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tintin:gmcp_setup [2023/04/19 22:39] – created ipeixtintin:gmcp_setup [2023/04/20 08:15] (current) – Added latency example script ipeix
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 } }
 </code> </code>
 +With this alias we can send GMCP commands like this: ''gmcp Core.Ping''
 +
 +===== Enable GMCP =====
 +
 +When the client connects to the server, there is a telnet level negotiation of capabilities. Amongst many options the server will "ask" the client if it supports GMCP. To handle this, we need to create a telnet event and respond with some basic information
 +
 +<code>
 +#EVENT {IAC WILL GMCP}
 +{
 +    #NOP Enable GMCP
 +    #SEND {$telnet[iac]$telnet[do]$telnet[gmcp]};
 +    
 +    #NOP Send some information about the client
 +    gmcp core.hello {"client":"$info[SYSTEM][CLIENT_NAME]","version":"$info[SYSTEM][CLIENT_VERSION]"};
 +    
 +    #NOP Notify the server about supported packages
 +    gmcp core.supports.set ["Room 1","Room.Info 1","Char 1","Char.Items 1","Char.Vitals 1","Char.Status 1"];
 +}
 +</code>
 +
 +From this moment forward, the server will send us GMCP messages. To see these messages, turn on telnet debugging with:
 +<code>
 +#CONFIG {DEBUG TELNET} {ON}
 +</code>
 +Example debug output:
 +<code>
 +RCVD IAC SB GMCP
 +SKIP SB (3)
 +RCVD IAC SB GMCP
 +SKIP SB (529)
 +RCVD IAC SB GMCP
 +IAC SB GMCP Room.Info IAC SE
 +</code>
 +The last line from the output is exactly the name of the event we are going to create to handle information the server sends
 +
 +===== Handling events =====
 +
 +Knowing the events we are  interested in from debugging telnet, now we can create events and process the information as we see fit
 +<code>
 +#EVENT {IAC SB GMCP Room.Info IAC SE} {
 +    #VAR roominfo {%1};
 +}
 +</code>
 +All GMCP events have the first argument ''%1'' set to a value that can be used directly in a variable. The second argument ''%2'' is a JSON that can be used with a 3rd party script.
 +
 +Room info example:
 +<code>
 +#VARIABLE {roominfo}
 +{
 +    {area} {giedi prime}
 +    {environment} {outdoors}
 +    {exits}
 +    {
 +        {east} {9c5db8bd76cc853faa53631e9d1a4928}
 +        {north} {66a833124afab82ce30f5b3b975bf6ef}
 +        {northeast} {86830bfbf2ab8212807525ca2fbd63dc}
 +        {northwest} {c6d0904a9303b3fd26a8db4d6b84956e}
 +        {south} {2d87f8f423954bbc65b9bc6cbf414b81}
 +        {southeast} {797d375df742b54e1cf72e02ce7cf2b9}
 +        {southwest} {27c28b1106b01e1119a3b4069b0fce4d}
 +        {west} {c07dbd96d862f9d2b5bbc5591bd2d539}
 +    }
 +    {name} {Giedi Prime Astro Port}
 +    {num} {b6c8cc8712e0e855ab4702574e5b8e6d}
 +}
 +</code>
 +
 +===== GMCP Events =====
 +
 +Some event names and what they might return
 +
 +| Char.Vitals | { "string": "H:4197\/3735 M:1097\/1032", "maxsp": 1032, "maxhp": 3735, "hp": 4197, "sp": 1097 } |
 +| Char.Name | { "fullname": "Fufa the inexperienced Reverend Mother", "name": "fufa" } |
 +| Char.Stats | { "con": 109, "wis": 119, "int": 60, "dex": 116, "qui": 118, "str": 114 } |
 +| Char.MaxStats | { "maxstr": 92, "maxqui": 96, "maxdex": 97, "maxint": 43, "maxwis": 100, "maxcon": 92 } |
 +
 +There are a lot more and as always you can enable even more by tweaking the package names in ''core.supports.set'' (keep in mind that they need to be enabled/implemented on the server also)
 +
 +===== Examples =====
 +=== Latency checker ===
 +A rough Round Trip Time measurement for network latency in milliseconds based on Core.Ping GMCP command
 +<code>
 +#ALIAS {latency} {
 +    #FORMAT {LATENCY_TIME_SENT} {%U};
 +    gmcp Core.Ping;
 +}
 +
 +#EVENT {IAC SB GMCP Core.Ping IAC SE} {
 +    #FORMAT {LATENCY_TIME_EVENT} {%U};
 +    #MATH {LATENCY_TIME_TRIP} {($LATENCY_TIME_EVENT-$LATENCY_TIME_SENT)/1000};
 +    #SHOWME {Latency: ${LATENCY_TIME_TRIP}ms}
 +}
 +</code>
 +
 +| Usage | Output |
 +| ''latency'' | ''Latency: 263ms'' |
 +
 +Happy Scripting!
 +