python web框架之Tornado

说Tornado之前分享几个前端不错的网站:

    -- Bootstrap
http://www.bootcss.com/ -- Font Awesome
http://fontawesome.io/ -- bxslider
http://bxslider.com/ -- jQuery EasyUI
http://www.jeasyui.com/download/index.php -- jQuery UI
http://jqueryui.com/ -- parsleyjs
http://parsleyjs.org/ -- jQuery Validate
http://jqueryvalidation.org/

web框架的本质

总所周知,对于所有的Web应用,本质上其实就是一个socket服务端,用户的浏览器其实就是一个socket客户端。

#!/usr/bin/env python
# _*_ coding:utf-8 _*_
import socket def request_handler(client):
a = client.recv(1024)
client.send(bytes("HTTP/1.1 200 OK\r\n\r\n",encoding='utf-8'))
client.send(bytes("hello",encoding="utf-8")) def main():
sock = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
sock.bind(("127.0.0.1",8000))
sock.listen(5)
while True:
con,add = sock.accept()
request_handler(con)
con.close() if __name__ == '__main__':
main()

上述通过socket来实现了其本质,而对于真实开发中的python web程序来说,一般会分为两部分:服务器程序和应用程序。服务器程序负责对socket服务器进行封装,并在请求到来时,对请求的各种数据进行整理。应用程序则负责具体的逻辑处理。为了方便应用程序的开发,就出现了众多的Web框架,例如:Django、Flask、web.py 等。不同的框架有不同的开发方式,但是无论如何,开发出的应用程序都要和服务器程序配合,才能为用户提供服务。这样,服务器程序就需要为不同的框架提供不同的支持。这样混乱的局面无论对于服务器还是框架,都是不好的。对服务器来说,需要支持各种不同框架,对框架来说,只有支持它的服务器才能被开发出的应用使用。这时候,标准化就变得尤为重要。我们可以设立一个标准,只要服务器程序支持这个标准,框架也支持这个标准,那么他们就可以配合使用。一旦标准确定,双方各自实现。这样,服务器可以支持更多支持标准的框架,框架也可以使用更多支持标准的服务器。

WSGI(Web Server Gateway Interface)是一种规范,它定义了使用python编写的web app与web server之间接口格式,实现web app与web server间的解耦。

python标准库提供的独立WSGI服务器称为wsgiref。

2.x环境运行

from wsgiref.simple_server import make_server

def RunServer(environ, start_response):
start_response('200 OK', [('Content-Type', 'text/html')])
return '<h1>Hello, web!</h1>' if __name__ == '__main__':
httpd = make_server('', 8888, RunServer)
httpd.serve_forever()

自定义Web框架  

#!/usr/bin/env python
# _*_ coding:utf-8 _*_ from wsgiref.simple_server import make_server def index():
return "hi" URLS = {
"/index":index,
} def RunServer(environ, start_response): #environ 封装了请求头信息
start_response('200 OK', [('Content-Type', 'text/html')])
url = environ["PATH_INFO"]
if url in URLS.keys():
ret=URLS[url]() else:
ret = "404"
return ret if __name__ == '__main__':
httpd = make_server('', 8000, RunServer)
httpd.serve_forever()

在上一步骤中,对于所有的index返回给用户浏览器一个简单的字符串,在现实的Web请求中一般会返回一个复杂的符合HTML规则的字符串,所以我们一般将要返回给用户的HTML写在指定文件中,然后再返回。如:  

<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<form>
<input type="text" />
<input type="text" />
<input type="submit" />
</form>
</body>
</html>

返回表单

#!/usr/bin/env python
# _*_ coding:utf-8 _*_ from wsgiref.simple_server import make_server def login():
file_list = open("temp/s2.html",'r')
data = file_list.read()
return data def index():
file_list = open("temp/s1.html",'r')
data = file_list.read()
return data URLS = {
"/index":index,
"/login":login,
} def RunServer(environ, start_response):
start_response('200 OK', [('Content-Type', 'text/html')])
url = environ["PATH_INFO"]
if url in URLS.keys():
ret=URLS[url]()
else:
ret = "404"
return ret if __name__ == '__main__':
httpd = make_server('', 8000, RunServer)
httpd.serve_forever()

对于上述代码,虽然可以返回给用户HTML的内容以现实复杂的页面,但是还是存在问题:如何给用户返回动态内容?  

