數據
        self.get_query_argument()
        self.get_query_arguments()
        # 去請求體中獲取傳遞的數據
        self.get_body_argument()
        self.get_body_arguments()
        # 去get&post雙方去取數據
        user = self.get_argument('username')
        print(user)
        self.redirect('www.baidu.com')

註冊模版文件路徑：

# 申明settings，字典格式
settings = {
    'template_path': 'tmp'
}

# 註冊進tornado內部
application = tornado.web.Application([
    (r"/index", MainHandler),
    (r"/login", LoginHandler),
], **settings)

總體app文件：

#!/usr/bin/env python3
# encoding: utf-8
# Author: Dandy


import tornado.ioloop
import tornado.web


class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("Hello, world")


class LoginHandler(tornado.web.RequestHandler):
    def get(self):
        self.render("login.html")

    def post(self, *args, **kwargs):
        # 獲取url中以GET形式傳遞的數據
        self.get_query_argument()
        self.get_query_arguments()
        # 去請求體中獲取傳遞的數據
        self.get_body_argument()
        self.get_body_arguments()
        # 去get&post雙方去取數據
        user = self.get_argument('username')
        print(user)
        self.redirect('www.baidu.com')


settings = {
    'template_path': 'tmp'
}


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

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

View Code

此時即可執行

關於靜態文件

首先添加靜態文件夾，並放入一張圖片

靜態路徑註冊：

settings = {
    'template_path': 'tmp',
    'static_path': 'statics'
}

login頁面加入圖片、注意如下路徑寫的是static，標準用法

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form method="POST" action="/login">
        <input type="text" name="username" />
        <input type="submit" value="提交" />
    </form>
    <img src="/static/炫雅.jpeg" />
</body>
</html>

此時訪問頁面

那能不能不用static做爲靜態文件夾名稱呢？

答案固然是能夠的，只須要這樣註冊：

settings = {
    'template_path': 'tmp',
    'static_path': 'statics',
    'static_url_prefix': '/jingtai/',  # 這裏就是用戶自定義的靜態路徑名稱
}

再去修改login網頁裏的就行了。

詳細介紹

上面簡單的介紹了一下totornado的一些基本運用搭建。如今花點篇幅詳細的解決各個模塊的基本問題。

1、路由系統

路由系統從前面Django的學習過程當中不難總結出來，其實就是url和視圖函數的對應關係。固然啦，在Django裏面，有FBV和CBV的概念；而在tornado每一個url對應的函數均是一個類，即CBV。

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 HomeHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("dandy")


application = tornado.web.Application([
    (r"/index", MainHandler),
    (r"/story/([0-9]+)", StoryHandler),
])

application.add_handlers(r"^a\.com$", [
    (r"/", HomeHandler),  # 路由a.com:8888/
])

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

View Code

Tornado中原生支持二級域名的路由，如：

2、模版引擎

Tornao中的模板語言和django中相似，模板引擎將模板文件載入內存，而後將數據嵌入其中，最終獲取到一個完整的字符串，再將字符串返回給請求者。

Tornado 的模板支持「控制語句」和「表達語句」，控制語句是使用 {% 和 %} 包起來的例如 {% if len(items) > 2 %}。表達語句是使用 {{ 和 }} 包起來的，例如 {{ items[0] }}。

控制語句和對應的 Python 語句的格式基本徹底相同。咱們支持 if、for、while 和 try，這些語句邏輯結束的位置須要用 {% end %} 作標記。還經過 extends 和 block 語句實現了模板繼承。

注：在使用模板前須要在setting中設置模板路徑："template_path" : "tpl"

一、基本使用

import tornado.ioloop
import tornado.web


class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.render("index.html", list_info=[11, 22, 33], key1='value1')


settings = {
    'template_path': 'tmp'
}

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



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

app.py

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link href='{{static_url("css/common.css")}}' rel="stylesheet" />
</head>
<body>
    <h1>{{ key1 }}</h1>
    <ul>
    {% for item in list_info %}
        {% if item > 12 %}
            <li>{{ item }}</li>
        {% end %}
    {% end %}
    </ul>
</body>
</html>

index.html

相似於static_url的其餘方法

在模板中默認提供了一些函數、字段、類以供模板使用：

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 模組
handler: 當前的 RequestHandler 對象
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

View Code

二、母版

<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
    <title>title</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

View Code

{% 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 %}

繼承頁

三、導入小標籤

<div>
    <ul>
        <li>dandy</li>
        <li>durant</li>
    </ul>
</div>

tag

<!DOCTYPE html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
    <title></title>
</head>
<body>

