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import { compose } from "./composition.ts";import { type Middleware } from "./route.ts";import { type Context } from "./context.ts";
export type ServerHandlerOptions<S> = {  state?: S;  enableXResponseTimeHeader?: boolean;  enableLogger?: boolean;};
function setXResponseTimeHeader<C extends Context>(ctx: C) {  const ms = Date.now() - ctx.startTime;  ctx.response.headers.set("X-Response-Time", `${ms}ms`);}
function log<C extends Context>(ctx: C) {  const rt = ctx.response.headers.get("X-Response-Time");  console.log(    `${ctx.request.method} ${ctx.request.url} [${ctx.response.status}] - ${rt}`,  );  if (ctx.error) console.log(ctx.error);}
export function assertError(caught: unknown): Error {  return caught instanceof Error ? caught : new Error("[non-error thrown]");}
/** * A curried function which takes a `Context` class, `tryMiddlewares`, * `catchMiddlewares` and `finallyMiddlewares` and returns a `Deno.ServeHandler` * which can be passed to `Deno.serve`. It also handles the HTTP method * `HEAD` appropriately, sets the `X-Response-Time` header and logs to the * console by default. Optionally you can enable the logger or pass an * initial `state` object. * ```ts * const handler = createHandler(Ctx)(tryMiddlewares)(catchMiddlewares)(finallyMiddlewares) * Deno.serve(handler); * ``` */export function createHandler<C extends Context, S>(  Context: new (    request: Request,    connInfo: Deno.ServeHandlerInfo,    state?: S,  ) => C,  {    state,    enableXResponseTimeHeader = true,    enableLogger = false,  }: ServerHandlerOptions<S> = {},) {  return (...tryMiddlewares: Middleware<C>[]) =>  (...catchMiddlewares: Middleware<C>[]) =>  (...finallyMiddlewares: Middleware<C>[]): Deno.ServeHandler =>  async (    request: Request,    connInfo: Deno.ServeHandlerInfo,  ): Promise<Response> => {    const ctx = new Context(request, connInfo, state);    try {      ctx.startTime = Date.now();      await (compose(...tryMiddlewares)(ctx));    } catch (caught) {      ctx.error = assertError(caught);      await (compose(...catchMiddlewares)(ctx));    } finally {      await (compose(...finallyMiddlewares)(ctx));      if (enableXResponseTimeHeader) setXResponseTimeHeader(ctx);      if (enableLogger) log(ctx);    }    return request.method === "HEAD"      ? new Response(null, ctx.response)      : ctx.response;  };}