cchat

A set of stabilized interfaces for cchat implementations, joining the backend and frontend together.

Backend

Methods implemented by the backend that have frontend containers as arguments can do IO. Frontends must NOT rely on individual backend caches and should always assume that they will block.

Note: IO in most cases usually refer to networking, but they should files and anything that could block, such as mutexes or semaphores.

Service

A service is a complete service that's capable of multiple sessions. It has to implement the Authenticate() method, which returns an implementation of Authenticator.

A service can implement SessionRestorer, which would indicate the frontend that it can restore past sessions. Sessions are saved using the SessionSaver interface that Session can implement.

A service can also implement Configurator if it has additional configurations. The current API is a flat key-value map, which can be parsed by the backend itself into more meaningful data structures. All configurations must be optional, as frontends may not implement a configurator UI.

Interfaces

• SessionRestorer (optional)
• Configurator (optional)
• Icon (optional)

Authenticator

The authenticator interface allows for a multistage initial authentication API that the backend could use. Multistage is done by calling AuthenticateForm then Authenticate again forever until no errors are returned.

Reference Implementation

var s *cchat.Session
var err error

for {
	// Pseudo-function to render the form and return the results of those forms
	// when the user confirms it.
	outputs := renderAuthForm(svc.AuthenticateForm())

	s, err = svc.Authenticate(outputs)
	if err != nil {
		renderError(errors.Wrap(err, "Error while authenticating"))
		continue // retry
	}

	break // success
}

Session

A session is returned after authentication on the service. Session implements Name(), which should return the username most of the time. It also implements UserID(), which might be used by frontends to check against MessageAuthor.ID() and other things.

A session can implement SessionSaver, which would allow the frontend to save the session into its keyring at any time. Whether the keyring is completely secure or not is up to the frontend. For cchat-gtk, that would be using the Gnome Keyring daemon.

Interfaces

• ServerList
• Icon (optional)
• Commander (optional)
• SessionSaver (optional)

Commander

The commander interface allows the backend to implement custom commands to easily extend the API.

Interfaces

• CommandCompleter (optional)

Identifier

The identifier interface forces whatever interface that embeds this one to be uniquely identifiable.

Configurator

The configurator interface is a way for the frontend to display configuration options that the backend has.

Server

A server is any entity that is usually a channel or a guild.

Interfaces

• ServerList and/or ServerMessage
• ServerNickname
• Icon (optional)
• ServerMessageEditor
• ServerMessageActioner

ServerMessage

A server message is an entity that contains messages to be displayed. An example would be channels in Discord and IRC.

Interfaces

• ServerMessageSender (optional): adds message sending capability.
• ServerMessageSendCompleter (optional): adds message completion capability.

Messages

Interfaces

• MessageHeader: the minimum for a proper message.
• MessageCreate or MessageUpdate or MessageDelete
• MessageNonce (optional)
• MessageMentionable (optional)

MessageAuthor

MessageAuthor is the interface that a message author would implement. ID would typically return the user ID, or the username if that's the unique identifier.

Interfaces

• MessageAuthorAvatar (optional)

Frontend

Frontend contains all interfaces that a frontend can or must implement. The backend may call these methods any time from any goroutine. Thus, they should be thread-safe. They should also not block the call by doing so, as backends may call these methods in its own main thread.

It is worth pointing out that frontend container interfaces will not have an error handling API, as frontends can do that themselves. Errors returned by backend methods will be errors from the backend itself and never the frontend errors.

Most functions that take in frontend containers will return a callback as a cancel function.

ServersContainer

A servers container is any type of view that displays the list of servers. It should implement a SetServers([]Server) that the backend could use to call anytime the server list changes (at all).

Typically, most frontend should implement this interface onto a tree node instead of a tree view, as servers can be infinitely nested.

This interface expects the frontend to handle its own errors.

MessagesContainer

A messages container is a view implementation that displays a list of messages live. This implements the 3 most common message events: CreateMessage, UpdateMessage and DeleteMessage. The frontend must handle all 3.

Since this container interface extends a single Server, the frontend is allowed to have multiple views. This is usually done with tabs or splits, but the backend should update them all nonetheless.

LabelContainer

A label container is a generic abstraction for any container that can hold texts. It's typically used for labels that can update itself, such as usernames.

SendableMessage

The frontend can make its own send message data implementation to indicate extra capabilities that the backend may want.

An example of this is MessageNonce, which is similar to IRCv3's labeled response extension. The frontend could implement this interface and check if incoming MessageCreate events implement the same interface.

Interfaces (only known)

• MessageNonce (optional)