Plugin Architecture

The architecture of a plugin wrapper's code is flexible. Still, there are some simple requirements and best practices that may guide its code structure.

Required Exports#

A plugin must export a PluginFactory to be used by the Polywrap Client. A PluginFactory is a function that returns a PluginPackageManifest and a factory method that generates an instance of the plugin.

TypeScript Support#

The Polywrap CLI's codegen and build commands will generate a wrap folder containing useful types. The generated types will save you time and energy. You won't have to manually create or update your types every time you change your schema, and your code will have fewer bugs. You can forget about boilerplate code and focus on your plugin's logic. While the types are not strictly required, we recommend them as a best practice.

The generated types include:

Module - An interface containing the methods declared in the plugin's schema
Args_* - An interface for each method, containing the method arguments declared in the schema
Custom Types - An interface for each custom type declared in the schema
manifest - A PluginPackageManifest for the plugin (also useful for JavaScript developers!)

Example#

import { Module, Args_sampleMethod, manifest } from "./wrap"; // imports from generated "wrap" folder

import { PluginFactory } from "@polywrap/core-js"; // plugin must export a PluginFactory

export interface SamplePluginConfig {
  defaultValue: string;
}

export class SamplePlugin extends Module<SamplePluginConfig> { // Plugin inherits from Module
  constructor(config: SamplePluginConfig) {
    super(config);
  }
  public sampleMethod(args: Args_sampleMethod): string { // Plugin method accepts Args_* as sole argument
    return args.data + this.config.defaultValue;
  }
}

export const samplePlugin: PluginFactory<SamplePluginConfig> = ( // exported PluginFactory is used by Polywrap client
  config: SamplePluginConfig
) => {
  return {
    factory: () => new SamplePlugin(config), // factory method produces a Module
    manifest, // imported from ./wrap
  };
};

export const plugin = samplePlugin; // PluginFactory is exported with name "plugin"