# @askrjs/server > Published API exports for @askrjs/server. Source: [https://askrjs.com/docs/reference/api/server/root](https://askrjs.com/docs/reference/api/server/root) Status: stable. Packages: @askrjs/server. **Published packages are authoritative.** Examples may lag behind a published contract. When guidance differs, verify the exports and TypeScript declarations in your installed package, then file an issue. ## Exports This entrypoint publishes 84 exports from the declarations shipped by @askrjs/server. ### `accepted` ```ts accepted: (value?: JsonValue, init?: ResponseInit) => Response ``` Builds a `202 Accepted` response; JSON-serializes `value` if given, otherwise an empty body. ### `accepts` ```ts accepts: (value: string, expected: string) => boolean ``` ### `AccessDeniedHandler` ```ts AccessDeniedHandler: (decision: Extract, context: ServerContext) => Response | Promise ``` Handler invoked to produce a response when an auth decision denies access. ### `ApiRoute` ```ts ApiRoute: any ``` A single registered route: a path/method pattern paired with a handler (or WebSocket upgrade handler). - `path`: path: string; - `method`: method?: string | readonly string[]; - `handler`: handler: Handler; - `upgrade`: upgrade?: WebSocketHandler; ### `ApiRouteOptions` ```ts ApiRouteOptions: any ``` Per-route configuration shared by {@link ApiRoute}. - `auth`: auth?: AuthRequirement; - `middleware`: middleware?: readonly Middleware[]; - `maxRequestBytes`: maxRequestBytes?: number; ### `AuthCredentials` ```ts AuthCredentials: any ``` Email/password credentials submitted to the register or authenticate endpoints. - `email`: email: string; - `password`: password: string; ### `AuthRouteError` ```ts AuthRouteError: typeof AuthRouteError ``` Error thrown from `register`/`authenticate`/etc. callbacks to short-circuit an auth route with a specific status. - `status`: readonly status: 401 | 409 | 429; ### `AuthRouteOptions` ```ts AuthRouteOptions: any ``` Configuration for {@link registerAuthRoutes}. - `issuer`: issuer: TokenIssuer

; - `cookie`: cookie: CookieOptions & { name: string; }; - `principalSchema`: principalSchema: Schema; - `register`: register(context: ServerContext, credentials: AuthCredentials): P | Promise

; - `authenticate`: authenticate(context: ServerContext, credentials: AuthCredentials): P | null | Promise

; - `allowAttempt`: allowAttempt(context: ServerContext, operation: "register" | "authenticate", normalizedEmail: string): boolean | Promise; - `revoke`: revoke?(context: ServerContext): void | Promise; - `redirect`: redirect?: (context: ServerContext, operation: "register" | "authenticate", principal: P) => string | undefined; ### `bad` ```ts bad: (detail?: string, init?: ResponseInit) => Response ``` Alias for {@link badRequest}. ### `badRequest` ```ts badRequest: (detail?: string, init?: ResponseInit) => Response ``` Builds a `400 Bad Request` Problem Details response. ### `bind` ```ts bind: >(context: BindContext) => Promise ``` Merges a request's body, query string, and path parameters into a single object, in that precedence order (path parameters win, then query string, then body). Supports JSON, URL-encoded, and multipart/form-data bodies; unrecognized content types yield an empty body. ### `BindContext` ```ts BindContext: any ``` Minimal request context required by {@link bind} to gather body, query, and path values. - `request`: request: Request; - `params`: params: Params; - `url`: url: URL; - `query`: query: URLSearchParams; ### `BindingError` ```ts BindingError: typeof BindingError ``` Error thrown when request data cannot be bound, e.g. an unreadable or malformed body. - `field`: readonly field?: string | undefined; - `status`: readonly status = 400; ### `challenge` ```ts challenge: (options?: