[5.5] Support custom validation rule objects.

src/Illuminate/Contracts/Validation/ImplicitRule.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Illuminate\Contracts\Validation;
+
+interface ImplicitRule extends Rule
+{
+    //
+}

src/Illuminate/Contracts/Validation/Rule.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace Illuminate\Contracts\Validation;
+
+interface Rule
+{
+    /**
+     * Determine if the validation rule passes.
+     *
+     * @param  string  $attribute
+     * @param  mixed  $value
+     * @return bool
+     */
+    public function passes($attribute, $value);
+
+    /**
+     * Get the validation error message.
+     *
+     * @return string
+     */
+    public function message();
+}

src/Illuminate/Validation/ClosureValidationRule.php

@@ -0,0 +1,70 @@
+<?php
+
+namespace Illuminate\Validation;
+
+use Illuminate\Contracts\Validation\Rule as RuleContract;
+
+class ClosureValidationRule implements RuleContract
+{
+    /**
+     * The callback that validates the attribute.
+     *
+     * @var \Closure
+     */
+    public $callback;
+
+    /**
+     * Indicates if the validation callback failed.
+     *
+     * @var bool
+     */
+    public $failed = false;
+
+    /**
+     * The validation error message.
+     *
+     * @var string|null
+     */
+    public $message;
+
+    /**
+     * Create a new Closure based validation rule.
+     *
+     * @param  \Closure  $callback
+     * @return void
+     */
+    public function __construct($callback)
+    {
+        $this->callback = $callback;
+    }
+
+    /**
+     * Determine if the validation rule passes.
+     *
+     * @param  string  $attribute
+     * @param  mixed  $value
+     * @return bool
+     */
+    public function passes($attribute, $value)
+    {
+        $this->failed = false;
+
+        $this->callback->__invoke($attribute, $value, function ($message) {
+            $this->failed = true;
+
+            $this->message = $message;
+        });
+
+        return ! $this->failed;
+    }
+
+    /**
+     * Get the validation error message.
+     *
+     * @return string
+     */
+    public function message()
+    {
+        return $this->message;
+    }
+}

src/Illuminate/Validation/ValidationRuleParser.php

@@ -2,10 +2,12 @@
 
 namespace Illuminate\Validation;
 
+use Closure;
 use Illuminate\Support\Arr;
 use Illuminate\Support\Str;
 use Illuminate\Validation\Rules\Exists;
 use Illuminate\Validation\Rules\Unique;
+use Illuminate\Contracts\Validation\Rule as RuleContract;
 
 class ValidationRuleParser
 {
@@ -98,7 +100,12 @@ protected function explodeExplicitRule($rule)
      */
     protected function prepareRule($rule)
     {
+        if ($rule instanceof Closure) {
+            $rule = new ClosureValidationRule($rule);
+        }
+
         if (! is_object($rule) ||
+            $rule instanceof RuleContract ||
             ($rule instanceof Exists && $rule->queryCallbacks()) ||
             ($rule instanceof Unique && $rule->queryCallbacks())) {
             return $rule;
@@ -184,6 +191,10 @@ protected function mergeRulesForAttribute($results, $attribute, $rules)
      */
     public static function parse($rules)
     {
+        if ($rules instanceof RuleContract) {
+            return [$rules, []];
+        }
+
         if (is_array($rules)) {
             $rules = static::parseArrayRule($rules);
         } else {

src/Illuminate/Validation/Validator.php

@@ -11,7 +11,9 @@
 use Illuminate\Support\MessageBag;
 use Illuminate\Contracts\Container\Container;
 use Illuminate\Contracts\Translation\Translator;
+use Illuminate\Contracts\Validation\ImplicitRule;
 use Symfony\Component\HttpFoundation\File\UploadedFile;
+use Illuminate\Contracts\Validation\Rule as RuleContract;
 use Illuminate\Contracts\Validation\Validator as ValidatorContract;
 
 class Validator implements ValidatorContract
@@ -333,6 +335,10 @@ protected function validateAttribute($attribute, $rule)
         // attribute is invalid and we will add a failure message for this failing attribute.
         $validatable = $this->isValidatable($rule, $attribute, $value);
 
+        if ($validatable && $rule instanceof RuleContract) {
+            return $this->validateUsingCustomRule($attribute, $value, $rule);
+        }
+
         $method = "validate{$rule}";
 
         if ($validatable && ! $this->$method($attribute, $value, $parameters, $this)) {
@@ -408,7 +414,7 @@ protected function replaceAsterisksInParameters(array $parameters, array $keys)
     /**
      * Determine if the attribute is validatable.
      *
-     * @param  string  $rule
+     * @param  object|string  $rule
      * @param  string  $attribute
      * @param  mixed   $value
      * @return bool
@@ -424,7 +430,7 @@ protected function isValidatable($rule, $attribute, $value)
     /**
      * Determine if the field is present, or the rule implies required.
      *
-     * @param  string  $rule
+     * @param  object|string  $rule
      * @param  string  $attribute
      * @param  mixed   $value
      * @return bool
@@ -435,18 +441,20 @@ protected function presentOrRuleIsImplicit($rule, $attribute, $value)
             return $this->isImplicit($rule);
         }
 
-        return $this->validatePresent($attribute, $value) || $this->isImplicit($rule);
+        return $this->validatePresent($attribute, $value) ||
+               $this->isImplicit($rule);
     }
 
     /**
      * Determine if a given rule implies the attribute is required.
      *
-     * @param  string  $rule
+     * @param  object|string  $rule
      * @return bool
      */
     protected function isImplicit($rule)
     {
-        return in_array($rule, $this->implicitRules);
+        return $rule instanceof ImplicitRule ||
+               in_array($rule, $this->implicitRules);
     }
 