  • 自定义一套特殊的语法,进行替换
  • 使用开源工具jinja2,遵循其指定语法
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<h1>{{name}}</h1> <ul>
{% for item in user_list %}
<li>{{item}}</li>
{% endfor %}
</ul> </body>
</html>

index

#!/usr/bin/env python
# _*_ coding:utf-8 _*_ from wsgiref.simple_server import make_server
from jinja2 import Template def index():
file_list = open("temp/s3.html",'r')
file_text = file_list.read()
temp = Template(file_text)
data = temp.render(name="john Doe",user_list = ['tangseng','wukong'])
return data.encode("utf-8") def login():
file_list = open("temp/s2.html",'r')
data = file_list.read() return data URLS = {
"/index":index,
"/login":login,
} def RunServer(environ, start_response):
start_response('200 OK', [('Content-Type', 'text/html')])
url = environ["PATH_INFO"]
if url in URLS.keys():
ret=URLS[url]()
else:
ret = "404"
return ret if __name__ == '__main__':
httpd = make_server('', 8000, RunServer)
httpd.serve_forever()

遵循jinja2的语法规则,其内部会对指定的语法进行相应的替换,从而达到动态的返回内容

 Tornado 前戏

执行字符串表示的函数,并为该函数提供全局变量

本篇的内容从题目中就可以看出来,就是为之后剖析tornado模板做准备,也是由于该知识点使用的巧妙,所有就单独用一篇来介绍了。废话不多说,直接上代码:

#!usr/bin/env python
#coding:utf-8 namespace = {'name':'wukong','data':[18,73,84]} code = '''def hellocute():return "name %s ,age %d" %(name,data[0],) ''' func = compile(code, '<string>', "exec") exec func in namespace result = namespace['hellocute']()

此段代码的执行结果是:name wukong,age 18  

上述代码解析:

  • 第6行,code是一个字符串,该字符串的内容是一个函数体。
  • 第8行,将code字符串编译成函数 hello
  • 第10行,将函数 hello 添加到namespace字典中(key为hello),同时也将python的所有内置函数添加到namespace字段中(key为__builtins__),如此一来,namespace中的内容好比是一个个的全局变量,即
  • 第12行,执行Hello函数并将返回值复制给result
  • 第14行,输入result
name = wupeiqi
data = [18,73,84] def hellocute():
return "name %s ,age %d" %(name,data[0],)

这段代码用的很是巧妙有木有,亮瞎狗眼有木有,居然把字符串变成了函数并且还为该函数提供了全局变量。对于该功能,它就是python的web框架中模板语言部分至关重要的部分,因为在模板处理过程中,首先会读取html文件,然后分割html文件,再然后讲分割的文件组成一个字符串表示的函数,再再然后就是利用上述方法执行字符串表示的函数。

快速上手Tornado

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。)

 一、安装如下:

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

第一次运行Tornado代码:  

#!/usr/bin/env python
# -*- coding:utf-8 -*- import tornado.ioloop
import tornado.web class MainHandler(tornado.web.RequestHandler):
def get(self):
self.write("Hello, world") application = tornado.web.Application([
(r"/index", MainHandler),
]) if __name__ == "__main__":
application.listen(8888)
tornado.ioloop.IOLoop.instance().start()

第一步:执行脚本,监听 8888 端口

第二步:浏览器客户端访问 /index  -->  http://127.0.0.1:8888/index

第三步:服务器接受请求,并交由对应的类处理该请求

第四步:类接受到请求之后,根据请求方式(post / get / delete ...)的不同调用并执行相应的方法

第五步:方法返回值的字符串内容发送浏览器

#!/usr/bin/env python
# -*- coding:utf-8 -*- import tornado.ioloop
import tornado.web
from tornado import httpclient
from tornado.web import asynchronous
from tornado import gen import uimodules as md
import uimethods as mt class MainHandler(tornado.web.RequestHandler):
@asynchronous
@gen.coroutine
def get(self):
print 'start get '
http = httpclient.AsyncHTTPClient()
http.fetch("http://127.0.0.1:8008/post/", self.callback)
self.write('end') def callback(self, response):
print response.body settings = {
'template_path': 'template',
'static_path': 'static',
'static_url_prefix': '/static/',
'ui_methods': mt,
'ui_modules': md,
} application = tornado.web.Application([
(r"/index", MainHandler),
], **settings) if __name__ == "__main__":
application.listen(8009)
tornado.ioloop.IOLoop.instance().start()

