platform/angel_graphql/README.md
2018-11-01 17:51:03 -04:00

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![Logo](https://github.com/angel-dart/graphql/raw/master/img/angel_logo.png)
<div style="text-align: center">
<hr>
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</div>
* [Installation](#installation)
* [Usage](#usage)
* [Integration with Angel `Service`s](#using-services)
* [Documenting API's](#documentation)
A complete implementation of the official
[GraphQL specification](http://facebook.github.io/graphql/October2016/#sec-Language) - these
are the [Angel framework](https://angel-dart.github.io)-specific
bindings.
The goal of this project is to provide to server-side
users of Dart an alternative to REST API's. `package:angel_graphql`, which, when combined with the allows
server-side Dart users to build backends with GraphQL and
virtually any database imaginable.
## Installation
To install `package:angel_graphql`, add the following to your
`pubspec.yaml`:
```yaml
dependencies:
angel_framework: ^2.0.0-alpha
angel_graphql: ^1.0.0-alpha
```
## Usage
Using this package is very similar to GraphQL.js - you define
a schema, and then mount `graphQLHttp` in your router to start
serving. This implementation supports GraphQL features like
introspection, so you can play around with `graphiql` as well!
Firstly, define your schema. A GraphQL schema contains an
*object type* that defines all querying operations that can be
applied to the backend.
A GraphQL schema may also have a *mutation* object type,
which defines operations that change the backend's state, and
optionally a *subscription* type, which defines real-time
interactions (coming soon!).
You can use the `convertDartType` helper to wrap your existing
`Model`/PODO classes, and make GraphQL aware of them without duplicated
effort.
```dart
import 'package:angel_framework/angel_framework.dart';
import 'package:angel_graphql/angel_graphql.dart';
import 'package:graphql_schema/graphql_schema.dart';
import 'package:graphql_server/graphql_server.dart';
import 'package:graphql_server/mirrors.dart';
Future configureServer(Angel app) async {
var queryType = objectType(
'Query',
description: 'A simple API that manages your to-do list.',
fields: [
field(
'todos',
listOf(convertDartType(Todo).nonNullable()),
resolve: resolveViaServiceIndex(todoService),
),
field(
'todo',
convertDartType(Todo),
resolve: resolveViaServiceRead(todoService),
inputs: [
new GraphQLFieldInput('id', graphQLId.nonNullable()),
],
),
],
);
var mutationType = objectType(
'Mutation',
description: 'Modify the to-do list.',
fields: [
field(
'create',
graphQLString,
),
],
);
var schema = graphQLSchema(
queryType: queryType,
mutationType: mutationType,
);
}
```
After you've created your `GraphQLSchema`, you just need to
wrap in a call to `graphQLHttp`, a request handler that responds
to GraphQL.
In *development*, it's also highly recommended to mount the
`graphiQL` handler, which serves GraphQL's official visual
interface, for easy querying and feedback.
```dart
app.all('/graphql', graphQLHttp(new GraphQL(schema)));
app.get('/graphiql', graphiQL());
```
All that's left now is just to start the server!
```dart
var server = await http.startServer('127.0.0.1', 3000);
var uri =
new Uri(scheme: 'http', host: server.address.address, port: server.port);
var graphiqlUri = uri.replace(path: 'graphiql');
print('Listening at $uri');
print('Access graphiql at $graphiqlUri');
```
Visit your `/graphiql` endpoint, and you'll see the `graphiql`
UI, ready-to-go!
![Graphiql screenshot](https://github.com/angel-dart/graphql/raw/master/img/angel_graphql.png)
Now you're ready to build a GraphQL API!
## Documentation
The `convertDartType` function can automatically read the documentation
from a type like the following:
```dart
@GraphQLDocumentation(description: 'Any object with a .text (String) property.')
abstract class HasText {
String get text;
}
@serializable
@GraphQLDocumentation(
description: 'A task that might not be completed yet. **Yay! Markdown!**')
class Todo extends Model implements HasText {
String text;
@GraphQLDocumentation(deprecationReason: 'Use `completion_status` instead.')
bool completed;
CompletionStatus completionStatus;
Todo({this.text, this.completed, this.completionStatus});
}
@GraphQLDocumentation(description: 'The completion status of a to-do item.')
enum CompletionStatus { COMPLETE, INCOMPLETE }
```
You can also manually provide documentation for
parameters and endpoints, via a `description` parameter on almost
all related functions.
See [`package:graphql_schema`](https://github.com/angel-dart/graphql/tree/master/graphql_schema)
for more documentation.