ESP8266 with NodeMCU firmware: receiving empty messages with secured MQTT subscription - esp8266

I'm trying to securely connect ESP8266 to MQTT Azure Protocol Gateway broker on cloud or local computer (tried both) like this (not important - connection works correctly):
m = mqtt.Client("{deviceId}", "3600", "{iotHub}/{deviceId}", "{SASToken}")
...
m:on("message", function(conn, top, data)
print(data) -- EMPTY string here!
end)
...
m:connect({IP}, 8883, 1, function(conn)
m:subscribe("devices/{deviceId}/messages/devicebound/#", 1, function(conn)
...
end)
end)
ESP connects to server and handshake is completed successfully. When I publish some data, I can read it on server properly, it is OK. I subscribe to topic without problems. When I send data in cloud-to-device message from server to ESP to subscribed topic, 'on message' event is called but data attribute passed to the function is EMPTY string.
I'm using latest NodeMCU master build based on 1.4.0 SDK (tried both integer and float version). I can't turn on debugging, because i don't have NodeMCU developer yet.
I tried following:
dev version - not help
free memory up to 32kB - not help
captured packets with WireShark: packets contain encrypted data with some lenght, so it is not empty and packet size is less than 2kB buffer size
Can someone please advise me where could be a problem or how to debug it for more info? I would approciate any ideas. Thank you.
EDIT:
I've tried debug mode, and there is nothing interesting on output:
enter mqtt_socket_received.
MQTT_DATA: type: 3, qos: 0, msg_id: 0, pending_id: 0
enter deliver_publish.
string
userdata: 3fff3e88
devices/ESP/messages/devicebound
<- here should be printed data
On
leave deliver_publish.
receive, queue size: 0
leave mqtt_socket_received.
enter mqtt_socket_timer.
timer, queue size: 0
keep_alive_tick: 71
leave mqtt_socket_timer.
enter mqtt_socket_received.
MQTT_DATA: type: 7, qos: 1, msg_id: 8813, pending_id: 0
receive, queue size: 0
leave mqtt_socket_received.

This may be stupid but sometimes lua expects specific names in some functions.
Change this
function(conn, top, data)
for this
function(conn, topic, data)
I have worked previously with mqtt in lua with password protection, and i had to drop it beacuse i wasnt recieving the message content either, however i think mine was due to the amount of messages i was recieving/delivering. I also changed broker from mosquitto to mosca.
I hope you find a fix soon and please share it we might be able to use it to :)

Related

Telnet server example

Today I installed NodeMCU on one ESP8266 module.
I made a simple telnet server (logging in to the AP is already done and connected)
srv=net.createServer(net.TCP,7200)
srv:listen(23,function(conn)
conn:on("receive", function(conn,telnetdata)
print(telnetdata)
conn:send("Got it\r\n")
end)
conn:on("sent",function(conn)
print("[Sent]");
--conn:close();
--collectgarbage();
end)
end)
I can telnet into the ESP8266 using Putty and I can send static data back to Putty (conn:send("Got it\r\n")).
What I want to do is to send data to Putty from the esp serial port (UART). I've googled for an example without success. BTW I'm using ESPlorer to program the ESP and to send data back to putty.
Instead of using conn:send("Got it\r\n") I want to dynamically type the response. I've tried uart:on callback but I haven't fully understood how it works.
NodeMCU has an "official" Telnet example in the repository. However, that one is also WiFi/socket-based.
If you're connected to the device through ESPlorer (i.e. serial/UART) you can't open another serial connection. See https://stackoverflow.com/a/36779799/131929 for details.
Marcel thank you for your answer.
The link posted is not exactly what I need but it offered good info.
I finally came up with this code that works as a simple bridge between putty and a micro controller (arduino mega 2560 in this case)
socket = net.createServer(net.TCP,7200)
socket:listen(23,function(c)
c:on("receive",function(c,l)
uart.write(0, l)
end)
c:on("disconnection",function(c)
-- not yet implemented
end)
uart.on("data", 0,
function(data)
c:send(data)
end, 0)
end)

