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

Introduction

Hey there, fellow Go enthusiast! Ready to dive into the world of Teamleader API integration? You're in for a treat. We'll be building a robust integration that'll have you managing contacts, deals, and invoices like a pro. Let's get cracking!

Prerequisites

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

• Go installed (I know, obvious, right?)
• Teamleader API credentials (if you don't have these, hop over to their dev portal)
• Your favorite Go IDE or text editor

Setting up the project

First things first, let's get our project structure sorted:

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

Easy peasy! Now we've got our Go module initialized and ready to rock.

Authentication

Teamleader uses OAuth 2.0, so let's tackle that:

import (
    "golang.org/x/oauth2"
)

func getClient() *http.Client {
    config := &oauth2.Config{
        ClientID:     "your-client-id",
        ClientSecret: "your-client-secret",
        Endpoint:     oauth2.Endpoint{
            AuthURL:  "https://app.teamleader.eu/oauth2/authorize",
            TokenURL: "https://app.teamleader.eu/oauth2/access_token",
        },
    }

    token := &oauth2.Token{
        AccessToken: "your-access-token",
        TokenType:   "Bearer",
    }

    return config.Client(context.Background(), token)
}

Pro tip: In a real-world scenario, you'd want to implement token refreshing. But let's keep it simple for now.

Making API requests

Time to create our API client:

type TeamleaderClient struct {
    BaseURL    string
    HTTPClient *http.Client
}

func NewTeamleaderClient(httpClient *http.Client) *TeamleaderClient {
    return &TeamleaderClient{
        BaseURL:    "https://api.teamleader.eu",
        HTTPClient: httpClient,
    }
}

func (c *TeamleaderClient) makeRequest(method, endpoint string, body interface{}) (*http.Response, error) {
    // Implement request logic here
}

Implementing key Teamleader API endpoints

Let's implement a method for fetching contacts:

func (c *TeamleaderClient) GetContacts() ([]Contact, error) {
    resp, err := c.makeRequest("GET", "/contacts.list", nil)
    if err != nil {
        return nil, err
    }
    // Parse response and return contacts
}

You can follow a similar pattern for companies, deals, and invoices.

Error handling and logging

Don't forget to implement proper error handling:

if err != nil {
    log.Printf("Error fetching contacts: %v", err)
    return nil, fmt.Errorf("failed to fetch contacts: %w", err)
}

Testing the integration

Testing is crucial. Here's a quick example:

func TestGetContacts(t *testing.T) {
    client := NewTeamleaderClient(getClient())
    contacts, err := client.GetContacts()
    if err != nil {
        t.Fatalf("Expected no error, got %v", err)
    }
    if len(contacts) == 0 {
        t.Fatal("Expected contacts, got none")
    }
}

Best practices and optimization

Consider implementing caching for frequently accessed data and use goroutines for concurrent requests to boost performance.

Conclusion

And there you have it! You've just built a Teamleader API integration in Go. Pretty cool, right? Remember, this is just the beginning. There's always room for improvement and expansion. Keep exploring the Teamleader API docs and happy coding!