Hasura Connect Package

Connect your Flutter/Dart apps to Hasura simply.

Install

Add dependency in your pubspec.yaml file:

dependencies:
  hasura_connect:

or use Slidy:

slidy install hasura_connect

Usage

A simple usage example:

//import
import 'package:hasura_connect/hasura_connect.dart';

String url = 'http://localhost:8080/v1/graphql';
HasuraConnect hasuraConnect = HasuraConnect(url);

You can encapsulate this instance into a BLoC class or directly into a Provider.

Create a document with Query:

//document
String docQuery = """
  query {
    authors {
        id
        email
        name
      }
  }
""";

Now just add the document to the "query" method of the HasuraConnect instance.

var r = await hasuraConnect.query(docQuery);
print(r);

//OR USE MUTATION
var r = await hasuraConnect.mutation(docQuery);

Subscriptions

Subscriptions will notify you each time you have a change to the searched items. Use the "hasuraConnect.subscription" method to receive a stream.

Snapshot snapshot = hasuraConnect.subscription(docSubscription);
  snapshot.stream.listen((data) {
    print(data);
  }).onError((err) {
    print(err);
  });

Mutation + Subscriptions

You can to use mutation directly from the subscription snapshot. This will allow you to update your local list even before it has been notified by Hasura.

Snapshot snapshot = hasuraConnect.subscription(docSubscription);
...
snapshot.mutation(docMutation, onNotify: (data) {
   return data..insert(a, {"name": "next offline item" });
}

Mapped Subscription

Use the Map operator to convert json data to a Dart object;

Snapshot<PostModel> snapshot = hasuraConnect.subscription(docSubscription)
                                            .map((data) => PostModel.fromJson(data) );

snapshot.stream.listen((PostModel data) {
   print(data);
 }).onError((err) {
   print(err);
 });

Mapped Subscription with List of results

Use the Map operator to convert list of results in json data to a List of Dart object;

Snapshot<List<PostModel>> snapshot = hasuraConnect.subscription(docSubscription)
                               .map((data) => 
                               data.map((post) => PostModel.fromJson(post)).toList());

snapshot.stream.listen(List<PostModel> data) {
   print(data);
 }).onError((err) {
   print(err);
 });

Using variables

Variables maintain the integrity of Querys, see an example:

String docSubscription = """
  subscription algumaCoisa($limit:Int!){
    users(limit: $limit, order_by: {user_id: desc}) {
      id
      email
      name
    }
  }
""";

Snapshot snapshot = hasuraConnect.subscription(docSubscription, variables: {"limit": 10});

//change values of variables for PAGINATIONS
snapshot.changeVariable({"limit": 20});

Authorization (JWT Token)

View Hasura's official Authorization documentation.

  String url = 'http://localhost:8080/v1/graphql';
HasuraConnect hasuraConnect = HasuraConnect(url, token: () async {
  //sharedPreferences or other storage logic
  return "Bearer YOUR-JWT-TOKEN";
});

Dispose

HasuraConnect provides a dispose () method for use in Provider or BlocProvider. Subscription will start only when someone is listening, and when all listeners are closed HasuraConnect automatically disconnects.

Therefore, we only connect to Hasura when we are actually using it;

Roadmap

This is currently our roadmap, please feel free to request additions/changes.

Feature	Progress
Queries	✅
Mutations	✅
Subscriptions	✅
Change Variable in Subscriptions	✅
Auto-Reconnect	✅
Dynamic JWT Token	✅
bloc_pattern Integration	✅
Provider Integration	✅
Variables	✅
Cache Intercept	🔜

Features and bugs

Please send feature requests and bugs at the [issue tracker][tracker]. [tracker]: http://example.com/issues/replaceme

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