    <div class="pg-header">
        {% include 'header.html' %}
    </div>
    
</body>
</html>

index.html

四、模版函數擴展UIMethod&UIModule

a、申明

def tab(self):
    return 'UIMethod'

uimethods.py

from tornado.web import UIModule
from tornado import escape

class custom(UIModule):

    def render(self, *args, **kwargs):
        return escape.xhtml_escape('<h1>wuzdandz</h1>')

uimodules.py

b、註冊

import uimodules as md
import uimethods as mt
settings = {
    'template_path': 'template',
    'static_path': 'static',
    'ui_methods': mt,
    'ui_modules': md,
}

app.py

c、使用

<body>
    {% module custom(123) %}
    <br>
    {{ tab() }}
</body>

html文本

注意一下這幾個方法：

embedded_css/javascript 用來產生css或js語句的

javascript/css_files用來產生link指向文件

3、靜態文件

對於靜態文件，能夠配置靜態文件的目錄和前段使用時的前綴，而且Tornaodo還支持靜態文件緩存。

settings = {
    'template_path': 'template',
    'static_path': 'static',
    'static_url_prefix': '/static/',
}
application = tornado.web.Application([
    (r"/index", MainHandler),
], **settings)

View Code

<img src="/static/炫雅.jpeg" />
<link href='{{static_url("commons.css")}}' rel="stylesheet" />

html

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()

實現靜態文件緩存

4、cookie

Tornado中能夠對cookie進行操做，而且還能夠對cookie進行簽名以放置僞造。

一、基本操做

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        if not self.get_cookie("username"):  # 獲取cookie
            self.set_cookie("username", "dandy")  # 設置cookie
            self.write("Your cookie was not set yet!")
        else:
            self.write("Your cookie was set!")

View Code

二、加密cookie（簽名）

Cookie 很容易被惡意的客戶端僞造。加入你想在 cookie 中保存當前登錄用戶的 id 之類的信息，你須要對 cookie 做簽名以防止僞造。Tornado 經過 set_secure_cookie 和 get_secure_cookie 方法直接支持了這種功能。要使用這些方法，你須要在建立應用時提供一個密鑰，名字爲 cookie_secret。你能夠把它做爲一個關鍵詞參數傳入應用的設置中：

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

內部算法

簽名Cookie的本質是：

寫cookie過程：

將值進行base64加密
對除值之外的內容進行簽名，哈希算法（沒法逆向解析）
拼接 簽名 + 加密值
讀cookie過程：

讀取 簽名 + 加密值
對簽名進行驗證
base64解密，獲取值內容

注：許多API驗證機制和安全cookie的實現機制相同。

#!/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', '武沛齊')
            self.redirect('/')
        else:
            self.render('login.html', **{'status': '用戶名或密碼錯誤'})
 
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()

基於Cookie實現用戶驗證-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', '武沛齊')
            self.redirect('/')
        else:
            self.render('login.html', **{'status': '用戶名或密碼錯誤'})
 
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()

基於簽名Cookie實現用戶驗證-Demo

三、javascript操做cookie

因爲Cookie保存在瀏覽器端，因此在瀏覽器端也可使用JavaScript來操做Cookie。

/*
設置cookie，指定秒數過時
 */
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();
}

固然更推薦使用jquery cookie來操做cookie

5、CSRF

Tornado中的跨站請求僞造和Django中的類似

一、啓用設置

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

setting啓動xsrf

二、表單

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

form

三、ajax

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

注：Ajax使用時，本質上就是去獲取本地的cookie，攜帶cookie再來發送請求

6、上傳文件

一、form表單上傳

<body>
    <form name="form" action="/index" method="POST"  enctype="multipart/form-data" >
        <input name="fafafa" id="my_file"  type="file" />
        <input type="submit" value="提交"  />
    </form>
</body>

form

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["fafafa"]
        # 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()

二、ajax上傳

<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 - xmlhttprequest

<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 - jquery

<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 - iframe

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()

<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>

基於iframe實現Ajax上傳示例

$('#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);
                    }
                })

            })
        }

其餘

。。。。

7、異步非阻塞

一、基本使用

首先，先看一段代碼

class AsyncHandler(tornado.web.RequestHandler):

    def get(self):
        import time
        time.sleep(20)
        self.write('666')

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

對於異步非阻塞的瞭解，第一點確定是，單線程；因此測試一下上面的代碼，不難發現：先打開async頁面，沒有任何返回，一直顯示在加載，此時打開index，發現index頁面同時也在加載出不來。

當async執行完，index頁面也很快就返回了。

此時修改一下代碼：

#!/usr/bin/env python
# -*- coding:utf-8 -*-

import tornado.ioloop
import tornado.web
from tornado.web import UIModule
from tornado import gen
from tornado.concurrent import Future
import time


class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.render("index.html", list_info=[11, 22, 33], key1='value1')


class AsyncHandler(tornado.web.RequestHandler):