MQTT / ESP8266 / NodeMCU / Lua code not publishing

I have a problem with the following Lua code on an ESP8266...
function sendData(humidity,temperature)
-- Setup MQTT client and events
print("sendData() entered")
print("Setting up mqtt.Client...")
m = mqtt.Client(mqtt_client_id, 120, username, password)
print("Attempting client connect...")
m:connect(mqtt_broker_ip , mqtt_broker_port, 0, function(conn)
print("Connected to MQTT")
print(" IP: " .. mqtt_broker_ip)
print(" Port: " .. mqtt_broker_port)
print(" Client ID: " .. mqtt_client_id)
print(" Username: " .. mqtt_username)
payload = "Temp: " .. temperature .. " Hmdy: " .. humidity
m:publish("pt/env",payload, 0, 0, function(conn)
print("Going to deep sleep for " .. (DSLEEPTIME/1000) .. " seconds")
node.dsleep(DSLEEPTIME*1000,4)
end)
end)
end
The code is being successfully called with the following...
-- Connect to network
wifi.setmode(wifi.STATION)
wifi.setphymode(wifi_signal_mode)
wifi.sta.config(wifi_SSID, wifi_password)
wifi.sta.connect()
print("Attempting to connect...")
ip = wifi.sta.getip()
if ip ~= nil then
print("Got IP: " .. ip)
print("About to call sendData()...")
sendData(humidity, temperature)
print("Returned from sendData()...")
end
Using ESPlorer I see the following...
Attempting to connect...
Attempting to connect...
Attempting to connect...
Attempting to connect...
Attempting to connect...
Attempting to connect...
Got IP: 192.168.0.39
About to call sendData()...
sendData() entered
Setting up mqtt.Client...
Attempting client connect...
Returned from sendData()...
So it basically enters sendData(...) and I see the output from the line...
print("Attempting client connect...")
...but I never see the logging in the m:connect(...) block such as...
print("Connected to MQTT")
...it seems it simply returns immediately.
The MQTT broker is a Raspberry Pi running Mosquitto and I've tested it with apps on my Android phone and tablet. I get successful publishing / subscription between phone and tablet in both directions.
I'm a Lua novice and only understand the basics of MQTT and I'm at a loss for what's wrong with the m:connect(...) block if anyone can help it would be appreciated.
UPDATE: PROBLEM SOLVED - Apologies for not getting back to this thread sooner. The problem was simply down to the version of Mosquitto I was running on my RPi (which complied to MQTT v3.1). The NodeMCU MQTT library supports MQTT v3.1.1 and is NOT backward compatible. In essence there wasn't very much wrong with my code although I did make some changes - it was simply down to MQTT versions being incompatible.
You didn't tell us what NodeMCU version you use. Warning: do NOT use any of the pre-built 0.9.x binaries available at https://github.com/nodemcu/nodemcu-firmware/releases. Build your own firmware as per http://nodemcu.readthedocs.io/en/dev/en/build/.
I always helps to strip a failing function and to make use of all available callback functions. I can confirm the following works on a nearly 2 months old firmware from the dev branch sending data to cloudmqtt.com:
function sendData(humidity, temperature)
print("Setting up mqtt.Client...")
m = mqtt.Client("SO-36667049", 120, "user", "password")
print("Attempting client connect...")
m:connect("m20.cloudmqtt.com", 12703, 0, 0,
function(conn)
print("Connected to MQTT")
payload = "Temp: " .. temperature .. " Hmdy: " .. humidity
m:publish("topic", payload, 0, 0,
function(client)
print("Message sent")
end)
end,
function(client, reason)
print("Connection failed, reason: " .. reason)
end)
end
Differences:
m:connect defines secure y/n and autoreconnect y/n explicitly. It always confuses me if only a subset of all optional parameters is set. Is your 0 in m:connect interpreted as secure or as autoreconnect? I don't know Lua well enough to tell why I code it explicitly.
Make use of the extra callback for function for failed connection attempts. See http://nodemcu.readthedocs.org/en/dev/en/modules/mqtt/#connection-failure-callback-reason-codes for failure reason codes.
Do NOT use the same name for variables in callback functions as used in "parent" functions. Note how you use m:connect(..., function(conn) and then inside that function you use m:publish(..., function(conn) again. You don't interact with the conn object in your code, so no harm done. However, this may bite you in other projects.
Your code is looking fine. If m:connect fails nothing will happen as you did not provide a callback function for failed connection attempts.
Also you don't check m:connect's return value for success.
Refer to
http://nodemcu.readthedocs.org/en/dev/en/modules/mqtt/#mqttclientconnect
And check if your connection attempt fails.

