compress and write a file in another container with azure blob storage trigger in nodejs - node.js

Question

i have to make an api call passing a compressed file as input. i have a working example on premise but I would like to move the solution in cloud. i was thinking to use azure blob storage and the azure function trigger. i have the below code that works for file but I don't know how to do the same with azure blob storage and azure function in nodejs
const zlib = require('zlib');
const fs = require('fs');
const def = zlib.createDeflate();
input = fs.createReadStream('claudio.json')
output = fs.createWriteStream('claudio-def.json')
input.pipe(def).pipe(output)
this code read a file as stream , compress the file and write another file as stream.
what I would like to do is reading the file any time I upload it in a container of azure blob storage, then I want to compress it and save in a different container with different name, then make an API call passing as input the compressed file saved in the other container
I tried this code for compressing the incoming file
const fs = require("fs");
const zlib = require('zlib');
const {Readable, Writable} = require('stream');
module.exports = async function (context, myBlob) {
context.log("JavaScript blob trigger function processed blob \n Blob:", context.bindingData.blobTrigger, "\n Blob Size:", myBlob.length, "Bytes");
// const fin = fs.createReadStream(context.bindingData.blobTrigger);
const def = zlib.createDeflate();
const s = Readable.from(myBlob.toString())
context.log(myBlob);
context.bindings.outputBlob = s.pipe(def)
};
the problem with this approach is that in the last line of the code
context.bindings.outputBlob = s.pipe(def)
i don't have the compressed file, while if i use this
s.pipe(def).pipe(process.stdout)
i can read the compressed file
as you can see above i also tried to use the fs.createReadStream(context.bindingData.blobTrigger) that contains the name of the uploaded file with the container name, but it doesn't work
any idea?
thank you

Answer 1

this is the solution
var input = context.bindings.myBlob;
var inputBuffer = Buffer.from(input);
var deflatedOutput = zlib.deflateSync(inputBuffer);
context.bindings.myOutputBlob = deflatedOutput;
https://learn.microsoft.com/en-us/answers/questions/500368/compress-and-write-a-file-in-another-container-wit.html