Firebase Storage REST API - firebase

Question

I need very simple static image server for my flutter app. I am thinking about Cloud Storage, because I don't want to worry about own server administrating. I am using experimental Flutter for Desktop as tool for preparation data for mobile app, so I can use only REST API. I found out that Firebase Storage doesn't have own REST API and uses Google Cloud's one. To upload image to Cloud Storage I should make something like this:
curl -X POST --data-binary #[IMAGE_LOCATION] \
-H "Authorization: Bearer [OAUTH2_TOKEN]" \
-H "Content-Type: image/jpeg" \
"https://www.googleapis.com/upload/storage/v1/b/[BUCKET_NAME]/o?uploadType=media&name=[IMAGE_NAME]"
The problem is I can't understand how to get [OAUTH2_TOKEN] (access token) from my Dart code, and how to administrate my images (should I do something with Firebase Admin SDK?)
Could anyone help me, please?

Answer 1

I found answer to this question. First you need to create private key for service account in Firebase settings. Then use it to get access token using dart packages googleapis_auth and http.
var accountCredentials = ServiceAccountCredentials.fromJson({
"private_key_id": "<please fill in>",
"private_key": "<please fill in>",
"client_email": "<please fill in>#developer.gserviceaccount.com",
"client_id": "<please fill in>.apps.googleusercontent.com",
"type": "service_account"
});
var scopes = [
'https://www.googleapis.com/auth/cloud-platform',
];
var client = Client();
AccessCredentials credentials = await obtainAccessCredentialsViaServiceAccount(accountCredentials, scopes, client);
String accessToken = credentials.accessToken.data;
File image = File('path/to/image');
var request = Request(
'POST',
Uri.parse('https://storage.googleapis.com/upload/storage/v1/b/[BUCKET_NAME]/o?uploadType=media&name=images/$imageName'),
);
request.headers['Authorization'] = "Bearer $accessToken";
request.headers['Content-Type'] = "image/jpeg";
request.bodyBytes = await image.readAsBytes();
Response response = await Response.fromStream(await request.send());
print(response.statusCode);
client.close();
Get request you can make the similar way, but you have to encode firebase path to image:
var imagePath = 'images/img.jpg';
var encodedImagePath = Uri.encodeQueryComponent(imagePath);
var request = Request(
'GET',
Uri.parse('https://storage.googleapis.com/storage/v1/b/[BUCKET_NAME]/o/$encodedImagePath?alt=media'),
);
request.headers['Authorization'] = "Bearer $accessToken";
Google Cloud REST API: https://cloud.google.com/storage/docs/downloading-objects

Answer 2

The Firebase Storage REST API allows you to upload and download files from Cloud Storage using HTTP requests. You can use this API to build server-side applications that interact with Cloud Storage, or to integrate Cloud Storage into your existing server-side application.
To use the Firebase Storage REST API, you will need to have a Firebase project and a Cloud Storage bucket set up. You can set up a new Firebase project and Cloud Storage bucket by following the instructions in the Firebase documentation.
Once you have a Cloud Storage bucket set up, you can use the following HTTP methods to access and manipulate files in your bucket:
POST: To upload a new file to Cloud Storage, you can send a POST request to the /upload endpoint, along with the file data in the request body.
GET: To download a file from Cloud Storage, you can send a GET request to the /download endpoint, specifying the file's path in the bucket as a query parameter.
DELETE: To delete a file from Cloud Storage, you can send a DELETE request to the /delete endpoint, specifying the file's path in the bucket as a query parameter.
To authenticate your requests to the Firebase Storage REST API, you will need to provide a valid Firebase Authorization header with each request. You can generate this header using a JSON service account key file, which you can obtain from the Firebase console.
For more information about using the Firebase Storage REST API, including examples of how to make requests and handle responses, you can refer to the Firebase Storage REST documentation.
I hope this helps!