Receiving Uint8Array on Node.js and Saving on Google Cloud Storage
Although I’ve written a similar post about sending an image from Flutter to Node.js server to Google Cloud Storage and vice-versa, I’ve found that it didn’t work when I ran the app on my phone (while it did work on my iOS and Android emulators). So, this will be a super short post on receiving Uint8Array on Node.js to send to Google Cloud Storage.
Flutter
On my app, when the user selects a photo or multiple photos, I save it accordingly to my Photo class, which is composed of (String) fileName and (Uint8List) bytes. (1) Bytes — you can get it by await xFile.readAsBytes() (XFile is the format you get your image in when you use image_picker). (2) FileName — I just get the last bit of the full path of the image using .split(“/”).last.
In my Photo class, I have a factory constructor to convert my data from JSON to Photo, a method to convert the Photo to JSON, and a static method to convert a List<Photo> to List<JSON format>. In my POST request, I attach the returned value from photoListToJson() to the body[“photos”].
Node.js
My Node.js is divided into index.js, routers, and controllers. In index.js, I’ve found that you need the below Express middleware, or you’ll get “request entity is too large” error.
app.use(express.json({ limit: "50mb" }));
In my previous post, I used bucket.upload() but after some googling, I’ve switched to file.save(), which takes a Buffer as an argument. (1) When you receive the bytes array, create an instance of Uint8Array, which is extended by the Buffer class. (2) Use bucket.file(filename) to create a File object. (3) await file.save(Uint8Array) to upload.
Note: my server receives a List of Photo data, which is why I had to use Promise().
Done! If you need to know how to get the images from cloud storage and send it to Flutter, please refer to my previous post.
