[PLA-1946] Add after param validation

lang/en/validation.php

@@ -40,4 +40,5 @@
     'string_too_large' => 'The :attribute field is too large.',
     'not_daemon_wallet' => 'The :attribute is a daemon wallet and should not be used as a signingAccount.',
     'keep_existential_deposit' => 'The :attribute is not enough to keep the existential deposit of :existentialDeposit.',
+    'invalid_after' => 'The :attribute contains and invalid encoded data.',
 ];

src/GraphQL/Schemas/Primary/Substrate/Queries/GetTokensQuery.php

@@ -12,6 +12,7 @@
 use Enjin\Platform\Models\Token;
 use GraphQL\Type\Definition\ResolveInfo;
 use GraphQL\Type\Definition\Type;
+use Illuminate\Pagination\Cursor;
 use Illuminate\Support\Arr;
 use Illuminate\Support\Facades\DB;
 use Rebing\GraphQL\Support\Facades\GraphQL;
@@ -81,4 +82,22 @@ public function resolve($root, $args, $context, ResolveInfo $resolveInfo, Closur
             ->when(Arr::get($args, 'tokenIds'), fn ($query) => $query->whereIn('token_chain_id', $args['tokenIds']))
             ->cursorPaginateWithTotalDesc('identifier', $args['first']);
     }
+
+    /**
+     * Get the validatio rules.
+     */
+    protected function rules(array $args = []): array
+    {
+        return [
+            'after' => [
+                'nullable',
+                function (string $attribute, mixed $value, Closure $fail): void {
+                    if (!Arr::get(Cursor::fromEncoded($value)?->toArray(), 'identifier')) {
+                        $fail('enjin-platform::validation.invalid_after')->translate();
+                    }
+
+                },
+            ],
+        ];
+    }
 }

tests/Feature/GraphQL/Queries/GetTokensTest.php

@@ -139,6 +139,19 @@ public function test_it_can_fetch_tokens_from_a_collection(): void
         $this->assertTrue($response['totalCount'] >= 1);
     }
 
+    public function test_it_can_validate_invalid_after_param(): void
+    {
+        $response = $this->graphql($this->method, [
+            'collectionId' => $this->collection->collection_chain_id,
+            'after' => 'eyJjb2xsZWN0aW9uX2lkIjoxMDM2MywiX3BvaW50c1RvTmV4dEl0ZW1zIjp0cnVlfQ',
+        ], true);
+
+        $this->assertEquals(
+            ['after' => ['The after contains and invalid encoded data.']],
+            $response['error'],
+        );
+    }
+
     public function test_it_can_fetch_tokens_next_page_from_a_collection(): void
     {
         $after = '';