Merge Fields not Working

[mide]

I'm trying to send emails through the mailgun-ruby gem, and it doesn't seem to be merging the fields when sent.

I've been able to reproduce the problem with the following code:

require 'mailgun'

mailgun_client = Mailgun::Client.new("[MAILGUN KEY]")

message = Mailgun::BatchMessage.new(mailgun_client, "mail.domain.com")
message.set_from_address("system@mail.domain.com")
message.set_subject("Merge Fields Test")
message.set_text_body("Hello %recipient.first%, this is a test. Your full name is %recipient.first% %last%.")

message.add_recipient(:to, "john.doe@gmail.com", {"first" => "John", "last" => "Doe"})
message.add_recipient(:to, "jane.doe@gmail.com", {"first" => "Jane", "last" => "Doe"})

message.finalize

Each recipient is getting the non-merged emails with all recipients in the "to" address.

[mide]

I feel like this could be related to #12.

[mide]

I've traced the Gem's flow to the following code, with the problem still happening. I'm still working on finding the root cause.

http_client = RestClient::Resource.new("https://api.mailgun.net/v2",
                :user       => "api",
                :password   => "[MAILGUN KEY]",
                :user_agent => "mailgun-sdk-ruby/1.0.2")

data = {"from"                 => ["system@mail.domain.com"],
        "subject"              => ["Merge Fields Test"],
        "text"                 => ["Hello %recipient.first%, this is a test. Your full name is %recipient.first% %last%."],
        "to"                   => ["'John Doe' <john.doe@gmail.com>", "'Jane Doe' <jane.doe@gmail.com>"],
        "recipient-variables"  => [ {"system@mail.domain.com" => {"id" => nil},
                                     "john.doe@gmail.com" => {"first" => "John", "last" => "Doe"},
                                     "jane.doe@gmail.com" => {"first" => "Jane", "last" => "Doe"}
                                  ]
        }

response = http_client["mail.domain.com/messages"].post(data)

[mide]

Well this is interesting: The API documentation shows that

POST /<domain>/messages

does not accept a recipient-variables parameter.

[mide]

Alright, I've figured out the following works:

http_client = RestClient::Resource.new("https://api.mailgun.net/v2",
               :user       => "api",
               :password   => "[MAILGUN KEY]",
               :user_agent => "mailgun-sdk-ruby/1.0.2")

data = {"from"                 => ["system@mail.domain.com"],
        "subject"              => ["Merge Fields Test"],
        "text"                 => ["Hello %recipient.first%, this is a test. Your full name is %recipient.first% %last%."],
        "to"                   => ["'John Doe' <john.doe@gmail.com>", "'Jane Doe' <jane.doe@gmail.com>"],
        "recipient-variables"  =>  {"system@mail.domain.com" => {"id" => nil},
                                     "john.doe@gmail.com" => {"first" => "John", "last" => "Doe"},
                                     "jane.doe@gmail.com" => {"first" => "Jane", "last" => "Doe"}
                                   }.to_json

        }

response = http_client["mail.domain.com/messages"].post(data)

Mainly I made sure that the recipient-variables was JSON (not a Hash) and it was outside the parent array.

[mide]

I've added some code to the send_message method that seems to eliminate the problem. I'm not sure if this is the best way to solve it, but the issue is that the recipient-variables are inside an array.

mailgun-ruby/lib/mailgun/messages/batch_message.rb:

...
def send_message(message)
  simple_setter("recipient-variables", JSON.generate(@recipient_variables))

  if @message.has_key?("recipient-variables")
    @message["recipient-variables"] = @message["recipient-variables"].first
  end

  response = @client.send_message(@domain, @message).to_h!
  message_id = response['id'].gsub(/\>|\</, '')
  @message_ids[message_id] = count_recipients()
  reset_message()
end
...

Edit: I've moved the code into batch_message.rb

[mide]

I've opened PR #23.

[travelton]

👍 I'll review this soon! Thanks for the details.

[mide]

Thanks! For what it's worth, I've dug a little deeper and I've found that both simple_setter and complex_setter will set variables inside of arrays. It looks like that might be part of the problem, since recipient-variables can't be inside an array.

[erm213]

Is there a workaround for this or an ETA for the pull request to be accepted?

[travelton]

This has been merged. Cutting a new Gem in an hour or so. Thanks for your work on this!

[erm213]

Works now. Thank you.