ENH Improved validation

README.md

@@ -164,6 +164,10 @@ class MyCustomLink extends Link
 }
 ```
 
+## Custom link validation
+
+Custom links can have validation set using standard [model validation]([https://docs.silverstripe.org/en/5/developer_guides/forms/validation/#model-validation).
+
 ## Migrating from Shae Dawson's Linkable module
 
 https://github.com/sheadawson/silverstripe-linkable

lang/en.yml

@@ -3,6 +3,8 @@ en:
     CREATE_LINK: 'Create link'
     MENUTITLE: 'Link fields'
     UPDATE_LINK: 'Update link'
+  SilverStripe\LinkField\Form\ExternalLinkField:
+    INVALID: 'Please enter a valid URL'
   SilverStripe\LinkField\Form\Traits\AllowedLinkClassesTrait:
     INVALID_TYPECLASS: '"{class}": {typeclass} is not a valid Link Type'
     INVALID_TYPECLASS_EMPTY: '"{class}": Allowed types cannot be empty'
@@ -16,14 +18,15 @@ en:
     SINGULARNAME: 'Email Link'
     db_Email: Email
   SilverStripe\LinkField\Models\ExternalLink:
-    EXTERNAL_URL_FIELD: 'External url'
+    EXTERNAL_URL_FIELD: 'External URL'
+    EXTERNAL_URL_FIELD_DESCRIPTION: 'Ensure the URL starts with http:// or https://'
     LINKLABEL: 'Link to external URL'
     PLURALNAME: 'External Links'
     PLURALS:
       one: 'An External Link'
       other: '{count} External Links'
     SINGULARNAME: 'External Link'
-    db_ExternalUrl: 'External url'
+    db_ExternalUrl: 'External URL'
   SilverStripe\LinkField\Models\FileLink:
     CANNOT_VIEW_FILE: 'Cannot view file'
     FILE_DOES_NOT_EXIST: 'File does not exist'

src/Form/ExternalLinkField.php

@@ -0,0 +1,55 @@
+<?php
+
+namespace SilverStripe\LinkField\Form;
+
+use SilverStripe\Forms\TextField;
+use SilverStripe\Forms\Validator;
+
+/**
+ * Text input field with validation for a url
+ * Only intended to be used with the ExternalLink DataObject
+ */
+class ExternalLinkField extends TextField
+{
+    /**
+     * This needs to be not surronded by regex delimiters so that it works on the frontend
+     * https://urlregex.com/
+     */
+    private const JS_RX = '((([A-Za-z]{3,9}:(?:\/\/)?)(?:[\-;:&=\+\$,\w]+@)?[A-Za-z0-9\.\-]+|(?:www\.|[\-;:&=\+\$,\w]+@)[A-Za-z0-9\.\-]+)((?:\/[\+~%\/\.\w\-_]*)?\??(?:[\-\+=&;%@\.\w_]*)#?(?:[\.\!\/\\\w]*))?)';
+
+    /**
+     * https://urlregex.com/
+     */
+    private const PHP_RX = '%^(?:(?:https?|ftp)://)(?:\S+(?::\S*)?@|\d{1,3}(?:\.\d{1,3}){3}|(?:(?:[a-z\d\x{00a1}-\x{ffff}]+-?)*[a-z\d\x{00a1}-\x{ffff}]+)(?:\.(?:[a-z\d\x{00a1}-\x{ffff}]+-?)*[a-z\d\x{00a1}-\x{ffff}]+)*(?:\.[a-z\x{00a1}-\x{ffff}]{2,6}))(?::\d+)?(?:[^\s]*)?$%iu';
+
+    /**
+     * @param Validator $validator
+     *
+     * @return string
+     */
+    public function validate($validator)
+    {
+        $result = true;
+        $this->value = trim($this->value ?? '');
+        if ($this->value && !preg_match(self::PHP_RX, $this->value)) {
+            $validator->validationError(
+                $this->name,
+                _t(__CLASS__ . '.INVALID', 'Please enter a valid URL'),
+                'validation'
+            );
+            $result = false;
+        }
+        return $this->extendValidationResult($result, $validator);
+    }
+
+    /**
+     * This is passed to the frontent via FormField::getSchemaValidation()
+     * and used in Validator.js
+     */
+    public function getSchemaValidation()
+    {
+        $rules = parent::getSchemaValidation();
+        $rules['regex'] = ['pattern' => self::JS_RX];
+        return $rules;
+    }
+}

src/Models/EmailLink.php

@@ -4,6 +4,8 @@
 
 use SilverStripe\Forms\EmailField;
 use SilverStripe\Forms\FieldList;
+use SilverStripe\Forms\CompositeValidator;
+use SilverStripe\Forms\RequiredFields;
 
 /**
  * A link to an Email address.
