浅析tornado 中demo的 blog模块

#!/usr/bin/env python
#
# Copyright 2009 Facebook
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

import markdown
import os.path
import re
import torndb
import tornado.auth
import tornado.httpserver
import tornado.ioloop
import tornado.options
import tornado.web
import unicodedata

from tornado.options import define, options
#定义一些通用的配置信息,比如数据库的连接信息,端口信息
define("port", default=8888, help="run on the given port", type=int)
define("mysql_host", default="127.0.0.1:3306", help="blog database host")
define("mysql_database", default="blog", help="blog database name")
define("mysql_user", default="root", help="blog database user")
define("mysql_password", default="sa123", help="blog database password")

#定义Application信息,它是继承tornado.web.Application 的
class Application(tornado.web.Application):
   # __init__ 函数自动调用
    def __init__(self):
      #这里就是url对应的控制器,下面分别对应一个类,来处理里面的逻辑
        handlers = [
            (r"/", HomeHandler),
            (r"/archive", ArchiveHandler),
            (r"/feed", FeedHandler),
            (r"/entry/([^/]+)", EntryHandler),
            (r"/compose", ComposeHandler),
            (r"/auth/login", AuthLoginHandler),
            (r"/auth/logout", AuthLogoutHandler),
        ]
      #设置,如博客标题,模板目录,静态文件目录,xsrf,是否调试
        settings = dict(
            blog_title=u"Tornado Blog",
            template_path=os.path.join(os.path.dirname(__file__), "templates"),
            static_path=os.path.join(os.path.dirname(__file__), "static"),
            ui_modules={"Entry": EntryModule},
            xsrf_cookies=True,
            cookie_secret="__TODO:_GENERATE_YOUR_OWN_RANDOM_VALUE_HERE__",
            login_url="/auth/login",
            debug=True,
        )
       #然后调用tornado.web.Application类的__init__函数加载进来
        tornado.web.Application.__init__(self, handlers, **settings)

        # Have one global connection to the blog DB across all handlers
       #数据库连接信息
        self.db = torndb.Connection(
            host=options.mysql_host, database=options.mysql_database,
            user=options.mysql_user, password=options.mysql_password)

#基类,继承自tornado.web.RequestHandler 的,后面的类都是继承这个类的
class BaseHandler(tornado.web.RequestHandler):
  #属性装饰器,使db函数变成一个属性,便于后面直接使用
    @property
    def db(self):
        return self.application.db
  #获得当前的用户
    def get_current_user(self):
        user_id = self.get_secure_cookie("blogdemo_user")
        if not user_id: return None
        return self.db.get("SELECT * FROM authors WHERE id = %s", int(user_id))

#首页
class HomeHandler(BaseHandler):
    def get(self):
     #query 查询很多列
        entries = self.db.query("SELECT * FROM entries ORDER BY published "
                                "DESC LIMIT 5")
        if not entries:
         #redirect 重定向到一个url
            self.redirect("/compose")
            return
     #render 渲染一个模板,后面是参数
        self.render("home.html", entries=entries)


class EntryHandler(BaseHandler):
    def get(self, slug):
    #get 得到一个值
        entry = self.db.get("SELECT * FROM entries WHERE slug = %s", slug)
    #raise 触发一个错误信息,后面必须接类型
        if not entry: raise tornado.web.HTTPError(404)
        self.render("entry.html", entry=entry)


class ArchiveHandler(BaseHandler):
    def get(self):
        entries = self.db.query("SELECT * FROM entries ORDER BY published "
                                "DESC")
        self.render("archive.html", entries=entries)


class FeedHandler(BaseHandler):
    def get(self):
        entries = self.db.query("SELECT * FROM entries ORDER BY published "
                                "DESC LIMIT 10")
        self.set_header("Content-Type", "application/atom+xml")
        self.render("feed.xml", entries=entries)


class ComposeHandler(BaseHandler):
#装饰器 @tornado.web.authenticated
def get(self): id = self.get_argument("id", None) entry = None if id: entry = self.db.get("SELECT * FROM entries WHERE id = %s", int(id)) self.render("compose.html", entry=entry) @tornado.web.authenticated def post(self): id = self.get_argument("id", None) title = self.get_argument("title") text = self.get_argument("markdown") html = markdown.markdown(text) if id: entry = self.db.get("SELECT * FROM entries WHERE id = %s", int(id)) if not entry: raise tornado.web.HTTPError(404) slug = entry.slug    #execute是执行的意思 self.db.execute( "UPDATE entries SET title = %s, markdown = %s, html = %s " "WHERE id = %s", title, text, html, int(id)) else: slug = unicodedata.normalize("NFKD", title).encode( "ascii", "ignore") slug = re.sub(r"[^\w]+", " ", slug) slug = "-".join(slug.lower().strip().split()) if not slug: slug = "entry" while True: e = self.db.get("SELECT * FROM entries WHERE slug = %s", slug) if not e: break slug += "-2" self.db.execute( "INSERT INTO entries (author_id,title,slug,markdown,html," "published) VALUES (%s,%s,%s,%s,%s,UTC_TIMESTAMP())", self.current_user.id, title, slug, text, html) self.redirect("/entry/" + slug) class AuthLoginHandler(BaseHandler, tornado.auth.GoogleMixin): @tornado.web.asynchronous def get(self): if self.get_argument("openid.mode", None): self.get_authenticated_user(self.async_callback(self._on_auth)) return self.authenticate_redirect()   #这里定义一个函数,来供上面调用 def _on_auth(self, user): if not user: raise tornado.web.HTTPError(500, "Google auth failed") author = self.db.get("SELECT * FROM authors WHERE email = %s", user["email"]) if not author: # Auto-create first author any_author = self.db.get("SELECT * FROM authors LIMIT 1") if not any_author: author_id = self.db.execute( "INSERT INTO authors (email,name) VALUES (%s,%s)", user["email"], user["name"]) else: self.redirect("/") return else: author_id = author["id"] self.set_secure_cookie("blogdemo_user", str(author_id)) self.redirect(self.get_argument("next", "/")) class AuthLogoutHandler(BaseHandler): def get(self): self.clear_cookie("blogdemo_user")    #get_argument为获得next参数的值,默认为"/" self.redirect(self.get_argument("next", "/")) class EntryModule(tornado.web.UIModule): def render(self, entry): return self.render_string("modules/entry.html", entry=entry) #入口函数 def main(): tornado.options.parse_command_line()   #创建一个服务器 http_server = tornado.httpserver.HTTPServer(Application())   #监听端口 http_server.listen(options.port)   #启动服务 tornado.ioloop.IOLoop.instance().start() #调用的入口 if __name__ == "__main__": main()   

 最后总结一下:

1)tornado框架中提供的几个demo,都是以这种形式来创建一个应用的

2)对每一个控制器函数,要么是,只可能有2个对外的函数,一个是get,一个是post

3)数据库有3中调用方式,query,get,exec

4)获取参数的值使用 get_argument 函数

5)重定向用redirect 函数

6)所有的函数都是属性这个类的,所有都用self调用

7)渲染模板用render函数

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