graphql-php/docs/getting-started.md
Ben Zhu 57c77623ee fix port bug
(cherry picked from commit 72e8607)
2018-06-23 11:29:27 +07:00

126 lines
4.1 KiB
Markdown

# Prerequisites
This documentation assumes your familiarity with GraphQL concepts. If it is not the case -
first learn about GraphQL on [the official website](http://graphql.org/learn/).
# Installation
Using [composer](https://getcomposer.org/doc/00-intro.md), simply run:
```sh
composer require webonyx/graphql-php
```
# Upgrading
We try to keep library releases backwards compatible. But when breaking changes are inevitable
they are explained in [upgrade instructions](https://github.com/webonyx/graphql-php/blob/master/UPGRADE.md).
# Install Tools (optional)
While it is possible to communicate with GraphQL API using regular HTTP tools it is way
more convenient for humans to use [GraphiQL](https://github.com/graphql/graphiql) - an in-browser
IDE for exploring GraphQL APIs.
It provides syntax-highlighting, auto-completion and auto-generated documentation for
GraphQL API.
The easiest way to use it is to install one of the existing Google Chrome extensions:
- [ChromeiQL](https://chrome.google.com/webstore/detail/chromeiql/fkkiamalmpiidkljmicmjfbieiclmeij)
- [GraphiQL Feen](https://chrome.google.com/webstore/detail/graphiql-feen/mcbfdonlkfpbfdpimkjilhdneikhfklp)
Alternatively, you can follow instructions on [the GraphiQL](https://github.com/graphql/graphiql)
page and install it locally.
# Hello World
Let's create a type system that will be capable to process following simple query:
```
query {
echo(message: "Hello World")
}
```
To do so we need an object type with field `echo`:
```php
<?php
use GraphQL\Type\Definition\ObjectType;
use GraphQL\Type\Definition\Type;
$queryType = new ObjectType([
'name' => 'Query',
'fields' => [
'echo' => [
'type' => Type::string(),
'args' => [
'message' => Type::nonNull(Type::string()),
],
'resolve' => function ($root, $args) {
return $root['prefix'] . $args['message'];
}
],
],
]);
```
(Note: type definition can be expressed in [different styles](type-system/index.md#type-definition-styles),
but this example uses **inline** style for simplicity)
The interesting piece here is **resolve** option of field definition. It is responsible for returning
a value of our field. Values of **scalar** fields will be directly included in response while values of
**composite** fields (objects, interfaces, unions) will be passed down to nested field resolvers
(not in this example though).
Now when our type is ready, let's create GraphQL endpoint file for it **graphql.php**:
```php
<?php
use GraphQL\GraphQL;
use GraphQL\Type\Schema;
$schema = new Schema([
'query' => $queryType
]);
$rawInput = file_get_contents('php://input');
$input = json_decode($rawInput, true);
$query = $input['query'];
$variableValues = isset($input['variables']) ? $input['variables'] : null;
try {
$rootValue = ['prefix' => 'You said: '];
$result = GraphQL::executeQuery($schema, $query, $rootValue, null, $variableValues);
$output = $result->toArray();
} catch (\Exception $e) {
$output = [
'errors' => [
[
'message' => $e->getMessage()
]
]
];
}
header('Content-Type: application/json');
echo json_encode($output);
```
Our example is finished. Try it by running:
```sh
php -S localhost:8080 graphql.php
curl http://localhost:8080 -d '{"query": "query { echo(message: \"Hello World\") }" }'
```
Check out the full [source code](https://github.com/webonyx/graphql-php/blob/master/examples/00-hello-world) of this example
which also includes simple mutation.
Obviously hello world only scratches the surface of what is possible.
So check out next example, which is closer to real-world apps.
Or keep reading about [schema definition](type-system/index.md).
# Blog example
It is often easier to start with a full-featured example and then get back to documentation
for your own work.
Check out [Blog example of GraphQL API](https://github.com/webonyx/graphql-php/tree/master/examples/01-blog).
It is quite close to real-world GraphQL hierarchies. Follow instructions and try it yourself in ~10 minutes.