example.go

/*

example.go

This is a golang example of how to use SendGrid for transactional
email that uses substitutions (e.g. replace "firstName" with
"Grover"). It assumes you have a SendGrid API key.

I made this because I had to move away from Mandrill by April 27, and
SendGrid is basically across the street from me so they were the first
alternative that came to mind.

*/
package main

import (
	"fmt"
	"github.com/sendgrid/sendgrid-go"
	"net/mail"
	"os"
)

func main() {

	// Make a SendGrid Transactional template and have it look like this
	// (in Design mode):
	/*
	   <%body%>

	   Welcome *|firstName|* *|lastName|*!

	   I hope you like this email. It is **configurable**.
	*/

	// Create a client with an API key
	sendgridKey := "<insert your sendgrid api key here>"
	sg := sendgrid.NewSendGridClientWithApiKey(sendgridKey)

	// Create message and configure with empty text to force template
	// body to be used instead. You have to set up a transactional
	// template on SendGrid's web site and reference its ID below where
	// it says <template_id>.
	message := sendgrid.NewMail()
	message.SetText("\n")
	message.SetHTML(" ")
	message.SetSubject("This is a **configurable** subject line")
	message.AddFilter("templates", "enable", "1")
	message.AddFilter("templates", "template_id", "<template_id>")

	// Add substitutions that will replace the left value with the right
	// value whenever it is seen in the subject or body. The subject
	// line, for example, will be transformed to "This is a fantastic
	// subject line".
	//
	// Notice that I'm using MailChimp-flavored escape sequences for the
	// first and last names. I used double asterisks for the last one
	// because I felt like it. You don't in fact need to escape the
	// substitution phrase at all.
	message.AddSubstitution("*|firstName|*", "Grover")
	message.AddSubstitution("*|lastName|*", "Cleveland")
	message.AddSubstitution("**configurable**", "fantastic")

	// Configure where the message will come from.
	address, err := mail.ParseAddress("[email protected]")
	if err != nil {
		fmt.Println("Malformed 'from' email address.")
		os.Exit(-1)
	}
	message.SetFromEmail(address)
	message.SetFromName("YourDomain Support")

	// Add categories for our own tracking purposes
	var categories = []string{
		"Welcome Email",
	}
	message.AddCategories(categories)

	// Specify who the message will be to
	recipients := []string{
		"[email protected]",
	}
	message.AddTos(recipients)

	// Send the mail.
	err = sg.Send(message)
	if err != nil {
		fmt.Printf("%v\n", err)
		os.Exit(-1)
	}
	fmt.Println("Got to the end without exploding. Mail sent!")

	// The resulting email should be:
	// Subject: This is a fantastic subject line
	// Body: Welcome Grover Cleveland! I hope you like this email. It is fantastic.
}