异步非阻塞

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 LoginHandler(tornado.web.RequestHandler): def get(self, *args, **kwargs):
self.render("s2.html") class IndexHandler(tornado.web.RequestHandler): def get(self, *args, **kwargs):
self.render("index.html")
#路由系统
settings = {
"template_path":"templates", } application = tornado.web.Application([
(r"/index",IndexHandler),
(r"/login",LoginHandler),
]) if __name__ == '__main__':
httpd = application.listen(8888)
tornado.ioloop.IOLoop.instance().start()

Tornado中原生支持二级域名的路由,如:

python web框架之Tornado

三、模板

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

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

控制语句和对应的 Python 语句的格式基本完全相同。我们支持 ifforwhile 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。

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

<!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" />
</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

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.母板

<!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

<!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

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

1、定义

# uimethods.py

def tab(self):
return 'UIMethod'

uimethods.py

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

uimmodule

注册

#!/usr/bin/env python
# -*- coding:utf-8 -*-
#!/usr/bin/env python
# -*- coding:utf-8 -*- import tornado.ioloop
import tornado.web
from tornado.escape import linkify
import uimodules as md
import uimethods as mt class MainHandler(tornado.web.RequestHandler):
def get(self):
self.render('index.html') settings = {
'template_path': 'template',
'static_path': 'static',
'static_url_prefix': '/static/',
'ui_methods': mt,
'ui_modules': md,
} application = tornado.web.Application([
(r"/index", MainHandler),
], **settings) if __name__ == "__main__":
application.listen(8009)
tornado.ioloop.IOLoop.instance().start()

main.py

使用

<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<link href="{{static_url("commons.css")}}" rel="stylesheet" />
</head>
<body>
<h1>hello</h1>
{% module custom(123) %}
{{ tab() }}
</body>

index

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', //静态资源的的路径比如 css,js
'static_url_prefix': '/static/', // 静态资源的的 URL 前缀
} application = tornado.web.Application([
(r"/index", MainHandler),
], **settings) if __name__ == "__main__":
application.listen(80)
tornado.ioloop.IOLoop.instance().start()

备注:静态文件缓存的实现

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。

a、基本操作

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

b、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=")//随意增加

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

内部算法

def create_signed_value(secret, name, value, version=None, clock=None,
key_version=None):
if version is None:
version = DEFAULT_SIGNED_VALUE_VERSION
if clock is None:
clock = time.time timestamp = utf8(str(int(clock())))
value = base64.b64encode(utf8(value))
if version == 1:
signature = _create_signature_v1(secret, name, value, timestamp)
value = b"|".join([value, timestamp, signature])
return value
elif version == 2:
# The v2 format consists of a version number and a series of
# length-prefixed fields "%d:%s", the last of which is a
# signature, all separated by pipes. All numbers are in
# decimal format with no leading zeros. The signature is an
# HMAC-SHA256 of the whole string up to that point, including
# the final pipe.
#
# The fields are:
# - format version (i.e. 2; no length prefix)
# - key version (integer, default is 0)
# - timestamp (integer seconds since epoch)
# - name (not encoded; assumed to be ~alphanumeric)
# - value (base64-encoded)
# - signature (hex-encoded; no length prefix)
def format_field(s):
return utf8("%d:" % len(s)) + utf8(s)
to_sign = b"|".join([
b"",
format_field(str(key_version or 0)),
format_field(timestamp),
format_field(name),
format_field(value),
b'']) if isinstance(secret, dict):
assert key_version is not None, 'Key version must be set when sign key dict is used'
assert version >= 2, 'Version must be at least 2 for key version support'
secret = secret[key_version] signature = _create_signature_v2(secret, to_sign)
return to_sign + signature
else:
raise ValueError("Unsupported version %d" % version)