ChallengeOptions) => Response ``` Builds a `401`/`407` Problem Details response with a `WWW-Authenticate` (or `Proxy-Authenticate` for `407`) challenge header. ### `ChallengeOptions` ```ts ChallengeOptions: any ``` Options for building a `WWW-Authenticate` challenge response via {@link ServerContext.challenge}. - `scheme`: scheme?: string; - `realm`: realm?: string; - `status`: status?: 401 | 407; - `detail`: detail?: string; - `init`: init?: ResponseInit; ### `clearCookie` ```ts clearCookie: (response: Response, name: string, options?: CookieOptions) => Response ``` Returns a clone of `response` with a `Set-Cookie` header that expires and clears `name`. ### `conflict` ```ts conflict: (detail?: string, init?: ResponseInit) => Response ``` Builds a `409 Conflict` Problem Details response. ### `contentType` ```ts contentType: (value: string | null) => string | undefined ``` ### `CookieOptions` ```ts CookieOptions: any ``` Options controlling how a cookie is set via {@link ServerContext.setCookie}. Do not derive `domain` or `path` from untrusted input; invalid attribute characters are rejected. - `domain`: ASCII cookie domain without whitespace or attribute delimiters. - `expires`: expires?: Date; - `httpOnly`: httpOnly?: boolean; - `maxAge`: maxAge?: number; - `path`: Cookie path without control characters or the `;` attribute delimiter. - `sameSite`: sameSite?: CookieSameSite; - `secure`: secure?: boolean; ### `CookieSameSite` ```ts CookieSameSite: "strict" | "lax" | "none" ``` Valid values for the `SameSite` cookie attribute. ### `createCspNonce` ```ts createCspNonce: () => CspNonceProvider ``` Creates a {@link CspNonceProvider} that lazily generates a cryptographically random, URL-safe base64 nonce per {@link ServerContext} and caches it for the lifetime of that context, so repeated calls within the same request return the same value. ### `created` ```ts created: (value?: JsonValue, init?: ResponseInit) => Response ``` Builds a `201 Created` response; JSON-serializes `value` if given, otherwise an empty body. ### `createEventStream` ```ts createEventStream: (options?: EventStreamOptions) => EventStream ``` Creates a Server-Sent Events stream backed by a `text/event-stream` `Response`, with bounded backpressure-aware writes, optional heartbeat comments, and automatic closing when `options.signal` aborts or `close()` is called. ### `createRouter` ```ts createRouter: () => Router ``` Creates an empty, mutable {@link Router} with chainable HTTP-method route builders (`get`, `post`, `put`, `patch`, `delete`, `options`, `head`, `trace`, `connect`, `ws`) and a `use` method for registering middleware. ### `createServerApp` ```ts createServerApp: { (router: Router): ServerApp; (options?: ServerAppOptions): ServerApp; } ``` Creates a transport-neutral server application that dispatches Web `Request`s to a router's routes and middleware, returning Web `Response`s. Accepts either a bare {@link Router} or a full {@link ServerAppOptions} object (which may itself reference a router). Builds a path matcher from the combined routes, validates request-size limits, and wraps dispatch with auth resolution, telemetry, and error handling (payload-too-large, malformed path parameters, binding errors, and a fallback `onError`). Creates a transport-neutral server application. See the {@link Router} overload for details. ```tsx const app = createServerApp(router); export default { fetch: app.fetch }; ``` ### `CspNonceProvider` ```ts CspNonceProvider: (context: ServerContext) => string ``` A function that returns a CSP nonce for a given request context, stable across calls for the same context. ### `DEFAULT_MAX_REQUEST_BYTES` ```ts DEFAULT_MAX_REQUEST_BYTES: 1048576 ``` Default maximum request body size, in bytes (1 MiB), used when no limit