Step by Step Guide to Building a Cognito Forms API Integration in C#

Aug 11, 2024 • 7 minute read

Introduction

Hey there, fellow developer! Ready to dive into the world of Cognito Forms API integration? You're in for a treat. This guide will walk you through creating a robust C# integration that'll have you manipulating forms and entries like a pro. Let's get cracking!

Prerequisites

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

Visual Studio or your favorite C# IDE
.NET Core 3.1 or later
A Cognito Forms account with API access
Your API key (keep it secret, keep it safe!)

Setting up the project

Fire up your IDE and create a new C# project. We'll be using a console app for simplicity, but feel free to adapt this to your needs.

Next, let's grab the necessary NuGet packages:

Install-Package Newtonsoft.Json
Install-Package RestSharp

Authentication

Alright, let's get that API key working for us. Create a new class called CognitoFormsClient:

public class CognitoFormsClient
{
    private readonly RestClient _client;
    private readonly string _apiKey;

    public CognitoFormsClient(string apiKey)
    {
        _apiKey = apiKey;
        _client = new RestClient("https://www.cognitoforms.com/api/1");
    }

    // We'll add more methods here soon!
}

Basic API operations

Let's start with the basics - fetching forms:

public async Task<List<Form>> GetFormsAsync()
{
    var request = new RestRequest("forms", Method.GET);
    request.AddHeader("Authorization", $"Bearer {_apiKey}");

    var response = await _client.ExecuteAsync<List<Form>>(request);
    return response.Data;
}

Working with entries

Now for the fun part - CRUD operations on entries:

public async Task<Entry> CreateEntryAsync(string formId, object entryData)
{
    var request = new RestRequest($"forms/{formId}/entries", Method.POST);
    request.AddHeader("Authorization", $"Bearer {_apiKey}");
    request.AddJsonBody(entryData);

    var response = await _client.ExecuteAsync<Entry>(request);
    return response.Data;
}

// Implement similar methods for Get, Update, and Delete

Handling file uploads

Got files? We've got you covered:

public async Task<string> UploadFileAsync(string formId, string fieldName, byte[] fileData, string fileName)
{
    var request = new RestRequest($"forms/{formId}/files", Method.POST);
    request.AddHeader("Authorization", $"Bearer {_apiKey}");
    request.AddFile(fieldName, fileData, fileName);

    var response = await _client.ExecuteAsync(request);
    return response.Content; // This will be the file ID
}

Error handling and logging

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

private async Task<T> ExecuteWithErrorHandlingAsync<T>(RestRequest request)
{
    try
    {
        var response = await _client.ExecuteAsync<T>(request);
        if (!response.IsSuccessful)
        {
            // Log the error, maybe throw a custom exception
            Console.WriteLine($"API Error: {response.ErrorMessage}");
        }
        return response.Data;
    }
    catch (Exception ex)
    {
        // Log the exception
        Console.WriteLine($"Exception: {ex.Message}");
        throw;
    }
}

Optimizing API calls

Let's not hammer that API unnecessarily:

private readonly MemoryCache _cache = new MemoryCache(new MemoryCacheOptions());

public async Task<Form> GetFormAsync(string formId)
{
    if (!_cache.TryGetValue(formId, out Form cachedForm))
    {
        var request = new RestRequest($"forms/{formId}", Method.GET);
        cachedForm = await ExecuteWithErrorHandlingAsync<Form>(request);
        _cache.Set(formId, cachedForm, TimeSpan.FromMinutes(10));
    }
    return cachedForm;
}

Testing the integration

Don't forget to test! Here's a quick unit test to get you started:

[Fact]
public async Task GetFormsAsync_ReturnsListOfForms()
{
    var client = new CognitoFormsClient("your-api-key");
    var forms = await client.GetFormsAsync();
    Assert.NotNull(forms);
    Assert.True(forms.Count > 0);
}

Best practices and security considerations

Remember:

Never hardcode your API key
Use HTTPS for all requests
Implement proper rate limiting
Validate and sanitize all input data

Conclusion

And there you have it! You've just built a solid foundation for your Cognito Forms API integration. With these building blocks, you can create, read, update, and delete entries, handle file uploads, and even optimize your API calls.

Remember, this is just the beginning. The Cognito Forms API has a lot more to offer, so don't be afraid to explore and expand on what we've built here. Happy coding!

Additional resources

Now go forth and build something awesome!