Nodejs Wait image will be downloaded - node.js

Question

I can't understand why this function exit before image is downloaded and saved.
I need to wait image will be saved before exiting.
function downloadImagefromRemote(url_immagine, filename) {
console.log('[2] Salvo l\'immagine remota in locale');
const downloadFile = async (fileUrl, downloadFolder, filename) => {
// Get the file name
const fileName = path.basename(fileUrl);
// The path of the downloaded file on our machine
const localFilePath = path.resolve(__dirname, downloadFolder, filename);
try {
const response = await axios({ // <----- here jump out
method: "GET",
url: fileUrl,
responseType: "stream",
});
await response.data.pipe(fs.createWriteStream(localFilePath));
console.log("Successfully downloaded file!");
} catch (err) {
throw new Error(err);
}
};
const IMAGE_URL = 'https://www.kindacode.com/wp-content/uploads/2021/01/test.jpg';
let rel_path = __dirname + '/../../public/images/';
downloadFile(IMAGE_URL, rel_path, filename);
}

Answer 1

The main problem is that using
axios({...})
you need to specify
url: imgUrl
More generally speaking:
avoid unnecessary nested functions
clean your unused and unnecessary params
Here a functioning example:
'use strict'
const fs = require('fs')
const path = require('path')
const axios = require('axios')
async function downloadImage(imgUrl, saveRelPath, saveName) {
const _path = path.resolve(__dirname, saveRelPath, saveName)
const writer = fs.createWriteStream(_path)
const response = await axios({
url: imgUrl,
method: 'GET',
responseType: 'stream',
})
response.data.pipe(writer)
return new Promise((resolve, reject) => {
writer.on('finish', resolve)
writer.on('error', reject)
})
}
async function anotherFunction() {
const IMG_URL = 'https://www.kindacode.com/wp-content/uploads/2021/01/test.jpg'
const REL_PATH = '.'
const NAME = 'test.jpg'
console.log('Get and save image')
await downloadImage(IMG_URL, REL_PATH, NAME)
console.log('Image saving done, other stuff here')
}
anotherFunction()
EDIT: as response to
I can't understand why this function exit before image is downloaded and saved
the stream piping doesn't return a promise, so you can't await it.
You pipe a stream into a write stream that is an EventEmitter, so you should use a listener.

Answer 2

You can try that, it should work. for the pipeline() explaination, see this answer Promise completed before file is written. I promisified your flow to be able to resolve as soon as the stream process ends (note that i don t know about the other parts of your code, like if axios does not return a stream it will not work)
const { pipeline } = require('stream')
async function downloadImagefromRemote(url_immagine, filename) {
console.log('[2] Salvo l\'immagine remota in locale');
const downloadFile = (fileUrl, downloadFolder, filename) => {
return new Promise(async(resolve, reject) => {
// Get the file name
const fileName = path.basename(fileUrl);
// The path of the downloaded file on our machine
const localFilePath = path.resolve(__dirname, downloadFolder, filename);
try {
const response = await axios({ // <----- here jump out
method: "GET",
url: fileUrl,
responseType: "stream",
});
pipeline(
response.data,
fs.createWriteStream(localFilePath),
e => {
if(e) reject(e)
else resolve("Successfully downloaded file!")
}
)
} catch (err) {
reject(Error(err))
}
})
};
const IMAGE_URL = 'https://www.kindacode.com/wp-content/uploads/2021/01/test.jpg';
let rel_path = __dirname + '/../../public/images/';
try{
const confirmDownload = await downloadFile(IMAGE_URL, rel_path, filename);
console.log(confirmDownload)
} catch(e) {
console.log('catched err:', e)
}
}