Accessing python server (web server) using ngrok - python

I have a python network server code.
import socket
HOST, PORT = '', 5000
listen_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
listen_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
listen_socket.bind((HOST, PORT))
listen_socket.listen(1)
print('Serving HTTP on port %s ...' % PORT)
while True:
client_connection, client_address = listen_socket.accept()
request = client_connection.recv(1024)
print(request)
http_response = """\
HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8
<H1>Hello, World!</H1>
"""
client_connection.sendall(http_response.encode())
client_connection.close()
I have a client code that accesses the server.
import socket
HOST = '127.0.0.1'
PORT = 5000 # The port used by the server
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print "Socket successfully created"
s.connect((HOST, PORT))
s.sendall('GET /')
data = s.recv(1000)
print('Received', repr(data))
s.close
except socket.error as err:
print "socket creation failed with error %s" %(err)
It works fine with the expected output when I executed the server and client.
Socket successfully created
('Received', "'HTTP/1.1 200 OK\\nContent-Type: text/html; charset=utf-8\\n\\n<H1>Hello, World!</H1>\\n'")
Then, I tried to execute the python server using ngrok.
Session Status online
Account ...
Version 2.3.34
Region United States (us)
Web Interface http://127.0.0.1:4040
Forwarding http://d2fccf7f.ngrok.io -> http://localhost:5000
Using curl, I could access the webserver with ngrok.
> curl http://d2fccf7f.ngrok.io
<H1>Hello, World!</H1>
However, when I tried to use the same client code with minor modifications, the server doesn't seem to respond.
import socket
ip = socket.gethostbyname('d2fccf7f.ngrok.io')
print(ip)
HOST = ip
PORT = 5000
# the rest of the code is the same
I changed the PORT to 80 or 8080, but I had same results.
What might be wrong?

Might I suggest trying something like pyngrok to programmatically manage your ngrok tunnel for you? Full disclosure, I am the developer of it. Socket and other TCP examples are here.

From oguz ismail's hint, I made the following REQUEST header to make it work. I see that the Host information and blank line should be required.
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print "Socket successfully created"
s.connect((HOST, PORT))
header = '''GET / HTTP/1.1\r\nHost: d2fccf7f.ngrok.io\r\n\r\n'''
...

Related

can't write to socket from cmd using sock.recv on windows

I'm trying to make basic synchronous hello world with sockets
(server is supposed to send some message as answer for any message from client).
I bind localhost:5000 to socket
I'm trying to receive console input with sock.recv(4096)
I try to connect to socket from the console using curl localhost:5000, but I can't write to the console. Also, server sends message when i connect to it, but nothing more
here is the code:
import socket
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
server_socket.bind(("localhost", 5000))
server_socket.listen()
def accept_connection(server_socket):
while True:
client_socket, addr = server_socket.accept()
print("connection from", addr)
send_message(client_socket)
def send_message(client_socket):
while True:
request = client_socket.recv(4096)
if request:
response = "request recieved\n".encode()
client_socket.send(response)
else:
break
print("done with sending stuff")
client_socket.close()
if __name__ == "__main__":
print("stuff_started")
accept_connection(server_socket)
server output:
C:\Users\USER\Desktop\stuff\pth>python testing.py
stuff_started
connection from ('127.0.0.1', 53053)
client output:
C:\Users\USER\Desktop\stuff\pth>curl localhost:5000
request recieved
As written in the comments, curl is used to HTTP servers and not for generic sockets.
You can use netcat for that:
nc 127.0.0.1 5000
or just plain old Python in your favorite shell like so:
> py -c "import socket; s = socket.create_connection(('localhost', 5000)); s.sendall(b'data'); print(s.recv(1024))"
b'request recieved\n'

