淺析tornado 中demo的 blog模塊

時間 2019-11-11
原文原文鏈接
#!/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
#定義一些通用的配置信息，好比數據庫的鏈接信息，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")

#定義Application信息，它是繼承tornado.web.Application 的
class Application(tornado.web.Application):
　　 # __init__ 函數自動調用
    def __init__(self):
　　    #這裏就是url對應的控制器，下面分別對應一個類，來處理裏面的邏輯
        handlers = [
            (r"/", HomeHandler),
            (r"/archive", ArchiveHandler),
            (r"/feed", FeedHandler),
            (r"/entry/([^/]+)", EntryHandler),
            (r"/compose", ComposeHandler),
            (r"/auth/login", AuthLoginHandler),
            (r"/auth/logout", AuthLogoutHandler),
        ]
　　    #設置，如博客標題，模板目錄，靜態文件目錄，xsrf，是否調試
        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,
        )
　　     #而後調用tornado.web.Application類的__init__函數加載進來
        tornado.web.Application.__init__(self, handlers, **settings)

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

#基類，繼承自tornado.web.RequestHandler 的，後面的類都是繼承這個類的
class BaseHandler(tornado.web.RequestHandler):
　　#屬性裝飾器，使db函數變成一個屬性，便於後面直接使用
    @property
    def db(self):
        return self.application.db
　　#得到當前的用戶
    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))

#首頁
class HomeHandler(BaseHandler):
    def get(self):
　　　　 #query 查詢不少列
        entries = self.db.query("SELECT * FROM entries ORDER BY published "
                                "DESC LIMIT 5")
        if not entries:
　　　　     #redirect 重定向到一個url
            self.redirect("/compose")
            return
　　　　 #render 渲染一個模板，後面是參數
        self.render("home.html", entries=entries)


class EntryHandler(BaseHandler):
    def get(self, slug):
　　　　#get 獲得一個值
        entry = self.db.get("SELECT * FROM entries WHERE slug = %s", slug)
　　　　#raise 觸發一個錯誤信息，後面必須接類型
        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):
    #裝飾器
    @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是執行的意思
            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()
　　#這裏定義一個函數，來供上面調用
    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爲得到next參數的值，默認爲"/"
        self.redirect(self.get_argument("next", "/"))


class EntryModule(tornado.web.UIModule):
    def render(self, entry):
        return self.render_string("modules/entry.html", entry=entry)

#入口函數
def main():
    tornado.options.parse_command_line()
　  #建立一個服務器
    http_server = tornado.httpserver.HTTPServer(Application())
　  #監聽端口
    http_server.listen(options.port)
　　#啓動服務
    tornado.ioloop.IOLoop.instance().start()

#調用的入口
if __name__ == "__main__":
    main()