Send a file from one Lopy to another Lopy

[zceld]

It seems that finally they are between lopys and connect because the server prints this:

Now the client seems to give me another error but this one I do not know what it means:

OSError: (Errno 113) EHOSTUNREACH

¿?

[seb]

@zceld

error host unreachable - this means the lopy could not find a route to the destination

[zceld]

@seb said in Send a file from one Lopy to another Lopy:

error host unreachable - this means the lopy could not find a route to the destination

If you do not find it as it is on the print server ('connected') when I run the client code? What am I missing?

[seb]

can you post your complete code and I will have a look

[zceld]

@seb said in Send a file from one Lopy to another Lopy:

can you post your complete code and I will have a look

Thank you very much for looking at it. This is the full code of the Lopy Server:

import socket                   # Import socket module

def iniciarFTP():
    try:
        import network
        from network import WLAN
        wlan = network.WLAN(mode=network.WLAN.STA)
        wlan.init(mode=WLAN.AP, ssid='Gateway1', auth=(WLAN.WPA2,'witeklab@2018'), channel=7, antenna=WLAN.INT_ANT)
        from network import Server
        server = Server(login=('micro', 'python'), timeout=600)
        server.timeout(300)
        server.timeout()
        print(server.isrunning())
        return True
    except:
        return False

#Iniciamos servidor:
iniciarFTP()
host = ''
port = 8206                     # Reserve a port for your service.
s = socket.socket()             # Create a socket object

s.bind((host, port))            # Bind to the port
s.listen(5)                     # Now wait for client connection.

print ('Server listening....')

while True:
    conn, addr = s.accept()     # Establish connection with client.
    print ('Got connection from', addr)
    data = conn.recv(1024)
    print('Server received', repr(data))

    with open('received_file.txt', 'wb') as f:
        print ('file opened')
        while True:
            print('receiving data...')
            data = s.recv(1024)
            print('data=%s', (data))
            if not data:
                break
            # write data to a file
            f.write(data)

        f.close()
        print('Successfully get the file')
        s.close()
        print('connection closed')

        conn.send('Thank you for connecting')
    conn.close()

No more, now I give you a screenshot of what you do when you run it, but I already told you that it stops when you print ('Server listening ....')
As the programming indicates waiting for some connection. But the one that receives a connection from the client fails with the error 'OSError: 128':

Now we go to the client Lopy code:

 from network import WLAN
import socket
import sys

def buscarWifi(ssid):
    wlan = WLAN(mode=WLAN.STA)
    redes = wlan.scan()
    print('Redes disponibles: ',len(redes))
    for red in redes:
        if red.ssid == ssid:
            wlan.connect(red.ssid, auth=(red.sec,'witeklab@2018'), timeout=5000)
            while not wlan.isconnected():
                machine.idle() # save power while waiting
            print('WLAN connection succeeded!')
            return True,wlan
            break
        else:
            return False,wlan

ok,w = buscarWifi('Gateway1')
if ok:
    print('ok')
    s = socket.socket() 
    ip = w.ifconfig()
    print('ip destino = ',ip[0])
    print('Configuracion de red:',w.ifconfig())
    print('Estoy conectado=',w.isconnected())
    ip = w.ifconfig()
    host = ip[2]
    #print(type(HOST),'--->>',HOST)
    port = 8206
    s.connect((host, port))
    s.send("Hello server!")
    filename='prueba.txt'
    f = open(filename,'rb')
    l = f.read(1024)
    while (l):
       conn.send(l)
       print('Sent ',repr(l))
       l = f.read(1024)
    f.close()
    s.close()

and the error that appears to me in this case is:

I do not know what that error means, nor do I know if I'm doing things right. The only thing I know is that at least now they connect to Lopy client and Lopy server, which is already a lot, having to study how the socket system works.

That's why in some comment I said, I was requesting some exemplary code of how the system should connect between a client and server and transfer a file.

I have taken the code example from here:
http://www.bogotobogo.com/python/python_network_programming_server_client_file_transfer.php

Although I would like to be able to use the last one with Thread but I have not known how to adapt it to mircro python:
http://www.bogotobogo.com/python/python_network_programming_server_client_file_transfer.php#ec2

[seb]

