NEW Maximum email attachment size can be configured

Previously hard coded size of 1MB meant any file larger was excluded
from recipient emails - often confusing for CMS admins configuring an
advanced use case for a userform, expecting to recieve files to begin a
business process external to the website.

The configuration has been made to support PHP 'shorthand byte values'
https://www.php.net/manual/en/faq.using.php#faq.using.shorthandbytes
in the configuration option. This give flexibility around oddly
specific limits, but can also be used to set as 0, disabling attachments

Tests are updated to set up a known state before testing, as to be able
to accurately assert the results. One should test the class they intend,
not an Injector service of some unknown element.

code/Control/UserDefinedFormController.php

@@ -56,6 +56,16 @@ class UserDefinedFormController extends PageController
 
     private static string $file_upload_stage = Versioned::DRAFT;
 
+    /**
+     * Size that an uploaded file must not excede for it to be attached to an email
+     * Follows PHP "shorthand bytes" definition rules.
+     * @see self::parseByteSizeString()
+     *
+     * @var int
+     * @config
+     */
+    private static $maximum_email_attachment_size = '1M';
+
     protected function init()
     {
         parent::init();
@@ -215,6 +225,42 @@ JS
         }
     }
 
+    /**
+     * Returns the maximum size uploaded files can be before they're excluded from CMS configured recipient emails
+     *
+     * @return int size in megabytes
+     */
+    public function getMaximumAllowedEmailAttachmentSize()
+    {
+        return $this->parseByteSizeString($this->config()->get('maximum_email_attachment_size'));
+    }
+
+    /**
+     * Convert file sizes with a single character for unit size to true byte count.
+     * Just as with php.ini and e.g. 128M -> 1024 * 1024 * 128 bytes.
+     * @see https://www.php.net/manual/en/faq.using.php#faq.using.shorthandbytes
+     *
+     * @param string $byteSize
+     * @return int bytes
+     */
+    protected function parseByteSizeString($byteSize)
+    {
+        // kilo, mega, giga
+        $validUnits = 'kmg';
+        $valid = preg_match("/^(?<number>\d+)((?<unit>[$validUnits])b?)?$/i", $byteSize, $matches);
+        if (!$valid) {
+            throw new \InvalidArgumentException(
+                "Expected a positive integer followed optionally by K, M, or G. Found '$byteSize' instead"
+            );
+        }
+        $power = 0;
+        // prepend b for bytes to $validUnits to give correct mapping of ordinal position to exponent
+        if (isset($matches['unit'])) {
+            $power = stripos("b$validUnits", $matches['unit']);
+        }
+        return intval($matches['number']) * pow(1024, $power);
+    }
+
     /**
      * Process the form that is submitted through the site
      *
@@ -268,7 +314,7 @@ JS
                         if (!$field->getFolderExists()) {
                             $field->createProtectedFolder();
                         }
-                        
+
                         $file = Versioned::withVersionedMode(function () use ($field, $form) {
                             $stage = Injector::inst()->get(self::class)->config()->get('file_upload_stage');
                             Versioned::set_stage($stage);
@@ -308,8 +354,8 @@ JS
                         // write file to form field
                         $submittedField->UploadedFileID = $file->ID;
 
-                        // attach a file only if lower than 1MB
+                        // attach a file to recipient email only if lower than configured size
-                        if ($file->getAbsoluteSize() < 1024 * 1024 * 1) {
+                        if ($file->getAbsoluteSize() <= $this->getMaximumAllowedEmailAttachmentSize()) {
                             $attachments[] = $file;
                         }
                     }

tests/php/Control/UserDefinedFormControllerTest.php

@@ -24,6 +24,7 @@ use SilverStripe\UserForms\Model\EditableFormField\EditableTextField;
 use SilverStripe\UserForms\Model\Recipient\EmailRecipient;
 use SilverStripe\UserForms\Model\Submission\SubmittedFormField;
 use SilverStripe\UserForms\Model\UserDefinedForm;
+use SilverStripe\UserForms\Tests\Control\fixtures\SizeStringTestableController;
 use SilverStripe\Versioned\Versioned;
 use SilverStripe\View\ArrayData;
 use SilverStripe\View\SSViewer;
@@ -47,7 +48,9 @@ class UserDefinedFormControllerTest extends FunctionalTest
         // Set backend and base url
         TestAssetStore::activate('AssetStoreTest');
 
-        Config::modify()->merge(SSViewer::class, 'themes', ['simple', '$default']);
+        $config = Config::modify();
+        $config->set(UserDefinedFormController::class, 'maximum_email_attachment_size', "1M");
+        $config->merge(SSViewer::class, 'themes', ['simple', '$default']);
     }
 
     protected function tearDown(): void
@@ -273,7 +276,8 @@ class UserDefinedFormControllerTest extends FunctionalTest
         $actions = $controller->Form()->getFormActions();
 
