Spaces:
Running
Running
| import process from "node:process"; | |
| import { handler } from "./build/handler.js"; | |
| import polka from "polka"; | |
| import compression from "@polka/compression"; | |
| // SvelteKit's adapter-node docs recommend @polka/compression over the more popular | |
| // `compression` package because SvelteKit streams responses and `compression`'s | |
| // streaming implementation has a long-standing unresolved bug (expressjs/compression#183). | |
| // @polka/compression's own defaults are still unsafe for this app though: | |
| // - its default `mimes` regex matches both application/jsonl (via the "/json" substring) | |
| // and text/event-stream (via "text"), so token-streamed responses would get buffered | |
| // inside the gzip/brotli transform instead of delivered as they're produced. | |
| // - its brotli `level` defaults to -1, which resolves to BROTLI_MAX_QUALITY (11) instead | |
| // of a balanced default, making dynamic compression expensive on every request. | |
| // - it never sets `Vary: Accept-Encoding`, so a downstream cache could serve a | |
| // compressed body to a client that sent no Accept-Encoding. | |
| const mimes = | |
| /^(?!application\/jsonl(?:;|$))(?!text\/event-stream(?:;|$)).*(?:text|javascript|\/json|xml)/i; | |
| const compress = compression({ | |
| threshold: 1024, | |
| gzip: true, | |
| brotli: true, | |
| level: 4, | |
| mimes, | |
| }); | |
| // SvelteKit writes its own headers late (res.writeHead with a full header | |
| // object, e.g. `Vary: Accept` on routes that have both a page and a | |
| // co-located +server.ts), which would silently overwrite a Vary header set | |
| // up-front by middleware. Merge "Accept-Encoding" into any Vary value at | |
| // set-time instead, whichever code path writes it. | |
| function keepVaryAcceptEncoding(res) { | |
| const mergeVary = (value) => | |
| [ | |
| ...new Set( | |
| String(value ?? "") | |
| .split(",") | |
| .map((part) => part.trim()) | |
| .filter(Boolean) | |
| .concat("Accept-Encoding") | |
| ), | |
| ].join(", "); | |
| const setHeader = res.setHeader.bind(res); | |
| res.setHeader = (name, value) => | |
| String(name).toLowerCase() === "vary" | |
| ? setHeader(name, mergeVary(value)) | |
| : setHeader(name, value); | |
| const writeHead = res.writeHead.bind(res); | |
| res.writeHead = (status, ...rest) => { | |
| for (const arg of rest) { | |
| if (arg && typeof arg === "object" && !Array.isArray(arg)) { | |
| for (const key of Object.keys(arg)) { | |
| if (key.toLowerCase() === "vary") arg[key] = mergeVary(arg[key]); | |
| } | |
| } | |
| } | |
| return writeHead(status, ...rest); | |
| }; | |
| setHeader("Vary", "Accept-Encoding"); | |
| } | |
| const server = polka() | |
| .use((req, res, next) => { | |
| keepVaryAcceptEncoding(res); | |
| next(); | |
| }) | |
| .use(compress) | |
| .use(handler); | |
| // Mirrors the env vars adapter-node's generated build/index.js reads, since a custom | |
| // server doesn't get that lifecycle handling for free (see adapter-node docs: "Server | |
| // lifecycle variables must be implemented separately"). | |
| const path = process.env.SOCKET_PATH; | |
| const host = process.env.HOST ?? "0.0.0.0"; | |
| const port = process.env.PORT ?? "3000"; | |
| const shutdownTimeout = parseInt(process.env.SHUTDOWN_TIMEOUT ?? "30", 10); | |
| // Node treats any listen-options object carrying host/port as a TCP listen | |
| // (empirically, `{ path, host, port: undefined }` binds a random TCP port and | |
| // never creates the socket), so the socket path must be the only key present | |
| // when it is configured. | |
| const listenOptions = path ? { path } : { host, port }; | |
| server.listen(listenOptions, () => { | |
| console.log(`Listening on ${path || `http://${host}:${port}`}`); | |
| }); | |
| let shutdownTimeoutId; | |
| // Without this, SIGTERM during a rolling deploy kills in-flight requests immediately | |
| // instead of draining them, since the custom server has no shutdown handling by default. | |
| function gracefulShutdown() { | |
| if (shutdownTimeoutId) return; | |
| server.server.closeIdleConnections(); | |
| server.server.close(() => { | |
| if (shutdownTimeoutId) clearTimeout(shutdownTimeoutId); | |
| }); | |
| shutdownTimeoutId = setTimeout(() => server.server.closeAllConnections(), shutdownTimeout * 1000); | |
| } | |
| process.on("SIGTERM", gracefulShutdown); | |
| process.on("SIGINT", gracefulShutdown); | |