算法加密

def _decode_signed_value_v1(secret, name, value, max_age_days, clock):
parts = utf8(value).split(b"|")
if len(parts) != 3:
return None
signature = _create_signature_v1(secret, name, parts[0], parts[1])
if not _time_independent_equals(parts[2], signature):
gen_log.warning("Invalid cookie signature %r", value)
return None
timestamp = int(parts[1])
if timestamp < clock() - max_age_days * 86400:
gen_log.warning("Expired cookie %r", value)
return None
if timestamp > clock() + 31 * 86400:
# _cookie_signature does not hash a delimiter between the
# parts of the cookie, so an attacker could transfer trailing
# digits from the payload to the timestamp without altering the
# signature. For backwards compatibility, sanity-check timestamp
# here instead of modifying _cookie_signature.
gen_log.warning("Cookie timestamp in future; possible tampering %r",
value)
return None
if parts[1].startswith(b""):
gen_log.warning("Tampered cookie %r", value)
return None
try:
return base64.b64decode(parts[0])
except Exception:
return None def _decode_fields_v2(value):
def _consume_field(s):
length, _, rest = s.partition(b':')
n = int(length)
field_value = rest[:n]
# In python 3, indexing bytes returns small integers; we must
# use a slice to get a byte string as in python 2.
if rest[n:n + 1] != b'|':
raise ValueError("malformed v2 signed value field")
rest = rest[n + 1:]
return field_value, rest rest = value[2:] # remove version number
key_version, rest = _consume_field(rest)
timestamp, rest = _consume_field(rest)
name_field, rest = _consume_field(rest)
value_field, passed_sig = _consume_field(rest)
return int(key_version), timestamp, name_field, value_field, passed_sig def _decode_signed_value_v2(secret, name, value, max_age_days, clock):
try:
key_version, timestamp, name_field, value_field, passed_sig = _decode_fields_v2(value)
except ValueError:
return None
signed_string = value[:-len(passed_sig)] if isinstance(secret, dict):
try:
secret = secret[key_version]
except KeyError:
return None expected_sig = _create_signature_v2(secret, signed_string)
if not _time_independent_equals(passed_sig, expected_sig):
return None
if name_field != utf8(name):
return None
timestamp = int(timestamp)
if timestamp < clock() - max_age_days * 86400:
# The signature has expired.
return None
try:
return base64.b64decode(value_field)
except Exception:
return None def get_signature_key_version(value):
value = utf8(value)
version = _get_version(value)
if version < 2:
return None
try:
key_version, _, _, _, _ = _decode_fields_v2(value)
except ValueError:
return None return key_version

算法解密

签名Cookie的本质是:

写cookie过程:

将值进行base64加密
对除值以外的内容进行签名,哈希算法(无法逆向解析)
拼接 签名 + 加密值
读cookie过程: 读取 签名 + 加密值
对签名进行验证
base64解密,获取值内容

注:许多API验证机制和安全cookie的实现机制相同。

#!/usr/bin/env python
# -*- coding:utf-8 -*- import tornado.ioloop
import tornado.web class MainHandler(tornado.web.RequestHandler): def get(self):
login_user = self.get_secure_cookie("login_user", None)
if login_user:
self.write(login_user)
else:
self.redirect('/login') class LoginHandler(tornado.web.RequestHandler):
def get(self):
self.current_user() self.render('login.html', **{'status': ''}) def post(self, *args, **kwargs): username = self.get_argument('name')
password = self.get_argument('pwd')
if username == 'wukong' and password == '':
self.set_secure_cookie('login_user', '悟空')
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进行用户验证

#!/usr/bin/env python
# -*- coding:utf-8 -*- import tornado.ioloop
import tornado.web class BaseHandler(tornado.web.RequestHandler): def get_current_user(self):
return self.get_secure_cookie("login_user") class MainHandler(BaseHandler): @tornado.web.authenticated
def get(self):
login_user = self.current_user
self.write(login_user) class LoginHandler(tornado.web.RequestHandler):
def get(self):
self.current_user() self.render('login.html', **{'status': ''}) def post(self, *args, **kwargs): username = self.get_argument('name')
password = self.get_argument('pwd')
if username == 'wukong' and password == '':
self.set_secure_cookie('login_user', '悟空')
self.redirect('/')
else:
self.render('login.html', **{'status': '用户名或密码错误'}) settings = {
'template_path': 'template',
'static_path': 'static',
'static_url_prefix': '/static/',
'cookie_secret': 'aiuasdhflashjdfoiuashdfiuh',
'login_url': '/login'
} application = tornado.web.Application([
(r"/index", MainHandler),
(r"/login", LoginHandler),
], **settings) if __name__ == "__main__":
application.listen(8888)
tornado.ioloop.IOLoop.instance().start()

