neume-network-strategies

purpose

The goal of this repository and the overall idea of separating neume-network-core's source from its strategies, is to allow any type of music platform to quickly define their on-chain schema - allowing them to re-use neume-network-core to index and distribute their and other platform's music ecosystem.

installation and contributing

It's best to install the strategies repository via neume-network/core as npm i will download the submodule and install its dependencies
To run the tests via npm run test a properly set up .env is necessary. We recommend softlinking from core's .env file using ln

implementing new strategies

Checkout the quickstart guide for a in-depth walkthrough.

high-level checklist for implementation

Any external request message passed to @neume-network/extraction-worker must result in an idempotent response (aka. if the request is repeated the same result must be returned).
Extraction of information from external requests must not be coupled to e.g. transformation of responses. It must be possible to run transformation independently from e.g. extraction.
Request patterns should be scoped through e.g. time or block periods.

To implement a strategy with maximum efficiency, we recommend doing all on-chain and off-chain requests using the extraction Worker API.

extractor strategy interface definition

An extractor strategy must implement the following interface:

interface Extractor {
  name: String;
  props: Object;
  init(args...): Object<messages:  Message[], write: String>;
  update(message: Message): Object<messages: Message[], write: String>;
}

Where Message is defined as any JSON object compliant to the definitions in neume-network/message-schema.

A neume-network extraction message is layed out similarly to a react.js component in that foundamentally, it is a component implementing lifecycle methods.

A component has props as in "properties" that can be defined before instantiation of the component.
The init function is called when the component is mounted into the core process.
Upon completion of the init task, update is called until update's returned messages list is empty.

Below is a visual overview of a neume-network extractor component's lifecycle.

transformer strategy interface definition

A transformer strategy must implement the following interface:

interface Transformer {
  name: String;
  onLine(line: String): Object<messages:  Message[], write: String>;
  onError(error: Error): any;
  onClose(): Object<messages:  Message[], write: String>;
}