I'm trying to connect rabbitMQ in one machine (Windows 10) to other machine (Raspberry pi 4). The windows machine is the producer, and the pi is the receiver. Both are connected to the same network, and defined with the same localhost. Although the message is sent correctly to the queue, it is not received by the Pi.
Is there any steps that I'm missing?
Below is the producer code (python in PC- Windows)
import pika
connection = pika.BlockingConnection(
pika.ConnectionParameters(host='localhost'))
channel = connection.channel()
channel.queue_declare(queue='my-queue')
channel.basic_publish(exchange='', routing_key='my-queue', body='Hello World from windows!!')
print(" [x] Sent 'Hello World from windows!'")
connection.close()
Consumer code (in Pi)
import pika
host = 'localhost'
queue = 'my-queue'
def on_message(ch, method, properties, body):
message = body.decode('UTF-8')
print(message)
def main():
connection_params = pika.ConnectionParameters(host=host)
connection = pika.BlockingConnection(connection_params)
channel = connection.channel()
channel.queue_declare(queue=queue)
channel.basic_consume(queue=queue, on_message_callback=on_message,
auto_ack=True)
print('Subscribed to ' + queue + ', waiting for messages...')
channel.start_consuming()
if __name__ == '__main__':
main()
I am using micropython on my esp32. I want to send data from esp32 to AWS IoT MQTT Broker Endpoint.
But in micropython socket module, getaddrinfo(hostname, port) method return empty list every time. How can I solve it?
It is working when I use IP address instead of host name. But AWS MQTT broker endpoint has no static IP for its broker endpoint.
# My code:
sta_if = network.WLAN(network.STA_IF)
sta_if.active(True)
sta_if.connect("wifiname", "password")
KEY_PATH = "/619e3d582c-private.pem.key"
CERT_PATH = "/619e3d582c-certificate.pem"
with open(KEY_PATH, 'r') as f:
PVT_KEY = f.read()
with open(CERT_PATH, 'r') as f:
CERT_KEY = f.read()
client = MQTTClient(client_id="esp32_micropython_shafik",
server="xxxxxxxxxxx.iot.eu-west-1.amazonaws.com",
port = 8883,
keepalive = 10000,
ssl = True,
ssl_params = {
"cert": CERT_KEY,
"key": PVT_KEY,
"server_side":False
} )
def checkwifi():
while not sta_if.isconnected():
time.sleep_ms(500)
print(".")
sta_if.connect()
def publish():
while True:
checkwifi()
msg = b'hello shafik'
client.publish(b"weather", msg)
time.sleep(1)
print("type", type(PVT_KEY))
client.connect()
publish()`
I am getting continuously this error:
umqtt/simple.py in 57 line,
IndexError: list index out of range.
How can I solve it?
I have solved this problem just changing my wifi network.
Actually this problem occurred for my ISP network issue, that's why socket module didn't work properly for fetching IP address properly.
i've made a local server using flask and mongoDB which works great on windows, but when i moved my code to the raspberry pi, i've got an error which i couldn't figure out why it occurs.
the code im using:
1) for the flask server
from flask import Flask
from flask import jsonify
from flask import request
import pymongo
import time
import datetime
import json
app = Flask(__name__)
client = pymongo.MongoClient("localhost", 27017)
db = client['mqtt-db']
obs_collection = db['mqtt-collection']
#app.route("/obs")
def obs():
data_str = request.args.get("data")
print data_str
data = json.loads(data_str)
print data
data["date"] = datetime.datetime.now()
obs_collection.save(data)
return "success"
#app.route("/get_obs")
def get_obs():
res = []
for row in obs_collection.find():
del row['_id']
res.append(row)
return jsonify(res)
#app.route("/delete_all")
def delete_all():
res = obs_collection.delete_many({})
return jsonify({"deleted": res.deleted_count})
if __name__ == "__main__":
app.run(host="0.0.0.0", debug=True)
2) script for inserting messages into db , using mqtt protocol:
import paho.mqtt.client as mqtt
import pymongo
import json
import datetime
topic = "sensor"
host = "10.0.0.6"
client = pymongo.MongoClient("localhost", 27017)
db = client['mqtt-db']
mqtt_collection = db['mqtt-collection']
# The callback for when the client receives a CONNACK response from the server.
def on_connect(client, userdata, flags, rc):
print("Connected with result code "+str(rc))
# Subscribing in on_connect() means that if we lose the connection and
# reconnect then subscriptions will be renewed.
client.subscribe(topic)
# The callback for when a PUBLISH message is received from the server.
def on_message(client, userdata, msg):
data_str = str(msg.payload)
data = json.loads(data_str)
print data_str
print data
data["date"] = datetime.datetime.now()
mqtt_collection.save(data)
print(msg.topic+" "+str(msg.payload))
client = mqtt.Client()
client.on_connect = on_connect
client.on_message = on_message
client.connect(host, 1883, 60)
# Blocking call that processes network traffic, dispatches callbacks and
# handles reconnecting.
# Other loop*() functions are available that give a threaded interface and a
# manual interface.
client.loop_forever()
the error occurs when i try to retrieve data from the server using "get_obs" function.
the error is: "Value Error: dictionary update sequence element #0 has length 4; 2 is required"
appreciate your help.
as #davidism suggested, the solution was to update to the latest version of Flask
I want to create a chat program between two machines. I am using machine one which has the IP address 192.168.0.5, I can successfully send a message to machine two 192.168.0.2, and then send a message in response from machine two, to machine 1.