Demo-Toando内部提供基于cookie进行用户验证

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)

限制与POST请求


普通表单使用
ajax使用

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

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="" 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

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:

python web框架之Tornado  

验证码Demo源码下载:猛击这里

源码中有两个文件要注意Monaco.ttf和check_code.py 要引入到工程内;demo

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'] = 'wupeiqi'
#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 = "wupeiqi" 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会话的容器,其必须依赖cookie才能实现。

import  hashlib
import time container = {}
class Session:
def __init__(self, handler):
self.handler = handler
self.random_str = None def __genarate_random_str(self):
'''
用于生成加密字符串
:return:
''' obj = hashlib.md5()
obj.update(bytes(str(time.time()), encoding='utf-8'))
random_str = obj.hexdigest()
return random_str def __setitem__(self, key, value):
# 在container中加入随机字符串
# 定义专属于自己的数据
# 在客户端中写入随机字符串
# 判断,请求的用户是否已有随机字符串
if not self.random_str:
random_str = self.handler.get_cookie('__kakaka__')
if not random_str:
random_str = self.__genarate_random_str()
container[random_str] = {}
else:
# 客户端有随机字符串
if random_str in container.keys(): #判断字符串是否在container中
pass
else:
random_str = self.__genarate_random_str() #生成字符串
container[random_str] = {} #生成专属的字典
self.random_str = random_str # self.random_str = asdfasdfasdfasdf container[self.random_str][key] = value
self.handler.set_cookie("__kakaka__", self.random_str) def __getitem__(self,key):
# 获取客户端的随机字符串
# 从container中获取专属于我的数据
# 专属信息【key】
random_str = self.handler.get_cookie("__kakaka__")
if not random_str:
return None
# 客户端有随机字符串
user_info_dict = container.get(random_str,None)
if not user_info_dict:
return None
value = user_info_dict.get(key, None)
return value