is configured. ### `defineRoutes` ```ts defineRoutes: (definition: (route: RouteBuilder) => void) => ApiRoute[] ``` Builds a flat list of {@link ApiRoute}s by invoking `definition` with a {@link RouteBuilder}. Useful for defining a set of routes without a full {@link Router} (e.g. to compose into one). ### `error` ```ts error: (status?: number, detail?: string, init?: ResponseInit) => Response ``` Builds a Problem Details error response with a configurable status (default `500`). ### `EventStream` ```ts EventStream: any ``` A live Server-Sent Events stream, backed by a streaming `Response`. - `response`: readonly response: Response; - `closed`: readonly closed: Promise; - `send`: Queues an event in order. Await or otherwise handle the returned promise before producing without bound. Rejects with `QuotaExceededError` when the pending-write limit is full. - `comment`: Queues an SSE comment in order. Rejects with `QuotaExceededError` when the pending-write limit is full. - `close`: close(): Promise; ### `EventStreamOptions` ```ts EventStreamOptions: any ``` Options for {@link createEventStream}. - `signal`: Aborting this signal closes the stream. - `heartbeatInterval`: If set, sends a `heartbeat` comment on this interval (in ms) to keep the connection alive. - `highWaterMark`: Backpressure threshold for the underlying `ReadableStream` and maximum number of unresolved `send()`/`comment()` calls admitted at once. Defaults to 16. - `headers`: headers?: HeadersInit; ### `explicitlyAccepts` ```ts explicitlyAccepts: (value: string, expected: string) => boolean ``` ### `forbidden` ```ts forbidden: (detail?: string, init?: ResponseInit) => Response ``` Builds a `403 Forbidden` Problem Details response. ### `formatServerSentEvent` ```ts formatServerSentEvent: (event: ServerSentEvent) => string ``` Serializes a {@link ServerSentEvent} to the `text/event-stream` wire format, escaping multi-line data/comment fields and validating that `event`/`id` contain no line breaks. ### `Handler` ```ts Handler: { bivarianceHack(context: ServerContext): Response | Promise; }["bivarianceHack"] ``` A route handler function that produces a response for a given {@link ServerContext}. ### `internalServerError` ```ts internalServerError: (detail?: string, init?: ResponseInit) => Response ``` Builds a `500 Internal Server Error` Problem Details response. ### `json` ```ts json: (value: JsonValue, init?: ResponseInit) => Response ``` Builds a `200 OK`-shaped JSON response, serializing `value` and setting the JSON content type. ### `JsonValue` ```ts JsonValue: unknown ``` A value that can be serialized as JSON. ### `methodNotAllowed` ```ts methodNotAllowed: (allow?: string | readonly string[], init?: ResponseInit) => Response ``` Builds a `405 Method Not Allowed` Problem Details response, setting the `Allow` header if given. ### `Middleware` ```ts Middleware: { bivarianceHack(context: ServerContext, next: Next): Response | Promise; }["bivarianceHack"] ``` A middleware function that may short-circuit or delegate to `next` to produce a response. ### `Next` ```ts Next: () => Response | Promise ``` Continuation function passed to a {@link Middleware}, invoking the next handler in the chain. ### `noContent` ```ts noContent: (init?: ResponseInit) => Response ``` Builds a `204 No Content` response with an empty body. ### `notFound` ```ts notFound: (detail?: string, init?: ResponseInit) => Response ``` Builds a `404 Not Found` Problem Details response. ### `notImplemented` ```ts notImplemented: (detail?: string, init?: ResponseInit) => Response ``` Builds a `501 Not Implemented` Problem Details response. ### `ok` ```ts ok: (value?: JsonValue, init?: ResponseInit) => Response ``` Builds a `200 OK` response; JSON-serializes `value` if given, otherwise an empty