Pick any line to see why it is the way it is: the commit, the pull request and issue it came from, and what the agent was thinking.
| Deployments: a preview for every pull request, production on g1t.page | 1 | /** |
| 2 | * The dispatcher for g1t.page: every app deployed by g1t is served here. | |
| 3 | * | |
| 4 | * The hostname's first label is the app's script name in the Workers for | |
| 5 | * Platforms namespace (`pr-12--web--acme.g1t.page` is pull request 12's | |
| 6 | * preview of acme/web), so a request needs no lookup: the app is fetched | |
| 7 | * by name and runs only for as long as it answers. An app no one visits | |
| 8 | * runs nothing and costs nothing. | |
| 9 | * | |
| 10 | * Kept apart from g1t.sh, so apps share no cookies or origin with the site | |
| 11 | * people sign in to. | |
| 12 | */ | |
| 13 | ||
| 14 | type Env = { | |
| 15 | APPS: DispatchNamespace; | |
| 16 | }; | |
| 17 | ||
| 18 | const DOMAIN = "g1t.page"; | |
| 19 | ||
| 20 | function page(status: number, title: string, body: string): Response { | |
| 21 | const html = `<!doctype html> | |
| 22 | <html lang="en"> | |
| 23 | <head> | |
| 24 | <meta charset="utf-8"> | |
| 25 | <meta name="viewport" content="width=device-width, initial-scale=1"> | |
| 26 | <meta name="robots" content="noindex"> | |
| 27 | <title>${title} · g1t.page</title> | |
| 28 | <style> | |
| 29 | :root { color-scheme: dark; --bg: #121214; --fg: #ececf1; --muted: #9a9aa6; --accent: #b4a7f5; } | |
| 30 | body { margin: 0; min-height: 100vh; display: grid; place-items: center; background: var(--bg); color: var(--fg); | |
| 31 | font: 16px/1.6 ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif; padding: 0 16px; } | |
| 32 | main { max-width: 32rem; } | |
| 33 | h1 { font-size: 1.5rem; margin: 0 0 .5rem; letter-spacing: -.01em; } | |
| 34 | p { color: var(--muted); margin: .5rem 0; } | |
| 35 | a { color: var(--accent); } | |
| 36 | code { font: .9em ui-monospace, SFMono-Regular, Menlo, monospace; color: var(--fg); } | |
| 37 | </style> | |
| 38 | </head> | |
| 39 | <body><main><h1>${title}</h1>${body}</main></body> | |
| 40 | </html>`; | |
| 41 | return new Response(html, { | |
| 42 | status, | |
| 43 | headers: { "content-type": "text/html; charset=utf-8", "x-robots-tag": "noindex" }, | |
| 44 | }); | |
| 45 | } | |
| 46 | ||
| 47 | function escape(text: string): string { | |
| 48 | return text.replace(/[&<>"']/g, (c) => `&#${c.charCodeAt(0)};`); | |
| 49 | } | |
| 50 | ||
| 51 | export default { | |
| 52 | async fetch(request: Request, env: Env): Promise<Response> { | |
| 53 | const host = new URL(request.url).hostname.toLowerCase(); | |
| 54 | if (host === DOMAIN) { | |
| 55 | return page( | |
| 56 | 200, | |
| 57 | "g1t.page", | |
| 58 | `<p>Apps deployed by <a href="https://g1t.sh">g1t</a>: every pull request's preview, and each repository's production.</p> | |
| 59 | <p><a href="https://docs.g1t.sh/guides/deployments/">How deployments work</a></p>`, | |
| 60 | ); | |
| 61 | } | |
| 62 | const label = host.endsWith(`.${DOMAIN}`) ? host.slice(0, -DOMAIN.length - 1) : ""; | |
| 63 | if (!/^[a-z0-9-]{1,63}$/.test(label)) { | |
| 64 | return page(404, "Nothing here", "<p>This is not the address of an app on g1t.page.</p>"); | |
| 65 | } | |
| 66 | let app: Fetcher; | |
| 67 | try { | |
| 68 | app = env.APPS.get(label); | |
| 69 | } catch { | |
| 70 | return missing(label); | |
| 71 | } | |
| 72 | let response: Response; | |
| 73 | try { | |
| 74 | response = await app.fetch(request); | |
| 75 | } catch (error) { | |
| 76 | if (/worker not found|script not found|does not exist/i.test(String(error))) return missing(label); | |
| 77 | return page( | |
| 78 | 502, | |
| 79 | "The app failed", | |
| 80 | `<p>The app at <code>${escape(host)}</code> threw an error before it could answer.</p>`, | |
| 81 | ); | |
| 82 | } | |
| 83 | // Previews are for the people reviewing a change, not search engines. | |
| 84 | if (label.startsWith("pr-")) { | |
| 85 | response = new Response(response.body, response); | |
| 86 | response.headers.set("x-robots-tag", "noindex"); | |
| 87 | } | |
| 88 | return response; | |
| 89 | }, | |
| 90 | } satisfies ExportedHandler<Env>; | |
| 91 | ||
| 92 | function missing(label: string): Response { | |
| 93 | const preview = label.startsWith("pr-"); | |
| 94 | return page( | |
| 95 | 404, | |
| 96 | preview ? "This preview is not up" : "Nothing deployed here", | |
| 97 | preview | |
| 98 | ? `<p>A preview comes down when its pull request is closed or merged, or after its repository's idle days without a visit. Pushing to the pull request, or redeploying it from the repository's Deployments page, brings it back.</p>` | |
| 99 | : `<p>No app is deployed at <code>${escape(label)}.${DOMAIN}</code>. Deployments are turned on per repository, from its Deployments page on g1t.</p>`, | |
| 100 | ); | |
| 101 | } |