How to convert UploadedFile object to Swift_Mime_MimeEntity - php

Question

I have a Symfony 3.3 contact form that sends an email. Now I am trying to add an attachment to the form. I insert the following line in my sendEmail function:
->attach($data["attachment"])
... and I get the following error:
Argument 1 passed to Swift_Mime_SimpleMessage::attach() must implement
interface Swift_Mime_MimeEntity, instance of
Symfony\Component\HttpFoundation\File\UploadedFile given
So my question is: How do I convert my UploadedFile object into something that SwiftMailer will be happy with?
====
Edit #1: I tried this with no success:
$fullFilePath = $data["attachment"]->getPath() . '/' . $data["attachment"]->getClientOriginalName();
$attachment = \Swift_Attachment::fromPath($fullFilePath);
Attaching that "attachment" just resulted in the email not being sent, though the application acted as if it had sent the form.
====
Edit #2: Progress! I'm now able to get a useful error. This code ...
$extension = $data["attachment"]->guessExtension();
if($extension !== 'rtf'){
die('Please give us an rtf file. TODO: Put a better message here!');
}
$newFilePath = '/tmp';
$newFileName = 'temporary.rtf';
$data["attachment"]->move($newFilePath, $newFileName);
... gives me an error like this:
Could not move the file "/tmp/phpnIqXDr" to "/tmp/temporary.rtf" ()
... which is very frustrating, since I know that /tmp is writeable by every user.

Answer 1

You don't need to move the file, Symfony\Component\HttpFoundation\File\UploadedFile class returns the path and has methods to get the filename and mimetype.
This code works for me:
$message->attach(
\Swift_Attachment::fromPath($data["attachment"])
->setFilename(
$data["attachment"]->getClientOriginalName()
)
->setContentType(
$data["attachment"]->getClientMimeType()
)
);
Credit to toolpixx

Answer 2

Here is the code that ended up working for me:
private function sendEmail($data)
{
$vgmsContactMail = self::contactMail;
$mailer = $this->get('mailer');
/* #var $uploadedFile UploadedFile */
$uploadedFile = $data["attachment"];
$extension = $uploadedFile->guessExtension();
if(!in_array($extension, ['pdf','rtf']) ){
die('Please upload a .pdf or .rtf file.');
}
$newFilePath = '/tmp';
$newFileName = 'temporary' . rand(0,10000) . '.rtf';
$uploadedFile->move($newFilePath, $newFileName);
$attachment = \Swift_Attachment::fromPath('/tmp/' . $newFileName);
$message = \Swift_Message::newInstance("VGMS Contact Form: ". $data["subject"])
->setFrom(array($vgmsContactMail => "Message by ".$data["name"]))
->setTo(array(
$vgmsContactMail => $vgmsContactMail
))
->setBody($data["message"]."<br>ContactMail :".$data["email"])
->attach($attachment)
;
return $mailer->send($message);
}