[Freeciv] Re: play by email version

[John Allman <allmanj@xxxxxxxxxxxxxxxxxx>]

Jason Short wrote:

>I had a few thoughts on what would be needed for such an
>implementation.  But then I ran into a wall, and I'm sure in any case
>there are many things I haven't thought of.
>
>I assume we want to be sending one e-mail per player per turn.  This
>e-mail is sent to the server, which also receives every other player's
>emails and sends an e-mail back to each player.
>  
>
First off, thanks for your response. You've clearly put some time into 
considering this! I'm just a little concerned by the way you said "sent 
to the server". The way i'm envisioning such a system is that any email 
server could collect the "turn files". Once all files are collected for 
a round they could be then processed in bulk by a server. All the server 
would need would be the current game state and the turn files and it 
would only ever need to be run once per turn. It would produce "update 
files" explaining the new state to the clients. Scripts for automating 
this could be made for each particular setup, but i think the idea of 
keeping the email server completely seperate from the game server is 
important both for security (i wouldn't like to write an email server, 
even a minimal one from scratch - i'd be far too wary of introducing a 
backdoor) and for convenience (you could run your game server on a dial 
up machine if you wanted - no need to be permanently connected to the 
internet).

I'm guessing that's what you were thinking of yourself (certainly that's 
the way most play by email games work) but i just wanted to make sure!

>There are two things this implementation would need:
>
>1. Change the network protocol to deal with binary files that can be
>emailed rather than a continuous stream.
>
>2. Extend client functionality & change game rules so that the server
>and client don't need to communicate at all *during* a turn.  This is
>assuming one email per turn will be sent.
>
>
>#1 should be pretty easy; the dataio code just needs to be extended. 
>Basically, we still do have a continuous stream of data - it's being
>sent in e-mail rather than through TCP.
>  
>
Sounds good:)

>
>#2 would be much harder.  To begin with, nobody can make moves during
>the turn - we'd need something like the proposed goto-at-end-of-turn
>system where everyone enters goto moves and the server processes them
>all at the end of the turn.
>
>But this is just the beginning.  Currently almost every player action
>involves the client sending a packet to the server and receiving another
>packet in return.  Here the return packet needs to be cut out.  In most
>cases this just means the client needs to know more about the game
>logic.
>  
>
Ah - now again i dont know too much about the internal workings of the 
game. Each action in a turn alters the games state? So action A by 
client 1 before action B by client 2 could produce a different result 
than action B before action A? This indeed is a problem. As far as i 
understand it, most pbem games are processed in stages. A moving stage, 
a constructing stage, an attack stage or whatever. The system is 
designed so that the order in which actions were taken during a turn 
makes no difference. Clearly this could be a real problem for making a 
pbem version of freeciv. I'd really need to know more about how actions 
are processed by the server before i could say more though...

>
>My question is, what is the point?  The only advantage I can see to
>play-by-email is that a direct connection to the server is not
>required.  But the implementation would have many spin-off benefits from
>reduced lag effects.
>
>jason
>
The point would be 1) that you wouldn't need to have a server 
permanently connected to the internet, 2) you wouln't need to all be 
online at the same time to take your turns 3) firewalls wouldn't be an 
issue and 4) everything else i cant think of off the top of my head:)

Realistically a pbem version of the game would possibly be a little 
different than the current version of freeciv. As i understood it 
freeciv was a true turn based game, in which case it should lend itself 
very easily to becoming a pbem game. Maybe somebody could point me to a 
place where i could gain a better understanding of the internal workings 
of the game and how client actions are processed? I feel freeciv as a 
pbem game would be a great feature and would love to see it integrated 
into freeciv as opposed to becoming a code fork.

If anyone is willing to help i'd be more than willing to put time and 
effort into trying to see how feasible this really is.

Thanks

PS: Again please CC me in any replies!