         $expected = new FieldList(new FormAction('process', 'Custom Button'));
-        $expected->push(FormAction::create('clearForm', 'Clear')->setAttribute('type', 'reset'));
+        $clearAction = new FormAction('clearForm', 'Clear');
+        $expected->push($clearAction->setAttribute('type', 'reset'));
         $expected->setForm($controller->Form());
 
         $this->assertEquals($actions, $expected);
@@ -404,7 +408,7 @@ class UserDefinedFormControllerTest extends FunctionalTest
         Config::modify()->set(Upload_Validator::class, 'use_is_uploaded_file', false);
 
         $userForm = $this->setupFormFrontend('upload-form');
-        $controller = UserDefinedFormController::create($userForm);
+        $controller = new UserDefinedFormController($userForm);
         $field = $this->objFromFixture(EditableFileField::class, 'file-field-1');
 
         $path = realpath(__DIR__ . '/fixtures/testfile.jpg');
@@ -440,7 +444,7 @@ class UserDefinedFormControllerTest extends FunctionalTest
         Config::modify()->set(Upload_Validator::class, 'use_is_uploaded_file', false);
 
         $userForm = $this->setupFormFrontend('upload-form');
-        $controller = UserDefinedFormController::create($userForm);
+        $controller = new UserDefinedFormController($userForm);
         $field = $this->objFromFixture(EditableFileField::class, 'file-field-1');
 
         $path = realpath(__DIR__ . '/fixtures/testfile.jpg');
@@ -511,4 +515,71 @@ class UserDefinedFormControllerTest extends FunctionalTest
         $this->assertEquals(1, $fileDraftCount);
         $this->assertEquals(0, $fileLiveCount);
     }
+
+    public function testEmailAttachmentMaximumSizeCanBeConfigured()
+    {
+        $udfController = new UserDefinedFormController();
+        $config = Config::modify();
+        $config->set(UserDefinedFormController::class, 'maximum_email_attachment_size', '1M');
+        $this->assertSame(1 * 1024 * 1024, $udfController->getMaximumAllowedEmailAttachmentSize());
+        $config->set(UserDefinedFormController::class, 'maximum_email_attachment_size', '5M');
+        $this->assertSame(5 * 1024 * 1024, $udfController->getMaximumAllowedEmailAttachmentSize());
+    }
+
+    public function getParseByteSizeStringTestValues()
+    {
+        return [
+            ['9846', 9846],
+            ['1048576', 1048576],
+            ['1k', 1024],
+            ['1K', 1024],
+            ['4k', 4096],
+            ['4K', 4096],
+            ['1kb', 1024],
+            ['1KB', 1024],
+            ['4kB', 4096],
+            ['4Kb', 4096],
+            ['1m', 1048576],
+            ['1M', 1048576],
+            ['4mb', 4194304],
+            ['4MB', 4194304],
+            ['25mB', 26214400],
+            ['25Mb', 26214400],
+            ['1g', 1073741824],
+            ['2GB', 2147483648],
+        ];
+    }
+
+    /**
+     * @dataProvider getParseByteSizeStringTestValues
+     */
+    public function testParseByteSizeString($input, $expectedOutput)
+    {
+        $controller = new SizeStringTestableController(); // extends UserDefinedFormController
+        $this->assertSame($expectedOutput, $controller->convertSizeStringToBytes($input));
+    }
+
+    public function getParseByteSizeStringTestBadValues()
+    {
+        return [
+            ['1234b'],
+            ['9846B'],
+            ['1kilobyte'],
+            ['1 K'],
+            ['Four kilobytes'],
+            ['4Mbs'],
+            ['12Gigs'],
+        ];
+    }
+
+    /**
+     * @dataProvider getParseByteSizeStringTestBadValues
+     * @expectedException \InvalidArgumentException
+     */
+    public function testParseByteSizeStringBadValuesThrowException($input)
+    {
+        $this->expectException('\InvalidArgumentException');
+        $controller = new SizeStringTestableController(); // extends UserDefinedFormController
+        $controller->convertSizeStringToBytes($input);
+    }
 }

tests/php/Control/fixtures/SizeStringTestableController.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace SilverStripe\UserForms\Tests\Control\fixtures;
+
+use SilverStripe\Dev\TestOnly;
+use SilverStripe\UserForms\Control\UserDefinedFormController;
+
+class SizeStringTestableController extends UserDefinedFormController implements TestOnly
+{
+    public function convertSizeStringToBytes($sizeString)
+    {
+        return $this->parseByteSizeString($sizeString);
+    }
+}