mqtt web sockets code publish.single(topic, payload,....does not work.

The example code

Publish Using WebSockets in Python on a Raspberry Pi

https://au.mathworks.com/help/thingspeak/use-raspberry-pi-board-that-runs-python-websockets-to-publish-to-a-channel.html

does not work.

my python 3 code executes to the last line of the ThingSpeak example code

print ("There was an error while publishing the data.")

I have been successfully using the same channelID, writeAPIKey and mqttAPIKey with a Arduino for some time using code at

https://au.mathworks.com/help/thingspeak/use-arduino-client-to-publish-to-a-channel.html

How do do I identify the error with the web sockets publish code.

try:

publish.single(topic,payload,...

i can print on Terminal the topic and payload strings. they appear correct.

[Barnard Richards]

My python3 code now executes without error. But there is no data being published on my channel.

[Barnard Richards]

Now getting channel updates.

Why does the example code sometimes use

channelID = "<YOUR-CHANNEL-ID>"

and other times

mqttAPIKey = "XXXXXXXXXXXXXXXX" without < >

What is the purpose of using < and > for some strings?

My code does not publish if I use < > to enclose my strings

[Graham Coulby]

You probably already figured this out by now, but generally when you see <> in strings on APIs it means a placeholder. Therefore you must replace the string in the documentation (including the <>) with what is specified inside the <>:

e.g.:

If it states

channelID = "<YOUR-CHANNEL-ID>"

This becomes:

channelID = "1234567".

Did you ever get data on your channel? My arduino connects, and even publishes the message the payload without error to what appears to be the correct topic /channels/<channel_id>/publish/<channel_write_api>. However, no data is received on the channel.

[Barnard Richards]

Graham, You are correct my Rasp Pi connects and uploads correctly.

I am also uploading from a couple of Arduino MKR1010 successfully.