Email capture: standalone Cloudflare Worker + D1 (lighter variant of #26)

[unforced]

What & why

A SIMPLE place to capture visitor emails for later sync into a Parachute vault — "start simple, just a place to capture emails." A quiet "Stay in the loop" form in the home's closing section posts to our own store.

This is the lighter variant of #26: the site stays on GitHub Pages (no apex DNS migration). Only the email-capture backend goes to Cloudflare — a standalone Worker + D1, instead of #26's Pages Functions (which would have required moving hosting to CF Pages).

How it differs from #26's Pages Function

• Repackaged onRequestPost: PagesFunction → a Worker export default { async fetch(request, env) } (worker/subscribe.ts). Same email validate/normalize (EMAIL_RE, 254 cap), source-path-from-Referer, parameterized D1 insert, two reserved columns.
• Absolute redirects — the Worker is a different origin from the site, so Location must be absolute (https://parachute.computer/subscribe/thanks/ on success, …/?subscribe_error=1 on failure). A relative path would resolve against the Worker origin.
• No CORS — the form is a native cross-origin <form method="POST">; the browser follows the Worker's 303 itself and the page never reads the cross-origin response with JS, so there's no preflight and no CORS headers needed.
• wrangler.toml adapted for a Worker (main = "worker/subscribe.ts" + [[d1_databases]] DB binding, database_id = "PLACEHOLDER"), not pages_build_output_dir.
• Dropped V1 interest list — homepage subscribe form, Pages Function, D1 #26's hosting-migration parts (no GH Pages workflow archival, no apex DNS swap, no CF Pages project).

The form

Quiet, serif/muted block in the home-close section (below "Get started", above the thin footer). One email input + a Subscribe button reusing .home-cta + existing tokens. Endpoint is a single documented constant: _data/site.json → subscribeEndpoint (default https://subscribe.parachute.computer/), referenced as {{ site.subscribeEndpoint }}. Kept the tiny inline ?subscribe_error=1 script that reveals a discreet error message.

Files

• worker/subscribe.ts, worker/tsconfig.json
• migrations/0001_interests.sql (verbatim from V1 interest list — homepage subscribe form, Pages Function, D1 #26)
• wrangler.toml
• _data/site.json
• subscribe/thanks.njk
• index.njk (form + scoped CSS + error script)
• eleventy.config.js (ignore worker/, migrations/, wrangler.toml, DEPLOY-subscribe.md)
• package.json (+ wrangler, @cloudflare/workers-types; dev:worker / db:migrate)
• DEPLOY-subscribe.md ("what's left for Aaron")

What's left for Aaron (Cloudflare)

wrangler login → wrangler d1 create parachute-interests (paste database_id into wrangler.toml) → wrangler d1 migrations apply parachute-interests --remote → wrangler deploy → set custom domain subscribe.parachute.computer (or update _data/site.json to the workers.dev URL) → smoke-test a real submission + confirm a D1 row. Full checklist in DEPLOY-subscribe.md.

Verification

• npx @11ty/eleventy builds clean; _site/index.html form posts to the configured endpoint; _site/subscribe/thanks/index.html exists; worker/, migrations/, wrangler.toml are not copied into _site/.
• Worker typechecks (tsc --noEmit strict against @cloudflare/workers-types, clean) and bundles via wrangler deploy --dry-run (2.43 KiB, D1 binding recognized).
• Rendered home + error state + thanks page verified in a real browser (HTTP-served so style.css resolves).

Security

• Worker holds no secret beyond the D1 binding (DB); insert is parameterized.
• Permissive email validation (typo-catching, not RFC 5322).
• No rate limiting yet — known simple-start gap, fine for early volume; add Turnstile / WAF rate-limit on the route when it matters (no code redeploy for a WAF rule).

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