Asset validation: piggyback on Laravel validation rules

src/Fieldtypes/Assets/AssetRule.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace Statamic\Fieldtypes\Assets;
+
+use Illuminate\Contracts\Validation\Rule;
+use Illuminate\Validation\Concerns\ValidatesAttributes;
+use Statamic\Facades\Asset;
+use Statamic\Support\Str;
+use Symfony\Component\HttpFoundation\File\File;
+use Symfony\Component\HttpFoundation\File\UploadedFile;
+
+class AssetRule implements Rule
+{
+    use ValidatesAttributes;
+
+    protected $name;
+    protected $parameters;
+    protected $message;
+
+    public function __construct($name, $message, $parameters = null)
+    {
+        $this->name = $name;
+        $this->message = $message;
+        $this->parameters = $parameters;
+    }
+
+    /**
+     * Determine if the validation rule passes.
+     *
+     * @param  string  $attribute
+     * @param  mixed  $value
+     * @return bool
+     */
+    public function passes($attribute, $value)
+    {
+        $method = 'validate'.Str::studly($this->name);
+
+        return collect($value)->every(function ($file) use ($attribute, $method) {
+            if (! ($file instanceof UploadedFile)) {
+                if (! $asset = Asset::find($file)) {
+                    return false;
+                }
+
+                $file = new File($asset->resolvedPath());
+            }
+
+            return $this->{$method}($attribute, $file, $this->parameters);
+        });
+    }
+
+    /**
+     * Get the validation error message.
+     *
+     * @return string
+     */
+    public function message()
+    {
+        return $this->message;
+    }
+}

src/Fieldtypes/Assets/Assets.php

@@ -174,21 +174,22 @@ public function fieldRules()
     {
         return collect(parent::fieldRules())->map(function ($rule) {
             $name = Str::before($rule, ':');
-            $parameters = explode(',', Str::after($rule, ':'));
 
-            if ($name === 'image') {
-                return new ImageRule();
-            }
-
-            if ($name === 'mimes') {
-                return new MimesRule($parameters);
-            }
+            $parameters = Str::contains($rule, ':')
+                ? explode(',', Str::after($rule, ':'))
+                : null;
 
-            if ($name === 'mimetypes') {
-                return new MimetypesRule($parameters);
+            if ($name === 'dimensions') {
+                $message = __('statamic::validation.dimensions');
+            } elseif ($name === 'image') {
+                $message = __('statamic::validation.image');
+            } elseif ($name === 'mimes') {
+                $message = str_replace(':values', join(', ', $parameters), __('statamic::validation.mimes'));
+            } elseif ($name === 'mimetypes') {
+                $message = str_replace(':values', join(', ', $parameters), __('statamic::validation.mimetypes'));
             }
 
-            return $rule;
+            return $message ? new AssetRule($name, $message, $parameters) : $rule;
         })->all();
     }
 

tests/Fieldtypes/AssetsTest.php

@@ -8,9 +8,8 @@
 use Statamic\Data\AugmentedCollection;
 use Statamic\Facades\AssetContainer;
 use Statamic\Fields\Field;
+use Statamic\Fieldtypes\Assets\AssetRule;
 use Statamic\Fieldtypes\Assets\Assets;
-use Statamic\Fieldtypes\Assets\ImageRule;
-use Statamic\Fieldtypes\Assets\MimesRule;
 use Tests\PreventSavingStacheItemsToDisk;
 use Tests\TestCase;
 
@@ -87,14 +86,24 @@ public function it_shallow_augments_to_a_single_asset_when_max_files_is_one()
         ], $augmented->toArray());
     }
 
+    /** @test */
+    public function it_replaces_dimensions_rule()
+    {
+        $replaced = $this->fieldtype(['validate' => ['dimensions:width=180,height=180']])->fieldRules();
+
+        $this->assertIsArray($replaced);
+        $this->assertCount(1, $replaced);
+        $this->assertInstanceOf(AssetRule::class, $replaced[0]);
+    }
+
     /** @test */
     public function it_replaces_image_rule()
     {
         $replaced = $this->fieldtype(['validate' => ['image']])->fieldRules();
 
         $this->assertIsArray($replaced);
         $this->assertCount(1, $replaced);
-        $this->assertInstanceOf(ImageRule::class, $replaced[0]);
+        $this->assertInstanceOf(AssetRule::class, $replaced[0]);
     }
 
     /** @test */
@@ -104,7 +113,17 @@ public function it_replaces_mimes_rule()
 
         $this->assertIsArray($replaced);
         $this->assertCount(1, $replaced);
-        $this->assertInstanceOf(MimesRule::class, $replaced[0]);
+        $this->assertInstanceOf(AssetRule::class, $replaced[0]);
+    }
+
+    /** @test */
+    public function it_replaces_mimestypes_rule()
+    {
+        $replaced = $this->fieldtype(['validate' => ['mimetypes:image/jpg,image/png']])->fieldRules();
+
+        $this->assertIsArray($replaced);
+        $this->assertCount(1, $replaced);
+        $this->assertInstanceOf(AssetRule::class, $replaced[0]);
     }
 
     public function fieldtype($config = [])