This is the code I am trying to run. But the program produces a socket.error. I have a network proxy with port 8080 which connects me to the Internet, what more details do I have to add here to create this socket connection?
import socket
mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
mysock.connect(('www.pythonlearn.com', 80))
mysock.send('GET http://www.pythonlearn.com/code/intro-short.txt HTTP/1.0\n\n')
while True:
data = mysock.recv(512)
if ( len(data) < 1 ) :
break
print data;
mysock.close()
If I run your code I get the error TypeError: a bytes-like object is required, not 'str' from line 5.
Try using: mysock.send(b'GET http://www.pythonlearn.com/code/intro-short.txt HTTP/1.0\n\n') with the b before your string indicating a bytestring.
I too got a type error upon running your code, and did not have an error connecting the socket. When using the socket library, make use of the makefile method so you won't have to deal with annoying details.
mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
my_sock_input = mysock.makefile('r')
my_sock_output = mysock.makefile('w')
Now my_sock_input can use methods like readline(), without any details on bytes to reserve or wotnot. Same convenience stuff for output, but with write. Remember to close all of them!
As to your problem, I tried writing similar things using my makefile variables and I wasn't recieving any message back. So there is some other issue there.
Now, the solution. A simpler way to download a url and read its contents is using the urllib.request library. If you are on Python 2.7, just import urrlib.
import urllib.request
data = urllib.request.urlopen('http://www.pythonlearn.com/code/intro-short.txt')
readable = data.read()
print(readable)
Related
I am in a UCI Coursera course on RaspberryPi, which is using Python.
There seem to be some mistakes in the video lecture's code. This is the code in the lecture video, verbatim:
import socket
mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = socket.gethostbyname("www.google.com")
mysock.connect(host, 80)
message = "GET / HTTP/1.1\r\n\r\n"
mysock.sendall(message)
data=mysock.recv(1000)
mysock.close()
I was able to fix one error, which is that .connect() only takes one argument, a tuple, so it should be mysock.connect((host, 80)) instead of mysock.connect(host, 80).
However, there appears to be a type error with the example message value. When I run mysock.sendall(message) it throws:
TypeError: a bytes-like object is required, not 'str'
I have to imagine that the instructor's code was close to being correct but has some small typo in it, or something. So I'm trying to figure out what they meant to write and why this is different and therefore throws this type error as being a string.
I would follow up directly within the course, but this one unfortunately has no discussion forum, so any help here will be greatly appreciated.
import socket
mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = socket.gethostbyname("www.google.com")
mysock.connect((host, 80))
message = "GET / HTTP/1.1\r\n\r\n"
mysock.sendall(message.encode())
data=mysock.recv(1000)
mysock.close()
Just add encode.
If you take a look at the socket documentation, you can see that sendall requires bytes to be sent. Python has a built-in function to convert a String to bytes, called encode. So, you must use
mysock.sendall(message.encode())
to convert it to bytes so it can be sent.
before sending message through socket encode it.
sc.send(message.encode())
after receiving decode it:
message.decode()
you are all done
import socket
mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
host = socket.gethostbyname("www.google.com")
mysock.connect((host, 80))
message = b"GET / HTTP/1.1\r\n\r\n"
mysock.sendall(message)
data=mysock.recv(1000)
mysock.close()
I have already checked answers regarding my problem, but I couldn't find what's wrong. I am new to Python and that might be a problem. I have written this simple code to connect to a site, but I get this error:
socket.gaierror: [Errno 11004] getaddrinfo failed
This is my code:
import socket
mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
mysock.connect(('http://www.py4e.com', 80))
mysock.send('GET http://www.py4e.com/code3/mbox-short.txt HTTP/1.0\n\n')
while True:
data = mysock.recv(512)
if(len(data) < 1):
break
print (data)
mysock.close()
import socket
mysock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
mysock.connect(('www.py4e.com', 80))
mysock.send('GET http://www.py4e.com/code3/mbox-short.txt HTTP/1.0\n\n')
while True:
data = mysock.recv(512)
if(len(data) < 1):
break
print (data)
mysock.close()
Quite simple, don't use http:// in your host declaration on .connect().
http:// is a protocol and www.py4e.com is a host (or A record in a DNS server). The standard socket library doesn't know anything regarding protocols and there for requires only a host and a port number.
If you want automated processes check out urllib.request or #Mego's answer using Requests which handles the connection and HTTP parsing for you.
Also if you're using Python3 which you probably should, you need to send bytes data when doing .send().
There's two ways of converting your string to bytes data:
mysock.send(b'GET http://www.py4e.com/code3/mbox-short.txt HTTP/1.0\n\n')
mysock.send(bytes('GET http://www.py4e.com/code3/mbox-short.txt HTTP/1.0\n\n', 'UTF-8'))
Both does the same thing basically.
Finally, in a GET request you don't request http:// either.
Instead you just send the path to the file you want to retrieve:
mysock.send(b'GET /code3/mbox-short.txt HTTP/1.0\n\n')
The reason is (again) that http:// is a protocol descriptor and not part of the actual protocol data being sent. You also don't need the host declaration in your GET request because the server that you connected to already knows which host you're on - since you're... connected to it.
