CCats/Client-Server Protocol.md

Client-Server Protocol

1. Start a connection

To start a connection you have to check the versions, generate the sessonID and verify the login. Only if step 1.1 is accomplished and the sessionID of the client was valid or if step 1.1 and 1.2 have been accomplished a usable connection is negotiated.

1.1 Version check

Client:

{
	"version": string,
	"sid": string
}

Only sends sid if client has an old sessionID.

Server:

{
	"version": string,
	"accept": bool,
	"sid": string
}

If accept is true the connection is valid. Else the connection will be terminated. sid can be set if accept is true and must be set if the sid of the client is invalid. So the server gives a new sid if the session is invalid. The server can as well use no sid. If the server forbids sids but the client is offering one then the connection is to be immediately closed!

1.2 Login

Client:

{
	"user": string,
	"pass": string,
	"sid": string
}

Server:

{
	"accept": bool
}

If accept is true the connection is valid and the user is logged in. Else the connection will be terminated. The server is not obligated to send sid back.

2. Sending commands

Commands can be sent by the client after a connection has been negotiated (See 1). Commands can be used unrelated to each other.

2.1 Status command

Client:

{
	"command": "status"
}

Server:

{
	"command": "status",
	"response": string
}

TODO

3. Close connection

3.1 Close command

Client:

{
	"command": "close",
	"remembersID": bool
}

remembersID is optional. If it's true then the sID shall be remembered by the server. Else it shall be forgotten.

Server:

{
	"command": "close",
	"response": "bye"
}