python:記一次簡(jiǎn)單的模擬flask和cgi服務(wù)器

Aldous 發(fā)布于2019-07-31 11:05 / 2275人閱讀

摘要：目前來(lái)說(shuō)文章亮點(diǎn)就是解耦做的還行，有一定的可擴(kuò)展性簡(jiǎn)單的仿實(shí)現(xiàn)路由分發(fā)規(guī)定應(yīng)用程序需要是一個(gè)可調(diào)用的對(duì)象可調(diào)用對(duì)象接收兩個(gè)參數(shù)可調(diào)用對(duì)象要返回一個(gè)值，這個(gè)值是可迭代的。

最近web服務(wù)器知識(shí)，中間懶癌犯了，斷了一兩天后思路有點(diǎn)接不上來(lái)，手頭上也有其他事情要做，先簡(jiǎn)單的總結(jié)下學(xué)習(xí)進(jìn)度，很多重要的功能都沒(méi)跑通，目前flask只是簡(jiǎn)單實(shí)現(xiàn)路由分顯示不同的結(jié)果，cgi可以根據(jù)不同的靜態(tài)資源或者py腳本文件路徑顯示不同的結(jié)果。目前來(lái)說(shuō)文章亮點(diǎn)就是解耦做的還行，有一定的可擴(kuò)展性

簡(jiǎn)單的仿flask實(shí)現(xiàn)路由分發(fā)

from wsgiref.simple_server import make_server


""""
WSGI規(guī)定：
1. 應(yīng)用程序需要是一個(gè)可調(diào)用的對(duì)象
2. 可調(diào)用對(duì)象接收兩個(gè)參數(shù)
3.可調(diào)用對(duì)象要返回一個(gè)值，這個(gè)值是可迭代的。
具體參考附錄一，pep-0333標(biāo)準(zhǔn)
"""
class SimServer(object):
    def __init__(self):
        self.url_map = {}
    
    def __call__(self, environ, start_response):
        status = u"200 OK"
        response_headers = [("Content-type", "text/plain")]
        start_response(status, response_headers)
        data=self.dispatch_request(environ)
        return [data.encode("utf-8"),]
    
    def run(self, ip=None, host=None):
        if not ip:
            ip = ""
        if not host:
            host = 8080
        httpd = make_server(ip, host, self)
        httpd.serve_forever()
    
    #路由裝飾器
    def route(self, rule):  
        def decorator(f):  
            self.url_map[rule.lstrip("/")] = f
            return f
        
        return decorator
    
    #路由的分發(fā)
    def dispatch_request(self, request):
        print(request)
        path = request.get("PATH_INFO", "").lstrip("/")
        print(path)
        return self.url_map[path]()  # 從url_map中找到對(duì)應(yīng)的處理函數(shù)，并調(diào)用



#創(chuàng)建一個(gè)app
app=SimServer()

@app.route("/index")
def index():
    return  "hello world"


@app.route("/login")
def login():
    return "please login"

if __name__=="__main__":
    app.run()


if __name__=="__main__":
    app.run()

CGI web服務(wù)器，靜態(tài)資源的轉(zhuǎn)發(fā)

handler.py

import os
import subprocess

class BaseHandler(object):
    """Parent for case handlers."""
    
    def handle_file(self, handler, full_path):
        try :
            with open(full_path, "rb") as reader:
                content = reader.read()
            handler.send_content(content)
        except IOError as msg:
            msg = ""{0}" cannot be read: {1}".format(full_path, msg)
            handler.handle_error(msg)
    
    def index_path(self, handler):
        return os.path.join(handler.full_path, "index.html")
    
    def test(self, handler):
        assert False, "Not implemented."
    
    def act(self, handler):
        assert False, "Not implemented."

#處理首頁(yè)
class Case_directory_idnex_file(BaseHandler):
    def test(self, handler):
        return (os.path.isdir(handler.full_path) and
                os.path.isfile(self.index_path(handler)))
    
    def act(self, handler):
        self.handle_file(handler, self.index_path(handler))
    

#處理普通html文件
class Case_existing_file(BaseHandler):
    def test(self, handler):
        return os.path.isfile((handler.full_path))
    
    def act(self, handler):
        self.handle_file(handler,handler.full_path)

#處理python腳本        
class Case_cgi_file(BaseHandler):
    def run_cgi(self, handler):
        print("dfs")
        print(handler.full_path)
        data=subprocess.getoutput(["python",handler.full_path])
        print("data={}".format(data))
        #python3默認(rèn)使用unicode，需要encode("utf-8")
        return handler.send_content(data.encode("utf-8"))
        
    def test(self,handler):
        return os.path.isfile(handler.full_path) and 
               handler.full_path.endswith(".py")
    def act(self,handler):
        self.run_cgi(handler)

requestHandler.py

from http.server import BaseHTTPRequestHandler,HTTPServer
import os
from simpleServer.handler import *


class RequestHandler(BaseHTTPRequestHandler):
    Cases = [Case_cgi_file(),Case_directory_idnex_file(),Case_existing_file() ,]
    
    # How to display an error.
    Error_Page = """
        
        
        Error accessing {path}
        {msg}
        
        
        """
    
    # Classify and handle request.
    def do_GET(self):
        try:
            # 使用join會(huì)有問(wèn)題，目前還沒(méi)搞清楚+可以，join會(huì)有問(wèn)題
            self.full_path = os.getcwd()+self.path
            # Figure out how to handle it.
            print("cases{}".format(self.Cases))
            for case in self.Cases:
                if case.test(self):
                    case.act(self)
                    break
        
        # 處理異常
        except Exception as msg:
            print(msg)
            self.handle_error(msg)
    
    # Handle unknown objects.
    def handle_error(self, msg):
        content = self.Error_Page.format(path=self.path, msg=msg)
        self.send_content(content.encode("utf-8"), 404)
    
    # Send actual content.
    def send_content(self, content, status=200):
        self.send_response(status)
        self.send_header("Content-type", "text/html")
        self.send_header("Content-Length", str(len(content)))
        self.end_headers()
        self.wfile.write(content)

if __name__=="__main__":
    severAddress=("",8000)
    server=HTTPServer(severAddress,RequestHandler)
    server.serve_forever()

參考附錄

1, pyton：pep-0333
2, flask作者博客文章：getting-started-with-wsgi
3, 自己寫(xiě)一個(gè) wsgi 服務(wù)器運(yùn)行 Django 、Tornado 等框架應(yīng)用
4, 500L:a-simple-web-server
5, python wsgi簡(jiǎn)介
6, 從零開(kāi)始搭建論壇（二）：Web服務(wù)器網(wǎng)關(guān)接口
7, python的 WSGI 簡(jiǎn)介
8，本文github源碼