I wrote a code of a Server that uses HTTP protocol to communicate with chrome browser, and for some reason I am getting an Exception.
the exception is an index out of bound exception but the server still gives a response to chrome and I can see the answer on the html file displayed on the screen. (the exception is in recv in the function get_clients_req()).
I would be happy if someone could explain me why.
import socket
IP = '127.0.0.1'
PORT = 80
def get_clients_req(client):
recv = client.recv(2 ** 16).decode()
recv = recv.split('\n')[0].split('/')
recv = recv[1].split(' ')[0].split('?')
return recv[0], recv[1].split('&')
def clean_data(request, params):
valid = False
clean_params = []
error_msg = 'Not Valid Request'
if request == 'calculate-area' and len(params) == 2:
if 'height' in params[0] and 'width' in params[1]:
print(params[0], params[1])
valid = True
error_msg = 'Everything is just Fine <3<3'
clean_params.append(params[0].replace('height=', ''))
clean_params.append(params[1].replace('width=', ''))
print(clean_params[0], clean_params[1])
else:
valid = False
error_msg = 'Parameters are not valid'
clean_params = []
else:
valid = False
error_msg = 'Request is not valid'
clean_params = []
return (valid, error_msg, clean_params)
def handle_request(client, clean_params):
area = int(clean_params[0]) * int(clean_params[1]) / 2
data = 'HTTP/1.1 200 OK \r\n'
data = 'HTTP/1.1 200 OK \r\n'
data += 'Connect-Type: text/html; charset=utf-8\r\n'
data += '\r\n'
data += f'<html><body>{area}</body></html>\r\n\r\n'
client.sendall(data.encode())
client.shutdown(socket.SHUT_WR)
server = socket.socket()
server.bind((IP, PORT))
server.listen()
print(f'URL: {IP}:{PORT}')
while 1:
client, client_add = server.accept()
request, params = get_clients_req(client)
(valid, error_msg, clean_params) = clean_data(request, params)
handle_request(client, clean_params)
the exception:
Traceback (most recent call last):
File "C:/Users/orlav/PycharmProjects/networks_book/chapter_4/e4.8.py", line 56, in <module>
request, params = get_clients_req(client)
File "C:/Users/orlav/PycharmProjects/networks_book/chapter_4/e4.8.py", line 11, in get_clients_req
return recv[0], recv[1].split('&')
IndexError: list index out of range
1 Answer 1
recv = recv[1].split(' ')[0].split('?') return recv[0], recv[1].split('&')
There is no recv[1] in the last line if there is no ? in the original request, which causes the stack trace you see. While you don't show the original request you intended to send, the browser will often try to access some /facicon.ico by itself and this request has no ?.
answered Oct 12, 2020 at 17:50
Steffen Ullrich
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