api/packages/rpc-provider/test/mockWs.ts

// Copyright 2017-2021 @polkadot/rpc-provider authors & contributors
// SPDX-License-Identifier: Apache-2.0

import { Server, WebSocket } from 'mock-socket';

import { stringify } from '@polkadot/util';

interface Scope {
  body: { [index: string]: Record<string, any> };
  requests: number;
  server: Server;
  done: any;
}

interface ErrorDef {
  id: number;
  error: {
    code: number;
    message: string;
  };
}

interface ReplyDef {
  id: number;
  reply: {
    result: unknown;
  };
}

global.WebSocket = WebSocket;

export const TEST_WS_URL = 'ws://localhost:9955';

// should be JSONRPC def return
function createError ({ error: { code, message }, id }: ErrorDef): any {
  return {
    error: {
      code,
      message
    },
    id,
    jsonrpc: '2.0'
  };
}

// should be JSONRPC def return
function createReply ({ id, reply: { result } }: ReplyDef): any {
  return {
    id,
    jsonrpc: '2.0',
    result
  };
}

// scope definition returned
export function mockWs (requests: ({ method: string } & ErrorDef)[], wsUrl: string = TEST_WS_URL): Scope {
  const server = new Server(wsUrl);

  let requestCount = 0;
  const scope: Scope = {
    body: {},
    done: (): void => {
      server.stop((): void => {
        // ignore
      });
    },
    requests: 0,
    server
  };

  server.on('connection', (socket): void => {
    // FIXME This whole any mess is a mess
    socket.on('message', (body: any): void => {
      const request: any = requests[requestCount];
      // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment,@typescript-eslint/no-unsafe-member-access
      const response: any = request.error
        ? createError(request)
        : createReply(request);

      // eslint-disable-next-line @typescript-eslint/no-unsafe-assignment,@typescript-eslint/no-unsafe-member-access
      scope.body[request.method] = body;
      requestCount++;

      socket.send(stringify(response));
    });
  });

  return scope;
}