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How to create and manage plugins

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Please note that this content is under development and is not ready for implementation. This status message will be updated as content development progresses.

Create a new plugin​

Step 1: Init a new package​

First, you need to navigate to project-vckit/packages and init a new package. In this guide, we implement a new plugin for hashing a string.

Step 2: Define the plugin interface​

Navigate to packages/core-types/src/types, create a new file and name it Itools (this is just an example). This interface extends IPluginMethodMap interface, and has a method computeHash with a string parameter.

import { IAgent, IPluginMethodMap } from './IAgent.js';

/**
 * @public
 */
export interface IToolsComputeHashArgs {
  content: string;
}

/**
 * @public
 */
export interface ITools extends IPluginMethodMap {
  computeHash(
    args: IToolsComputeHashArgs,
    context: { agent?: IAgent },
  ): Promise<string>;
}

Step 3: Implement the plugin​

Creating a new plugin means implementing the IAgentPlugin interface.

Example code of the Hash Tool:

import { IAgentPlugin, ITools, IToolsComputeHashArgs } from '@vckit/core-types';
import { sha256 } from 'multiformats/hashes/sha2';
import { base58btc } from 'multiformats/bases/base58';
import schema from '@vckit/core-types/build/plugin.schema.json' assert { type: 'json' };

export class MultibaseEncodedSHA256 implements IAgentPlugin {
  readonly methods: ITools;
  readonly schema = schema.ITools;

  constructor() {
    this.methods = {
      computeHash: this.computeHash.bind(this),
    };
  }

  async computeHash(args: IToolsComputeHashArgs): Promise<string> {
    if (
      typeof args !== 'object' ||
      !args?.content ||
      typeof args?.content !== 'string'
    ) {
      throw new Error('Value is invalid');
    }

    const bytes = new TextEncoder().encode(args.content);
    const hash = await sha256.digest(bytes);
    const multibasedHash = base58btc.encode(hash.bytes);
    return multibasedHash;
  }
}

There're 2 properties of the class are required, both of them are from @vckit/core-types:

  • methods
  • schema

Manage plugin within agent file​

As you may know, working with VCkit is all about the agent. If you have your custom plugin and want to use it as an extended function then you need to add it to the agent. Here's how to do it.

Step 1: Add the plugin to agent.yml​

Open the agent.yml file, and add this line - $require: '@vckit/tools#MultibaseEncodedSHA256' at the end of the agent. The updated agent will look like this.

# Agent
agent:
  $require: '@veramo/core#Agent'
  $args:
    plugins:
        ...
        # Add tools plugin for MultibaseEncodedSHA256
        - $require: '@vckit/tools?#MultibaseEncodedSHA256'

Step 2: Expose the method.​

Under constants > methods, and the new method from the plugin. Example: we expose the computeHash method at the end of the methods.

constants:
  methods:
    ...
    # Add method for MultibaseEncodedSHA256
    - computeHash

Now you can build the project-vckit and start the VCkit api server and test the new plugin.