Step by Step Guide to Building a Keap API Integration in C#

Introduction

Hey there, fellow developer! Ready to dive into the world of Keap API integration? You're in for a treat. Keap's API is a powerful tool that'll let you tap into their CRM and marketing automation features. In this guide, we'll walk through building a robust integration that'll make your life easier and your applications smarter.

Prerequisites

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

• Visual Studio or your favorite C# IDE
• .NET Core 3.1 or later
• A Keap developer account (if you don't have one, go grab it!)

Setting up the project

Let's kick things off by creating a new C# project. Fire up your IDE and create a new .NET Core Console Application. We'll use this as our playground.

Next, we need to grab some NuGet packages:

dotnet add package RestSharp
dotnet add package Newtonsoft.Json

These will make our lives much easier when dealing with HTTP requests and JSON parsing.

Authentication

Keap uses OAuth 2.0, so let's tackle that first. Here's a quick implementation:

using RestSharp;
using Newtonsoft.Json.Linq;

public class KeapAuthenticator
{
    private const string TokenUrl = "https://api.infusionsoft.com/token";
    private string _clientId;
    private string _clientSecret;
    private string _refreshToken;

    public KeapAuthenticator(string clientId, string clientSecret, string refreshToken)
    {
        _clientId = clientId;
        _clientSecret = clientSecret;
        _refreshToken = refreshToken;
    }

    public string GetAccessToken()
    {
        var client = new RestClient(TokenUrl);
        var request = new RestRequest(Method.POST);
        request.AddParameter("grant_type", "refresh_token");
        request.AddParameter("refresh_token", _refreshToken);
        request.AddParameter("client_id", _clientId);
        request.AddParameter("client_secret", _clientSecret);

        var response = client.Execute(request);
        var json = JObject.Parse(response.Content);
        return json["access_token"].ToString();
    }
}

Making API requests

Now that we've got authentication sorted, let's make some API calls:

public class KeapClient
{
    private const string BaseUrl = "https://api.infusionsoft.com/crm/rest/v1";
    private string _accessToken;

    public KeapClient(string accessToken)
    {
        _accessToken = accessToken;
    }

    public JObject GetContact(int contactId)
    {
        var client = new RestClient($"{BaseUrl}/contacts/{contactId}");
        var request = new RestRequest(Method.GET);
        request.AddHeader("Authorization", $"Bearer {_accessToken}");

        var response = client.Execute(request);
        return JObject.Parse(response.Content);
    }
}

Key Keap API endpoints

Keap's API is pretty extensive, but here are some endpoints you'll likely use often:

• Contacts: /contacts
• Companies: /companies
• Opportunities: /opportunities
• Invoices: /invoices

Implementing CRUD operations

Let's implement a basic CRUD operation for contacts:

public class ContactService
{
    private KeapClient _client;

    public ContactService(KeapClient client)
    {
        _client = client;
    }

    public JObject CreateContact(JObject contactData)
    {
        // Implementation here
    }

    public JObject GetContact(int contactId)
    {
        return _client.GetContact(contactId);
    }

    public JObject UpdateContact(int contactId, JObject updateData)
    {
        // Implementation here
    }

    public bool DeleteContact(int contactId)
    {
        // Implementation here
    }
}

Handling pagination and filtering

Keap's API uses cursor-based pagination. Here's how you might handle it:

public IEnumerable<JObject> GetAllContacts()
{
    string nextPage = null;
    do
    {
        var contacts = GetContactsPage(nextPage);
        foreach (var contact in contacts.Items)
        {
            yield return contact;
        }
        nextPage = contacts.NextPage;
    } while (nextPage != null);
}

private (IEnumerable<JObject> Items, string NextPage) GetContactsPage(string cursor)
{
    // Implementation here
}

Webhook integration

Keap supports webhooks for real-time updates. You'll need to set up an endpoint in your application to receive these webhooks. Here's a basic structure:

[HttpPost]
public IActionResult KeapWebhook([FromBody] JObject payload)
{
    // Process the webhook payload
    // You might want to queue this for processing to avoid blocking
    return Ok();
}

Error handling and logging

Always expect the unexpected! Implement robust error handling:

try
{
    // Your API call here
}
catch (ApiException ex)
{
    _logger.LogError($"API error: {ex.Message}");
    // Handle the error appropriately
}
catch (Exception ex)
{
    _logger.LogError($"Unexpected error: {ex.Message}");
    // Handle the error appropriately
}

Testing the integration

Don't forget to test! Here's a simple unit test example:

[Fact]
public void GetContact_ReturnsCorrectContact()
{
    var mockClient = new Mock<KeapClient>();
    mockClient.Setup(c => c.GetContact(It.IsAny<int>()))
        .Returns(new JObject { ["id"] = 1, ["email"] = "[email protected]" });

    var service = new ContactService(mockClient.Object);
    var result = service.GetContact(1);

    Assert.Equal(1, result["id"]);
    Assert.Equal("[email protected]", result["email"]);
}

Performance optimization

To keep your integration speedy:

1. Implement caching for frequently accessed data
2. Use batch operations where possible
3. Be mindful of Keap's rate limits

Conclusion

And there you have it! You're now equipped to build a solid Keap API integration in C#. Remember, this is just the beginning - there's a lot more you can do with Keap's API. Keep exploring, keep coding, and most importantly, have fun with it!

Got questions? Hit up the Keap developer forums or dive into their extensive API documentation. Happy coding!