ql_gen 0.1.2

A library for generating dart code from GraphQL schema.

QlGen

QlGen is a library for generating dart code from GraphQL schema.

Features

Given a GraphQL schema, QlGen generates dart code for the following:

• ✅ Types
• ✅ Queries
• ✅ Mutations
• [-] Subscriptions (not yet tested)

Getting started

To use this package, add ql_gen as a dependency in your pubspec.yaml file.

Usage

dart run ql_gen --help

-s, --source    The source file
                (defaults to "schema.gql")
-t, --target    The target file
                (defaults to "ql.dart")
-h, --help      Prints this help message

dart run ql_gen -s schema.gql -t lib/src/generated/ql.dart

Example

For this example, we will use a simple GraphQL schema with authors and books.

# schema.gql
type Author {
  id: ID
  name: String
  books: [Book!]
}

type Book {
  id: ID
  title: String
  author: Author
}

type Query {
  books: [Book!]
  authors: [Author!]
  book(id: ID!): Book
  author(id: ID!): Author
  version: String
}

The result (can be found here) will be a dart file having classes for each type and query (Query, Author, Book).

To fetch all the books of the author with id 1, you can use the following code:

Note: we are using graphql_flutter package to execute the query.

import 'package:graphql_flutter/graphql_flutter.dart';
import 'ql.dart'; // generated file

Future<Map<String, dynamic>?> query(
    (String, Map<String, dynamic>) qlAndVariables) async {
  logger.info('Query: ${qlAndVariables.$1}');
  logger.info('Variables: ${qlAndVariables.$2}');
  try {
    return await client
        .query(QueryOptions(
          document: gql(qlAndVariables.$1),
          variables: qlAndVariables.$2,
          cacheRereadPolicy: CacheRereadPolicy.ignoreAll,
        ))
        .then((value) => value.data);
  } catch (e) {
    logger.severe(e);
    rethrow;
  }
}

void main() async {
  final query = Query(query);
  List<Author>? authors = await query.authors(AuthorSelector(
    id: true,
    name: true,
    books: BookSelector(
        id: true,
        title: false, // or don't include it at all
    )
  ));
}

You can use any plugin for GraphQL, you just need to pass the executor a function that has the bellow signature.

Future<Map<String, dynamic>?> query(
    (String, Map<String, dynamic>) qlAndVariables)

qlAndVariables is a tuple of the query and the variables. The query is a string and the variables are a map of string to dynamic. It must return a Future of a map of string to dynamic. The map is the result of the query.

Issues

Please feel free to open an issue if you find any bugs or have any feature requests here.