Step by Step Guide to Building a MailerLite API Integration in Go

Hey there, fellow Go enthusiast! Ready to dive into the world of email marketing automation? Let's build a robust MailerLite API integration that'll make your life easier and your code more powerful.

Introduction

MailerLite's API is a powerhouse for managing subscribers, campaigns, and more. We're going to harness that power in Go, giving you programmatic control over your email marketing efforts. Buckle up!

Prerequisites

Before we jump in, make sure you've got:

• Go installed (I know you do, but just checking!)
• A MailerLite account with an API key handy

Setting up the project

Let's kick things off right:

mkdir mailerlite-integration && cd mailerlite-integration
go mod init github.com/yourusername/mailerlite-integration

Now, let's grab the HTTP client we'll be using:

go get github.com/go-resty/resty/v2

Authentication

Time to get cozy with the MailerLite API:

package main

import (
    "github.com/go-resty/resty/v2"
)

const baseURL = "https://api.mailerlite.com/api/v2"

func newClient(apiKey string) *resty.Client {
    return resty.New().
        SetHeader("X-MailerLite-ApiKey", apiKey).
        SetHostURL(baseURL)
}

Basic API Operations

Let's flex those API muscles:

Fetching subscriber lists

func getSubscriberLists(client *resty.Client) ([]SubscriberList, error) {
    var lists []SubscriberList
    _, err := client.R().
        SetResult(&lists).
        Get("/groups")
    return lists, err
}

Adding a new subscriber

func addSubscriber(client *resty.Client, email, name string) error {
    _, err := client.R().
        SetBody(map[string]interface{}{
            "email": email,
            "name": name,
        }).
        Post("/subscribers")
    return err
}

You get the idea - rinse and repeat for updating and deleting subscribers.

Error Handling

Don't let those pesky errors catch you off guard:

if err != nil {
    if restyErr, ok := err.(*resty.ResponseError); ok {
        if restyErr.Response.StatusCode() == 429 {
            // Handle rate limit
            time.Sleep(time.Second * 5)
            // Retry the request
        }
    }
    // Handle other errors
}

Advanced Features

Ready to level up? Let's tackle webhooks and batch operations. I'll leave the implementation as an exercise for you (wink, wink), but here's a tip: use goroutines for concurrent batch processing.

Testing

Testing is your friend. Here's a quick example:

func TestAddSubscriber(t *testing.T) {
    mockClient := newMockClient()
    err := addSubscriber(mockClient, "[email protected]", "Test User")
    assert.NoError(t, err)
}

Best Practices

• Respect rate limits: implement exponential backoff
• Keep your API key safe: use environment variables

Conclusion

And there you have it! You've just built a sleek MailerLite API integration in Go. Remember, this is just the beginning - there's so much more you can do with this API. Keep exploring, keep coding, and most importantly, have fun!

Want to see the full integration? Check out my GitHub repo here (just kidding, but you should totally make one).

Now go forth and conquer those email lists! 🚀