actionhero/src/initializers/connections.ts

The reusable, scalable, and quick node.js API server for stateless and stateful applications

import { api, redis, Initializer, Connection } from "../index";

/**
 * ```js
 *var connectionMiddleware = {
 *name: 'connection middleware',
 *priority: 1000,
 *create: (connection) => {
 *  // do stuff
 *},
 *destroy:(connection) => {
 *  // do stuff
 *}
 *}
 * ```
 */
export interface ConnectionMiddleware {
  /**Unique name for the middleware. */
  name: string;
  /**Module load order. Defaults to `api.config.general.defaultMiddlewarePriority`. */
  priority?: number;
  /**Called for each new connection when it is created. Connection is passed to the event handler*/
  create?: Function;
  /**Called for each connection before it is destroyed. Connection is passed to the event handler*/
  destroy?: Function;
}

export interface ConnectionsApi {
  connections: {
    [key: string]: Connection;
  };
  middleware: {
    [key: string]: ConnectionMiddleware;
  };
  globalMiddleware: Array<string>;
  allowedVerbs: Array<string>;
  cleanConnection: Function;
  apply: (
    connectionId: string,
    method?: string,
    args?: any
  ) => Promise<Connection>;
  addMiddleware: (ConnectionMiddleware) => void;
}

export class Connections extends Initializer {
  constructor() {
    super();
    this.name = "connections";
    this.loadPriority = 400;
  }

  async initialize(config) {
    api.connections = <ConnectionsApi>{
      connections: {},
      middleware: {},
      globalMiddleware: [],

      allowedVerbs: [
        "quit",
        "exit",
        "documentation",
        "paramAdd",
        "paramDelete",
        "paramView",
        "paramsView",
        "paramsDelete",
        "roomAdd",
        "roomLeave",
        "roomView",
        "detailsView",
        "say",
      ],

      /**
       * Find a connection on any server in the cluster and call a method on it.
       */
      apply: async (connectionId: string, method: string, args: any) => {
        return redis.doCluster(
          "api.connections.applyResponder",
          [connectionId, method, args],
          connectionId,
          true
        );
      },

      applyResponder: async (connectionId, method, args) => {
        const connection: Connection =
          api.connections.connections[connectionId];
        if (!connection) {
          return;
        }

        if (method && args) {
          if (method === "sendMessage" || method === "sendFile") {
            await connection[method](args);
          } else {
            await connection[method].apply(connection, args);
          }
        }
        return api.connections.cleanConnection(connection);
      },

      /**
       * Add a middleware component to connection handling.
       */
      addMiddleware: (data: ConnectionMiddleware) => {
        if (!data.name) {
          throw new Error("middleware.name is required");
        }
        if (!data.priority) {
          data.priority = config.general.defaultMiddlewarePriority;
        }
        data.priority = Number(data.priority);
        api.connections.middleware[data.name] = data;

        api.connections.globalMiddleware.push(data.name);
        api.connections.globalMiddleware.sort((a, b) => {
          if (
            api.connections.middleware[a].priority >
            api.connections.middleware[b].priority
          ) {
            return 1;
          } else {
            return -1;
          }
        });
      },

      cleanConnection: (connection: Connection) => {
        const clean = {};
        for (const i in connection) {
          if (i !== "rawConnection" && i !== "api") {
            try {
              JSON.stringify(connection[i]);
              clean[i] = connection[i];
            } catch (error) {}
          }
        }

        return clean;
      },
    };
  }
}