Fast Google Fonts with Cloudflare Workers

This article discusses how to use Cloudflare Workers to modify HTML content in real-time, specifically focusing on embedding Google Fonts CSS into web pages. The author provides a detailed step-by-step guide on how to create and deploy a worker that intercepts incoming HTTP requests, modifies the HTML content, and then forwards the modified response back to the browser. The main benefits of this approach are improved performance (since the font CSS is cached at the edge), reduced reliance on JavaScript for page modifications, and better control over how third-party resources like Google Fonts are loaded into web pages. To achieve this, the author uses various features of Cloudflare Workers such as Streams API, TransformStream, TextEncoder/Decoder, and Cache API. The code provided demonstrates how to handle character encodings other than UTF-8, detect unsupported charsets, and modify HTML content while preserving its integrity. Overall, this article showcases the power and flexibility of Cloudflare Workers for enhancing web performance and security by offloading complex tasks from the server or client side to the edge network.