Web框架之Tornado
Posted 黄土地上的黑石头
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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
import tornado pirnt(tornado.version)
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 -*- #!/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()
<!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>
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
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>
{% 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 %}
3、导入
<div> <ul> <li>1024</li> <li>42区</li> </ul> </div>
<!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>
4、自定义UIMethod以UIModule
a. 定义
# uimethods.py def tab(self): return \'UIMethod\'
#!/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>\')
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()
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>
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()
<!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>
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()
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!")
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=")
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以上是关于Web框架之Tornado的主要内容,如果未能解决你的问题,请参考以下文章