Instead the server expects you to supply a Host: <hostname>\r\n header if the host is serving multiple virtual hosts.
You might need a few other headers tho to be able to request actual content from certain web-servers.
But this is the basic jist of things.
Continue reading
Here's a good start:
https://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol#Client_request
It shows you what a raw GET request looks like.
An in the future I recommend using your browsers built-in Network Debugger which can show raw headers, raw responses and a whole bunch of other things.
I am trying to test socket communication on my laptop using python. However, I'm not sure why the connection is not being established? I keep getting error that the target machine is actively refusing connection. I am trying to use the same computer to run both the client and the server portion. The server is running fine but the client is the one not connecting. I think I have the hostname wrong (127.0.0.1) but not sure what Im supposed to be using? I also tried changing the server hostname to (0.0.0.0) and the IPV4 address for the hostname the client was to connect to but that didn't work either. Any help would be appreciated!
My code(server portion):
import socket
comms_socket =socket.socket()
comms_socket.bind(('127.0.0.1', 50000))
comms_socket.listen(10)
connection, address = comms_socket.accept()
while True:
print(connection.recv(4096).decode("UTF-8"))
send_data = input("Reply: ")
connection.send(bytes(send_data, "UTF-8"))
Client portion:
import socket
comms_socket = socket.socket()
comms_socket.connect(('127.0.0.1',50000))
while True:
send_data = input("Message: ")
comms_socket.send(bytes(send_data, "UTF-8"))
print(comms_socket.recv(4096).decode("UTF-8"))
Your code won't work with python 2.* , because of the differences in input(), raw_input(), bytes, etc. in python 3.* vs python 2.* . You'd have to minimally make the following changes to get it working with python 2.*. Otherwise, use python 3 to run your code:
Server program:
import socket
comms_socket =socket.socket()
comms_socket.bind(('127.0.0.1', 7000))
comms_socket.listen(10)
connection, address = comms_socket.accept()
while True:
print(connection.recv(4096).decode("UTF-8"))
send_data = raw_input("Reply: ") # Use raw_input() instead of input()
connection.send(send_data.encode("UTF-8"))
Client program:
import socket
comms_socket = socket.socket()
comms_socket.connect(('127.0.0.1',7000))
while True:
send_data = raw_input("Message: ")
comms_socket.send(send_data.encode("UTF-8"))
print(comms_socket.recv(4096).decode("UTF-8"))
If you want to use bytes as intended in your specific usecase, you should use bytesarray instead in python 2.6 or higher. Check this: the bytes type in python 2.7 and PEP-358
I was trying to create a python socket server that could send and receive data, so I created a socket on the server using the code here:
import socket
serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
serversocket.bind(('', 1208))
serversocket.listen(5)
(client,(ip,port)) = serversocket.accept()
Then I tried to create a sample connection from my machine by going to command prompt and typing
telnet www.filesendr.com 1208
However, the console simply replies with "Could not open connection to the host, on port 1208...Connection failed." I went back over my code but couldn't identify the problem. Any help would be greatly appreciated.
I think part of the problem is that after you accept the connection you don't do anything else. Once the accept happens, you get to the end of the script, python exits and closes all open file handles (including the socket you just opened). If you want to be able to talk to yourself through telnet, try something like this:
import socket
import select
import sys
port = 1208
listener = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
listener.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
listener.bind(('',port))
listener.listen(128)
newSock, addr = listener.accept()
while True:
r,w,e = select.select([newSock,sys.stdin],[],[])
if newSock in r:
data = newSock.recv(4096)
sys.stdout.write(data)
if sys.stdin in r:
newSock.send(sys.stdin.readline())
I'm trying to write a python web server using the socket library. I've been through several sources and can't figure out why the code I've written doesn't work. Others have run very similar code and claim it works. I'm new to python so I might be missing something simple.
The only way it will work now is I send the data variable back to the client. The browser prints the original GET request. When I try to send an HTTP response, the connection times out.
import socket
##Creates several variables, including the host name, the port to use
##the size of a transmission, and how many requests can be handled at once
host = ''
port = 8080
backlog = 5
size = 1024
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((host,port))
s.listen(backlog)
while 1:
client, address = s.accept()
data = client.recv(16)
if data:
client.send('HTTP/1.0 200 OK\r\n')
client.send("Content-Type: text/html\r\n\r\n")
client.send('<html><body><h1>Hello World</body></html>')
client.close()
s.close()
You need to consume the input before responding, and you shouldn't close the socket in your while loop:
Replace client.recv(16) with client.recv(size), to consume the request.
Move your last line, s.close() back one indent, so that it is not in your while loop. At the moment you are closing the connection, then trying to accept from it again, so your server will crash after the first request.
Unless you are doing this as an exercise, you should extend SimpleHTTPServer instead of using sockets directly.
Also, adding this line after your create the socket (before bind) fixes any "Address already in use" errors you might be getting.
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
Good luck!