graphql_schema

Description:

graphql schema

graphql_schema #


An implementation of GraphQL's type system in Dart. Supports any platform where Dart runs.
The decisions made in the design of this library were done to make the experience
as similar to the JavaScript reference implementation as possible, and to also
correctly implement the official specification.
Contains functionality to build all GraphQL types:

String
Int
Float
Boolean
GraphQLObjectType
GraphQLUnionType
GraphQLEnumType
GraphQLInputObjectType
Date - ISO-8601 Date string, deserializes to a Dart DateTime object

Of course, for a full description of GraphQL's type system, see the official
specification:
http://facebook.github.io/graphql/October2016/
Mostly analogous to graphql-js; many names are verbatim:
https://graphql.org/graphql-js/type/
Usage #
It's easy to define a schema with the
helper functions:
final GraphQLSchema todoSchema = new GraphQLSchema(
query: objectType('Todo', [
field('text', graphQLString.nonNullable()),
field('created_at', graphQLDate)
]));
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All GraphQL types are generic, in order to leverage Dart's strong typing support.
Serialization #
GraphQL types can serialize and deserialize input data.
The exact implementation of this depends on the type.
var iso8601String = graphQLDate.serialize(new DateTime.now());
var date = graphQLDate.deserialize(iso8601String);
print(date.millisecondsSinceEpoch);
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Validation #
GraphQL types can validate input data.
var validation = myType.validate('@root', {...});

if (validation.successful) {
doSomething(validation.value);
} else {
print(validation.errors);
}
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Helpers #

graphQLSchema - Create a GraphQLSchema
objectType - Create a GraphQLObjectType with fields
field - Create a GraphQLField with a type/argument/resolver
listOf - Create a GraphQLListType with the provided innerType
inputObjectType - Creates a GraphQLInputObjectType
inputField - Creates a field for a GraphQLInputObjectType

Types #
All of the GraphQL scalar types are built in, as well as a Date type:

graphQLString
graphQLId
graphQLBoolean
graphQLInt
graphQLFloat
graphQLDate

Non-Nullable Types #
You can easily make a type non-nullable by calling its nonNullable method.
List Types #
Support for list types is also included. Use the listType helper for convenience.
/// A non-nullable list of non-nullable integers
listOf(graphQLInt.nonNullable()).nonNullable();
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Input values and parameters #
Take the following GraphQL query:
{
anime {
characters(title: "Hunter x Hunter") {
name
age
}
}
}
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The field characters accepts a parameter, title. To reproduce this in
package:graphql_schema, use GraphQLFieldInput:
final GraphQLObjectType queryType = objectType('AnimeQuery', fields: [
field('characters',
listOf(characterType.nonNullable()),
inputs: [
new GraphQLFieldInput('title', graphQLString.nonNullable())
]
),
]);

final GraphQLObjectType characterType = objectType('Character', fields: [
field('name', graphQLString),
field('age', graphQLInt),
]);
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In the majority of cases where you use GraphQL, you will be delegate the
actual fetching of data to a database object, or some asynchronous resolver
function.
package:graphql_schema includes this functionality in the resolve property,
which is passed a context object and a Map<String, dynamic> of arguments.
A hypothetical example of the above might be:
var field = field(
'characters',
graphQLString,
resolve: (_, args) async {
return await myDatabase.findCharacters(args['title']);
},
);
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