NEW: getByLink plugin allows arrays of links (#2666)

* NEW: getByLink plugin allows arrays of links

* Allow configurable resolver

* Remove unused exception tag

* Refactor to preserve API backward compat

* Unit test

* Add plugin to readOne

* Fix test

* add new test

_graphql/config.yml

@@ -7,3 +7,7 @@ modelConfig:
         plugins:
           getByLink:
             after: filter
+      readOne:
+        plugins:
+          getByLink:
+            after: filter

code/GraphQL/LinkablePlugin.php

@@ -12,6 +12,7 @@ use SilverStripe\GraphQL\Schema\Exception\SchemaBuilderException;
 use SilverStripe\GraphQL\Schema\Field\ModelQuery;
 use SilverStripe\GraphQL\Schema\Interfaces\ModelQueryPlugin;
 use SilverStripe\GraphQL\Schema\Schema;
+use SilverStripe\ORM\ArrayList;
 use SilverStripe\ORM\DataList;
 
 if (!interface_exists(ModelQueryPlugin::class)) {
@@ -29,7 +30,18 @@ class LinkablePlugin implements ModelQueryPlugin
      * @var string
      * @config
      */
-    private static $field_name = 'link';
+    private static $single_field_name = 'link';
+
+    /**
+     * @var string
+     * @config
+     */
+    private static $list_field_name = 'links';
+
+    /**
+     * @var array
+     */
+    private static $resolver = [__CLASS__, 'applyLinkFilter'];
 
     /**
      * @return string
@@ -43,7 +55,6 @@ class LinkablePlugin implements ModelQueryPlugin
      * @param ModelQuery $query
      * @param Schema $schema
      * @param array $config
-     * @throws SchemaBuilderException
      */
     public function apply(ModelQuery $query, Schema $schema, array $config = []): void
     {
@@ -52,43 +63,42 @@ class LinkablePlugin implements ModelQueryPlugin
         if ($class !== SiteTree::class && !is_subclass_of($class, SiteTree::class)) {
             return;
         }
-        Schema::invariant(
+        $singleFieldName = $this->config()->get('single_field_name');
-            !$query->isList(),
+        $listFieldName = $this->config()->get('list_field_name');
-            'Plugin %s cannot be applied to queries that return lists. Query "%s" is a list',
+        $fieldName = $query->isList() ? $listFieldName : $singleFieldName;
-            static::getIdentifier(),
+        $type = $query->isList() ? '[String]' : 'String';
-            $query->getName()
+        $query->addArg($fieldName, $type);
+        $query->addResolverAfterware(
+            $config['resolver'] ?? static::config()->get('resolver')
         );
-        $fieldName = $this->config()->get('field_name');
-        
-        $query->addArg($fieldName, 'String');
-        $query->addResolverAfterware([static::class, 'applyLinkFilter']);
     }
 
     /**
-     * @param $obj
-     * @param array $args
      * @param array $context
-     * @param ResolveInfo $info
+     * @return callable
-     * @param callable $done
-     * @return SiteTree|DataList|null
      */
-    public static function applyLinkFilter(
+    public static function applyLinkFilter($obj, array $args, array $context, ResolveInfo $info)
-        $obj,
+    {
-        array $args,
+        $singleFieldName = static::config()->get('single_field_name');
-        array $context,
+        $listFieldName = static::config()->get('list_field_name');
-        ResolveInfo $info,
+        $filterLink = $args['filter'][$singleFieldName] ?? ($args['filter'][$listFieldName] ?? null);
-        callable $done
+        $argLink = $args[$singleFieldName] ?? ($args[$listFieldName] ?? null);
-    ) {
+        $linkData = $filterLink ?: $argLink;
-        $fieldName = static::config()->get('field_name');
+        if (!$linkData) {
-        $filterLink = $args['filter'][$fieldName] ?? null;
+            return $obj;
-        $argLink = $args[$fieldName] ?? null;
-        $filterLink = $filterLink ?: $argLink;
-
-        if ($filterLink) {
-            $done();
-            return SiteTree::get_by_link($filterLink);
         }
+        // Normalise to an array for both cases. The readOne operation will get
+        // ->first() run on it by the firstResult plugin.
+        $links = is_array($linkData) ? $linkData : [$linkData];
 