4、分布式Session

#!/usr/bin/env python
#coding:utf-8 import sys
import math
from bisect import bisect if sys.version_info >= (2, 5):
import hashlib
md5_constructor = hashlib.md5
else:
import md5
md5_constructor = md5.new class HashRing(object):
"""一致性哈希""" def __init__(self,nodes):
'''初始化
nodes : 初始化的节点,其中包含节点已经节点对应的权重
默认每一个节点有32个虚拟节点
对于权重,通过多创建虚拟节点来实现
如:nodes = [
{'host':'127.0.0.1:8000','weight':1},
{'host':'127.0.0.1:8001','weight':2},
{'host':'127.0.0.1:8002','weight':1},
]
''' self.ring = dict()
self._sorted_keys = [] self.total_weight = 0 self.__generate_circle(nodes) def __generate_circle(self,nodes):
for node_info in nodes:
self.total_weight += node_info.get('weight',1) for node_info in nodes:
weight = node_info.get('weight',1)
node = node_info.get('host',None) virtual_node_count = math.floor((32*len(nodes)*weight) / self.total_weight)
for i in xrange(0,int(virtual_node_count)):
key = self.gen_key_thirty_two( '%s-%s' % (node, i) )
if self._sorted_keys.__contains__(key):
raise Exception('该节点已经存在.')
self.ring[key] = node
self._sorted_keys.append(key) def add_node(self,node):
''' 新建节点
node : 要添加的节点,格式为:{'host':'127.0.0.1:8002','weight':1},其中第一个元素表示节点,第二个元素表示该节点的权重。
'''
node = node.get('host',None)
if not node:
raise Exception('节点的地址不能为空.') weight = node.get('weight',1) self.total_weight += weight
nodes_count = len(self._sorted_keys) + 1 virtual_node_count = math.floor((32 * nodes_count * weight) / self.total_weight)
for i in xrange(0,int(virtual_node_count)):
key = self.gen_key_thirty_two( '%s-%s' % (node, i) )
if self._sorted_keys.__contains__(key):
raise Exception('该节点已经存在.')
self.ring[key] = node
self._sorted_keys.append(key) def remove_node(self,node):
''' 移除节点
node : 要移除的节点 '127.0.0.1:8000'
'''
for key,value in self.ring.items():
if value == node:
del self.ring[key]
self._sorted_keys.remove(key) def get_node(self,string_key):
'''获取 string_key 所在的节点'''
pos = self.get_node_pos(string_key)
if pos is None:
return None
return self.ring[ self._sorted_keys[pos]].split(':') def get_node_pos(self,string_key):
'''获取 string_key 所在的节点的索引'''
if not self.ring:
return None key = self.gen_key_thirty_two(string_key)
nodes = self._sorted_keys
pos = bisect(nodes, key)
return pos def gen_key_thirty_two(self, key): m = md5_constructor()
m.update(key)
return long(m.hexdigest(), 16) def gen_key_sixteen(self,key): b_key = self.__hash_digest(key)
return self.__hash_val(b_key, lambda x: x) def __hash_val(self, b_key, entry_fn):
return (( b_key[entry_fn(3)] << 24)|(b_key[entry_fn(2)] << 16)|(b_key[entry_fn(1)] << 8)| b_key[entry_fn(0)] ) def __hash_digest(self, key):
m = md5_constructor()
m.update(key)
return map(ord, m.digest()) """
nodes = [
{'host':'127.0.0.1:8000','weight':1},
{'host':'127.0.0.1:8001','weight':2},
{'host':'127.0.0.1:8002','weight':1},
] ring = HashRing(nodes)
result = ring.get_node('98708798709870987098709879087')
print result """

一致性哈西

from hashlib import sha1
import os, time create_session_id = lambda: sha1('%s%s' % (os.urandom(16), time.time())).hexdigest() class Session(object): session_id = "__sessionId__" def __init__(self, request):
session_value = request.get_cookie(Session.session_id)
if not session_value:
self._id = create_session_id()
else:
self._id = session_value
request.set_cookie(Session.session_id, self._id) def __getitem__(self, key):
# 根据 self._id ,在一致性哈西中找到其对应的服务器IP
# 找到相对应的redis服务器,如: r = redis.StrictRedis(host='localhost', port=6379, db=0)
# 使用python redis api 链接
# 获取数据,即:
# return self._redis.hget(self._id, name) def __setitem__(self, key, value):
# 根据 self._id ,在一致性哈西中找到其对应的服务器IP
# 使用python redis api 链接
# 设置session
# self._redis.hset(self._id, name, value) def __delitem__(self, key):
# 根据 self._id 找到相对应的redis服务器
# 使用python redis api 链接
# 删除,即:
return self._redis.hdel(self._id, name)

session

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。

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

HTML

#!/usr/bin/env python
# -*- coding:utf-8 -*- import tornado.ioloop
import tornado.web
from hashlib import sha1
import os, time
import re class MainForm(object):
def __init__(self):
self.host = "(.*)"
self.ip = "^(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}$"
self.port = '(\d+)'
self.phone = '^1[3|4|5|8][0-9]\d{8}$' def check_valid(self, request):
form_dict = self.__dict__
for key, regular in form_dict.items():
post_value = request.get_argument(key)
# 让提交的数据 和 定义的正则表达式进行匹配
ret = re.match(regular, post_value)
print key,ret,post_value class MainHandler(tornado.web.RequestHandler):
def get(self):
self.render('index.html')
def post(self, *args, **kwargs):
obj = MainForm()
result = obj.check_valid(self)
self.write('ok') settings = {
'template_path': 'template',
'static_path': 'static',
'static_url_prefix': '/static/',
'cookie_secret': 'aiuasdhflashjdfoiuashdfiuh',
'login_url': '/login'
} application = tornado.web.Application([
(r"/index", MainHandler),
], **settings) if __name__ == "__main__":
application.listen(8888)
tornado.ioloop.IOLoop.instance().start()

