Framework API

[jakubkoci]

The goal of this issue is to discuss the design of a high-level framework API consumed by the developer using this library.

As I've been thinking about the framework architecture I see it consisting of the following parts/areas:

• Core Functionality
• Pluggable Protocols
• Pluggable Storage

Core Functionality

• providing crypto services: packing/unpacking messages, signing and verifying signatures, generating and storing keys
• dispatching inbound messages, responding and sending outbound messages via a specified transport layer
• emit events about protocol state changes (EventEmitter, Observable, ...) or any other mechanism allowing to react on state updates (aca-py emits event about every protocol state change), but developer should not be enforced to use events listener in her app
• executing commands (acceptInvitation, provision, downloadMessages, sendMessageToConnection, creating credential, ...)

Plugable Protocols

The idea is to be able to add/remove protocols which developer want to use without changing the core framework part (open-close principle)

...

Plugable Storage

...

API

Framework functionality should be provided via an instance of Agent class:

const agent = new Agent(...)

When a developer creates such instance, then she can access modules. Modules works like facade around similar features of the framework:

agent.connections.createConnection()
agent.connections.acceptInvitation(...)

agent.routing.provision(...)
agent.routing.downloadMessages(...)

...

A module can also provide an event emitter:

agent.connections.events.on('newState', connection => { ... })

Other parts of the framework should be hidden and ideally not possible to export and use outside.

NOTE: This description is still in progress, I'll put some updates soon.