Hello -- I need a simple example to help me understand how to write a Python client and C++ server. Can someone help me find an example of how to send hello world from a server running C++ to Python client? I tried searching Google and other websites for several hours and couldn't find a single example on how to send a parameter through tcp/ip.
Have a look at this http://www.cs.utah.edu/~swalton/listings/sockets/programs/part2/chap6/simple-server.c, It is a simple echo server that accepts connections on port 9999 and echos received message.
For python side this is not very hard, look at this example:
import socket, time
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(('localhost', 9999))
print client.send('Hello world!'), 'bytes sent.'
time.sleep(0.2)
print 'Received message:', client.recv(1024)
use zeromq lib.. .
c++ example of 'hello_world' for server and client are at :
http://zguide.zeromq.org/cpp:hwserver ,
http://zguide.zeromq.org/cpp:hwclient
respectively.. .
and in python.. . study the examples available at github.. .
https://github.com/zeromq/pyzmq/tree/master/examples
Well for my own purpose i am using python for both end.. .Also for more tutorial watch this pycon video
http://blip.tv/pycon-us-videos-2009-2010-2011/pycon-2011-advanced-network-architectures-with-zeromq-4896861
also there is another nice tutorial at http://blog.pythonisito.com/2012/08/distributed-systems-with-zeromq.html
Related
Good day. I apologize for asking for obvious things because I'm writing in PHP and I know Python at the level "I started learning this yesterday". I've already spent a few days on this - but to no avail.
I downloaded twisted example of the SSH server for version 20.3 from here https://docs.twistedmatrix.com/en/twisted-20.3.0/conch/examples/. Line 162 has an execCommand method that I need to implement to make it work. Then I noticed a comment in this method "We don't support command execution sessions". Therefore, the question: Is this comment apply only to the example, or twisted library entirely. Ie, is it possible to implement this method to make the example server will work as I need?
More information. I don't think that this info is required to answer my questions above.
Why do I need it? I'm trying to compile an environment for writing functional (!) tests (there would be no such problems with the unit tests, I guess). Our API uses the SSH client (phpseclib / SSH2) by 30%+ of endpoints. Whatever I do, I had only 3 options of the results depending on how did I implement this method: (result: success, response: "" - empty; result: success, response: "1"; result: failed, response: "Unable to fulfill channel request at… SSH2.php:3853"). Those were for an SSH2 Client. If the error occurs (3rd case), the server shows logs in the terminal:
[SSHServerTransport, 0,127.0.0.1] Got remote error, code 11 reason: ""
[SSHServerTransport, 0,127.0.0.1] connection lost
I just found this works:
def execCommand(self, protocol, cmd):
protocol.write('Some text to return')
protocol.session.conn.sendEOF(protocol.session)
If I don't send EOF the client throws a timeout error.
===SIMPLE & SHORT===
Does anybody have working application that talks with Poloniex through WAMP in these days (January, 2018)?
===MORE SPECIFIC===
I used several info sources to make it work using combo: autobahn-cpp & C++. Windows 10 OS.
I was able to connect to wss://api.poloniex.com, realm1. Plus I was able to subscribe and get subscription ID. But I never got any events even when everything established.
===RESEARCH===
During research in the web I saw a lot of controversial information:
1. Claims, that wss://api2.poloniex.com should be used, and channels names are actually numbers - How to connect to poloniex.com websocket api using a python library
2. This answer gave me base code, but I am getting anything more than just connections, also by following this answer - wss://api.poloniex.com is correct address - Connecting to Poloniex Push-API
3. I saw post (sorry, lost the link), there were comments made that websockets implementation are basically broken on poloniex. They were posted 6 months ago.
===SPECS===
1. Windows 10
2. Autobahn-Cpp
3. wss://api.poloniex.com:443 ; realm1
4. Different subscriptions: ticker, BTC_ETH, 148, 1002, etc..
5. Source code I got from here
===WILL HELP AS WELL===
Is there any way to get all valid subscriptions or, probably, those, that have more than 0 subscribers? I mean, does WAMP have a way to do that?
Is there any known issues with Autobahn-Cpp and poloniex combo?
