使用netcat在bash中发出http get请求

Question

I have written the following script (it does not support index yet). The issue I am having is regarding using netcat to load the page. I can do this manually using the command line but when I try to have my script issue the exact same commands I can it does nothing without error. The only possible thing I can think is that my output is going somewhere else?

#!/bin/bash
PORT=80

while [ true ]
do
    echo "Type the address you wish to visit then, followed by [ENTER]:"
    read address
    path=${address#*/}
    domain=${address%%/*}
    nc $domain $PORT
    printf "GET /$path HTTP/1.1\n" 
    printf "Host: $domain\n" 
    printf "\n" 
    printf "\n" 
done

Answer 1

You need to pass the request header to the standard input of nc .

One way to do that is input redirection:

while true
do
    echo "Type the address you wish to visit then, followed by [ENTER]:"
    read address
    path=${address#*/}
    domain=${address%%/*}
    nc $domain $PORT <<EOF
GET /$path
Host: $domain

EOF
done

Answer 2

nc works by copying standard input to the given address:port, and copying whatever it reads from there to standard output.

{
  printf "GET /%s HTTP/1.1\r\n" "$path"
  printf "Host: %s\r\n" "$domain"
  printf "\r\n" 
  printf "\r\n"
} | nc "$domain" "$port"

• HTTP requires \\r\\n at the end of each line. Some servers accept just \\n but some stick to the letter of the law and accept only \\r\\n as specified.

• You need to send these lines to the standard input of nc .

• It is better to use printf "Get %s HTTP/1.1\\r\\n" "$path" because $path may contain % signs and that would confuse printf`.