Python

由于验证规则可以代码重用,所以可以如此定义:

#!/usr/bin/env python
# -*- coding:utf-8 -*- import tornado.ioloop
import tornado.web
import re class Field(object): def __init__(self, error_msg_dict, required):
self.id_valid = False
self.value = None
self.error = None
self.name = None
self.error_msg = error_msg_dict
self.required = required def match(self, name, value):
self.name = name if not self.required:
self.id_valid = True
self.value = value
else:
if not value:
if self.error_msg.get('required', None):
self.error = self.error_msg['required']
else:
self.error = "%s is required" % name
else:
ret = re.match(self.REGULAR, value)
if ret:
self.id_valid = True
self.value = ret.group()
else:
if self.error_msg.get('valid', None):
self.error = self.error_msg['valid']
else:
self.error = "%s is invalid" % name class IPField(Field):
REGULAR = "^(25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2[0-4]\d|[0-1]?\d?\d)){3}$" def __init__(self, error_msg_dict=None, required=True): error_msg = {} # {'required': 'IP不能为空', 'valid': 'IP格式错误'}
if error_msg_dict:
error_msg.update(error_msg_dict) super(IPField, self).__init__(error_msg_dict=error_msg, required=required) class IntegerField(Field):
REGULAR = "^\d+$" def __init__(self, error_msg_dict=None, required=True):
error_msg = {'required': '数字不能为空', 'valid': '数字格式错误'}
if error_msg_dict:
error_msg.update(error_msg_dict) super(IntegerField, self).__init__(error_msg_dict=error_msg, required=required) class CheckBoxField(Field): def __init__(self, error_msg_dict=None, required=True):
error_msg = {} # {'required': 'IP不能为空', 'valid': 'IP格式错误'}
if error_msg_dict:
error_msg.update(error_msg_dict) super(CheckBoxField, self).__init__(error_msg_dict=error_msg, required=required) def match(self, name, value):
self.name = name if not self.required:
self.id_valid = True
self.value = value
else:
if not value:
if self.error_msg.get('required', None):
self.error = self.error_msg['required']
else:
self.error = "%s is required" % name
else:
if isinstance(name, list):
self.id_valid = True
self.value = value
else:
if self.error_msg.get('valid', None):
self.error = self.error_msg['valid']
else:
self.error = "%s is invalid" % name class FileField(Field):
REGULAR = "^(\w+\.pdf)|(\w+\.mp3)|(\w+\.py)$" def __init__(self, error_msg_dict=None, required=True):
error_msg = {} # {'required': '数字不能为空', 'valid': '数字格式错误'}
if error_msg_dict:
error_msg.update(error_msg_dict) super(FileField, self).__init__(error_msg_dict=error_msg, required=required) def match(self, name, value):
self.name = name
self.value = []
if not self.required:
self.id_valid = True
self.value = value
else:
if not value:
if self.error_msg.get('required', None):
self.error = self.error_msg['required']
else:
self.error = "%s is required" % name
else:
m = re.compile(self.REGULAR)
if isinstance(value, list):
for file_name in value:
r = m.match(file_name)
if r:
self.value.append(r.group())
self.id_valid = True
else:
self.id_valid = False
if self.error_msg.get('valid', None):
self.error = self.error_msg['valid']
else:
self.error = "%s is invalid" % name
break
else:
if self.error_msg.get('valid', None):
self.error = self.error_msg['valid']
else:
self.error = "%s is invalid" % name def save(self, request, upload_path=""): file_metas = request.files[self.name]
for meta in file_metas:
file_name = meta['filename']
with open(file_name,'wb') as up:
up.write(meta['body']) class Form(object): def __init__(self):
self.value_dict = {}
self.error_dict = {}
self.valid_status = True def validate(self, request, depth=10, pre_key=""): self.initialize()
self.__valid(self, request, depth, pre_key) def initialize(self):
pass def __valid(self, form_obj, request, depth, pre_key):
"""
验证用户表单请求的数据
:param form_obj: Form对象(Form派生类的对象)
:param request: Http请求上下文(用于从请求中获取用户提交的值)
:param depth: 对Form内容的深度的支持
:param pre_key: Html中name属性值的前缀(多层Form时,内部递归时设置,无需理会)
