exthos/src/utils/utils.ts

stream processing in nodejs using the power of golang

import { execaCommandSync } from "execa";
import axios from "axios";
import proxymise from "./proxymise.js";
import { IncomingMessage } from "http";
import { Stream } from "stream";

function checkExeExists(): boolean {
  try {
    execaCommandSync(`benthos -v`);
  } catch (err: any) {
    if (err.exitCode !== 0) return false;
  }
  return true;
}

function standardizeAxiosErrors(e: any): Error {
  if (axios.isAxiosError(e)) {
    if (e.response) {
      // take care of circular  reference errors
      delete e.response.request;
      delete (e.response as any)["config"];

      let dataIsStream =
        e.response.data instanceof IncomingMessage &&
        e.response.data instanceof Stream;
      let toReturnError = {
        name: "Error",
        message: "axios response has an error",
        response: {
          status: e.response.status,
          statusText: e.response.statusText,
          headers: e.response.headers,
          data: dataIsStream ? "" : e.response.data,
        },
        request: {
          host: e.request.getHeader("host"),
          path: e.request.path,
        },
      };
      return toReturnError;
      // return new Error(e.message)
      // not sending all the information. should we?
      // return new Error(JSON.stringify({ status: e.response.status, headers: e.response.headers, data: e.response.data }))
    } else if (e.request) {
      return new Error(e.message);
      // not sending all the information. should we?
      // return new Error(JSON.stringify(e.toJSON()))
    }
  }
  return e;
}

async function sleep(ms: number): Promise<boolean> {
  let resolve: (value: unknown) => void;
  let p = new Promise((r) => {
    resolve = r;
  });
  setTimeout(resolve!, ms);
  await p;
  return true;
}

class Deferred {
  public promise: Promise<unknown>;
  public reject!: (reason?: any) => void;
  public resolve!: (value?: any) => void;
  public fulfilled: boolean = false;
  public rejected: boolean = false;
  public resolved: boolean = false;

  constructor() {
    let self = this;
    this.promise = new Promise(function (resolve, reject) {
      self.reject = (reason?: any) => {
        self.fulfilled = true;
        self.rejected = true;
        reject(reason);
      };
      self.resolve = (value?: any) => {
        self.fulfilled = true;
        self.resolved = true;
        resolve(value);
      };
    });
  }
}

/**
 * iterates through the entire object to replace oldKey with newKey
 * CAUTION: it mutates the object itself
 * @param obj
 * @param keyMap
 * @returns
 */
function replaceKeys(obj: any, keyMap: { [oldKey: string]: () => string }) {
  let iterate = (obj: any) => {
    Object.keys(obj).forEach((key) => {
      if (Object.keys(keyMap).includes(key)) {
        let oldKey = key;
        let newKey = keyMap[oldKey];
        Object.defineProperty(
          obj,
          newKey(),
          Object.getOwnPropertyDescriptor(obj, oldKey)!
        );
        delete (obj as any)[oldKey];
        if (!(typeof obj[key] === "object" && obj[key] !== null)) {
          // reutrn if not an object, otherwise need to recurse
          return obj;
        }
      } //else {
      if (
        typeof obj[key] === "object" &&
        obj[key] !== null &&
        !Array.isArray(obj[key])
      ) {
        iterate(obj[key]);
      } else if (Array.isArray(obj[key])) {
        obj[key].forEach((el: any) => {
          iterate(el);
        });
      }
      //}
    });
  };
  iterate(obj);
  return obj;
}

/**
 * iterates through the entire object to remove existing values and replace values provided in the kv object
 * CAUTION: it mutates the object itself
 * CAUTION: completely removes existing value for the given k
 * @param obj
 * @param kv
 * @returns
 */
// function replaceValueForKey<O, T>(obj: O, kv: { [forKey: string]: (existingValue: T) => T }) {
function replaceValueForKey<O>(
  obj: O,
  kv: { [forKey: string]: (existingValue: any) => any }
) {
  let iterate = (obj: any) => {
    Object.keys(obj).forEach((key) => {
      if (Object.keys(kv).includes(key)) {
        obj[key] = kv[key](obj[key]); // assign the value, usually merged value will be provided by kv[forKey] func
        if (!(typeof obj[key] === "object" && obj[key] !== null)) {
          // return only if not an object, so that nested properties with same forKey are also taken care of
          return obj;
        }
      }
      if (
        typeof obj[key] === "object" &&
        obj[key] !== null &&
        !Array.isArray(obj[key])
      ) {
        // if an object, then recurse
        iterate(obj[key]);
      } else if (Array.isArray(obj[key])) {
        // if an array, then recurse for each element
        obj[key].forEach((el: any) => {
          iterate(el);
        });
      }
    });
  };
  iterate(obj);
  return obj;
}

/**
 * use proxymise to build fluent proxies for promises
 */
function proxyPromise<T extends (...args: any) => any>(t: T) {
  return proxymise(t) as (...params: Parameters<T>) => Awaited<
    ReturnType<T>
  > & {
    then: (value: (rt: Awaited<ReturnType<T>>) => void) => {
      catch: (value: (e: Error) => void) => {
        finally: (value: () => void) => void;
      };
    } & { finally: (value: () => void) => void };
    catch: (value: (e: Error) => void) => {
      finally: (value: () => void) => void;
    };
  };
}

function getISOStringLocalTz(date: Date = new Date()) {
  var tzo = -date.getTimezoneOffset(),
    dif = tzo >= 0 ? "+" : "-",
    pad = function (num: number) {
      return (num < 10 ? "0" : "") + num;
    };

  return (
    date.getFullYear() +
    "-" +
    pad(date.getMonth() + 1) +
    "-" +
    pad(date.getDate()) +
    "T" +
    pad(date.getHours()) +
    ":" +
    pad(date.getMinutes()) +
    ":" +
    pad(date.getSeconds()) +
    dif +
    pad(Math.floor(Math.abs(tzo) / 60)) +
    ":" +
    pad(Math.abs(tzo) % 60)
  );
}

function getCaller() {
  return (new Error().stack as any).split("at ")[3].trim();
}

function formatErrorForEvent(e: any) {
  // return `${e.code ? e.code + " ": ""} ${e.message ? e.message : ""}`
  let toReturn = {};
  Object.getOwnPropertyNames(e).forEach((p) => {
    (toReturn as any)[p] = e[p];
  });
  return toReturn;
}

export {
  checkExeExists,
  standardizeAxiosErrors,
  sleep,
  Deferred,
  replaceKeys,
  replaceValueForKey,
  proxyPromise,
  getISOStringLocalTz,
  getCaller,
  formatErrorForEvent,
};