     /**
@@ -476,7 +484,7 @@ protected function passesOptionalCheck($attribute)
      */
     protected function isNotNullIfMarkedAsNullable($rule, $attribute)
     {
-        if (in_array($rule, $this->implicitRules) || ! $this->hasRule($attribute, ['Nullable'])) {
+        if ($this->isImplicit($rule) || ! $this->hasRule($attribute, ['Nullable'])) {
             return true;
         }
 
@@ -497,6 +505,25 @@ protected function hasNotFailedPreviousRuleIfPresenceRule($rule, $attribute)
         return in_array($rule, ['Unique', 'Exists']) ? ! $this->messages->has($attribute) : true;
     }
 
+    /**
+     * Validate an attribute using a custom rule object.
+     *
+     * @param  string  $attribute
+     * @param  mixed  $value
+     * @param  \Illuminate\Contracts\Validation\Rule  $rule
+     * @return void
+     */
+    protected function validateUsingCustomRule($attribute, $value, $rule)
+    {
+        if (! $rule->passes($attribute, $value)) {
+            $this->failedRules[$attribute][get_class($rule)] = [];
+
+            $this->messages->add($attribute, $this->makeReplacements(
+                $rule->message(), $attribute, get_class($rule), []
+            ));
+        }
+    }
+
     /**
      * Check if we should stop further validations on a given attribute.
      *

tests/Validation/ValidationValidatorTest.php

@@ -9,7 +9,9 @@
 use Illuminate\Validation\Validator;
 use Illuminate\Validation\Rules\Exists;
 use Illuminate\Validation\Rules\Unique;
+use Illuminate\Contracts\Validation\Rule;
 use Symfony\Component\HttpFoundation\File\File;
+use Illuminate\Contracts\Validation\ImplicitRule;
 
 class ValidationValidatorTest extends TestCase
 {
@@ -3395,6 +3397,140 @@ public function testFileUploads()
         $this->assertFalse($v->passes());
     }
 
+    public function testCustomValidationObject()
+    {
+        // Test passing case...
+        $v = new Validator(
+            $this->getIlluminateArrayTranslator(),
+            ['name' => 'taylor'],
+            ['name' => new class implements Rule {
+                public function passes($attribute, $value)
+                {
+                    return $value === 'taylor';
+                }
+
+                public function message()
+                {
+                    return ':attribute must be taylor';
+                }
+            }]
+        );
+
+        $this->assertTrue($v->passes());
+
+        // Test failing case...
+        $v = new Validator(
+            $this->getIlluminateArrayTranslator(),
+            ['name' => 'adam'],
+            ['name' => [new class implements Rule {
+                public function passes($attribute, $value)
+                {
+                    return $value === 'taylor';
+                }
+
+                public function message()
+                {
+                    return ':attribute must be taylor';
+                }
+            }]]
+        );
+
+        $this->assertTrue($v->fails());
+        $this->assertEquals('name must be taylor', $v->errors()->all()[0]);
+
+        // Test passing case with Closure...
+        $v = new Validator(
+            $this->getIlluminateArrayTranslator(),
+            ['name' => 'taylor'],
+            ['name.*' => function ($attribute, $value, $fail) {
+                if ($value !== 'taylor') {
+                    $fail(':attribute was '.$value.' instead of taylor');
+                }
+            }]
+        );
+
+        $this->assertTrue($v->passes());
+
+        // Test failing case with Closure...
+        $v = new Validator(
+            $this->getIlluminateArrayTranslator(),
+            ['name' => 'adam'],
+            ['name' => function ($attribute, $value, $fail) {
+                if ($value !== 'taylor') {
+                    $fail(':attribute was '.$value.' instead of taylor');
+                }
+            }]
+        );
+
+        $this->assertTrue($v->fails());
+        $this->assertEquals('name was adam instead of taylor', $v->errors()->all()[0]);
+
+        // Test complex failing case...
+        $v = new Validator(
+            $this->getIlluminateArrayTranslator(),
+            ['name' => 'taylor', 'states' => ['AR', 'TX'], 'number' => 9],
+            [
+                'states.*' => new class implements Rule {
+                    public function passes($attribute, $value)
+                    {
+                        return in_array($value, ['AK', 'HI']);
+                    }
+
+                    public function message()
+                    {
+                        return ':attribute must be AR or TX';
+                    }
+                },
+                'name' => function ($attribute, $value, $fail) {
+                    if ($value !== 'taylor') {
+                        $fail(':attribute must be taylor');
+                    }
+                },
+                'number' => [
+                    'required',
+                    'integer',
+                    function ($attribute, $value, $fail) {
+                        if ($value % 4 !== 0) {
+                            $fail(':attribute must be divisible by 4');
+                        }
+                    },
+                ],
+            ]
+        );
+
+        $this->assertFalse($v->passes());
+        $this->assertEquals('states.0 must be AR or TX', $v->errors()->get('states.0')[0]);
+        $this->assertEquals('states.1 must be AR or TX', $v->errors()->get('states.1')[0]);
+        $this->assertEquals('number must be divisible by 4', $v->errors()->get('number')[0]);
+    }
+
+    public function testImplicitCustomValidationObjects()
+    {
+        // Test passing case...
+        $v = new Validator(
+            $this->getIlluminateArrayTranslator(),
+            ['name' => ''],
+            ['name' => $rule = new class implements ImplicitRule {
+                public $called = false;
+
+                public function passes($attribute, $value)
+                {
+                    $this->called = true;
+
+                    return true;
+                }
+
+                public function message()
+                {
+                    return 'message';
+                }
+            }]
+        );
+
+        $this->assertTrue($v->passes());
+        $this->assertTrue($rule->called);
+    }
+
     protected function getTranslator()
     {
         return m::mock('Illuminate\Contracts\Translation\Translator');