How can I establish the communication between my Flutter App and Cardano Blockchain?

Question

Did anybody succeed with building a Flutter App that can communicate with the Cardano Blockchain? I would be happy if I could get some more guidance.

I'm trying to build a cross-platform Dapp, so I do not want to rely on running a full node. So Blockfrost.io comes in handy. Unfortunately there seems to be no official Dart Package.

I've already tried with this blockfrost package but somehow I did not manage to put everything together correctly. Did it work for any of you?

I wanted to reach out before I try to build Flutter-Plugins for Android and iOS using the official Java-/Kotlin-/Swift-SDKs provided by Blockfrost.

Answer 1

I would check out this package, https://pub.dev/packages/blockfrost. I know this package is being used in at least one place for the Manzano app which can be found here, https://manzano.studio/#/

Answer 2

I got it working for me, these steps may work for you.

1. Work through this tutorial from flutter.dev
2. Afterwards it should be easy for you to change the code. Instead of class Album you want to have class CurrentBackendTime. Instead of the function <Future>Album fetchAlbum() you want to have <Future>CurrentBackendTime fetchCurrentBackendTime() and so on. From the API-Docs for GET /health/clock you can learn how to parse data from JSON, which datatypes are required and what data you will get.
3. Since GET /health/clock requires authentication (see API-Docs again) you need to create an HTTP-Header within your <Future>CurrentBackendTime fetchCurrentBackendTime() function:

   final Map<String, String> authHeader = Map<String, String>();
   authHeader['project_id'] = 'PUT YOUR BLOCKFROST API KEY IN HERE!'
   

   and then you just add the header to your http.get()-Call:

   final response = await http.get(
    Uri.parse('https://cardano-mainnet.blockfrost.io/api/v0/health/clock'),
    headers: authHeader,
   );
   

4. You could now create more classes like class AccountRewardHistory, class AddressDetails for all the objects you want to GET from blockfrost's API. Or you just use what you've learnt, and apply it when using a library like blockfrost.