-        return $obj;
+        $result = ArrayList::create();
+
+        foreach ($links as $link) {
+            $page = SiteTree::get_by_link($link);
+            if ($page) {
+                $result->push($page);
+            }
+        }
+        return $result;
     }
 }

tests/php/GraphQL/LinkablePluginTest.php

@@ -0,0 +1,112 @@
+<?php
+
+namespace SilverStripe\CMS\Tests\GraphQL;
+
+use SilverStripe\AssetAdmin\Tests\GraphQL\FakeResolveInfo;
+use SilverStripe\CMS\GraphQL\LinkablePlugin;
+use SilverStripe\CMS\Model\SiteTree;
+use SilverStripe\Dev\SapphireTest;
+use SilverStripe\GraphQL\Schema\DataObject\DataObjectModel;
+use SilverStripe\GraphQL\Schema\Field\ModelQuery;
+use SilverStripe\GraphQL\Schema\Schema;
+use SilverStripe\GraphQL\Schema\SchemaConfig;
+
+class LinkablePluginTest extends SapphireTest
+{
+    protected function setUp()
+    {
+        parent::setUp();
+
+        if (!class_exists(Schema::class)) {
+            $this->markTestSkipped('GraphQL 4 test ' . __CLASS__ . ' skipped');
+        }
+    }
+
+    /**
+     * @param bool $list
+     * @dataProvider provideApply
+     */
+    public function testApply(bool $list)
+    {
+        $query = new ModelQuery(
+            new DataObjectModel(SiteTree::class, new SchemaConfig()),
+            'testQuery'
+        );
+        $query->setType($list ? '[SiteTree]' : 'SiteTree');
+
+        $plugin = new LinkablePlugin();
+        $plugin->apply($query, new Schema('test'));
+        $args = $query->getArgs();
+        $field = $list ? 'links' : 'link';
+        $this->assertArrayHasKey($field, $args);
+        $this->assertEquals($list ? '[String]' : 'String', $args[$field]->getType());
+    }
+
+    public function testResolver()
+    {
+        $page = SiteTree::create([
+            'Title' => 'Test page',
+            'URLSegment' => 'test-page',
+            'ParentID' => 0,
+        ]);
+        $page->write();
+        $page->publishRecursive();
+
+        $page = SiteTree::create([
+            'Title' => 'Other test page',
+            'URLSegment' => 'other-test-page',
+            'ParentID' => 0,
+        ]);
+
+        $page->write();
+        $page->publishRecursive();
+
+        $result = LinkablePlugin::applyLinkFilter('test', ['link' => 'test-page'], [], new FakeResolveInfo());
+        $this->assertTrue($result->exists());
+        $this->assertEquals('Test page', $result->first()->Title);
+
+        $result = LinkablePlugin::applyLinkFilter('test', ['links' => ['test-page']], [], new FakeResolveInfo());
+        $this->assertTrue($result->exists());
+        $this->assertEquals('Test page', $result->first()->Title);
+
+        $result = LinkablePlugin::applyLinkFilter(
+            'test',
+            ['links' => ['test-page', 'other-test-page']],
+            [],
+            new FakeResolveInfo()
+        );
+        $this->assertTrue($result->exists());
+        $this->assertCount(2, $result);
+        $titles = $result->column('Title');
+        $this->assertTrue(in_array('Test page', $titles));
+        $this->assertTrue(in_array('Other test page', $titles));
+
+        $result = LinkablePlugin::applyLinkFilter(
+            'test',
+            ['links' => ['test-page', 'fail-page']],
+            [],
+            new FakeResolveInfo()
+        );
+        $this->assertTrue($result->exists());
+        $this->assertCount(1, $result);
+        $this->assertEquals('Test page', $result->first()->Title);
+
+        $result = LinkablePlugin::applyLinkFilter('test', ['link' => 'fail-page'], [], new FakeResolveInfo());
+        $this->assertFalse($result->exists());
+
+        $result = LinkablePlugin::applyLinkFilter('test', ['links' => ['fail-page']], [], new FakeResolveInfo());
+        $this->assertFalse($result->exists());
+
+        $result = LinkablePlugin::applyLinkFilter('test', ['notAnArg' => 'fail'], [], new FakeResolveInfo());
+        $this->assertEquals('test', $result);
+    }
+
+
+    public function provideApply()
+    {
+        return [
+            [true],
+            [false],
+        ];
+    }
+}