Step by Step Guide to Building a Formstack API Integration in Java

Introduction

Hey there, fellow developer! Ready to dive into the world of Formstack API integration? You're in for a treat. Formstack's API is a powerful tool that lets you programmatically interact with forms, submissions, and more. In this guide, we'll walk through building a robust integration in Java. Let's get cracking!

Prerequisites

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

• A Java development environment (I know you've got this covered!)
• A Formstack account with an API key
• Your favorite HTTP client library (we'll use OkHttp in this guide)

Setting up the project

First things first, let's set up our project:

1. Create a new Java project in your IDE of choice.
2. Add the OkHttp dependency to your pom.xml or build.gradle:

<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>4.10.0</version>
</dependency>

Authentication

Alright, time to get our hands dirty with authentication:

1. Grab your API key from your Formstack account.
2. Create a FormstackClient class:

public class FormstackClient {
    private static final String BASE_URL = "https://www.formstack.com/api/v2";
    private final OkHttpClient client;
    private final String apiKey;

    public FormstackClient(String apiKey) {
        this.apiKey = apiKey;
        this.client = new OkHttpClient();
    }

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

Making API requests

Now, let's add a method to make API requests:

private Response makeRequest(String endpoint, String method) throws IOException {
    Request request = new Request.Builder()
        .url(BASE_URL + endpoint)
        .header("Authorization", "Bearer " + apiKey)
        .method(method, method.equals("GET") ? null : RequestBody.create(null, new byte[0]))
        .build();

    return client.newCall(request).execute();
}

Core API operations

Let's implement some core operations:

Retrieving forms

public String getForms() throws IOException {
    Response response = makeRequest("/form.json", "GET");
    return response.body().string();
}

Submitting form data

public String submitForm(String formId, Map<String, String> data) throws IOException {
    FormBody.Builder formBuilder = new FormBody.Builder();
    for (Map.Entry<String, String> entry : data.entrySet()) {
        formBuilder.add(entry.getKey(), entry.getValue());
    }

    Request request = new Request.Builder()
        .url(BASE_URL + "/form/" + formId + "/submission.json")
        .header("Authorization", "Bearer " + apiKey)
        .post(formBuilder.build())
        .build();

    Response response = client.newCall(request).execute();
    return response.body().string();
}

Fetching submissions

public String getSubmissions(String formId) throws IOException {
    Response response = makeRequest("/form/" + formId + "/submission.json", "GET");
    return response.body().string();
}

Advanced features

Webhooks integration

To set up a webhook:

public String createWebhook(String formId, String url) throws IOException {
    RequestBody body = new FormBody.Builder()
        .add("url", url)
        .build();

    Request request = new Request.Builder()
        .url(BASE_URL + "/form/" + formId + "/webhook.json")
        .header("Authorization", "Bearer " + apiKey)
        .post(body)
        .build();

    Response response = client.newCall(request).execute();
    return response.body().string();
}

File uploads

For file uploads, you'll need to use a MultipartBody. Here's a quick example:

public String uploadFile(String formId, String fieldId, File file) throws IOException {
    RequestBody requestBody = new MultipartBody.Builder()
        .setType(MultipartBody.FORM)
        .addFormDataPart("field_" + fieldId, file.getName(),
            RequestBody.create(MediaType.parse("application/octet-stream"), file))
        .build();

    Request request = new Request.Builder()
        .url(BASE_URL + "/form/" + formId + "/submission.json")
        .header("Authorization", "Bearer " + apiKey)
        .post(requestBody)
        .build();

    Response response = client.newCall(request).execute();
    return response.body().string();
}

Error handling and best practices

Always check the response status code and handle errors appropriately. Here's a quick example:

if (!response.isSuccessful()) {
    throw new IOException("Unexpected code " + response);
}

Remember to respect rate limits. Formstack allows 14,400 API requests per day, so keep an eye on your usage!

Testing the integration

Don't forget to test your integration thoroughly. Here's a simple JUnit test to get you started:

@Test
public void testGetForms() throws IOException {
    FormstackClient client = new FormstackClient("your-api-key");
    String forms = client.getForms();
    assertNotNull(forms);
    assertTrue(forms.contains("form_id"));
}

Conclusion

And there you have it! You've just built a solid Formstack API integration in Java. Remember, this is just scratching the surface. The Formstack API offers a ton more features, so don't be afraid to explore and experiment.

For more details, check out the Formstack API documentation. Happy coding, and may your forms always be stack-tastic!