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请看如下代码片段中的class case_no_file中方法test中的handler
请问这个handler是什么东西，为什么可以调用.full_path属性？
以及在class case_existing_file中还能调用handle_file方法？
full_path，handle_file都是class RequestHandler 里面定义的，但是代码中是怎样将handler与RequestHandler相关联的？？
#-*- coding:utf-8 -*-
import sys, os
from http.server import BaseHTTPRequestHandler,HTTPServer
class ServerException(Exception):
'''服务器内部错误'''
pass
class case_no_file(object):
'''该路径不存在'''
def test(self, handler):
return not os.path.exists(handler.full_path)
def act(self, handler):
raise ServerException("'{0}' not found".format(handler.path))
class case_existing_file(object):
'''该路径是文件'''
def test(self, handler):
return os.path.isfile(handler.full_path)
def act(self, handler):
handler.handle_file(handler.full_path)
class case_always_fail(object):
'''所有情况都不符合时的默认处理类'''
def test(self, handler):
return True
def act(self, handler):
raise ServerException("Unknown object '{0}'".format(handler.path))
class case_directory_index_file(object):
def index_path(self, handler):
return os.path.join(handler.full_path, 'index.html')
#判断目标路径是否是目录&&目录下是否有index.html
def test(self, handler):
return os.path.isdir(handler.full_path) and \
os.path.isfile(self.index_path(handler))
#响应index.html的内容
def act(self, handler):
handler.handle_file(self.index_path(handler))
class RequestHandler(BaseHTTPRequestHandler):
'''
请求路径合法则返回相应处理
否则返回错误页面
'''
Cases = [case_no_file(),
case_existing_file(),
case_directory_index_file(),
case_always_fail()]
# 错误页面模板
Error_Page = """\
<html>
<body>
<h1>Error accessing {path}</h1>
<p>{msg}</p>
</body>
</html>
"""
def do_GET(self):
try:
# 得到完整的请求路径
self.full_path = os.getcwd() + self.path
# 遍历所有的情况并处理
for case in self.Cases:
if case.test(self):
case.act(self)
break
# 处理异常
except Exception as msg:
self.handle_error(msg)
def handle_error(self, msg):
content = self.Error_Page.format(path=self.path, msg=msg)
self.send_content(content.encode("utf-8"), 404)
# 发送数据到客户端
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)
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)
if __name__ == '__main__':
serverAddress = ('', 8080)
server = HTTPServer(serverAddress, RequestHandler)
server.serve_forever()
python
只要你找出调用者的位置，便知道参数的类型。