Routing

app.get("/teas/:id", {
  params: t.object({ id: t.int() }),
  response: { 200: Tea, 404: t.problem() },
}, ({ params, notFound }) => findTea(params.id) ?? notFound());

A route is a method, a path, a spec and a handler. The spec is the contract: what comes in, what goes out, and a few examples. Everything below is optional.

PathsCopy Anchor Link

app.get("/teas", list);             // a path
app.get("/teas/:id", one);          // a param: params.id
app.get("/files/*path", file);      // the rest of the path: params.path
app.get("/teas/new", form);         // wins over /teas/:id, in any order

Static segments win over params, and params over the rest, so /teas/new and /teas/:id can live side by side. A path without params is found with one lookup.

params, query, headersCopy Anchor Link

app.get("/teas", {
  query: t.object({ page: t.int().default(1), kind: t.enum(["green", "black"]).optional() }),
  headers: t.object({ "x-shop": t.string() }),
}, ({ query, headers }) => list(query.page, query.kind, headers["x-shop"]));

Params, query and headers arrive as text and are turned into what the schema asks for: ?page=2 is the number 2, ?tag=a&tag=b a list. A value that does not fit is a 400 problem that names it, before the handler runs.

bodyCopy Anchor Link

app.post("/teas", { body: t.object({ name: t.string().min(1), grams: t.int().min(1) }) }, ({ body }) => store.add(body));

JSON, a form or multipart, read and checked before the handler; a t.file() in the schema takes a file from a multipart body. t.binary() takes the bytes as they are, and t.stream() hands them to the handler unread, for uploads larger than memory.

bodyLimitCopy Anchor Link

app.post("/invoices", { body: t.binary().max(20 * 1024 * 1024) }, ({ body }) => store(body));
app.post("/notes", { bodyLimit: 64 * 1024, body: Note }, add);

The largest body a route takes, instead of the app's (1 MiB by default). The max of a t.binary() or t.stream() is its limit. A body that says it is larger is a 413 at once.

responseCopy Anchor Link

response: { 200: Tea, 201: Tea, 404: t.problem() }

Status → schema. The first 2xx is the status a plain value answers with, and no body means 204. Only what the schema lists leaves the server, in production too: a field the contract does not name never goes out by accident. In development the answer is also checked, and one that breaks the contract is a 500 with a message saying which field.

responseHeadersCopy Anchor Link

responseHeaders: { 201: { location: t.string() } }

Headers an answer promises. In development a missing or wrong one is a 500.

examplesCopy Anchor Link

examples: [
  { name: "found", params: { id: 1 } },
  { name: "missing", params: { id: 99 }, status: 404 },
]

The docs page shows them, and inkan check runs every one as a test. See Examples are tests.

securityCopy Anchor Link

security: "bearer" // or "basic", { apiKey: "x-key", in: "header" }, a list of them, or false

The credentials a route asks for. A request without them is a 401 before its input is read. Whether they are good is for your hook or handler to say.

timeoutCopy Anchor Link

app.get("/report", { timeout: 600_000 }, ({ signal }) => report(signal));

Milliseconds the handler may take. Past them the answer is a 504 problem and ctx.signal is aborted, so a database query behind it can stop. The app's timeout is the default.

cacheCopy Anchor Link

app.get("/stock/:id", { params, cache: { ttl: 600_000 } }, ({ params }) => stock(params.id));

Keeps the handler's answers: the same params and query within the time get the same answer without the handler, and requests that come in while it is still being worked out wait for that one answer instead of each asking the database again.

A handler that throws keeps nothing. The cache lives in the memory of each process.

useCopy Anchor Link

app.get("/teas", { use: [audit] }, list);

Middleware for this route only, after its input was checked.

metaCopy Anchor Link

app.get("/reports", { meta: { auth: { roles: ["admin"] } } }, list);

Free-form facts about the route for plugins to read in their hooks, as ctx.route.meta. It is not in OpenAPI. A plugin types what it reads by extending RouteMeta; see Writing a plugin. New in 0.7.0.

summary, description, tags, operationId, deprecated, hiddenCopy Anchor Link

For the docs page and OpenAPI; hidden keeps a route out of both.

What a handler returnsCopy Anchor Link

Rows, as they comeCopy Anchor Link

app.get("/articles", { response: { 200: t.array(Article) } }, async function* ({ signal }) {
  for await (const row of db.query("select * from articles", { signal })) yield row;
});

A list given row by row never sits in memory whole. Every row is written by the item's writer as it comes, so it holds only what the contract lists; in development each one is checked, and a row that breaks the contract ends the answer early, so no client takes a part for the whole. A client that sends accept: application/x-ndjson gets one JSON line per row.

GroupsCopy Anchor Link

import { routes } from "@vxnsin/inkan";

const admin = routes().security("bearer").use(audit).get("/stats", stats);
app.mount("/admin", admin);

routes() makes a group with middleware and credentials of its own; mount() puts it under a prefix, types and all. For hooks and decorations of their own, use a plugin.

Routes from filesCopy Anchor Link

// routes/teas/[id].ts
import { route, t } from "@vxnsin/inkan";

export const GET = route({ params: t.object({ id: t.int() }) }, ({ params }) => findTea(params.id));

app.load(new URL("./routes", import.meta.url));

routes/teas/[id].ts is /teas/:id, and routes/files/[...rest].ts is /files/*rest. Each file exports its methods, made with route() so the handler is typed from its contract.