Is there any simpler way to test WAMP elsewhere to make sure Autobahn isn't a problem? Like any other well documented & supported online projects that accept WAMP websocket communication?
I can receive the correct tick order book data from wss://api2.poloniex.com use python3
but sometime The channel 1002 may stop sending the new tick info.
wss://api.poloniex.com:443 ; realm1
This may be the issue as I've been using api2 and here is the code that works, and has been working for the past 2 quarters non-stop. Its in python, but should be easy enough to port to C++.
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import websocket
import json
def on_error(ws, error):
print(error)
def on_close(ws):
print("### closed ###")
connection.close()
def on_open(ws):
print("ONOPEN")
ws.send(json.dumps({'command':'subscribe','channel':'BTC_ETH'}))
def on_message(ws, message):
message = json.loads(message)
print(message)
websocket.enableTrace(True)
ws = websocket.WebSocketApp("wss://api2.poloniex.com/",
on_message = on_message,
on_error = on_error,
on_close = on_close)
ws.on_open = on_open
ws.run_forever()
the code is pretty much self-explanatory (You can check all channels/pairs on Poloniex API website), just save it and run in terminal
python3 fileName.py
should provide You with BTCETH raw stream of orders and trades on console output.
Playing with the message/subscriptions You can then do as You please with it.
It seems that websockets in Poloniex are unstable. Therefore I can stop my attempts make Autobahn-Cpp work with it at least by now and move on.
I have the following code sample
import socket
try:
sock=socket
sock.setdefaulttimeout(1)
for result in sock.gethostbyaddr("165.139.149.169"):
if result and "[" not in str(result):
print str(result)
except socket.herror:
print("Host Not Found")
which works as part of a network discovery type POC that I'm building (mostly to learn Python). As I said, the code works, but when an address has no DNS record it takes forever. Is there a way to change the timeout of the sock.gethostbyaddr() method so that it will throw host not found sooner?
I'm currently working with gloox in order to send XMPP messages from my C++ program. I work in local network with my private prosody XMPP server.
Sending text messages between two client works but not files. I tried the gloox examples (ft_rcv & ft_send) but it did not worked neither (obviously I modified the examples to match my configuration), I always have the same error :
<error type='cancel'><service-unavailable xmlns='urn:ietf:params:xml:ns:xmpp-stanzas'/>
At the beginning I thought it was due to my prosody server but I added the following lines in the conf files :
Component "proxy.jabberserver.local" "proxy65"
proxy65_address = "proxy.jabberserver.local"
proxy65_ports = { 7777 }
I tried different server and different port but I'm currently in a dead end. If someone have an idea it would be great.
Thank you
f->addStreamHost( JID("proxy.jabberserver.local"), "proxy.jabberserver.local", 7777 ); should do the trick. If no - show full XML log.
In the blocking way I can do this:
from scapy.all import *
sniff(filter"tcp and port 80", count=10, prn = labmda x:x.summary())
# Below code will be executed only after 10 packets have been received
do_stuff()
do_stuff2()
do_stuff3()
I want to be able to sniff packets with scapy in a non blocking way, something like this:
def packet_recevied_event(p):
print "Packet received event!"
print p.summary()
# The "event_handler" parameter is my wishful thinking
sniff(filter"tcp and port 80", count=10, prn=labmda x:x.summary(),
event_handler=packet_received_event)
#I want this to be executed immediately
do_stuff()
do_stuff2()
do_stuff3()
To sum-up: My question is pretty clear, I want to be able to continue executing code without the sniff function blocking it.
One option is to open a separate thread for this, but I would like to avoid it and use scapy native tools if possible.
Environment details:
python: 2.7
scapy: 2.1.0
os: ubuntu 12.04 64bit
This functionality was added in https://github.com/secdev/scapy/pull/1999.
I'll be available with Scapy 2.4.3+ (or the github branch). Have a look at the doc over: https://scapy.readthedocs.io/en/latest/usage.html#asynchronous-sniffing
>>> t = AsyncSniffer(prn=lambda x: x.summary(), store=False, filter="tcp")
>>> t.start()
>>> time.sleep(20)
>>> t.stop()
Scapy doesn't have an async version of the sniff function. You're going to have to fire threads.
There may be other issues with this, mostly having to do with resource locking.