MQTT on ESP8266 with NodeMCU - problems with publishing

I'm building a battery powered IoT device based on ESP8266 with NodeMCU.
I use mqtt to periodically perform measurements and publish results.
I know, that to allow network stack running, I should avoid tight loops and rely on callback functions. Therefore it seemed to me that the right organization of my measurement code should be:
interval=60000000
function sleep_till_next_sample()
node.dsleep(interval)
end
function close_after_sending()
m:close()
sleep_till_next_sample()
end
function publish_meas()
m:publish("/test",result,1,0,close_after_sending)
print("published:"..result)
end
function measurement()
-- The omitted part of the function accesses
-- the hardware and places results
-- in the "result" variable
m = mqtt.Client("clientid", 120, "user", "password")
m:connect("172.19.1.254",1883,0, publish_meas)
end
The init.lua ensures, that the node has connected to the WiFi AP (if not, it retries up to 20 times, and if no connection is established, it puts the node on sleep until the next measurement time).
After WiFi connection is done, it calls the measurement function.
The interesting thing is, that the above code doesn't work. There are no errors displayed in the console, but the mqtt broker does not receive published messages.
To make it working, i had to add additional idle time, by adding timers in the callback functions.
The finally working code looks like below:
interval=60000000
function sleep_till_next_sample()
node.dsleep(interval)
end
function close_after_sending()
m:close()
tmr.alarm(1,500,0,function() sleep_till_next_sample() end)
end
function publish_meas()
m:publish("/test",result,1,0,function() tmr.alarm(1,500,0,close_after_sending) end)
print("published:"..result)
end
function measurement()
-- The omitted part of the function accesses
-- the hardware and places results
-- in the "result" variable
m = mqtt.Client("clientid", 120, "user", "password")
m:connect("172.19.1.254",1883,0, function() tmr.alarm(1,500,0, publish_meas) end)
end
The above works, but I'm not sure if it is optimal. To conserve the battery power I'd like to minimize the time before the node is put on sleep after the measurement is completed and results published.
Is there any better way to chain the necessary calls to m:connect, m:publish, m:close and finally node.dsleep so, that the results are correctly published in the minimal time?
Perhaps this was solved by more recent firmware. I am working through a problem that I thought might be somewhat explained by this issue, so tried to reproduce the problem as described.
My simplified test code is substantially similar; it calls dsleep() from the PUBACK callback of mqtt.Client.publish():
m = mqtt.Client("clientid", 120, "8266test", "password")
m:lwt("/lwt", "offline", 0, 0)
function main(client)
print("connected - at top of main")
m:publish("someval",12345,1,0, function(client)
rtctime.dsleep(SLEEP_USEC)
end)
end
m:on("connect", main)
m:on("offline", function(client) is_connected = false print ("offline") end)
m:connect(MQQT_SVR, 1883, 0, mainloop,
function(client, reason) print("failed reason: "..reason) end)
and when run, does successfully publish to my MQTT broker.
I am using:
NodeMCU custom build by frightanic.com
branch: master
commit: 81ec3665cb5fe68eb8596612485cc206b65659c9
SSL: false
modules: dht,file,gpio,http,mdns,mqtt,net,node,rtctime,sntp,tmr,uart,wifi
build built on: 2017-01-01 20:51
powered by Lua 5.1.4 on SDK 1.5.4.1(39cb9a32)

Read a filestream (named pipe) with a timeout in Smalltalk

I posted this to the Squeak Beginners list too - I'll be sure to make sure any answers from there get here :)
I'm using Squeak 4.2 and working on the smalltalk end of a named pipe connection, which sends a message to the named pipe server with:
msg := 'Here''s Johnny!!!!'.
pipe nextPutAll: msg; flush.
It should then receive an acknowledgement, which will be a 32-byte md5 hash of the received message (which the smalltalk app can then verify). It's possible the named pipe server may have gone away or otherwise been unable to deal with the request, and so I'd like to set a timeout on reading the acknowledgement. I've tried using this:
ack := [ pipe next: 32 ] valueWithin: (Duration seconds: 3) onTimeout: [ 'timeout'. ].
and then made the pipe server pause artificially to test the code. But the smalltalk thread blocks on the read and doesn't carry on (even after the timeout), although if I then get the pipe server to send the correct response (after a 5 second delay, for example), the value of 'ack' is 'timeout'. Obviously the timeout did what it's supposed to do, but couldn't 'unblock' the blocking read on the pipe.
Is there a way to accomplish this even with a blocking FileStream read? I'd rather avoid a busy wait on there being 32 characters available if at all possible.
This one may come in handy but not on Windows I am afraid.
http://www.samadhiweb.com/blog/2013.07.27.unixdomainsockets.html

SOCKS 5 - Failure behaviour?

I have read the RFC1928 several times and still couldn't understand what a compliant SOCKS 5 server is supposed to reply in case of failure. This doubt comes from the fact that the ATYP, BND.ADDR and BND.PORT fields from a SOCKS reply simply don't make sense if, for instance, a request with an invalid command is received. Must the server not send these fields or just send blanks?
I just red putty source code, and found out that, when there is an error in reply (REP != 0) ATYP is IPv4 (1) BND.ADDR and BND.PORT are all NULL bytes.
I guess this behavior helps developpers to parse requests ?
In a failure reply, only the VER and REP fields are meaningful. The other fields may be present but are not used. You don't even need to look at those bytes unless REP is zero.

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