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Sockets = fail
Posted: Wed Apr 19, 2017 8:34 pm
by BobM
I am attempting to use sockets using the sample client and server stacks here: [forum won't let me post links!]
Stacks and code can be seen [forum won't let me post links!]
I am having exactly zero success, and because it seems that almost nothing happens on the server side I can't even begin to debug things.
Code: Select all
accept connections on port 9001 with message "someoneConnected"
As near as I can tell the message someoneConnected never gets sent.
Modifying the code a bit
Code: Select all
accept connections on port 9001 with message "someoneConnected"
put the opensockets
returns 9001 in the message box.
on the client side put the opensockets returns the full IP:port of the expected socket.
hardware is two laptops both running linux mint hanging on the same switch.
Firewalls are fully permissive, and each can connect to the other with Nemo.
The sample stacks appear to me to be fully consistent with the official lesson at [forum won't let me post links!]
I welcome any constructive suggestions about what to look at to help troubleshoot.
Re: Sockets = fail
Posted: Wed Apr 19, 2017 8:49 pm
by Klaus
Hi Bob,
1. welcome to the forum!
2. There is really no need for creating a report for your simple question!
Due to high spam traffic, you need to have at least 10 postings before you can post links and create attachments etc.
Hint:
Add a SPACE or something so the forum software cannot recognize your URL as such!
3. What version of LC are you using?
4. What did you script on the client side?
Best
Klaus
Re: Sockets = fail
Posted: Wed Apr 19, 2017 9:07 pm
by BobM
Attempted various mutations of link URLs without success.
on the client side:
where servAddr is a.b.c.d:9001
and a.b.c.d is the hostNameToAddress of the hostName from the server
LC v 8.1.3 community edition
Re: Sockets = fail
Posted: Wed Apr 19, 2017 9:10 pm
by Klaus
I'm not an expert at socket communication stuff, but did you actually write something to the socket on the client side?
I think only that will trigger the message "someoneConnected".
Re: Sockets = fail
Posted: Thu Apr 20, 2017 7:49 am
by AxWald
Hi,
from a running socket solution:
Server:
Code: Select all
accept connections on port gPort with message "ServerClientConnected"
...
on ServerClientConnected pSocket
put pSocket & return after gSockets
put "You're welcome!" into MyMsg
write "CON OK, " & length(MyMsg)& return & MyMsg to socket pSocket
read from socket pSocket until return with message "ServerMessageReceived"
...
Client:
Code: Select all
open socket to pServer & ":" & kPort with message "ClientConnected"
...
on ClientConnected pSocket
put pSocket into sSocket
read from socket sSocket with message "ClientMessageReceived"
...
on ClientSend
if sSocket is not empty then
Put the theCMD of this stack & "," & length(fld MyText) & return & fld MyText into myVar
write MyVar to socket sSocket
...
Runs flawlessly on Win XP and newer, LC in various v6 flavors.
Have fun!
Re: Sockets = fail
Posted: Thu Apr 20, 2017 8:29 pm
by BobM
Thank you AxWald
Based on your example, I have:
Code: Select all
Server:
on mouseUp #Button StartServer
close socket 9000
put empty into field "text"
accept connections on port 9000 with message "someoneConnected"
put the opensockets after field "text"
end mouseUp
on openCard
put the hostNameToAddress of the hostName into theAddr
set the itemDelimiter to return
put (item 1 of theAddr) into the field "serverAddr"
end openCard
on someoneConnected theirSocket
put theirSocket intofield"ClientID"
Write "Server got your message" to socket theirSocket
read from socket theirSocket until return with message "newMessage"
end someoneConnected
on newMessage theirSocket theMessage
put theirSocket & ":" && theMessage & returnafterfield"text"
read from socket theirSocket until return with message "newMessage"
end newMessage
and
Code: Select all
Client:
on mouseup #Button Connect
open socket to field "serverAddr" with message "ClientConnected"
end mouseUp
on ClientConnected pSocket
put pSocket into field "ConfirmServer"
read from socket pSocket with message "ClientMessageReceived"
end ClientConnected
on ClientMessageReceived
answer "Something was received"
end ClientMessageReceived
on mouseUp #Button Send
write field "message" & return to socket field "ServerAddr"
end mouseUp
This does not work.
Here is what happens.
On the Server.
on mouseUp #Button StartServer
close socket 9000
put empty into field "text"
accept connections on port 9000 with message "someoneConnected"
---> the message someoneConnect is not sent
put the opensockets after field "text"
-->the field "text" displays 9000
end mouseUp
On the Client.
on ClientConnected pSocket
put pSocket into field "ConfirmServer"
--->the full socket name IP:Port is place into the field
read from socket pSocket with message "ClientMessageReceived"
---> message never sent
end ClientConnected
Interestingly (to me at least) is that the message "ClientConnected" is sent even if the client computer is not connected to the network.
I don't know how to troubleshoot from here because nothing else happens. Suggestions welcome.
Re: Sockets = fail
Posted: Fri Apr 21, 2017 2:56 pm
by BobM
Looking at this in more detail:
LiveCode Language Dictionary
callbackMessage The name of a message to be sent when the connection is made.
Yet on my client laptop this line completes and sends the "ClientConnected" message
open socket to field "serverAddr" with message "ClientConnected"
Even when the client laptop has no connections to anything. WiFi off. Network cable unplugged.
It is clearly impossible for a connection to be made from a laptop that has no connectivity.
Why is the callbackMessage sent?
Re: Sockets = fail
Posted: Fri Apr 21, 2017 4:21 pm
by BobM
Solved:
the hostNameToAddress of the hostName
is expected to return the IPv4 address of the computer.
On Linux Mint it does NOT. [confirmed bug 5909 {unresolved in 9 years!
}]
Socket communication working correctly when correct IPv4 address is used with open socket to.