Refine example for $typeConfigDecorator usage (webonyx#1704)

Author: spawnia

CHANGELOG.md

@@ -9,10 +9,6 @@ You can find and compare releases at the [GitHub release page](https://github.co
 
 ## Unreleased
 
-### Added
-  - Add **examples/05-using-typeConfigDecorator-with-SDL** to provide a solid example about resolving
-  fields on using [SDL](https://webonyx.github.io/graphql-php/schema-definition-language/) instead of [Object Types](https://webonyx.github.io/graphql-php/type-definitions/object-types/). 
-
 ## v15.20.0
 
 ### Added

docs/schema-definition-language.md

@@ -53,7 +53,7 @@ $contents = file_get_contents('schema.graphql');
 $schema = BuildSchema::build($contents, $typeConfigDecorator);
 ```
 
-You can learn more about using `$typeConfigDecorator` in [examples/05-using-typeConfigDecorator-with-SDL](../examples/05-using-typeConfigDecorator-with-SDL/)
+You can learn more about using `$typeConfigDecorator` in [examples/05-type-config-decorator](https://github.com/webonyx/graphql-php/blob/master/examples/05-type-config-decorator).
 
 ## Performance considerations
 

examples/05-type-config-decorator/README.md

@@ -0,0 +1,32 @@
+# Using schema definition language and `typeConfigDecorator`
+
+This example shows how to resolve object types in a query using the schema definition language instead of defining the schema in pure PHP code. 
+
+The business logic matches [the Apollo GraphQL course](https://www.apollographql.com/tutorials/lift-off-part2/03-apollo-restdatasource).
+There is [an accompanying issue](https://github.com/webonyx/graphql-php/issues/1699) that provides further explanations. 
+
+## How to follow along?
+
+1. Navigate to [examples/05-type-config-decorator](/examples/05-type-config-decorator) using the command line
+2. Run `composer install`
+3. Run `php -S localhost:8080 graphql.php`
+4. You may use `curl` to make a request to the running API:
+    
+    ```
+    curl --data '{"query": "{ tracksForHome { title thumbnail author { id name } } }"}' --header "Content-Type: application/json" http://localhost:8080
+    ```
+
+    Alternatively, use your favorite API client and make a request to `localhost:8080` with the following request body: 
+
+    ```graphql
+    {
+      tracksForHome {
+        title
+        thumbnail
+        author {
+          id
+          name
+        }
+      }
+    }
+    ```

examples/05-type-config-decorator/app/Models/Author.php

@@ -0,0 +1,18 @@
+<?php declare(strict_types=1);
+
+namespace App\Models;
+
+use Core\Model;
+
+final class Author extends Model
+{
+    /**
+     * @throws \RuntimeException
+     *
+     * @return array<string, mixed>
+     */
+    public static function find(int $id): array
+    {
+        return static::get("author/{$id}");
+    }
+}

examples/05-type-config-decorator/app/Models/Track.php

@@ -0,0 +1,18 @@
+<?php declare(strict_types=1);
+
+namespace App\Models;
+
+use Core\Model;
+
+final class Track extends Model
+{
+    /**
+     * @throws \RuntimeException
+     *
+     * @return array<int, array<string, mixed>>
+     */
+    public static function all(): array
+    {
+        return self::get('tracks');
+    }
+}

examples/05-using-typeConfigDecorator-with-SDL/composer.json renamed to examples/05-type-config-decorator/composer.json

@@ -0,0 +1,23 @@
+<?php declare(strict_types=1);
+
+namespace Core;
+
+abstract class Model
+{
+    /**
+     * @throws \RuntimeException
+     *
+     * @return mixed
+     */
+    protected static function get(string $endpoint)
+    {
+        $url = "https://odyssey-lift-off-rest-api.herokuapp.com/{$endpoint}";
+
+        $contents = file_get_contents($url);
+        if ($contents === false) {
+            throw new \RuntimeException("Failed to fetch data from URL: {$url}.");
+        }
+
+        return json_decode($contents, true);
+    }
+}

examples/05-type-config-decorator/core/Model.php

@@ -0,0 +1,57 @@
+<?php declare(strict_types=1);
+
+require __DIR__ . '/vendor/autoload.php';
+
+use App\Models\Author;
+use App\Models\Track;
+use GraphQL\GraphQL;
+use GraphQL\Utils\BuildSchema;
+
+$typeConfigDecorator = function (array $typeConfig): array {
+    // For object types, the typeConfig array contains the name of the type and a closure that returns the fields of the type.
+    //
+    // For the Query type, it might look like this:
+    // [
+    //   'name': 'Query',
+    //   'fields': fn () => [...],
+    // ],
+    switch ($typeConfig['name']) {
+        case 'Query':
+            $typeConfig['fields'] = function () use ($typeConfig): array {
+                $fields = $typeConfig['fields']();
+                $fields['tracksForHome']['resolve'] = fn (): array => Track::all();
+
+                return $fields;
+            };
+
+            return $typeConfig;
+        case 'Track':
+            $typeConfig['fields'] = function () use ($typeConfig): array {
+                $fields = $typeConfig['fields']();
+                $fields['author']['resolve'] = fn (array $track): array => Author::find($track['authorId']);
+
+                return $fields;
+            };
+
+            return $typeConfig;
+    }
+
+    return $typeConfig;
+};
+$contents = file_get_contents(__DIR__ . '/schema.graphql');
+if ($contents === false) {
+    throw new RuntimeException('Failed to read schema.graphql.');
+}
+$schema = BuildSchema::build($contents, $typeConfigDecorator);
+
+$requestBody = file_get_contents('php://input');
+if ($requestBody === false) {
+    throw new RuntimeException('Failed to read php://input.');
+}
+$parsedBody = json_decode($requestBody, true, 10);
+$queryString = $parsedBody['query'];
+
+$result = GraphQL::executeQuery($schema, $queryString);
+
+header('Content-Type: application/json');
+echo json_encode($result);

examples/05-type-config-decorator/graphql.php

@@ -1,6 +1,5 @@
 type Query {
-  tracksForHome: [Track]
-
+  tracksForHome: [Track!]!
 }
 
 type Track {
@@ -16,4 +15,4 @@ type Author {
   id: ID!
   name: String
   photo: String
-}
+}