@zceld said in Send a file from one Lopy to another Lopy:

from network import WLAN
import socket
import sys

def buscarWifi(ssid):
wlan = WLAN(mode=WLAN.STA)
redes = wlan.scan()
print('Redes disponibles: ',len(redes))
for red in redes:
if red.ssid == ssid:
wlan.connect(red.ssid, auth=(red.sec,'witeklab@2018'), timeout=5000)
while not wlan.isconnected():
machine.idle() # save power while waiting
print('WLAN connection succeeded!')
return True,wlan
break
else:
return False,wlan

ok,w = buscarWifi('Gateway1')
if ok:
print('ok')
s = socket.socket()
ip = w.ifconfig()
print('ip destino = ',ip[0])
print('Configuracion de red:',w.ifconfig())
print('Estoy conectado=',w.isconnected())
ip = w.ifconfig()
host = ip[2]
#print(type(HOST),'--->>',HOST)
port = 8206
s.connect((host, port))
s.send("Hello server!")
filename='prueba.txt'
f = open(filename,'rb')
l = f.read(1024)
while (l):
conn.send(l)
print('Sent ',repr(l))
l = f.read(1024)
f.close()
s.close()

Looking at your second block of code it looks like you are trying to connect the device to itself? You are getting host from ifconfig() but then trying to connect to that address

[zceld]

@seb said in Send a file from one Lopy to another Lopy:

host = ip[2]

Hi, thanks again for checking it out!

In theory the server returns these values of WLAN.ifconfig ():

Of the data that ifconfig returns are:?

('ip assigned', 'subnet mask', 'ip server'?, 'and this last one I do not know' /0.0.0.0).

Capture of the client, this time trying to connect to the ip '192.168.4.1' that is supposed to be the server's Wi-Fi therefore the Lopy server does not?

[seb]

@zceld
The return of ifconfig is in the following format.
(ip, subnet, gateway, dns)

I see now from your code that you are using one of the modules as a wifi AP, can you first try connecting them to an existing network to see if this works, then we can narrow down if the issue lies with the networking or your logic

[zceld]

@seb said in Send a file from one Lopy to another Lopy:

@zceld
The return of ifconfig is in the following format.
(ip, subnet, gateway, dns)
I see now from your code that you are using one of the modules as a wifi AP, can you first try connecting them to an existing network to see if this works, then we can narrow down if the issue lies with the networking or your logic

Now I will try to reduce where the problem may be, but the need to connect and send data is to be used without a router, if you do not communicate with each other.

Regardless of the Wi-Fi, do you think that you could send two messages simultaneously with LoRa using thread?

[zceld]

@seb
This is the result that the server connected to Wi-Fi has given me, and to which it has begun to receive data from the client, it has failed:

code used in the superior test:

def buscarWifi(ssid):
    #Ponemos el wifi en modo estacion:
    wlan = WLAN(mode=WLAN.STA)

    #Buscamos wifi:
    redes = wlan.scan()
    print('Redes disponibles: ',len(redes))
    for red in redes:
        if red.ssid == ssid:
            wlan.connect(red.ssid, auth=(red.sec,'hszh6539'), timeout=5000)
            while not wlan.isconnected():
                machine.idle() # save power while waiting
            print('WLAN connection succeeded!')
            return True,wlan
            break
        else:
            return False,wlan

iniciarFTP()
ok,w = buscarWifi('S9+ Wifi')
if ok:
    print('ok')
    ip = w.ifconfig()
    host = ip[0]
    print('my ip = ',ip[0])
    port = 60000                     # Reserve a port for your service.
    s = socket.socket()             # Create a socket object
    gc.collect()
    s.bind((host, port))            # Bind to the port
    s.listen(5)                     # Now wait for client connection.

    print ('Server listening....')

    while True:
        conn, addr = s.accept()     # Establish connection with client.
        print ('Got connection from', addr)
        data = conn.recv(256)
        print('Server received', repr(data))

        with open('received_file.txt', 'wb') as f:
            print ('file opened')
            while True:
                print('receiving data...')
                s.setblocking(True)
                print('Memoria->',str(gc.mem_free()))
                data = s.recv(256)
                print('M despues->',str(gc.mem_free()))
                print('data=%s', (data))
                if not data:
                    break
                # write data to a file
                f.write(data)

            f.close()
            print('Successfully get the file')
            s.close()
            print('connection closed')

            conn.send('Thank you for connecting')
        conn.close()
        gc.collect()

---

Result of the Lopy that sends the file:

code used in the superior test:

from network import WLAN

import socket
import sys


def buscarWifi(ssid):
    #Ponemos el wifi en modo estacion:
    wlan = WLAN(mode=WLAN.STA)

    #Buscamos wifi:
    redes = wlan.scan()
    print('Redes disponibles: ',len(redes))
    #for c in range(len(redes)):
        #print(c,'->',redes[c])