body. ### `Params` ```ts Params: Record ``` A map of route path parameter names to their string values. ### `PathParams` ```ts PathParams: string extends Path ? Params : { [Name in PathParameterNames]: string; } ``` Infers a {@link Params}-shaped object type from a route path pattern, extracting the names of `{param}` and `{*param}` segments as required string keys. ### `PayloadTooLargeError` ```ts PayloadTooLargeError: typeof PayloadTooLargeError ``` Error thrown when a request body exceeds the configured maximum size. - `status`: readonly status = 413; ### `ProbeHandler` ```ts ProbeHandler: (context: ServerContext) => ProbeResult | Promise ``` A health-check handler used for liveness/readiness/startup probes. ### `ProbeOptions` ```ts ProbeOptions: any ``` Optional handlers for the built-in `livez`/`readyz`/`startupz`/`targetz` health probe routes. - `livez`: livez?: ProbeHandler; - `readyz`: readyz?: ProbeHandler; - `startupz`: startupz?: ProbeHandler; - `targetz`: targetz?: ProbeHandler; ### `ProbeResult` ```ts ProbeResult: boolean | Response | void ``` Result of a health probe: `true`/`false` for pass/fail, a `Response` to return as-is, or `void` for pass. ### `problem` ```ts problem: (status: number, detail?: string, options?: ProblemOptions & { init?: ResponseInit; }) => Response ``` Builds an RFC 9457 `application/problem+json` response, defaulting `type` to `about:blank` and `title` to a standard reason phrase for the given `status` (falling back to "HTTP Error"). ### `Problem` ```ts Problem: any ``` An RFC 9457 Problem Details object, as produced by {@link ServerContext.problem}. - `type`: type: string; - `title`: title: string; - `status`: status: number; - `detail`: detail?: string; - `instance`: instance?: string; ### `ProblemOptions` ```ts ProblemOptions: any ``` Optional fields used to customize a {@link Problem} response. - `type`: type?: string; - `title`: title?: string; - `instance`: instance?: string; - `extensions`: extensions?: Record; ### `readRequestBytes` ```ts readRequestBytes: (request: Request, maximum?: number) => Promise ``` Reads a request body into memory as raw bytes, enforcing a maximum size. The result is cached per-request so subsequent reads (e.g. for JSON, text, or form data) reuse the same buffered bytes instead of re-reading the stream. ### `readRequestFormData` ```ts readRequestFormData: (request: Request, maximum?: number) => Promise ``` Reads a request body and parses it as `multipart/form-data`, enforcing a maximum size. ### `readRequestText` ```ts readRequestText: (request: Request, maximum?: number) => Promise ``` Reads and decodes a request body as UTF-8 text, enforcing a maximum size. ### `redirect` ```ts redirect: (location: string, status?: 301 | 302 | 303 | 307 | 308) => Response ``` Builds a redirect response with an empty body and a `Location` header. Defaults to `302 Found`. ### `registerAuthRoutes` ```ts registerAuthRoutes: (api: Pick, "group">, options: AuthRouteOptions

) => void ``` Registers a standard set of authentication routes (`POST /auth/v1/accounts`, `GET/POST /auth/v1/session`, `DELETE /auth/v1/session`) on an OpenAPI-style API/group, handling registration, login, session lookup, and logout with CSRF protection via a same-origin `Origin` header check, per-attempt rate limiting, and cookie-based token storage. ### `RequestState` ```ts RequestState: Record ``` Arbitrary per-request state bag attached to a {@link ServerContext}. ### `RouteBuilder` ```ts RouteBuilder: any ``` Chainable, per-HTTP-method route registration methods, one per method plus `ws` for WebSockets. - `route`: route(method: string | readonly string[], path: Path, handler: Handler>, options?: ApiRouteOptions>): ApiRoute>; - `get`: get(path: Path, handler: Handler>, options?: ApiRouteOptions>): ApiRoute>; - `post`: post(path: Path, handler: Handler>, options?: ApiRouteOptions>): ApiRoute>; - `put`: put(path: Path, handler: Handler>, options?: ApiRouteOptions>): ApiRoute>; - `patch`: patch(path: Path, handler: Handler>, options?: ApiRouteOptions>): ApiRoute>; - `delete`: delete(path: Path, handler: Handler>, options?: ApiRouteOptions>): ApiRoute>; - `options`: options(path: Path, handler: Handler>, options?: ApiRouteOptions>): ApiRoute>; - `head`: head(path: Path, handler: Handler>, options?: ApiRouteOptions>): ApiRoute>; - `trace`: trace(path: Path, handler: Handler>, options?: ApiRouteOptions>): ApiRoute>; - `connect`: connect(path: Path, handler: Handler>, options?: ApiRouteOptions>): ApiRoute>; - `ws`: ws(path: Path, handler: WebSocketHandler>, options?: ApiRouteOptions>): ApiRoute>; ### `Router` ```ts Router: any ``` A mutable collection of routes and middleware, built with chainable per-method registration methods (each returning the router itself for chaining) and a `use` method for middleware. - `routes`: readonly routes: readonly ApiRoute[]; - `middleware`: readonly middleware: readonly Middleware[]; - `use`: use(...middleware: Middleware[]): Router; - `route`: route(method: string | readonly string[], path: Path, handler: Handler>, options?: ApiRouteOptions>): Router; - `get`: get(path: Path, handler: Handler>, options?: ApiRouteOptions>): Router; - `post`: post(path: Path, handler: Handler>, options?: ApiRouteOptions>): Router; - `put`: put(path: Path, handler: Handler>, options?: ApiRouteOptions>): Router; - `patch`: patch(path: Path, handler: Handler>, options?: ApiRouteOptions>): Router; - `delete`: delete(path: Path, handler: Handler>, options?: ApiRouteOptions>): Router; - `options`: options(path: Path, handler: Handler>, options?: ApiRouteOptions>): Router; - `head`: head(path: Path, handler: Handler>, options?: ApiRouteOptions>): Router; - `trace`: trace(path: Path, handler: Handler>, options?: ApiRouteOptions>): Router; - `connect`: connect(path: Path, handler: Handler>, options?: ApiRouteOptions>): Router; - `ws`: ws(path: Path, handler: WebSocketHandler>, options?: ApiRouteOptions>): Router; ### `safeRedirect` ```ts safeRedirect: (fallback: string, options?: SafeRedirectOptions) => (value: unknown) => string ``` Creates a validator that resolves an untrusted redirect target to a safe, same-origin, relative path — or to `fallback` if the value is unsafe (absolute, protocol-relative, contains a scheme, control characters, `..` traversal, backslashes, or an unwanted hash). ### `SafeRedirectOptions` ```ts SafeRedirectOptions: any ``` Options for {@link safeRedirect}. - `allowHash`: Allow redirect targets that include a URL fragment (`#...`). Defaults to disallowed. ### `ServerApp` ```ts ServerApp: any ``` A configured server application, as returned by {@link createServerApp }. - `fetch`: fetch(request: Request, dispatchOptions?: ServerDispatchOptions): Promise; ### `ServerAppOptions` ```ts ServerAppOptions: any ``` Options accepted by {@link createServerApp } to configure a server application. - `router`: router?: Router; - `routes`: routes?: readonly ApiRoute[]; - `middleware`: middleware?: readonly Middleware[]; - `onError`: onError?: (error: unknown, context: ServerContext) => Response | Promise; - `onAccessDenied`: onAccessDenied?: AccessDeniedHandler; - `auth`: auth?: AuthResolver; - `fallback`: fallback?: Handler; - `websocket`: websocket?: WebSocketAdapter; - `probes`: probes?: ProbeOptions; - `telemetry`: telemetry?: ServerTelemetry; - `maxRequestBytes`: maxRequestBytes?: number; ### `ServerContext` ```ts ServerContext: any ``` The per-request context passed to handlers and middleware, bundling the incoming request, parsed URL/params/query, auth state, and a family of