The Taho Background package can effectively be considered the background script for the Taho extension. It is designed to connect to external data providers including Ethereum nodes, as well as specific providers like Alchemy and Blocknative that may enable specific functionality beyond the standard node functions. It constructs a data model in the form of a Redux store, which is then synchronized to any consumer via a proxy store using functionality in the webext-redux library.
The API package is structured roughly using the Event
Sourcing architectural
pattern. At startup, the startApi function triggers the creation of a set of
services. Services in turn monitor their various data sources and
emit events with updates. They also manage snapshots of their own state,
persisted to the extension's IndexedDB (using Dexie
tables).
Events that affect UI rendering are dispatched as actions on the redux store,
which in turn updates its own internal aggregate state. The redux state is
handled using slices, as implemented by Redux
Toolkit. The wiring between events and redux
store is done in the Main class, which is instantiated in
startApi.
The following diagram describes the flow of data and events at a high level:
┌────────────────────────────────────────────────────────────────────────────────────┐
│ ____ _ _ │
│ | __ ) __ _ ___| | ____ _ _ __ ___ _ _ _ __ __| | │
│ | _ \ / _` |/ __| |/ / _` | '__/ _ \| | | | '_ \ / _` | │
│ | |_) | (_| | (__| < (_| | | | (_) | |_| | | | | (_| | │
│ |____/ \__,_|\___|_|\_\__, |_| \___/ \__,_|_| |_|\__,_| │
│ |___/ │
│ │
│ ┌────────────┐ │
│ │ │ │
│ ┌─────events───────▶│ Main │─────────actions──────┐ │
│ │ │ │ │ │
│ ┌──────────────────┐ └────────────┘ │ │
│ │ │ │ ▲ ▼ │
│ │ Services │ │ │ ┌───────────────────────┐ │
│ │ │ │ │ │ │ │
│ └──────────────────┘ │ │ │ Redux │ │
│ ▲ │ │ │ │ │
│ │ │ │ events │ ┌───────────────────┐ │ │
│ └─────forwarded events───┘ └───────────────│ │ │ │ │
│ │ │ Store │─┼──┼────────┐
│ │ │ │ │ │ │
│ │ └───────────────────┘ │ │ │
│ └───────────────────────┘ │ │
│ ▲ │ │
└─────────────────────────────────────────────────────────────────────┼──────────────┘ │
│ │
proxy actions │
│ data
┌─────────────────────────────────────────────────────────────────────┼──────────────┐ synchronization
│ _ _ ___ │ │ │
│ | | | |_ _| ┌───────────────────────┐ │ │
│ | | | || | │ │ │ │
│ | |_| || | ┌────────standard redux data────────────│ Redux │ │ │
│ \___/|___| │ │ │ │ │
│ ▼ │ ┌───────────────────┐ │ │ │
│ ┌────────────────────┐ │ │ │ │ │ │
│ │ │ │ │ Proxy Store │◀┼──┼────────┘
│ │ React Components │ │ │ │ │ │
│ │ │ │ └───────────────────┘ │ │
│ └────────────────────┘ └───────────────────────┘ │
│ │ ▲ │
│ │ │ │
│ └────────────standard redux actions─────────────────┘ │
│ │
│ │
│ │
└────────────────────────────────────────────────────────────────────────────────────┘
Network communication is central to the functionality of a web3 wallet. Due to the complexity of handling multiple concurrent network connections, we try to attribute networks (through variable and method naming) in the following way:
- Supported Network: A network that the extension is able to track
- Tracked Network: A network that the extension is tracking or has ever tracked.
- Active Network: A network that the extension is actively tracking / listening to.
- Current Network: The network that a given dapp (or the internal wallet) is connected to.
The only public API of the Taho Background package is what is exported directly on
index.ts. No submodule API is considered public, and all such
APIs are subject to arbitrary change without warning. Any API from a child
module that is meant for public consumption is re-exported in index.ts.
We use ajv for data validation and most of the time the JTD schema definition. These are useful links to get up to speed w/ JTD quickly
- https://github.com/ajv-validator/ajv/blob/master/spec/types/jtd-schema.spec.ts - jtd unit tests
- https://ajv.js.org/json-type-definition.html - jtd spec ajv
- https://jsontypedef.com/docs/jtd-in-5-minutes/ - jtd in 5 mins
- https://ajv.js.org/guide/typescript.html - using with ts
- https://github.com/jsontypedef/homebrew-jsontypedef - jtd tooling