    @gen.coroutine
    def get(self):
        future = Future()
        tornado.ioloop.IOLoop.current().add_timeout(time.time() + 20, self.doing)
        yield future

    def doing(self, *args, **kwargs):
        self.write('async')
        self.finish()


settings = {
    'template_path': 'tmp',
    'static_path': 'statics'
}

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


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

此時再執行上面的操做，就會發現當async阻塞等待返回的時候，其餘網頁是能夠繼續訪問的。這樣單位時間處理的請求也就更多了。在服務器端將單線程用到極致。

裝飾器 + Future 從而實現Tornado的異步非阻塞，異步非阻塞的核心其實就在這個Future上，這個future類有點相似於一個標記，當裝飾器裝飾函數，函數內部實例化Future，並添加回調函數後。執行代碼：

from tornado import gen
from tornado.concurrent import Future


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()

發現請求一直沒有返回。實際上實例化future以後，產生了一個flag，只有當準備好響應數據或者知足響應條件的時候才能夠回調callback函數，返回給客戶端。

二、同步阻塞與異步非阻塞對比

前面的第一個實例其實就是同步阻塞的實例了。

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()

異步非阻塞

三、httpclient類庫

Tornado提供了httpclient類庫用於發送Http請求，能夠配合異步非阻塞使用。

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('進入')
        http = httpclient.AsyncHTTPClient()
        data = yield http.fetch("http://www.google.com")
        print('K.O.',data)
        self.finish('6666')
 
# 方式二：
# class AsyncHandler(tornado.web.RequestHandler):
#     @gen.coroutine
#     def get(self):
#         print('進入')
#         http = httpclient.AsyncHTTPClient()
#         yield http.fetch("http://www.google.com", self.done)
#
#     def done(self, response):
#         print('K.O.')
#         self.finish('666')
 
 
 
application = tornado.web.Application([
    (r"/async", AsyncHandler),
])
 
if __name__ == "__main__":
    application.listen(8888)
    tornado.ioloop.IOLoop.instance().start()

View Code

說到這，咱們來測試下經過另外一個url來改變future的標記位。

補充：

import tornado.ioloop
import tornado.web
from tornado.web import UIModule
from tornado import gen
from tornado.concurrent import Future

future = None

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.render("index.html", list_info=[11, 22, 33], key1='value1')


class AsyncHandler(tornado.web.RequestHandler):

    @gen.coroutine
    def get(self):
        global future
        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()


class StopHandler(tornado.web.RequestHandler):
    def get(self, *args, **kwargs):
        future.set_result('...')

settings = {
    'template_path': 'tmp',
    'static_path': 'statics'
}

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


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

遠端url控制某個url的future

200行的自定義異步非阻塞web框架

#!/usr/bin/env python3
# encoding: utf-8
# Author: Dandy
import re
import socket
import select
import time


class HttpResponse(object):
    """
    封裝響應信息
    """
    def __init__(self, content=''):
        self.content = content

        self.headers = {}
        self.cookies = {}

    def response(self):
        return bytes(self.content, encoding='utf-8')


class HttpNotFound(HttpResponse):
    """
    404時的錯誤提示
    """
    def __init__(self):
        super(HttpNotFound, self).__init__('404 Not Found')


class HttpRequest(object):
    """
    用戶封裝用戶請求信息
    """
    def __init__(self, conn):
        self.conn = conn

        self.header_bytes = bytes()
        self.header_dict = {}
        self.body_bytes = bytes()

        self.method = ""
        self.url = ""
        self.protocol = ""

        self.initialize()
        self.initialize_headers()

    def initialize(self):

        header_flag = False
        while True:
            try:
                received = self.conn.recv(8096)
            except Exception as e:
                received = None
            if not received:
                break
            if header_flag:
                self.body_bytes += received
                continue
            temp = received.split(b'\r\n\r\n', 1)
            if len(temp) == 1:
                self.header_bytes += temp
            else:
                h, b = temp
                self.header_bytes += h
                self.body_bytes += b
                header_flag = True

    @property
    def header_str(self):
        return str(self.header_bytes, encoding='utf-8')

    def initialize_headers(self):
        headers = self.header_str.split('\r\n')
        first_line = headers[0].split(' ')
        if len(first_line) == 3:
            self.method, self.url, self.protocol = headers[0].split(' ')
            for line in headers:
                kv = line.split(':')
                if len(kv) == 2:
                    k, v = kv
                    self.header_dict[k] = v


class Future(object):
    """
    異步非阻塞模式時封裝回調函數以及是否準備就緒
    """
    def __init__(self, callback):
        self.callback = callback
        self._ready = False
        self.value = None

    def set_result(self, value=None):
        self.value = value
        self._ready = True