response-building helper methods (`json`, `ok`, `notFound`, `problem`, `setCookie`, `upgrade`, etc.). - `request`: request: Request; - `url`: url: URL; - `params`: params: RouteParams; - `headers`: headers: Headers; - `query`: query: URLSearchParams; - `state`: state: RequestState; - `auth`: auth: AuthContext; - `signal`: signal: AbortSignal; - `sse`: sse(options?: Omit): EventStream; - `telemetry`: telemetry?: ServerTelemetry; - `bind`: bind>(): Promise; - `json`: json(value: JsonValue, init?: ResponseInit): Response; - `text`: text(value: string, init?: ResponseInit): Response; - `redirect`: redirect(location: string, status?: 301 | 302 | 303 | 307 | 308): Response; - `ok`: ok(value?: JsonValue, init?: ResponseInit): Response; - `created`: created(value?: JsonValue, init?: ResponseInit): Response; - `accepted`: accepted(value?: JsonValue, init?: ResponseInit): Response; - `noContent`: noContent(init?: ResponseInit): Response; - `badRequest`: badRequest(message?: string, init?: ResponseInit): Response; - `bad`: bad(message?: string, init?: ResponseInit): Response; - `unauthorized`: unauthorized(message?: string, init?: ResponseInit): Response; - `forbidden`: forbidden(message?: string, init?: ResponseInit): Response; - `notFound`: notFound(message?: string, init?: ResponseInit): Response; - `conflict`: conflict(message?: string, init?: ResponseInit): Response; - `unprocessableEntity`: unprocessableEntity(message?: string, init?: ResponseInit): Response; - `tooManyRequests`: tooManyRequests(message?: string, init?: ResponseInit): Response; - `methodNotAllowed`: methodNotAllowed(allow?: string | readonly string[], init?: ResponseInit): Response; - `error`: error(status?: number, message?: string, init?: ResponseInit): Response; - `internalServerError`: internalServerError(message?: string, init?: ResponseInit): Response; - `serverError`: serverError(message?: string, init?: ResponseInit): Response; - `notImplemented`: notImplemented(message?: string, init?: ResponseInit): Response; - `serviceUnavailable`: serviceUnavailable(message?: string, init?: ResponseInit): Response; - `problem`: problem(status: number, detail?: string, options?: ProblemOptions): Response; - `challenge`: challenge(options?: ChallengeOptions): Response; - `setCookie`: setCookie(response: Response, name: string, value: string, options?: CookieOptions): Response; - `clearCookie`: clearCookie(response: Response, name: string, options?: CookieOptions): Response; - `upgrade`: upgrade(handler: WebSocketHandler): Response | Promise; ### `ServerDispatchOptions` ```ts ServerDispatchOptions: any ``` Per-request options passed to {@link ServerApp.fetch}. - `websocket`: websocket?: WebSocketAdapter; ### `serverError` ```ts serverError: (detail?: string, init?: ResponseInit) => Response ``` Alias for {@link internalServerError}. ### `ServerSentEvent` ```ts ServerSentEvent: any ``` A single Server-Sent Event; `data` is JSON-serialized unless already a string. - `data`: data?: unknown; - `event`: event?: string; - `id`: id?: string; - `retry`: retry?: number; ### `ServerTelemetry` ```ts ServerTelemetry: any ``` Telemetry hooks that a {@link ServerAppOptions.telemetry} implementation provides. Each `work`-wrapping method should run `work` inside an appropriately named span, propagating its return value. - `request`: request(fields: ServerTelemetryFields, work: () => T): T; - `routeMatch`: routeMatch(fields: ServerTelemetryFields, work: () => T): T; - `loader`: loader?(fields: ServerTelemetryFields, work: () => T): T; - `action`: action(fields: ServerTelemetryFields, work: () => T): T; - `apiOperation`: apiOperation(fields: ServerTelemetryFields, work: () => T): T; - `queryPrefetch`: queryPrefetch?(fields: ServerTelemetryFields, work: () => T): T; - `ssrRender`: ssrRender?