Create validation rule UNIQUE

Author: thecodeholic

core/Database.php

@@ -83,6 +83,11 @@ protected function saveMigrations(array $newMigrations)
         $statement->execute();
     }
 
+    public function prepare($sql): \PDOStatement
+    {
+        return $this->pdo->prepare($sql);
+    }
+
     private function log($message)
     {
         echo "[" . date("Y-m-d H:i:s") . "] - " . $message . PHP_EOL;

core/DbModel.php

@@ -30,7 +30,7 @@ public function save()
         $tableName = $this->tableName();
         $attributes = $this->attributes();
         $params = array_map(fn($attr) => ":$attr", $attributes);
-        $statement = $this->prepare("INSERT INTO $tableName (" . implode(",", $attributes) . ") 
+        $statement = self::prepare("INSERT INTO $tableName (" . implode(",", $attributes) . ") 
                 VALUES (" . implode(",", $params) . ")");
         foreach ($attributes as $attribute) {
             $statement->bindValue(":$attribute", $this->{$attribute});
@@ -39,8 +39,8 @@ public function save()
         return true;
     }
 
-    public function prepare($sql): \PDOStatement
+    public static function prepare($sql): \PDOStatement
     {
-        return Application::$app->db->pdo->prepare($sql);
+        return Application::$app->db->prepare($sql);
     }
 }

core/Model.php

@@ -21,6 +21,7 @@ class Model
     const RULE_MIN = 'min';
     const RULE_MAX = 'max';
     const RULE_MATCH = 'match';
+    const RULE_UNIQUE = 'unique';
 
     public array $errors = [];
 
@@ -62,6 +63,18 @@ public function validate()
                 if ($ruleName === self::RULE_MATCH && $value !== $this->{$rule['match']}) {
                     $this->addError($attribute, self::RULE_MATCH, ['match' => $rule['match']]);
                 }
+                if ($ruleName === self::RULE_UNIQUE) {
+                    $className = $rule['class'];
+                    $tableName = $className::tableName();
+                    $db = Application::$app->db;
+                    $statement = $db->prepare("SELECT * FROM $tableName WHERE $attribute = :$attribute");
+                    $statement->bindValue(":$attribute", $value);
+                    $statement->execute();
+                    $record = $statement->fetchObject();
+                    if ($record) {
+                        $this->addError($attribute, self::RULE_UNIQUE);
+                    }
+                }
             }
         }
         return empty($this->errors);
@@ -75,6 +88,7 @@ public function errorMessages()
             self::RULE_MIN => 'Min length of this field must be {min}',
             self::RULE_MAX => 'Max length of this field must be {max}',
             self::RULE_MATCH => 'This field must be the same as {match}',
+            self::RULE_UNIQUE => 'Record with with this {field} already exists',
         ];
     }
 
@@ -85,6 +99,7 @@ public function errorMessage($rule)
 
     public function addError(string $attribute, string $rule, $params = [])
     {
+        $params['field'] ??= $attribute;
         $errorMessage = $this->errorMessage($rule);
         foreach ($params as $key => $value) {
             $errorMessage = str_replace("{{$key}}", $value, $errorMessage);

models/User.php

@@ -40,7 +40,9 @@ public function rules()
         return [
             'firstname' => [self::RULE_REQUIRED],
             'lastname' => [self::RULE_REQUIRED],
-            'email' => [self::RULE_REQUIRED, self::RULE_EMAIL],
+            'email' => [self::RULE_REQUIRED, self::RULE_EMAIL, [
+                self::RULE_UNIQUE, 'class' => self::class
+            ]],
             'password' => [self::RULE_REQUIRED, [self::RULE_MIN, 'min' => 8]],
             'passwordConfirm' => [[self::RULE_MATCH, 'match' => 'password']],
         ];