However I encountered a problem on the second send attempt from either machine, (noticing that before sending the second time I wait for a response from the initial send) claiming that the IP address is already in use or connection is refused, how can this be changed so that a defined number of choices can be sent?
I appreciate that the following code is not the most efficient way of sending and receiving multiple messages, that would be some description of for loop. For example for sendAndRecieve in range(0,5).
The two machines are linked using ethernet cables running through a switch and the code is run simultaneously.
Machine 1 code:
#Sending first message
host = "192.168.0.5"
port = 4446
from socket import *
s = socket(AF_INET, SOCK_STREAM)
s.bind((host,port))
s.listen(1)
print("listening")
q,addr = s.accept(1024)
data = "This is the first message I am sending"
data = data.encode("utf-8")
q.send(data)
s.close
#Recieving response message 1
while True:
try:
host = "192.168.0.2"
port = 4446
from socket import*
s = socket(AF_INET, SOCK_STREAM)
s.connect((host,port))
msg = s.recv(1024)
msg = msg.decode("utf-8")
print(msg)
s.close()
except:
pass
#Sending second message this is where the problem happens
host = "192.168.0.5"
port = 4446
from socket import *
s = socket(AF_INET, SOCK_STREAM)
s.bind((host,port))
s.listen(1)
print("listening")
q,addr = s.accept(1024)
data = "This is the first message I am sending"
data = data.encode("utf-8")
q.send(data)
s.close
Machine 2 code:
#Recieving message 1
while True:
try:
host = "192.168.0.5"
port = 4446
from socket import*
s = socket(AF_INET, SOCK_STREAM)
s.connect((host,port))
msg = s.recv(1024)
msg = msg.decode("utf-8")
print(msg)
s.close()
except:
pass
#Sending first message
host = "192.168.0.2"
port = 4446
from socket import *
s = socket(AF_INET, SOCK_STREAM)
s.bind((host,port))
s.listen(1)
print("listening")
q,addr = s.accept(1024)
data = "This is the first message I am sending"
data = data.encode("utf-8")
q.send(data)
s.close
#Recieving response message 1 this is where the problem happens
while True:
try:
host = "192.168.0.25"
port = 4446
from socket import*
s = socket(AF_INET, SOCK_STREAM)
s.connect((host,port))
msg = s.recv(1024)
msg = msg.decode("utf-8")
print(msg)
s.close()
except:
pass
Reading through your code, I don't see how Machine 2's while loop will ever stop trying to receive data from Machine 1 (there's no break in the loop other than if an error is encountered). Machine 1 does continue on after Machine 2 connects the first time, but then tries to connect to Machine 2 while Machine 2 is trying to connect to Machine 1. That's probably the cause of the error that you're seeing, and why you only see the first message sent/received.
So I am working on an iPhone app that requires a socket to handle multiple clients for online gaming. I have tried Twisted, and with much effort, I have failed to get a bunch of info to be sent at once, which is why I am now going to attempt socket.
My question is, using the code below, how would you be able to have multiple clients connected? I've tried lists, but I just can't figure out the format for that. How can this be accomplished where multiple clients are connected at once and I am able to send a message to a specific client?
Thank you!
#!/usr/bin/python # This is server.py file
import socket # Import socket module
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 50000 # Reserve a port for your service.
print 'Server started!'
print 'Waiting for clients...'
s.bind((host, port)) # Bind to the port
s.listen(5) # Now wait for client connection.
c, addr = s.accept() # Establish connection with client.
print 'Got connection from', addr
while True:
msg = c.recv(1024)
print addr, ' >> ', msg
msg = raw_input('SERVER >> ')
c.send(msg);
#c.close() # Close the connection
Based on your question:
My question is, using the code below, how would you be able to have multiple clients connected? I've tried lists, but I just can't figure out the format for that. How can this be accomplished where multiple clients are connected at once and I am able to send a message to a specific client?
