Add rule username

Author: Ariful Alam

resources/lang/en/validation.php

@@ -14,5 +14,6 @@
     'float_number' => 'The :attribute must be a float number',
     'image_url' => 'The :attribute must be a valid image URL.',
     'phone' => 'The :attribute must be a valid phone number.',
+    'username' => 'The :attribute must be a valid username.',
     'without_spaces' => 'The :attribute must not contain spaces.',
 ];

src/Rules/Username.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace Arifszn\AdvancedValidation\Rules;
+
+use Illuminate\Contracts\Validation\Rule;
+
+/**
+ * The field under validation must be a valid username.
+ *
+ *  - starts with a letter (alpha)
+ *  - only alpha-numeric (a-z, A-Z, 0-9), underscore, minus and dot
+ *  - multiple underscores, minus and are not allowed (-- or __ or ..)
+ *  - underscores, minus and dot are not allowed at the beginning or end
+ *
+ * @package Arifszn\AdvancedValidation\Rules
+ */
+class Username implements Rule
+{
+    /**
+     * @var string
+     */
+    private $errorMessage;
+
+    /**
+     * Create a new rule instance.
+     *
+     * @param string|null $errorMessage   Custom error message.
+     * @return void
+     */
+    public function __construct(string $errorMessage = null)
+    {
+        $this->errorMessage = $errorMessage;
+    }
+
+    /**
+     * Determine if the validation rule passes.
+     *
+     * @param string $attribute
+     * @param mixed $value
+     * @return bool
+     */
+    public function passes($attribute, $value)
+    {
+        return preg_match('/^[a-z][a-z0-9]*(?:[_\-\.][a-z0-9]+)*$/i', $value);
+    }
+
+    /**
+     * Get the validation error message.
+     *
+     * @return string
+     */
+    public function message()
+    {
+        return $this->errorMessage ? $this->errorMessage : trans('advancedValidation::validation.username');
+    }
+}