@@ -55,4 +57,11 @@ public function getMenuTitle(): string
     {
         return _t(__CLASS__ . '.LINKLABEL', 'Link to email address');
     }
+
+    public function getCMSCompositeValidator(): CompositeValidator
+    {
+        $validator = parent::getCMSCompositeValidator();
+        $validator->addValidator(RequiredFields::create(['Email']));
+        return $validator;
+    }
 }

src/Models/ExternalLink.php

@@ -3,6 +3,9 @@
 namespace SilverStripe\LinkField\Models;
 
 use SilverStripe\Forms\FieldList;
+use SilverStripe\Forms\CompositeValidator;
+use SilverStripe\Forms\RequiredFields;
+use SilverStripe\LinkField\Form\ExternalLinkField;
 
 /**
  * A link to an external URL.
@@ -27,8 +30,13 @@ class ExternalLink extends Link
     public function getCMSFields(): FieldList
     {
         $this->beforeUpdateCMSFields(function (FieldList $fields) {
-            $linkField = $fields->dataFieldByName('ExternalUrl');
-            $linkField->setTitle(_t(__CLASS__ . '.EXTERNAL_URL_FIELD', 'External url'));
+            $field = ExternalLinkField::create('ExternalUrl');
+            $field->setTitle(_t(__CLASS__ . '.EXTERNAL_URL_FIELD', 'External URL'));
+            $field->setDescription(_t(
+                __CLASS__ . '.EXTERNAL_URL_FIELD_DESCRIPTION',
+                'Ensure the URL starts with http:// or https://'
+            ));
+            $fields->replaceField('ExternalUrl', $field);
         });
         return parent::getCMSFields();
     }
@@ -51,4 +59,11 @@ public function getMenuTitle(): string
     {
         return _t(__CLASS__ . '.LINKLABEL', 'Link to external URL');
     }
+
+    public function getCMSCompositeValidator(): CompositeValidator
+    {
+        $validator = parent::getCMSCompositeValidator();
+        $validator->addValidator(RequiredFields::create(['ExternalUrl']));
+        return $validator;
+    }
 }

src/Models/FileLink.php

@@ -4,6 +4,8 @@
 
 use SilverStripe\Assets\File;
 use SilverStripe\Forms\FieldList;
+use SilverStripe\Forms\CompositeValidator;
+use SilverStripe\Forms\RequiredFields;
 
 /**
  * A link to a File in the CMS
@@ -71,4 +73,11 @@ public function getMenuTitle(): string
     {
         return _t(__CLASS__ . '.LINKLABEL', 'Link to a file');
     }
+
+    public function getCMSCompositeValidator(): CompositeValidator
+    {
+        $validator = parent::getCMSCompositeValidator();
+        $validator->addValidator(RequiredFields::create(['File']));
+        return $validator;
+    }
 }

src/Models/PhoneLink.php

@@ -3,6 +3,9 @@
 namespace SilverStripe\LinkField\Models;
 
 use SilverStripe\Forms\FieldList;
+use SilverStripe\Forms\CompositeValidator;
+use SilverStripe\Forms\RequiredFields;
+use SilverStripe\LinkField\Form\PhoneField;
 
 /**
  * A link to a phone number
@@ -25,8 +28,8 @@ class PhoneLink extends Link
     public function getCMSFields(): FieldList
     {
         $this->beforeUpdateCMSFields(function (FieldList $fields) {
-            $linkField = $fields->dataFieldByName('Phone');
-            $linkField->setTitle(_t(__CLASS__ . '.PHONE_FIELD', 'Phone'));
+            $field = $fields->dataFieldByName('Phone');
+            $field->setTitle(_t(__CLASS__ . '.PHONE_FIELD', 'Phone'));
             $fields->removeByName('OpenInNew');
         });
         return parent::getCMSFields();
@@ -50,4 +53,11 @@ public function getMenuTitle(): string
     {
         return _t(__CLASS__ . '.LINKLABEL', 'Phone number');
     }
+
+    public function getCMSCompositeValidator(): CompositeValidator
+    {
+        $validator = parent::getCMSCompositeValidator();
+        $validator->addValidator(RequiredFields::create(['Phone']));
+        return $validator;
+    }
 }

src/Models/SiteTreeLink.php

@@ -8,6 +8,8 @@
 use SilverStripe\Forms\FieldList;
 use SilverStripe\Forms\TextField;
 use SilverStripe\Forms\TreeDropdownField;
+use SilverStripe\Forms\CompositeValidator;
+use SilverStripe\Forms\RequiredFields;
 
 /**
  * A link to a Page in the CMS
@@ -147,4 +149,11 @@ public function getMenuTitle(): string
     {
         return _t(__CLASS__ . '.LINKLABEL', 'Page on this site');
     }
+
+    public function getCMSCompositeValidator(): CompositeValidator
+    {
+        $validator = parent::getCMSCompositeValidator();
+        $validator->addValidator(RequiredFields::create(['PageID']));
+        return $validator;
+    }
 }