:return: 是否验证通过,True:验证成功;False:验证失败
""" depth -= 1
if depth < 0:
return None
form_field_dict = form_obj.__dict__
for key, field_obj in form_field_dict.items():
print key,field_obj
if isinstance(field_obj, Form) or isinstance(field_obj, Field):
if isinstance(field_obj, Form):
# 获取以key开头的所有的值,以参数的形式传至
self.__valid(field_obj, request, depth, key)
continue
if pre_key:
key = "%s.%s" % (pre_key, key) if isinstance(field_obj, CheckBoxField):
post_value = request.get_arguments(key, None)
elif isinstance(field_obj, FileField):
post_value = []
file_list = request.request.files.get(key, None)
for file_item in file_list:
post_value.append(file_item['filename'])
else:
post_value = request.get_argument(key, None) print post_value
# 让提交的数据 和 定义的正则表达式进行匹配
field_obj.match(key, post_value)
if field_obj.id_valid:
self.value_dict[key] = field_obj.value
else:
self.error_dict[key] = field_obj.error
self.valid_status = False class ListForm(object):
def __init__(self, form_type):
self.form_type = form_type
self.valid_status = True
self.value_dict = {}
self.error_dict = {} def validate(self, request):
name_list = request.request.arguments.keys() + request.request.files.keys()
index = 0
flag = False
while True:
pre_key = "[%d]" % index
for name in name_list:
if name.startswith(pre_key):
flag = True
break
if flag:
form_obj = self.form_type()
form_obj.validate(request, depth=10, pre_key="[%d]" % index)
if form_obj.valid_status:
self.value_dict[index] = form_obj.value_dict
else:
self.error_dict[index] = form_obj.error_dict
self.valid_status = False
else:
break index += 1
flag = False class MainForm(Form): def __init__(self):
# self.ip = IPField(required=True)
# self.port = IntegerField(required=True)
# self.new_ip = IPField(required=True)
# self.second = SecondForm()
self.fff = FileField(required=True)
super(MainForm, self).__init__() #
# class SecondForm(Form):
#
# def __init__(self):
# self.ip = IPField(required=True)
# self.new_ip = IPField(required=True)
#
# super(SecondForm, self).__init__() class MainHandler(tornado.web.RequestHandler):
def get(self):
self.render('index.html')
def post(self, *args, **kwargs):
# for i in dir(self.request):
# print i
# print self.request.arguments
# print self.request.files
# print self.request.query
# name_list = self.request.arguments.keys() + self.request.files.keys()
# print name_list # list_form = ListForm(MainForm)
# list_form.validate(self)
#
# print list_form.valid_status
# print list_form.value_dict
# print list_form.error_dict # obj = MainForm()
# obj.validate(self)
#
# print "验证结果:", obj.valid_status
# print "符合验证结果:", obj.value_dict
# print "错误信息:"
# for key, item in obj.error_dict.items():
# print key,item
# print self.get_arguments('favor'),type(self.get_arguments('favor'))
# print self.get_argument('favor'),type(self.get_argument('favor'))
# print type(self.get_argument('fff')),self.get_argument('fff')
# print self.request.files
# obj = MainForm()
# obj.validate(self)
# print obj.valid_status
# print obj.value_dict
# print obj.error_dict
# print self.request,type(self.request)
# obj.fff.save(self.request)
# from tornado.httputil import HTTPServerRequest
# name_list = self.request.arguments.keys() + self.request.files.keys()
# print name_list
# print self.request.files,type(self.request.files)
# print len(self.request.files.get('fff')) # obj = MainForm()
# obj.validate(self)
# print obj.valid_status
# print obj.value_dict
# print obj.error_dict
# obj.fff.save(self.request)
self.write('ok') settings = {
'template_path': 'template',
'static_path': 'static',
'static_url_prefix': '/static/',
'cookie_secret': 'aiuasdhflashjdfoiuashdfiuh',
'login_url': '/login'
} application = tornado.web.Application([
(r"/index", MainHandler),
], **settings) if __name__ == "__main__":
application.listen(8888)
tornado.ioloop.IOLoop.instance().start()
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