José Magalhães asked 3 years ago
Hi there!
I’m trying to learn Micropython from your book: MicroPython_Programming_with_ESP32_and_ESP8266_V1_2. I’d like some questions cleared if possible:
. page 159, line “conn, addr = s.accept() “
I believe you are creating two variables: conn and addr, the first being a new socket for connecting to the client, however I don’t understand how it is populated. The addr variable I believe to be the ip address of the client returned by s.accept()
.page160, line: “ print(‘Got a connection from %s’ % str(addr))
I get the client ip address printed in the terminal followed by a , and another number
the %s is a string defined by %str(addr) portion? right?
what is the other number printed on the terminal after the ip address?
Thanks in advance, sorry for my “noobness”
Sara Santos Staff answered 3 years ago
Hi.
That method returns two variables. Here’s the description from the documentation:
socket.accept()
“Accept a connection. The socket must be bound to an address and listening for connections. The return value is a pair (conn, address) where conn is a new socket object usable to send and receive data on the connection, and address is the address bound to the socket on the other end of the connection.” https://docs.micropython.org/en/latest/library/usocket.html#usocket.socket.accept
As for the other question. I’m not really sure what the number that follows the IP address means. Is it different for each connection, right? I think it is a unique number used to identify the connection.
I’m sorry that I can’t help much.
Regards,
Sara
José Magalhães answered 3 years ago
You have been most helpful. Thanks a lot.
By the way the %s is a string defined by %str(addr) portion? Or is it related to the socket variable s?
Sara Santos Staff answered 3 years ago
Hi again.
Yes. The %s is the string you get from the %str(addr).
The %s is like a placeholder for a string. At the end of the print() function, after the %, we insert what we want to replace the placeholder with.
I hope this is clear.
Regards,
Sara