parse_request handle_one_request

Python标准库源码分析：BaseHTTPServer.py

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从SocketServer.py分析中可以知道其设计思想是将socket编程的监听循环和客户端处理划分成Server类和RequestHandler类，而BaseHTTPServer是基于SocketServer基础之上的，因此可以知道BaseHTTPServer就是分别扩展Server类和RequestHandler类。BaseHTTPServer实现了一个简单的HTTP Server，可以知道主要工作应该是扩展RequestHandler的功能，处理客户端的HTTP请求，具体包括HTTP协议解析，给客户端返回HTTP响应，日志记录等功能。

1.HTTPServer

该类只是简单包装了SocketServer中的TCPServer[1]类

2.BaseHTTPRequestHandler

类定义

class BaseHTTPRequestHandler(SocketServer.StreamRequestHandler):

扩展RequestHandler需要覆盖一个接口handler()，定义如下：

def handle(self):
    """Handle multiple requests if necessary."""
    self.close_connection = 1
    self.handle_one_request()
    while not self.close_connection:
        self.handle_one_request()

主要处理的是HTTP是否保持连接的问题，如果保持连接就持续处理客户请求，否则就结束了。
handle_one_request()比较重要语句：

self.raw_requestline = self.rfile.readline(65537)
self.parse_request()
mname = 'do_' + self.command
if not hasattr(self, mname)
    self.send_error(501, "Unsupported method (%r)" % self.command)
    return
method = getattr(self, mname)
method() ###调用do_GET do_post
self.wfile.flush() #actually send the response if not already done.

读取第一行raw_requestline，一般格式应该是：COMMAND PATH VERSION\r\n；解析请求，下面具体分析；后面几行代码意思是根据HTTP方法获取对应处理函数，其实就是根据GET或POST请求调用对应的do_GET()或do_POST()方法，然后刷新输出。
parse_request()主要的代码都在处理raw_requestline，最终得到self.command, self.path, self.request_version几个变量，然后就是利用mimetools.Message解析头部。
至此主体流程就结束了。
下面还有几个的函数，功能都比较简单：

def send_error(self, code, message=None):
def send_response(self, code, message=None):
def send_header(self, keyword, value):
def end_headers(self):
def log_request(self, code='-', size='-'):
def log_error(self, format, *args):
def log_message(self, format, *args):

总结：可以看到，BaseHTTPRequestHandler主要实现了客户端HTTP请求解析，以及一些辅助功能，如日志记录、错误处理、发送响应代码等。但是还没有实现如何执行HTTP请求，简单来说就是还需要实现诸如do_GET(),do_POST()等函数，具体执行对应的HTTP命令。

 

CODE:===========================================================from http.server import HTTPServer, BaseHTTPRequestHandlerclass RequestHandler(BaseHTTPRequestHandler):def _header(self):self.send_response(200)self.send_header("Content-type", "text/html")self.end_headers()def do_HEAD(self):self._header()def do_GET(self):self._header()self.wfile.write('test')server = HTTPServer(('localhost', 80), RequestHandler)server.serve_forever()===========================================================ERROR:===========================================================localhost - - [13/Jun/2009 14:00:13] "GET / HTTP/1.1" 200 -----------------------------------------Exception happened during processing of request from ('127.0.0.1', 1907)Traceback (most recent call last):  File "C:\Python30\lib\socketserver.py", line 281, in _handle_request_noblock    self.process_request(request, client_address)  File "C:\Python30\lib\socketserver.py", line 307, in process_request    self.finish_request(request, client_address)  File "C:\Python30\lib\socketserver.py", line 320, in finish_request    self.RequestHandlerClass(request, client_address, self)  File "C:\Python30\lib\socketserver.py", line 614, in __init__    self.handle()  File "C:\Python30\lib\http\server.py", line 363, in handle    self.handle_one_request()  File "C:\Python30\lib\http\server.py", line 357, in handle_one_request    method()  File "C:\Documents and Settings\User\Desktop\mHome\webserver.py", line 18, indo_GET    self.wfile.write('human')  File "C:\Python30\lib\socket.py", line 219, in write    return self._sock.send(b)TypeError: send() argument 1 must be bytes or buffer, not str===========================================================

msg89395 -(view)Author: Amaury Forgeot d'Arc (amaury.forgeotdarc)* Date: 2009-06-15 07:38

the HTTP response should be a bytes string:    self.wfile.write(b'test')