HTTPRequest in Godot – Complete Guide

HTTP requests are the backbone of the web; they enable us to interact with websites and services by sending and receiving data over the internet. Whether you’re checking the weather, logging into social media, or even playing online games, HTTP requests are at work! In the realm of game development, the ability to harness this technology opens up a world of possibilities—from implementing multiplayer features to fetching live game updates and more.

What is an HTTPRequest?

An HTTPRequest is a powerful node in the Godot Engine that allows developers to send HTTP(S) requests. Its usage provides an array of capabilities, such as downloading or uploading files and web content via HTTP. It’s a versatile tool that uses HTTPClient internally and offers a high-level interface to make network communication straightforward for game developers.

What is it for?

The HTTPRequest node is designed to interact with the web. It can achieve multiple tasks such as:

  • Contacting RESTful APIs to send and receive data.
  • Downloading media like images or sound files to use within games.
  • Uploading game scores or player statistics to a server.
  • Checking for updates or new content that can be downloaded to the game.

Why should I learn it?

Understanding and using HTTP requests is fundamental in today’s interconnected world. By learning how to implement HTTPRequests in your Godot projects, you’re not only gaining a skill that’s broadly applicable in software development but also enhancing your games to be dynamic and up-to-date with live data. This elevates the gaming experience, allowing your creations to be more engaging and interactive.

Enabling this feature can also be a stepping stone to make fully-featured online games and applications, which is an invaluable skill in the game development industry. Let’s explore how to utilize this powerful class in your projects with Godot!

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Setting Up the HTTPRequest Node

To start using the HTTPRequest node in your Godot project, you first need to add it to your scene. You can do this either through code or by manually adding the node in the editor.

var http_request = HTTPRequest.new()
add_child(http_request)

Alternatively, you can drag and drop the HTTPRequest node into your scene tree from the “Add Node” window in the Godot editor. Once you have the node in place, you can configure it for your needs.

Sending a Simple GET Request

To send a GET request, which retrieves data from a specified resource, set up the URL to which you want to send the request and then call the `request()` method on your HTTPRequest node. Below is an example of how to send a GET request to a JSON placeholder service, which offers fake API data for testing:

func _ready():
    # Assuming http_request is a reference to your HTTPRequest node.
    var url = "https://jsonplaceholder.typicode.com/posts"
    http_request.request(url)

You will also need to connect the `request_completed` signal of the HTTPRequest node to get the response when the request is complete:

func _ready():
    http_request.connect("request_completed", self, "_on_request_completed")
    http_request.request("https://jsonplaceholder.typicode.com/posts")

func _on_request_completed(result, response_code, headers, body):
    var response = parse_json(body.get_string_from_utf8())
    print("Response: ", response)

Handling GET Request Parameters

Queries often require parameters, for example, when you need to fetch a specific resource or filter results. You can add these parameters to the request URL:

func _ready():
    var url = "https://jsonplaceholder.typicode.com/comments"
    var query_params = "?postId=1"
    http_request.request(url + query_params)

Sending POST Requests

POST requests are used to send data to create or update a resource. Here’s an example of how to send a POST request with JSON data:

func _ready():
    var url = "https://jsonplaceholder.typicode.com/posts"

    # The data we want to send
    var data = {"title": "foo", "body": "bar", "userId": 1}
    var query = JSON.print(data)

    # We need to specify the Content-Type header
    var headers = ["Content-Type: application/json"]

    http_request.request(url, headers, true, HTTPClient.METHOD_POST, query)

Remember to also handle the response in the `_on_request_completed` method. You will check if the POST was successful based on the response code and the body.

Downloading Files

You can use the HTTPRequest node to download files such as images, which can then be dynamically loaded into your game. Here is an example of downloading an image:

func _ready():
  http_request.connect("request_completed", self, "_on_file_downloaded")
  var url = "https://example.com/image.png"
  http_request.request(url)

func _on_file_downloaded(result, response_code, headers, body):
  if response_code == 200:
    var image = Image.new()
    var image_load_error = image.load_png_from_buffer(body)
    if image_load_error == OK:
      var texture = ImageTexture.new()
      texture.create_from_image(image)
      $Sprite.texture = texture

By now we’ve set the groundwork for making various types of HTTP requests with Godot’s HTTPRequest node. Stay tuned for the next part, where we will discuss additional details such as setting up timeouts, handling errors, and making secure HTTPS requests.