        #if ssid in redes[c]: //Otra opción de encontrar el ssid
        #print("Encontrado en:",redes[c])
        #return True
    for red in redes:
        if red.ssid == ssid:
            wlan.connect(red.ssid, auth=(red.sec,'hszh6539'), timeout=5000)
            while not wlan.isconnected():
                machine.idle() # save power while waiting
            print('WLAN connection succeeded!')
            return True,wlan
            break
        else:
            return False,wlan

ok,w = buscarWifi('S9+ Wifi')
if ok:
    print('ok')
    s = socket.socket()
    print('ip destino = 192.168.43.26')
    print('Configuracion de red:',w.ifconfig())
    print('Estoy conectado=',w.isconnected())
    #host = ip[]
    #print(type(HOST),'--->>',HOST)
    port = 60000
    s.connect(('192.168.43.26', port))
    s.send("Hello server!")
    filename='prueba.txt'
    f = open(filename,'rb')
    l = f.read(256)
    while (l):
       conn.send(l)
       print('Sent ',repr(l))
       l = f.read(256)
    f.close()
    s.close()

[seb]

Hi,

Please excuse the delay. I have gone ahead and written some code for you to demonstrate sending a file between devices. Be aware that this does no error checking/retries etc. but the basic functionality is there.

Client

from network import WLAN
import socket
import select
import machine
import time

# Connect to server AP
wlan = WLAN(mode=WLAN.STA)
nets = wlan.scan()
for net in nets:
    if net.ssid == 'Gateway1':
        print('Network found!')
        wlan.connect(net.ssid, auth=(net.sec, 'password'), timeout=5000)
        while not wlan.isconnected():
            machine.idle() # save power while waiting
        print('WLAN connection succeeded!')
        break
else:
    raise Exception("WiFi network not found")

# sleep just to make sure the wifi is connected
time.sleep(1)

ip, subnet, gateway, dns = wlan.ifconfig()

# Connect to server
port = 12345
s = socket.socket()
print("Connecting to: ", gateway, port)
s.connect((gateway, port))
s.setblocking(True)
s.settimeout(2)

file = "/flash/test.txt"
with open(file, 'wb') as f:
    while True:
        try:
            data = s.recv(1024)
            print(data)
            f.write(data)
        except TimeoutError:
            break

Server

from network import WLAN
import socket
import select
import time

#Setup WiFi AP
wlan = WLAN(mode=WLAN.AP,
            ssid='Gateway1',
            auth=(WLAN.WPA2,'password'),
            antenna=WLAN.INT_ANT)


# Bind to the port
port = 12345
s = socket.socket()
s.bind(socket.getaddrinfo("0.0.0.0", port)[0][4])
s.listen(1)

print("Running server")
while True:
    readable, writable, errored = select.select([s], [], [])

    for s in readable:
        cl, remote_addr = s.accept()
        cl.setblocking(True)
        print("Client connection from:", remote_addr)

        file = "/flash/test.txt"
        print("Sending: ", file)

        with open(file, 'rb') as f:
            data = f.read(1024)
            while(data):
                print("sending", data)
                cl.sendall(data)
                data = f.read(1024)
        print("Done Sending")
        cl.close()

[zceld]

@seb said in Send a file from one Lopy to another Lopy:

from network import WLAN
import socket
import select
import time

#Setup WiFi AP
wlan = WLAN(mode=WLAN.AP,
            ssid='Gateway1',
            auth=(WLAN.WPA2,'password'),
            antenna=WLAN.INT_ANT)


# Bind to the port
port = 12345
s = socket.socket()
s.bind(socket.getaddrinfo("0.0.0.0", port)[0][4])
s.listen(1)

print("Running server")
while True:
    readable, writable, errored = select.select([s], [], [])

    for s in readable:
        cl, remote_addr = s.accept()
        cl.setblocking(True)
        print("Client connection from:", remote_addr)

        file = "/flash/test.txt"
        print("Sending: ", file)

        with open(file, 'rb') as f:
            data = f.read(1024)
            while(data):
                print("sending", data)
                cl.sendall(data)
                data = f.read(1024)
        print("Done Sending")
        cl.close()

hi, forgive me for the delay, yesterday I could not look at it, today was the first thing I've done and has given a failure on the server.

[seb]

@zceld

Did you create a test.txt file on your device too? the server reads the file test.txt and client writes to a file called test.txt

[zceld]

@seb said in Send a file from one Lopy to another Lopy:

Did you create a test.txt file on your device too? the server reads the file test.txt and client writes to a file called test.txt

I had not realized that it was the other way around, that is, as my idea was to send the client to the server, I had not noticed sorry. Anyway now I have changed it to a file that is in the Lopy but now it tells me this error:

Captura de pantalla 2018-04-19 16.30.23

[seb]

@zceld

How big of a file are you trying to copy?

[zceld]

@zceld

I still do not know what that error means but it must be related to the socket and the listener method.

But I have reset the plates and it has worked :) I still do not believe it ...

hehe thank you very much at least I know that something works now I need many things to know but already with the base is much.

By the way when you put the socket = cl.setblocking (True)
Is there a way to cancel or interrupt this?
another question. this 's.listen (1)' which means you will be listening once?