python server socket closes immediately

I have a simple server-client combo running on 2 computers in 2 different networks. The server (a Raspberry) has a TCP tunnel running.
Now running on the code on localhost is fine, on 2 different machines with correct IP and port (I can ping the server via telnet and establish connection via ssh using the same IP and port), I just get the following on the client side AND NOTHING ELSE:
Received SSH-2.0-OpenSSH_7.9p1 Raspbian-10+deb10u2
I should instead receive: Received b'Hello, world'
On the serverside I receive no message at all.
What do I need to run it in 2 different networks? Below the source codes.
server.py:
#!/usr/bin/env python3
import socket
HOST = '' # Standard loopback interface address (localhost)
PORT = 65432 # Port to listen on (non-privileged ports are > 1023)
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
with conn:
print("Connected by", addr)
while True:
data = conn.recv(1024)
if not data:
break
conn.sendall(data)
client.py:
#!/usr/bin/env python3
import socket
HOST = 'xxx.xxx.xxx.xxx' # The server's hostname or GLOBAL IP address
PORT = 12345 # The port used by the server, not actually 12345
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.connect((HOST, PORT))
s.sendall(b"Hello, world")
data = s.recv(1024)
print("Received", repr(data))

How to exchange data on different networks using sockets?

I know this was already asked but the previous questions didn't help. I'm trying to send some data using sockets. Specifically I'm using my laptop as server and a Linux emulator (Termux) on my smartphone as a client. Here below you can see the two Python codes. For the server:
import socket
HOST = ''
PORT = 5555
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen()
conn, addr = s.accept()
print('Connected by', addr)
while True:
data = conn.recv(1024)
if not data:
break
conn.sendall(data)
s.close()
And for the client:
import socket
HOST = ''
PORT = 5555
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
s.sendall(b'Hello, world')
data = s.recv(1024)
print('Received', repr(data))
s.close()
When I'm connected to the same WiFi and in HOST (in both codes) I put the IP I see from ipconfig (192.168.---.---) everything works. It also works if in the HOST of the server I put 0.0.0.0.
However, when I put the IP of the machine (that I can see on https://whatismyipaddress.com/) and instead of using the WiFi I use the phone connection I get: ConnectionRefusedError: [Errno 111] Connection Refused.
Can someone explain me how can I connect client and server when the networks are different? I have been stuck with this for a while.
I also tried to open a port on the Firewall following this procedure and put it in the code instead of 5555 but still it didn't work.
Thank you in advance for the help.

How to connect python socket client side to server socket with url?

I am trying to create a client to connect to a server with given url address.
I used this way
host_ip = socket.gethostbyname('HOST_NAME')
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind(('127.0.0.1', 0))
sock.connect((host_ip, 8080))
but it printed the following error
OSError: [Errno 22] Invalid argument
Can someone explain me why is wrong and give me a solution?
You don't have to bind your socket, this is done server-side.
Here's the example code from the documentation for socket :
import socket
HOST = 'your-url.net' # The remote host
PORT = 8080 # The same port as used by the server
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
s.connect((HOST, PORT))
s.sendall(b'Hello, world')
data = s.recv(1024)
print('Received', repr(data))
This is a simple snippet, which connects to the server, sends some data, and prints the response.

TCP Python Socket Server Response

I'm writing a TCP python script that will act as a server and retrieve a temperature reading from a machine (the client). I need to pass a command to the client from the server and listen for an output of the response. I successfully reach the cmd definition line, but when s.accept() is called I'm left hanging with no response from the client.
Server.py
import socket
port = 7777
ip = raw_input('192.168.62.233')
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((ip, port))
s.listen(1)
print "waiting on port: ", port
while True:
cmd = raw_input('KRDG? A[term]')#command send to client
conn, addr = s.accept()
s.send(cmd)
print "It sent"
data = conn.recv(4096)
print "Received:", data, " from address ", addr
Edit:
I believe you're correct, I should consider my code the client and temperature readout at the server. I do now get left hanging after "here 2" when I go to s.recv().
Client.py
import socket
ip = '192.168.62.233'
port = 7777 # The same port as used by the server
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((ip, port))
print 'here'
s.send('KRDG? A[term]')
print 'here 2'
data = s.recv(4096)
print 'here 3'
s.close()
print 'Received', repr(data)
Usually, a TCP server accept will block while it waits for a client to connect. Have you checked to make sure that you client can and is connecting? You could use a tool like tcpdump or similar to watch the network activity and make sure the client is connecting.

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