drizzli/README.md

Drizz.li

An open-source, high-performance weather forecast website built with SvelteKit and powered by the Open-Meteo APIs.

Goals

Our objective is to provide a comprehensive, user-friendly weather platform for end-users. We aim to offer professional-grade weather visualizations and detailed meteorological data while maintaining the transparency and community-driven nature of open-source software.

Tech Stack

• Framework: SvelteKit
• Language: TypeScript
• Data Source: Open-Meteo API
• Visualization: custom canvas charts (src/lib/charts)

Developing

Once you've cloned the project and installed dependencies with npm install:

npm run dev

# or start the server and open the app in a new browser tab
npm run dev -- --open

Building

To create a production version of your app:

npm run build

You can preview the production build with npm run preview.

Deployment (static hosting)

The build output in build/ is a fully static site. Two pieces of server configuration are needed:

1. SPA fallback

Pages that are not prerendered (unlisted cities, GPS coordinate routes like /weather/week/52.09N5.12E/) are served by 404.html, which boots the app and resolves the location client-side. Configure the server to serve 404.html for unknown paths.

Serve it as an internal rewrite (200), not as an error page. error_page 404 /404.html sends the right body with a 404 status: the page works, but every hard reload of an unprerendered URL logs a 404 in the network panel and tells crawlers the page does not exist. try_files with a URI as its last argument does an internal redirect instead, and answers 200.

2. Cross-origin isolation (SharedArrayBuffer for the embedded map)

The /weather/maps/ page embeds maps.open-meteo.com, which uses SharedArrayBuffer for its decoding worker pool. A cross-origin iframe only gets SharedArrayBuffer when the embedding page is cross-origin isolated, so this site must be served with:

Cross-Origin-Opener-Policy: same-origin
Cross-Origin-Embedder-Policy: require-corp

(The map already serves Cross-Origin-Resource-Policy: cross-origin and its own COOP/COEP, so it is embeddable under these headers. All other assets are same-origin and the weather APIs are CORS requests, so require-corp is safe here.)

Example: Caddy

drizzli.example.com {
	root * /srv/drizzli
	file_server
	try_files {path} {path}/ /404.html
	header {
		Cross-Origin-Opener-Policy "same-origin"
		Cross-Origin-Embedder-Policy "require-corp"
	}
}

Example: nginx

server {
	server_name drizzli.example.com;
	root /srv/drizzli;
	add_header Cross-Origin-Opener-Policy "same-origin" always;
	add_header Cross-Origin-Embedder-Policy "require-corp" always;
	location / {
		# the trailing /404.html is a URI, so nginx rewrites internally and
		# answers 200 - `error_page 404 /404.html` would answer 404 instead
		try_files $uri $uri/index.html /404.html;
	}
}