Advanced Usage of HTTPRequest

While the basics can get you far, understanding more advanced features of the HTTPRequest node can greatly expand what your game can achieve online. Let’s dive into some of these.

Handling Timeouts

Setting timeouts can be crucial for maintaining a smooth user experience, especially if a server is taking too long to respond. You can set the timeout using the `timeout` property of the HTTPRequest node.

http_request.timeout = 5 # Timeout after 5 seconds

Asynchronous Requests

By default, HTTPRequest operates asynchronously, preventing your game from freezing while waiting for a response. It’s important to structurally prepare for this. Here, we process the game normally while a request is being processed:

func send_request():
    http_request.request("https://jsonplaceholder.typicode.com/posts")
    # Game continues to run normally, not waiting for response

func _process(delta):
    # Game processing code goes here

Handling Errors

When a request fails, handling errors gracefully is important. Connect to the `request_failed` signal to manage these scenarios.

# Connect the signal in your setup function
http_request.connect("request_failed", self, "_on_request_failed")

# Define the signal handler function
func _on_request_failed():
    print("The HTTP request failed.")
    # Additional error handling goes here

Posting Form Data

If you want to post form data, you need to set the correct headers and format your data as an HTTP form.

func send_form_data():
    var url = "https://jsonplaceholder.typicode.com/posts"
    var headers = ["Content-Type: application/x-www-form-urlencoded"]
    var data = "title=test&body=Just+testing&userId=3"
    http_request.request(url, headers, true, HTTPClient.METHOD_POST, data)

Custom Headers and Cookies

Sometimes, you need to send custom headers or cookies with your HTTP request. This can be done by adding them to your headers array.

var custom_headers = [
    "Content-Type: application/json",
    "Cookie: my_cookie=value",
    "Custom-Header: my_value"
]
http_request.request(url, custom_headers, true, HTTPClient.METHOD_GET)

Downloading and Saving Files

To save downloaded files to the user’s filesystem, you can write the response body to a file.

func _on_request_completed(result, response_code, headers, body):
    if response_code == 200:
        var file = File.new()
        file.open("user://downloaded_image.png", File.WRITE)
        file.store_buffer(body)
        file.close()

HTTPS and SSL Certificates

For secure requests over HTTPS, it may be necessary to validate SSL certificates. Godot makes this easy by allowing you to specify a trusted SSL certificate.

var ssl_cert = preload("res://path_to_cert.pem")
http_request.use_ssl = true
http_request.ssl_validate_domain = true
http_request.set_trusted_ssl_certificate(ssl_cert)

Handling HTTP requests elegantly can make your game feel much more dynamic and connected. Whether you’re looking to implement leaderboards, social features, or live content updates, Godot’s HTTPRequest node is an indispensable tool in your toolkit.

By utilizing these elements in your game projects, we can ensure that players get a polished and robust online experience that stands out in the digital marketplace. Happy coding, and we’re excited to see what you’ll create with these powerful features at your disposal!Certainly, let’s delve deeper into more intricate aspects of using the HTTPRequest node in Godot.

Processing JSON Data

One common use case for HTTP requests is to retrieve or send JSON data. Here’s how you could parse JSON data from a response:

func _on_request_completed(result, response_code, headers, body):
    var json_data = parse_json(body.get_string_from_utf8())
    # Now json_data is a dictionary with the JSON contents

When sending JSON data, you might want to convert a dictionary to a JSON string:

var dict_data = {"key": "value"}
var json_string = JSON.print(dict_data)
# Now json_string is a JSON-formatted string

Uploading Files

Uploading files, such as player-generated content or game states, can be done through a POST request. Here’s a basic example of uploading a text file:

func upload_file(file_path):
    var file = File.new()
    if file.open(file_path, File.READ) == OK:
        var content = file.get_as_text()
        var headers = ["Content-Type: text/plain"]
        http_request.request("https://youruploadendpoint.com", headers, true, HTTPClient.METHOD_POST, content)
        file.close()

