Firebase Storage Admin SDK: upload from image url - node.js

Question

In the web sdk of firebase storage you can upload an image from Blob data. I have a nodeJS app and want to upload images from a url to my storage bucket. In the docs it's recommended to use the admin SDK if running a node server environment. But i cannot find this feature in the firbase storage admin documentation.
Heres my code:
const admin = require('firebase-admin');
const serviceAccount = require(`./credentials/my-keyfile.json`);
const app = admin.initializeApp({
credential: admin.credential.cert(serviceAccount)
});
const storage = app.storage();
// Get Blob data from an external ImageUrl
const axios = require("axios");
const getBlobFromUrl = (url) => {
const response = await axios.get(url, { responseType: "blob" });
return response.data;
}
const blobData = getBlobFromUrl("https://images.unsplash.com/photo-1591476315349-faa1c8e6f567?ixlib=rb-1.2.1&q=80&fm=jpg&crop=entropy&cs=tinysrgb&w=1080&fit=max")
// MY QUESTION -> how can i upload that blob data to my storage?

Answer 1

I was recently trying to do something similar, writing an in-memory file from a Node server (with the Firebase Admin SDK) to Firebase Storage.
I solved it by realizing that I needed to use Google Cloud Storage's Node API to do so (mentioned in the docs). This is the relevant doc page to do streaming transfers with Google Cloud Storage: https://cloud.google.com/storage/docs/streaming#storage-stream-upload-object-nodejs.
Here are the basic steps:
Set the appropriate storageBucket address (e.g. gs://APP-NAME.appspot.com/), which you can get from your Firebase Storage console. Also, get the appropriate Firebase storage and bucket JS objects. Follow the example at https://firebase.google.com/docs/storage/admin/start
get the stream of byte data from your blob/file: https://developer.mozilla.org/en-US/docs/Web/API/Blob/stream
use Google Cloud Storage's API to pipe/write that stream to a specified location in your bucket: https://cloud.google.com/storage/docs/streaming#storage-stream-upload-object-nodejs
So, following the the docs above, you'd do something like:
// Create a reference to a file object.
// myBucket is the bucket obtained in step 1 above
const file = myBucket.file("directoryName/imageName.png");
// step 2: get ReadableStream from Blob
const stream = blobData.stream();
// step 3: asynchronously pipe/write to file in cloud
async function streamFileUpload() {
stream.pipe(file.createWriteStream()).on('finish', () => {
// The file upload is complete
});
}
streamFileUpload().catch(console.error);
After this you'll see your file uploaded to Firebase Storage under directoryName/imageName.png.

Answer 2

The first link you have posted on uploading an image with Blob data
contains information on how you would do it with the client sdk.
When you use the Admin SDK, the use case is for the backend, for example, cloud functions. What you have shown in your post is used for this use case.
For implementations on how to upload an image using the client sdk, check out some of the Quickstart guides as well as the code labs.
If you're working primarily with Blob, you can check out some libraries like busboy and send HTTP requests instead.