How to decompress gziped AWS gateway api lambda response in react?

Question

I followed this answer and successfully used gzip to compress the data and avoid AWS lambda 6MB response limitation. But I can't figure out how to decompress and convert to the string after the response is received in front end react app. My file is a log file.

I tried to solve:

// this is my “response.json()” will look like
const baseData = {
    “data”: “H4sIAAAAA.....”
}

// decode the base64 encoded data
const gzipedData = Buffer.from(baseData.data, “base64");

const ungzip = async (input) => {
  return new Promise((resolve, reject) =>
    zlib.gzip(input, (err, data) => {
      if (err) {
        reject(err);
      }
      resolve(data);
    })
  );
};

// unzip and return a Buffer
const ungzipedData = await ungzip(gzipedData);

// convert Buffer to string
const buf = Buffer.from(ungzipedData, ‘utf8’);
console.log(buf.toString());

The result was something like this:

g@����r��.{�/)fx^�R�d�J%��y�c��P��...

Answer 1

I figured out just to use zlib.unzip and use util.promisify to return the final value as a promise. If anyone knows any better solution (with pako maybe), please share, thank you!

import { Buffer } from 'buffer';
import zlib from "react-zlib-js";
import util from "util";

const getLog = async (itemName) => {
      const response = await fetch(
        "url?" +
        new URLSearchParams({
          some_param: "some_value",
        })
      );

      if (!response.ok) {
        throw new Error("Fail ....!");
      }

      const responseJson = await response.json();
      const buffer = Buffer.from(responseJson.data, "base64");
      const responseData = (await util.promisify(zlib.unzip)(buffer)).toString();

      return responseData;
    };