nasa-photo-proxy/README.md

nasa-photo-proxy

NASA's Astronomy Picture of the Day, fetched through your own tiny Node server. The same "fetch some data and show it" idea as the browser tutorials — but now with a real backend, so you learn why apps have servers: to keep secrets like API keys out of the browser.

Run

Get it: git clone https://git.devai.io/templates/nasa-photo-proxy.git

With Node.js 22 or newer — there are no npm packages to install:

cp .env.example .env    # optional: paste your own NASA key
node server.js

Then open http://localhost:8080.

Or run it like production:

docker compose up --build

Same address. Compose reads NASA_API_KEY from .env too, and falls back to NASA's shared DEMO_KEY.

How it works

In the browser-only tutorials the page called the API directly. That's fine for keyless APIs, but many APIs need a secret key — and anything in a web page is visible to anyone who opens "View Source". So put a server in the middle:

Browser  ──►  /api/apod (your server)  ──►  api.nasa.gov/planetary/apod?api_key=SECRET
         ◄──   title, date, image URL   ◄──

server.js has two jobs:

• Serve the page. Requests like /, /styles.css and /app.js read a file from public/ — and anything that tries to climb out of it (/../server.js) is refused.
• Be the proxy. /api/apod calls NASA with NASA_API_KEY from the environment (or .env, loaded with Node's built-in process.loadEnvFile()), and sends back only the fields the page needs.

public/app.js fetches /api/apod — its own server — never nasa.gov, so the key never reaches the browser. DEMO_KEY is shared by everyone and allows only a few dozen requests an hour; when NASA says "too many", the page tells you to get a free key at https://api.nasa.gov.

Try it: cache NASA's answer for an hour so reloads don't call NASA, add /api/apod?date=2022-07-11 (NASA accepts a date parameter), or swap NASA for any other key-protected API — the proxy pattern is identical.

Layout

server.js           the whole backend: static files + the /api/apod proxy
public/index.html   the page
public/app.js       calls /api/apod on our own server
public/styles.css   the look; follows your system's light or dark mode
.env.example        where the API key goes
package.json        name + "start" script; the lockfile is empty on purpose

Deploy

Push to your own GitHub repo and the shipped workflow (.github/workflows/ci.yml) tests the compose stack, publishes the image to GHCR, and — once you set the DEPLOY_HOST / DEPLOY_USER variables and DEPLOY_KEY secret — deploys it to your server over ssh. Put your real NASA_API_KEY in .env next to compose.yaml on the server.

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Part of devai.io — the APIs & Data track: fetch real data from the internet. Previous: ip-lookup.