Pagination and Handling Large Responses

When dealing with APIs that return large sets of data, requests often support pagination. You can handle pagination by sending requests in a loop, incrementing the page number until you have all the data:

var current_page = 1
var total_pages = 1

func fetch_all_pages():
    fetch_page(current_page)

func fetch_page(page):
    var url = "https://jsonplaceholder.typicode.com/posts?page=" + str(page)
    http_request.request(url)

func _on_request_completed(result, response_code, headers, body):
    var json_data = parse_json(body.get_string_from_utf8())
    process_page_data(json_data)

    if current_page < total_pages:
        current_page += 1
        fetch_page(current_page)

Caching Mechanisms

Sometimes, to reduce server load or increase speed, you may want to implement caching. When a file is downloaded, save it with a unique name and check for its existence before sending a request:

func download_image(image_url, cache_name):
    var file = File.new()
    if file.file_exists("user://cache/" + cache_name):
        print("Loading image from cache.")
        # Load and use the cached image
    else:
        http_request.request(image_url)

func _on_file_downloaded(result, response_code, headers, body):
    if response_code == 200:
        var file = File.new()
        file.open("user://cache/" + cache_name, File.WRITE)
        file.store_buffer(body)
        file.close()
        print("Image saved to cache.")

Handling Multiple Requests

You might need to handle multiple HTTP requests in parallel. Here’s an example where we send multiple requests and use a unique identifier to process them individually:

var request_id = 0
var pending_requests = {}

func send_request_with_id(url):
    var current_id = request_id
    pending_requests[current_id] = http_request.request(url)
    request_id += 1

func _on_request_completed(result, response_code, headers, body):
    for id in pending_requests:
        if pending_requests[id] == result:
            var json_data = parse_json(body.get_string_from_utf8())
            handle_response_for_id(json_data, id)
            pending_requests.erase(id)
            break

Rate Limiting

Respecting rate limits is important when working with third-party APIs. You might implement a cooldown system:

var cooldown_time = 5.0
var can_send_request = true

func send_request_if_possible(url):
    if can_send_request:
        http_request.request(url)
        start_cooldown()

func start_cooldown():
    can_send_request = false
    yield(get_tree().create_timer(cooldown_time), "timeout")
    can_send_request = true

These code snippets cover a multitude of scenarios and advanced techniques for utilizing the HTTPRequest node in Godot. By mastering these, you can create more complex and efficient network operations in your games, ensuring that your players have the most up-to-date content and smooth online interactions. Happy developing!

Continuing Your Game Development Journey with Godot

Embarking on the path to mastery with Godot doesn’t end here. We encourage you to keep experimenting with HTTPRequests and networked features to create richer game experiences. But where to go next? Our Godot Game Development Mini-Degree is a perfect next step to deepen your understanding of game development with Godot Engine.

By enrolling in our Mini-Degree, you’ll gain access to a series of comprehensive courses that cover a wide range of topics within Godot 4. Whether it’s mastering 2D and 3D game mechanics, scripting with GDScript, or building complex UI systems, these structured lessons will guide you through creating your own fully functional games. Build a portfolio of real-world projects and level up your skills—whether you’re a beginner or have already dabbled in Godot and want to advance further.

For an even broader exploration of what you can achieve with Godot, visit our full collection of Godot courses on Zenva Academy. Each of our courses is designed to help you progress at your own pace and solidify your capabilities as a game developer. Start your next chapter in game creation today, and see where your newfound knowledge and skills can take you!

Conclusion

Stepping into the realm of networked game development with the Godot Engine’s HTTPRequest node is just the beginning of a thrilling creative journey. Equipped with the know-how to send and receive web content, you’re now poised to craft dynamic multiplayer experiences, social interactions, and live content updates that keep players coming back for more. As you continue to build and innovate, remember that every skill you’ve honed and every line of code you’ve written is a stepping stone toward becoming a more accomplished game developer.

We at Zenva Academy are here to support and inspire you every step of the way. Dive into our Godot Game Development Mini-Degree to discover a wealth of knowledge that awaits. Whether you’re expanding your game development expertise or refreshing your arsenal of techniques, the adventure never truly ends—it evolves with every project. So go forth, experiment with passion, and create the games of your dreams!

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