client_http.py

import socket
import os,os.path

def get_server_addess(site):
#procssing to string to sepearate server and address for http request
        if site.startswith('http://'):
                site = site[7:]
        server,address = site.split('/',1)
        address = '/' + address
        return (server,address)


def connect(server):
        #tcp connection establish
        cs = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        server_address = (server,80)
        cs.connect(server_address)
        return cs

def download_file(site):

        server,address = get_server_addess(site)
        cs = connect(server)

        #generating request and sending to know length of data
        request = 'HEAD ' + address + ' HTTP/1.1\r\nHOST: ' + server +'\r\nAccept-Ranges: bytes\r\n\r\n'
        print(request)
        request_header = bytes(request,'utf-8') 
        cs.send(request_header)
        
        #processing header to find content length of file to be downloaded
        header = cs.recv(2096)
        print(header)
        header = header.split(b'\r\n')
        
        s = {}
        for i in range(1,len(header)-2):
            y = header[i].split(b':')
            s[y[0]] = y[1]
            print(y)
        contentlength = int(s[b'Content-Length'])

        #requesting again to download file
        if b'bytes' in s[b'Accept-Ranges']  :
                request = 'GET ' + address + ' HTTP/1.1\r\nHOST: ' + server + '\r\nRange: bytes=0-1023\r\n\r\n'
        else:
                print('Simulataneous connection not allowed using single connection')
                request = 'GET ' + address + ' HTTP/1.1\r\nHOST: ' + server + '\r\n\r\n'
                
        request_header = bytes(request,'utf-8')  
        cs.send(request_header)

        #downloading and saving
        full_msg = b''
        new_msg= True
        c=True
        while c:
            msg = cs.recv(4096)
            if new_msg:
                head = msg.split(b'\r\n\r\n')
                header=(len(head[0]))+4
                print(head[0])
                print(header)
                msg = head[1]
                new_msg = False

            full_msg += msg 

            if len(full_msg)== contentlength:
                print(full_msg[header:])
                print('Done')
                write_file(full_msg,2)
                new_msg = True
                full_msg = ""
                c= False
                cs.close()
                
def write_file(msg,x):
        f = open('Socket'+str(x)+'.jpg', 'wb')
        f.write(msg)
        f.close()
                
                
#Main Function
site = 'http://open-up.eu/files/Berlin%20group%20photo.jpg?width=600&height=600'
site = 'http://people.unica.it/vincenzofiorentini/files/2012/04/Halliday-Fundamentals-of-Physics-Extended-9th-HQ.pdf'
site = 'http://africhthy.org/sites/africhthy.org/files/styles/slideshow_large/public/Lukuga.jpg?itok=M6ByJTZQ'
site = 'http://ipaeg.org/sites/ipaeg.org/files/styles/medium/public/IMG_0499.JPG?itok=U8KP8f4j'
site = 'http://s0.cyberciti.org/images/misc/static/2012/11/ifdata-welcome-0.png'
site = 'http://i.imgur.com/z4d4kWk.jpg'

#server,address = get_server_address(site)
download_file(site)