Responsive Email Template in Twig file - symfony

Question

Trying to build a responsive email template in a Twig file. Using Swiftmailer within a Symfony application to send the emails. Two issues I am having so far is the images only show when I view the email on my localhost not when the email is viewed in Gmail, Inbox or Yahoo!
Linking the images using an absolute path (currently). Also, tried a relative path with the same result.
<img src="{{ absolute_url(asset('bundles/coreecommerce/images/logo.png')) }}">
Problem #2 is include stylesheets. I have some media queries in a stylesheet I am trying to include within a head tag like this.
{% block stylesheets %}
<link href="{{ asset('bundles/coreecommerce/css/email.css') }}" rel="stylesheet" />
{% endblock %}
I'm doing something wrong here. Just not sure what? Can you include stylesheets, inline styles for a responsive email in Twig?
Thanks for any help.

Answer 1

To inline images in your html mails you should take a look at this section of the documentation.
To show you the example with twig, you can start with something like this:
<?php
$message = \Swift_Message::newInstance();
$fileToEmbed = 'a path to image file';
$templateParams = [
'fileToEmbed' => $message->embed(\Swift_Image::fromPath($fileToEmbed)),
];
// then compose the mail like this
$message
// set subject etc...
->setBody($this->twigTemplating->render('yourMailTemplate.html.twig', $templateParams), 'text/html')
;
And then in you twig template you just create a IMG tag with template variable:
<img src="{{ fileToEmbed }}">
So TL;DR you just need that $message->embed(\Swift_Image::fromPath($fileToEmbed)) return value to be passed to your mailing template and use it as src attribute.
To locate the image file within your bundle you can use Kernel::locateResource method like this (assuming that your logo.png is located in CoreEcommerceBundle/Resources/public/images/ directory):
$fileToEmbed = $this->kernel->locateResource('#CoreEcommerceBundle/Resources/public/images/logo.png');