Integrating Rails mailer templates with Mailgun's HTTP API

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1

I’m trying to use Mailgun’s HTTP API to send emails from my Rails app. The problem is I can’t get the mailer views to work. Here’s what I’ve got in my mailer class:

class EmailSender < ActionMailer::Base
  def send_fancy_message
    content = Multimap.new
    content[:from] = "Happy User <notifications@#{@@site_domain}>"
    content[:to] = "[email protected]"
    content[:subject] = "Greetings"
    content[:html] = File.read("#{Rails.root}/app/views/email_sender/send_fancy_message.html.erb").html_safe
    # I also tried this:
    # content[:html] = render(template: "send_fancy_message.html.erb")
    result = RestClient.post "https://api:#{@@secret_key}@api.mailgun.net/v2/#{@@site_domain}/messages", content
    result = JSON.parse(result)
  end
end

But I get this error:

NoMethodError: undefined method ‘each_byte’ for nil:NilClass

How can I use my Rails views with the Mailgun API? I know there are gems for this, but I need the full API functionality. Any ideas on how to send emails using Rails views through the API? Thanks!

2

I’ve encountered this issue before. The problem likely stems from how you’re trying to read the template file. Instead of using File.read or render directly, try utilizing ActionController::Base.new.render_to_string method. Here’s a modified version of your code that should work:

def send_fancy_message
  content = Multimap.new
  content[:from] = "Happy User <notifications@#{@@site_domain}>"
  content[:to] = "[email protected]"
  content[:subject] = "Greetings"
  content[:html] = ActionController::Base.new.render_to_string(
    template: 'email_sender/send_fancy_message',
    layout: false
  )
  result = RestClient.post "https://api:#{@@secret_key}@api.mailgun.net/v2/#{@@site_domain}/messages", content
  JSON.parse(result)
end

This approach should correctly render your template and integrate it with Mailgun’s HTTP API. Remember to ensure your template file is in the correct location within your Rails app structure.

3

I’ve had success integrating Rails mailer templates with Mailgun’s HTTP API by leveraging ActionMailer’s built-in rendering capabilities. Here’s an approach that worked for me:

Instead of reading the file directly or using render_to_string, try using ActionMailer’s mail method to generate the email content. You can then extract the HTML and send it via the Mailgun API. Here’s how I modified the send_fancy_message method:

def send_fancy_message
email = mail(to: ‘[email protected]’, subject: ‘Greetings’)
html_content = email.body.encoded

content = Multimap.new
content[:from] = “Happy User <notifications@#{@@site_domain}>”
content[:to] = ‘[email protected]’
content[:subject] = ‘Greetings’
content[:html] = html_content

result = RestClient.post “https://api:#{@@secret_key}@api.mailgun.net/v2/#{@@site_domain}/messages”, content
JSON.parse(result)
end

This method lets you use all of ActionMailer’s features while still sending through Mailgun’s API. It also ensures that your views are properly rendered with all the Rails helpers and layouts intact.

4

hey zack, i’ve faced similar issues. have u tried using render_to_string instead? something like:

content[:html] = render_to_string(template: ‘email_sender/send_fancy_message’, layout: false)

this might work better with the api. also, double-check ur file path and make sure the template exists. lemme know if that helps!