Client.ino File Reference

Detailed Description

Educational tutorial for FastLED HTTP fetch API with explicit types.

Author

FastLED Community

This tutorial demonstrates network functionality in FastLED WASM builds, specifically the fetch API for making HTTP requests. It shows two different approaches for handling asynchronous operations with EXPLICIT TYPES for educational clarity.

EDUCATIONAL FOCUS: All types are explicitly declared instead of using 'auto' to help you understand the FastLED type system and async patterns.

TWO ASYNC APPROACHES DEMONSTRATED:

APPROACH 1: Promise-based with .then() and .catch_() callbacks (JavaScript-like)

• Uses method chaining for async operations
• Callbacks handle success and error cases
• Non-blocking, event-driven pattern

APPROACH 2: fl::task::await_top_level() pattern for synchronous-style async code

• Uses explicit types: fl::task::Promise<T>, fl::task::PromiseResult<T>, fl::optional<T>
• Blocks until async operation completes (only safe in Arduino loop()!)
• More traditional imperative programming style

The example toggles between these approaches every 10 seconds to demonstrate both patterns working with the same underlying fetch API.

FASTLED ASYNC TYPE SYSTEM TUTORIAL:

Key Types You'll Learn:

• fl::task::Promise<T> - Represents a future value of type T
• fl::task::PromiseResult<T> - Wraps either a successful T value or an Error
• fl::net::http::Response - HTTP response with status, headers, and body
• fl::net::http::FetchOptions - Configuration object for HTTP requests
• fl::optional<T> - May or may not contain a value of type T
• fl::task::Error - Error information with message and context

NEW FETCH API STRUCTURE:

• FetchOptions is a pure data configuration object
• fetch_get() returns fl::task::Promise<fl::net::http::Response> (not auto!)
• Promises can be handled with .then()/.catch_() OR await_top_level()
• All async operations integrate with FastLED's engine automatically

EXPLICIT TYPE EXAMPLES:

Promise-based approach:

fl::task::Promise<fl::net::http::Response> promise = fl::net::http::fetch_get("http://example.com");
promise.then([](const fl::net::http::Response& response) { /* handle success *&zwj;/ })
       .catch_([](const fl::task::Error& error) { /* handle error *&zwj;/ });

Await-based approach:

fl::task::Promise<fl::net::http::Response> promise = fl::net::http::fetch_get("http://example.com");
fl::task::PromiseResult<fl::net::http::Response> result = fl::task::await_top_level(promise);
if (result.ok()) {
    const fl::net::http::Response& response = result.value();
    // Use response...
}

TO RUN THIS TUTORIAL:

For WASM (recommended for networking):

1. Install FastLED: pip install fastled
2. cd into this examples directory
   
3. Run: fastled Client.ino
4. Open the web page and check browser console for detailed fetch results

For other platforms: Uses mock responses for testing the API without network connectivity

Definition in file Client.ino.

#include "FastLED.h"
#include "ClientReal.h"

Include dependency graph for Client.ino:

Go to the source code of this file.