python简易web服务器学习笔记
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import BaseHTTPServer
#-------------------------------------------------------------------------------
class RequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
‘‘‘Respond to HTTP requests with info about the request.‘‘‘
# Template for page to send back.
Page = ‘‘‘<html>
<body>
<table>
<tr> <td>Header</td> <td>Value</td> </tr>
<tr> <td>Date and time</td> <td>{date_time}</td> </tr>
<tr> <td>Client host</td> <td>{client_host}</td> </tr>
<tr> <td>Client port</td> <td>{client_port}s</td> </tr>
<tr> <td>Command</td> <td>{command}</td> </tr>
<tr> <td>Path</td> <td>{path}</td> </tr>
</table>
</body>
</html>
‘‘‘
# Handle a request by constructing an HTML page that echoes the
# request back to the caller.
def do_GET(self):
page = self.create_page()
self.send_page(page)
# Create an information page to send.
def create_page(self):
values = {
‘date_time‘ : self.date_time_string(),
‘client_host‘ : self.client_address[0],
‘client_port‘ : self.client_address[1],
‘command‘ : self.command,
‘path‘ : self.path
}
page = self.Page.format(**values)
return page
# Send the created page.
def send_page(self, page):
self.send_response(200)
self.send_header("Content-type", "text/html")
self.send_header("Content-Length", str(len(page)))
self.end_headers()
self.wfile.write(page)
#-------------------------------------------------------------------------------
if __name__ == ‘__main__‘:
serverAddress = (‘‘, 8080)
server = BaseHTTPServer.HTTPServer(serverAddress, RequestHandler)
server.serve_forever()
上述代码可以输出调试信息。
下一步我们需要让服务器能够提供静态文件。首先我们要做的，是异常处理
import sys, os, BaseHTTPServer
#-------------------------------------------------------------------------------
class ServerException(Exception):
‘‘‘For internal error reporting.‘‘‘
pass
#-------------------------------------------------------------------------------
class RequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
‘‘‘
If the requested path maps to a file, that file is served.
If anything goes wrong, an error page is constructed.
‘‘‘
# How to display an error.
Error_Page = """ <html>
<body>
<h1>Error accessing {path}</h1>
<p>{msg}</p>
</body>
</html>
"""
# Classify and handle request.
def do_GET(self):
try:
# Figure out what exactly is being requested.
full_path = os.getcwd() + self.path
# It doesn‘t exist...
if not os.path.exists(full_path):
raise ServerException("‘{0}‘ not found".format(self.path))
# ...it‘s a file...
elif os.path.isfile(full_path):
self.handle_file(full_path)
# ...it‘s something we don‘t handle.
else:
raise ServerException("Unknown object ‘{0}‘".format(self.path))
# Handle errors.
except Exception as msg:
self.handle_error(msg)
def handle_file(self, full_path):
try:
with open(full_path, ‘rb‘) as reader:
content = reader.read()
self.send_content(content)
except IOError as msg:
msg = "‘{0}‘ cannot be read: {1}".format(self.path, 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, 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__‘:
serverAddress = (‘‘, 8080)
server = BaseHTTPServer.HTTPServer(serverAddress, RequestHandler)
server.serve_forever()
假设程序允许使用该目录下的任何文件提供服务，它会结合url提供的路径（以‘/‘开始，BaseHTTPServer会自动将它放入self.path），以获取用户想要的文件路径。若文件不存在，或者路径并不指向文件，上述方法将通过获取并抛出异常来报告错误。若匹配到文件，do_GET方法将调用handfile来读取并返回内容，然后调用send_content将文件内容返回给客户端。哇，显然我们是以二进制方式打开的文件（由‘rb‘和‘b‘标识)，并把整个文件读到中的呢，所以这样的方法不能处理大型程序喔
其中的细节在于，其中的hand_error，如果我们直接send_content（content)一个错误页面，则返回码是200。这样的错误信息不好判别：hand_error处理的是页面找不到的情况，应该返回404才对。
os是python的基础模块，上述代码中用来获取文件路径。raise就是用抛出异常的。具体用发是和try，except配合使用。若print一些调试信息，就能清楚的看到它的过程了
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