(fields: ServerTelemetryFields, work: () => T): T; - `log`: log(level: "debug" | "info" | "warn" | "error", event: ServerTelemetryOperation, fields?: ServerTelemetryFields): void; - `traceId`: traceId(): string | undefined; - `extract`: extract?(carrier: Carrier, getter: { keys(value: Carrier): string[]; get(value: Carrier, key: string): string | string[] | undefined; }): unknown; - `withContext`: withContext?(context: unknown, work: () => T): T; ### `ServerTelemetryFields` ```ts ServerTelemetryFields: any ``` Contextual fields attached to a telemetry span or log entry. - `requestId`: requestId?: string; - `traceId`: traceId?: string; - `route`: route?: string; - `action`: action?: string; - `operation`: operation?: string; - `status`: status?: number; - `durationMs`: durationMs?: number; ### `ServerTelemetryOperation` ```ts ServerTelemetryOperation: "askr.request" | "askr.route.match" | "askr.loader" | "askr.action" | "askr.api.operation" | "askr.query.prefetch" | "askr.ssr.render" | "askr.vite.document" ``` Identifies the kind of operation a {@link ServerTelemetry} call is instrumenting. ### `serviceUnavailable` ```ts serviceUnavailable: (detail?: string, init?: ResponseInit) => Response ``` Builds a `503 Service Unavailable` Problem Details response. ### `setCookie` ```ts setCookie: (response: Response, name: string, value: string, options?: CookieOptions) => Response ``` Returns a clone of `response` with an additional `Set-Cookie` header appended, serialized from `name`, `value`, and `options`. ### `text` ```ts text: (value: string, init?: ResponseInit) => Response ``` Builds a plain-text response, setting the `text/plain; charset=utf-8` content type. ### `TokenIssuer` ```ts TokenIssuer: any ``` Issues auth tokens for a principal, used by {@link registerAuthRoutes} to mint session tokens. - `issue`: issue(principal: Omit & { subject: string; }): Promise; ### `tooManyRequests` ```ts tooManyRequests: (detail?: string, init?: ResponseInit) => Response ``` Builds a `429 Too Many Requests` Problem Details response. ### `unauthorized` ```ts unauthorized: (detail?: string, init?: ResponseInit) => Response ``` Builds a `401 Unauthorized` Problem Details response. ### `unprocessableEntity` ```ts unprocessableEntity: (detail?: string, init?: ResponseInit) => Response ``` Builds a `422 Unprocessable Entity` Problem Details response. ### `WebSocketAdapter` ```ts WebSocketAdapter: any ``` Adapter that performs the transport-specific work of upgrading a request to a WebSocket. - `upgrade`: upgrade(request: Request, handler: WebSocketHandler, context: ServerContext): Response | Promise; ### `WebSocketCloseEvent` ```ts WebSocketCloseEvent: any ``` Details of a WebSocket close event, mirroring the DOM `CloseEvent` fields used here. - `code`: readonly code: number; - `reason`: readonly reason: string; - `wasClean`: readonly wasClean: boolean; ### `WebSocketHandler` ```ts WebSocketHandler: { bivarianceHack(socket: WebSocketLike, context: ServerContext): void | Promise; }["bivarianceHack"] ``` Handler invoked with a live {@link WebSocketLike} once a connection has been upgraded. ### `WebSocketLike` ```ts WebSocketLike: any ``` Transport-neutral interface for an upgraded WebSocket connection. - `send`: send(data: string | ArrayBufferLike | ArrayBufferView): void; - `close`: close(code?: number, reason?: string): void; - `onMessage`: onMessage(listener: (data: string | Uint8Array) => void): () => void; - `onClose`: onClose(listener: (event: WebSocketCloseEvent) => void): () => void; - `onError`: onError(listener: (error: unknown) => void): () => void; ## Documentation navigation [Previous](https://askrjs.com/docs/reference/api/schema/root/index.md) | [Next](https://askrjs.com/docs/reference/api/server/router/index.md)