    @property
    def ready(self):
        return self._ready


class TimeoutFuture(Future):
    """
    異步非阻塞超時
    """
    def __init__(self, timeout):
        super(TimeoutFuture, self).__init__(callback=None)
        self.timeout = timeout
        self.start_time = time.time()

    @property
    def ready(self):
        current_time = time.time()
        if current_time > self.start_time + self.timeout:
            self._ready = True
        return self._ready


class Snow(object):
    """
    微型Web框架類
    """
    def __init__(self, routes):
        self.routes = routes
        self.inputs = set()
        self.request = None
        self.async_request_handler = {}

    def run(self, host='localhost', port=9999):
        """
        事件循環
        :param host:
        :param port:
        :return:
        """
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        sock.bind((host, port,))
        sock.setblocking(False)  # 非阻塞
        sock.listen(128)
        sock.setblocking(0)
        self.inputs.add(sock)  # 將此socket添加到inputs這個集合裏
        try:
            while True:
                readable_list, writeable_list, error_list = select.select(self.inputs, [], self.inputs,0.005)  # 監聽
                for conn in readable_list:  # 循環可讀的集合
                    if sock == conn:  # socket有新的鏈接進來
                        client, address = conn.accept()  # 獲取conn、addr
                        client.setblocking(False)
                        self.inputs.add(client)  # 將此鏈接conn加入監聽
                    else:
                        gen = self.process(conn)  # 獲取、處理鏈接conn，拿請求體請求體
                        if isinstance(gen, HttpResponse):  # 若是返回的是HttpResponse類型的，表明是正常的請求
                            conn.sendall(gen.response())  # 發送給客戶端
                            self.inputs.remove(conn)  # 既然返回了，則須要從監聽隊列移除
                            conn.close()  # 關閉此socket鏈接
                        else:
                            yielded = next(gen)  # 不是正常的請求就一定是yield future
                            self.async_request_handler[conn] = yielded  # future對象加入字典中key==》conn，value==》future對象
                self.polling_callback()  # for 循環執行完，執行此函數

        except Exception as e:
            pass
        finally:
            sock.close()

    def polling_callback(self):
        """
        遍歷觸發異步非阻塞的回調函數
        :return:
        """
        for conn in list(self.async_request_handler.keys()):  # 循環取key
            yielded = self.async_request_handler[conn]  # 根據循環的key取value
            # conn：socket對象
            # yielded：future對象
            if not yielded.ready:  # ready是布爾值，若是執行了set_result，就變成true，表示已經就緒
                continue  # 不然循環繼續
            if yielded.callback:  # 若是被set result
                ret = yielded.callback(self.request, yielded)
                conn.sendall(ret.response())  # 發送數據
            self.inputs.remove(conn)  # 從監聽內移除此conn
            del self.async_request_handler[conn]  # 從循環字典刪除
            conn.close()  # 關閉conn

    def process(self, conn):
        """
        處理路由系統以及執行函數
        :param conn:
        :return:
        """
        self.request = HttpRequest(conn)
        func = None
        for route in self.routes:
            if re.match(route[0], self.request.url):
                func = route[1]
                break
        if not func:
            return HttpNotFound()
        else:
            return func(self.request)

自定義異步非阻塞框架

使用

from snow import Snow
from snow import HttpResponse
 
 
def index(request):
    return HttpResponse('OK')
 
 
routes = [
    (r'/index/', index),
]
 
app = Snow(routes)
app.run(port=8012)

基本使用

from snow import Snow
from snow import HttpResponse
from snow import TimeoutFuture
 
request_list = []
 
 
def async(request):
    obj = TimeoutFuture(5)
    yield obj
 
 
def home(request):
    return HttpResponse('home')
 
 
routes = [
    (r'/home/', home),
    (r'/async/', async),
]
 
app = Snow(routes)
app.run(port=8012)

異步非阻塞：超時

from snow import Snow
from snow import HttpResponse
from snow import Future
 
request_list = []
 
 
def callback(request, future):
    return HttpResponse(future.value)
 
 
def req(request):
    obj = Future(callback=callback)
    request_list.append(obj)
    yield obj
 
 
def stop(request):
    obj = request_list[0]
    del request_list[0]
    obj.set_result('done')
    return HttpResponse('stop')
 
 
routes = [
    (r'/req/', req),
    (r'/stop/', stop),
]
 
app = Snow(routes)
app.run(port=8012)