Support SendGrid's hosted templates

@Perignon, did you start any work on this? I would like to contribute to this functionality if possible, since I need in on an ongoing project.

I might post a proper patch for this later, but in the mean time I can tell you how I enabled Sendgrid templates.

First in your own _mail() or _mail_alter() function you want to attach the template_id and variables substitutions like this

$message['sendgrid'] = [
                'template_id' => 'TEMPLATE_ID',
                'substitutions' => [
                    '-name-' => [$name],
                    '-reset_url-' => [$url]
                ]
            ];

Then unfortunately you have to hack the mail() function in the sendgrid.mail.inc file.
I put it in the area where the $sendgrid_message object gets all the sets..

if(!empty($message['sendgrid']['template_id'])) {
  $sendgrid_message->setTemplateId($message['sendgrid']['template_id']);
}

if (!empty($message['sendgrid']['substitutions'])) {
  $sendgrid_message->setSubstitutions($message['sendgrid']['substitutions']);
 }

I can confirm johannez's hack works. Here is the patch for sendgrid.mail.inc

Ok try this one then, previously I had just used the patch generated from the PAAS I use, whereas I've now cloned 7.x-1.x and created this patch on my local machine.

I have been working on my own mapping implementation (as per issue https://www.drupal.org/node/2821974), and have integrated so the code in this patch. But my finding was that you need to include the below line for it to work with HTML templates along with setTemplateId for it to use the HTML template (otherwise you just get the plain text template)

$sendgrid_message->setHtml(' ');

Did you have a different workaround for this? Wonder if it also needs to be part of this patch for it to work with HTML templates.

As we maybe only want this for some users, maybe a config setting like the others would be a solution

Dan

When I add a template_id to $message['sendgrid']['template_id'], it gets posted to SendGrid but SendGrid blocks it from being sent out.
I am getting this:
"This email was not sent because the SMTPAPI header was invalid."

Doesn't really say what is invalid. If I don't include the template_id, the email is sent ok.

Anyone else have this issue?

@drfuzetto - 2 things to solve that:
1. make sure you're using the legacy templates, not the new version.
2. add $message['headers']['content-type']= 'text/html'; to the mail_alter hook.