I have more questions ... If I use for example Wi-Fi or Lora with _threads, can I send and listen to the same chip at the same time?

[seb]

@zceld

1. You can cancel it by using setblocking(False)

2. you can find out what s.listen(1) means here: https://docs.pycom.io/chapter/firmwareapi/micropython/usocket.html#socketlistenbacklog its basically how many unaccepted connections you can queue up

3. Yeah that should be fine, the underlying drivers for wifi/lora will handle multiplexing access to them

[zceld]

@seb said in Send a file from one Lopy to another Lopy:

You can cancel it by using setblocking(False)

you can find out what s.listen(1) means here: https://docs.pycom.io/chapter/firmwareapi/micropython/usocket.html#socketlistenbacklog its basically how many unaccepted connections you can queue up

Yeah that should be fine, the underlying drivers for wifi/lora will handle multiplexing access to them

Would you know to tell me that I failed in all the previous examples??

On the other hand I already ask you in your day for the same thing of s.setblocking (True / False) you know where I could find an exhaustive explanation about that?

Finally on the _treads, to confirm. It would be possible to put in a Lopy a _tread that established the wifi in WLAN.AP mode and in turn in the same Lopy through another _tread the wifi was put in WLAN.STA mode at the same time?

[seb]

@zceld

The docs are the best place to look at what these functions do: https://docs.pycom.io/chapter/firmwareapi/micropython/usocket.html

Here is a basic run down, s.setblocking(True) will make any sending or recieving functions block, this means the lopy will get stuck at that line of code until it receives the amount of bytes asked for (or it timesout, if a timeout is set) or until all data is send. When it is False calls to any sending or receiving functions will return immediately. In the case of a send, it will place the data in a queue and it will be send in the background in a different thread. In the case of a recieve, if there is less data than expected available it simply returns that and doesnt wait for the full expected amount.

You can change the WLAN modes but this will become messy because you will need to make sure the threads have proper locks and that they are aware of what state the WLAN is in before trying to use it. You might be better off just using the WLAN.STA_AP mode which is both modes at once.

[zceld]

Good again.

I return to post, because I would need the LoPy that receives the txt file is the one that starts the wifi as

wlan = WLAN (mode = WLAN.AP,
ssid = 'Gateway1',
auth = (WLAN.WPA2, 'password'),
antenna = WLAN.INT_ANT)

I have tried to modify the code as I have the partner that works so that it is but I get error everywhere.

Once trying once more, if I do not restart the board and try to execute the code, I always get the error:

Traceback (most recent call last):
File "<stdin>", line 17, in <module>
OSError: [Errno 12] ENOMEM

Because it is ? If someone can give me a hand code please!

Capture Errors:

used code:
Server And Wifi AP:

from network import WLAN
import socket
import select
import time

#Setup WiFi AP
wlan = WLAN(mode=WLAN.AP,
            ssid='Gateway1',
            auth=(WLAN.WPA2,'password'),
            antenna=WLAN.INT_ANT)

port = 12345
s = socket.socket()
s.bind(socket.getaddrinfo("0.0.0.0", port)[0][4])
s.listen(1)

print("Running server")
while True:
    cl, remote_addr = s.accept()
    cl.setblocking(True)
    print("Client connection from:", remote_addr)

    file = "/flash/registro2.txt"
    with open(file, 'wb') as f:
        try:
            data = s.recv(1024)
            print(data)
            f.write(data)
        except TimeoutError:
            break

Client and Lopy and in charge to send file:

from network import WLAN
import socket
import select
import machine
import time

# Abrimos wifi
wlan = WLAN(mode=WLAN.STA)
nets = wlan.scan()
for net in nets:
    if net.ssid == 'Gateway1':
        print('Network found!')
        wlan.connect(net.ssid, auth=(net.sec, 'password'), timeout=5000)
        while not wlan.isconnected():
            machine.idle() # save power while waiting
        print('WLAN connection succeeded!')
        break
else:
    raise Exception("WiFi network not found")

# sleep just to make sure the wifi is connected
time.sleep(1)

ip, subnet, gateway, dns = wlan.ifconfig()

# Connect to server
# Bind to the port
port = 12345
s = socket.socket()
s.connect((gateway, port))
s.setblocking(True)
s.settimeout(2)

while True:
    readable, writable, errored = select.select([s], [], [])
    
    for s in readable:
        cl, remote_addr = s.accept()
        cl.setblocking(True)
        print("Client connection from:", remote_addr)

        file = "/flash/registro.txt"
        print("Sending: ", file)

        with open(file, 'rb') as f:
            data = f.read(1024)
            while(data):
                print("sending", data)
                cl.sendall(data)
                data = f.read(1024)
        print("Done Sending")
        cl.close()