graphql-php/docs/getting-started.md
2016-11-05 23:55:51 +07:00

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# Prerequisites
This documentation assumes your familiarity with GraphQL concepts. If it is not the case -
first learn about GraphQL on [official website](http://graphql.org/learn/).
# Installation
Using [composer](https://getcomposer.org/doc/00-intro.md):
add `composer.json` file to your project root folder with following contents:
```
{
"require": {
"webonyx/graphql-php": "^0.7"
}
}
```
and run `composer install`.
If you already have composer.json file - simply run: `composer require webonyx/graphql-php`
If you are upgrading, see [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 [GraphiQL](https://github.com/graphql/graphiql)
page and install it locally.
# Hello World
Let's create 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/#type-definition-styles),
including **inheritance**, **composition** and **inline**. This example uses **inline** style for simplicity)
The interesting piece here is `resolve` option of field definition. It is responsible for retuning
value of our field. Values of **scalar** fields will be directly included in response while values of
**complex** 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 for it `graphql.php`:
```php
<?php
use GraphQL\GraphQL;
use GraphQL\Schema;
$schema = new Schema([
'query' => $queryType
]);
$rawInput = file_get_contents('php://input');
try {
$rootValue = ['prefix' => 'You said: '];
$result = GraphQL::execute($schema, $rawInput, $rootValue);
} catch (\Exception $e) {
$result = [
'error' => [
'message' => $e->getMessage()
]
];
}
header('Content-Type: application/json; charset=UTF-8');
echo json_encode($result);
```
Our example is ready. Try it by running:
```sh
php -S localhost:8000 graphql.php
curl http://localhost:8000 -d "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.
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/).
# Blog example
It is often easier to start with 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.