Unable to open file for reading [filename.pdf] yii2 swiftmailer - yii2

Question

I am trying to send an email with attachment when I used var_dump($filename)it returns the filename and gettype($filename) it returns string. but when I am trying to send an attachment it still returns Unable to open file for reading [filename.pdf] even if $file_attachment was looped I tried to change UploadedFile::getInstancesByName('file_attachment'); to UploadedFile::getInstanceByName('file_attachment'); but nothing happened. Please help me.
This is my controller
if(Yii::$app->request->isPost){
$email = Yii::$app->request->post('email');
$message = Yii::$app->request->post('message');
$file_attachment = UploadedFile::getInstancesByName('file_attachment');
if($file_attachment){
$mail = Yii::$app->mailer->compose()
->setFrom(['myemail#gmail.com' => 'My Email'])
->setTo($email)
->setSubject('My Subject')
->setHtmlBody($message);
foreach ($file_attachment as $file) {
$filename = $file->baseName. '.' . $file->extension;
$mail->attach($filename);
}
//$mail->send();
//echo gettype($filename);
// var_dump($filename);
$mail->send();
}else{
$mail = Yii::$app->mailer->compose()
->setFrom(['myemail#gmail.com' => 'My Email'])
->setTo($email)
->setSubject('My Subject')
->setHtmlBody($message)
->send();
}
}
This is the view
<?php
echo FileInput::widget([
'name' => 'file_attachment',
'attribute' => 'file_attachment',
'options' => ['multiple' => true]
]);
?>

Answer 1

The baseName property of yii\web\UploadedFile contains the original filename but the file is not present on the server under its original filename. You need to use tempName property that contains path to the uploaded file on server.
Your for each cycle that attaches files to mail should look like:
foreach ($file_attachment as $file) {
$filename = $file->baseName. '.' . $file->extension;
$mail->attach(
$file->tempName,
['fileName' => $filename]
);
}
It might also be a good idea to check hasError property of yii\web\UploadedFile before attempting to attach file to see if the upload was successful.
Also make sure that you've set 'enctype' => 'multipart/form-data' in you form options when you are not using ActiveForm with ActiveField::fileInput() otherwise the files might not be uploaded.