Using the code you gave, you can do this:
#!/usr/bin/python # This is server.py file
import socket # Import socket module
import thread
def on_new_client(clientsocket,addr):
while True:
msg = clientsocket.recv(1024)
#do some checks and if msg == someWeirdSignal: break:
print addr, ' >> ', msg
msg = raw_input('SERVER >> ')
#Maybe some code to compute the last digit of PI, play game or anything else can go here and when you are done.
clientsocket.send(msg)
clientsocket.close()
s = socket.socket() # Create a socket object
host = socket.gethostname() # Get local machine name
port = 50000 # Reserve a port for your service.
print 'Server started!'
print 'Waiting for clients...'
s.bind((host, port)) # Bind to the port
s.listen(5) # Now wait for client connection.
print 'Got connection from', addr
while True:
c, addr = s.accept() # Establish connection with client.
thread.start_new_thread(on_new_client,(c,addr))
#Note it's (addr,) not (addr) because second parameter is a tuple
#Edit: (c,addr)
#that's how you pass arguments to functions when creating new threads using thread module.
s.close()
As Eli Bendersky mentioned, you can use processes instead of threads, you can also check python threading module or other async sockets framework. Note: checks are left for you to implement how you want and this is just a basic framework.
accept can continuously provide new client connections. However, note that it, and other socket calls are usually blocking. Therefore you have a few options at this point:
Open new threads to handle clients, while the main thread goes back to accepting new clients
As above but with processes, instead of threads
Use asynchronous socket frameworks like Twisted, or a plethora of others
Here is the example from the SocketServer documentation which would make an excellent starting point
import SocketServer
class MyTCPHandler(SocketServer.BaseRequestHandler):
"""
The RequestHandler class for our server.
It is instantiated once per connection to the server, and must
override the handle() method to implement communication to the
client.
"""
def handle(self):
# self.request is the TCP socket connected to the client
self.data = self.request.recv(1024).strip()
print "{} wrote:".format(self.client_address[0])
print self.data
# just send back the same data, but upper-cased
self.request.sendall(self.data.upper())
if __name__ == "__main__":
HOST, PORT = "localhost", 9999
# Create the server, binding to localhost on port 9999
server = SocketServer.TCPServer((HOST, PORT), MyTCPHandler)
# Activate the server; this will keep running until you
# interrupt the program with Ctrl-C
server.serve_forever()
Try it from a terminal like this
$ telnet localhost 9999
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Hello
HELLOConnection closed by foreign host.
$ telnet localhost 9999
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Sausage
SAUSAGEConnection closed by foreign host.
You'll probably need to use A Forking or Threading Mixin too
This program will open 26 sockets where you would be able to connect a lot of TCP clients to it.
#!usr/bin/python
from thread import *
import socket
import sys
def clientthread(conn):
buffer=""
while True:
data = conn.recv(8192)
buffer+=data
print buffer
#conn.sendall(reply)
conn.close()
def main():
try:
host = '192.168.1.3'
port = 6666
tot_socket = 26
list_sock = []
for i in range(tot_socket):
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
s.bind((host, port+i))
s.listen(10)
list_sock.append(s)
print "[*] Server listening on %s %d" %(host, (port+i))
while 1:
for j in range(len(list_sock)):
conn, addr = list_sock[j].accept()
print '[*] Connected with ' + addr[0] + ':' + str(addr[1])
start_new_thread(clientthread ,(conn,))
s.close()
except KeyboardInterrupt as msg:
sys.exit(0)
if __name__ == "__main__":
main()
def get_clients():
first_run = True
startMainMenu = False
while True:
if first_run:
global done
done = False
Thread(target=animate, args=("Waiting For Connection",)).start()
Client, address = objSocket.accept()
global menuIsOn
if menuIsOn:
menuIsOn = False # will stop main menu
startMainMenu = True
done = True
# Get Current Directory in Client Machine
current_client_directory = Client.recv(1024).decode("utf-8", errors="ignore")
# beep on connection
beep()
print(f"{bcolors.OKBLUE}\n***** Incoming Connection *****{bcolors.OKGREEN}")
print('* Connected to: ' + address[0] + ':' + str(address[1]))
try:
get_client_info(Client, first_run)
except Exception as e:
print("Error data received is not a json!")
print(e)
now = datetime.now()
current_time = now.strftime("%D %H:%M:%S")
print("* Current Time =", current_time)
print("* Current Folder in Client: " + current_client_directory + bcolors.WARNING)
connections.append(Client)
addresses.append(address)
if first_run:
Thread(target=threaded_main_menu, daemon=True).start()
first_run = False
else:
print(f"{bcolors.OKBLUE}* Hit Enter To Continue.{bcolors.WARNING}\n#>", end="")
if startMainMenu == True:
Thread(target=threaded_main_menu, daemon=True).start()
startMainMenu = False
#!/usr/bin/python
import sys
import os
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
port = 50000
try:
s.bind((socket.gethostname() , port))
except socket.error as msg:
print(str(msg))
s.listen(10)
conn, addr = s.accept()
print 'Got connection from'+addr[0]+':'+str(addr[1]))
while 1:
msg = s.recv(1024)
print +addr[0]+, ' >> ', msg
msg = raw_input('SERVER >>'),host
s.send(msg)
s.close()