Basic browser in Python. Taking URL from user

Question

I'm working through a book called Python For Everbody and have been stuck on a problem for a couple of days. I'm pretty sure it's something super-simple I'm not seeing but just can't seem to crack it.

Apologies in advance if this is posted in the wrong place or not formatted correctly. This is my first post and am getting my head around it all.

So, the exercise is to start with a basic internet browser...

import socket

mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
mysock.connect(('data.pr4e.org', 80))
cmd = 'GET http://data.pr4e.org/romeo.txt HTTP/1.0\r\n\r\n'.encode()
mysock.send(cmd)

while True:
    data = mysock.recv(512)
    if len(data) < 1:
        break
    print(data.decode(),end='')

mysock.close()

The task is to rewrite the code so it takes a url as an input. The problem I'm having is adding the input variable into the cmd line. I've tried the below:

import socket

# Establish url and server from user input
url = input('Please enter url>>')
clnpos = url.find(':')
server = url[clnpos +3:len(url)]

# Run program with variable
mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
mysock.connect((server), 80)
cmd = ('GET', (url), 'HTTP/1.0\r\n\r\n'.encode())
mysock.send(cmd)

while True:
    data = mysock.recv(512)
    if len(data) < 1:
        break
    print(data.decode(),end='')

mysock.close()

I've also tried making the cmd line a variable of its own...

import socket

url = input('Please enter url>>')

clnpos = url.find(':')
server = url[clnpos +3:len(url)]
cmdline = ('GET', (url), 'HTTP/1.0\r\n\r\n'.encode())

mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
mysock.connect((server), 80)
cmd = (cmdline)
mysock.send(cmd)

while True:
    data = mysock.recv(512)
    if len(data) < 1:
        break
    print(data.decode(),end='')

mysock.close()

Like I say, I'm pretty sure there's something silly I'm missing, almost feel embarrassed posting but I just can't see where I'm going wrong.

Any help offered would be very gratefully recieved.

Answer 1

mysock.connect takes only one argument and it's must be a tuple. You just have to move your parenthesis a little bit

mysock.connect((server, 80))

Your cmd variable has also an error, it has to be a string.

You have to concatenate the three parts of your string. The best way to do it is to use f-string

cmd  = f'GET {url} HTTP/1.0\r\n\r\n'.encode()

or you can do

cmd = "GET {} HTTP/1.0\r\n\r\n".format(url).encode()

Full code :

import socket

# Establish url and server from user input
url = input('Please enter url>>')
clnpos = url.find(':')
server = url[clnpos +3:len(url)]

# Run program with variable
mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
mysock.connect((server, 80))
# mysock.connect((server, 80))
cmd = f'GET {url} HTTP/1.0\r\n\r\n'.encode()
mysock.send(cmd)

while True:
    data = mysock.recv(512)
    if len(data) < 1:
        break
    print(data.decode(),end='')

mysock.close()