Typescript 如何在 deno 中强类型化 Oak 上下文状态对象

发布于07月19日

我想强烈地键入上下文.状态对象由deno中的oak提供.我已经看到了这种方法是如何工作的(例如Deno oak v10.5.1 context.cookies never being set)，但还没有在我自己的代码中实现它.

我的目标是访问强类型上下文.在我的每个中间件中声明.

这是上下文的接口.状态:

interface State {
    userID: number;
    sessionID: number;
}

这将是我用于设置上下文的中间件功能之一.我试图访问上下文状态属性的状态:

const contextMiddleware = async (context: Context, next: () => Promise<unknown>): Promise<void> => {
    context.state.userID = 123;
    context.state.sessionID = 456;
    await next();
    delete context.state.userID;
    delete context.state.sessionID;
}

我的问题是，在contextMiddleware函数中，这两个属性的类型是any，而不是预期的数字类型.此外，intellisense无法识别这些属性以实现自动补全.

我已经看到，解决方案可能是将IState接口作为泛型传递给调用中间件的应用程序和路由对象，然后将contextMiddlewate函数设置为从oak import mod键入RouterMiddleware或具有相同泛型的中间件.ts.

这可能看起来像这样，但目前不起作用:

import {
  Application,
  type Context,
  type Middleware,
  Router,
} from "https://deno.land/x/oak@v10.6.0/mod.ts";

interface State {
    userID: number;
    sessionID: number;
}

const contextMiddleware: Middleware<State, Context<State, State>> = async (context: Context, next: () => Promise<unknown>): Promise<void> => {
    context.state.userID = 123;
    context.state.sessionID= 456;
    await next();
    delete context.state.userID;
    delete context.state.sessionID;
}

const defaultRouter = new Router<State>();

defaultRouter
  .use(contextMiddleware)
  .get("/(.*)", (context: Context) => {
    context.response.status = 404;
    context.response.body = "Endpoint not available!";
  });

const app = new Application<State>();

app.use(defaultRouter.routes(), defaultRouter.allowedMethods());

app.addEventListener("listen", ({ hostname, port, secure }) => {
  console.log(
    `Listening on ${secure ? "https://" : "http://"}${
      hostname || "localhost"
    }:${port}`,
  );
});

await app.listen({ port: 8080 });

我错过了什么？

提前感谢您的帮助！

class Application<AS extends State = Record<string, any>> extends EventTarget { constructor(options?: ApplicationOptions<AS, ServerRequest>); // --- snip --- state: AS; // --- snip --- use<S extends State = AS>( middleware: Middleware<S, Context<S, AS>>, ...middlewares: Middleware<S, Context<S, AS>>[] ): Application<S extends AS ? S : (S & AS)>; use<S extends State = AS>( ...middleware: Middleware<S, Context<S, AS>>[] ): Application<S extends AS ? S : (S & AS)>; // --- snip --- }

interface ApplicationOptions <S, R extends ServerRequest> { contextState?: | "clone" | "prototype" | "alias" | "empty"; keys?: KeyStack | Key[]; logErrors?: boolean; proxy?: boolean; serverConstructor?: ServerConstructor<R>; state?: S; }

// This means "an object with no property names and no values" (e.g. `{}`) type EmptyObject = Record<never, never>; type AppState = EmptyObject; const app = new Application<AppState>({ state: {} });

class Context<S extends AS = State, AS extends State = Record<string, any>> { constructor( app: Application<AS>, serverRequest: ServerRequest, state: S, secure?, ); // --- snip --- app: Application<AS>; // { state: AS } // --- snip --- state: S; // --- snip --- }

interface RouterContext < R extends string, P extends RouteParams<R> = RouteParams<R>, S extends State = Record<string, any>, > extends Context<S> { captures: string[]; matched?: Layer<R, P, S>[]; params: P; routeName?: string; router: Router; routerPath?: string; }

import { type Context, type RouteParams, Router, type RouterContext, type State as AnyOakState, } from "https://deno.land/x/oak@v10.6.0/mod.ts"; type EmptyObject = Record<never, never>; interface RouterContextStrongerState< R extends string, AS extends AnyOakState = EmptyObject, S extends AS = AS, P extends RouteParams<R> = RouteParams<R>, > extends Context<S, AS> { captures: string[]; matched?: Exclude<RouterContext<R, P, S>["matched"], undefined>; params: P; routeName?: string; router: Router; routerPath?: string; }

interface Middleware< S extends State = Record<string, any>, T extends Context = Context<S>, > { (context: T, next: () => Promise<unknown>): Promise<unknown> | unknown; } interface RouterMiddleware< R extends string, P extends RouteParams<R> = RouteParams<R>, S extends State = Record<string, any>, > { ( context: RouterContext<R, P, S>, next: () => Promise<unknown>, ): Promise<unknown> | unknown; param?: keyof P; router?: Router<any>; }

type NextFn = () => Promise<unknown>; async function assignContextStateValuesAtTheBeginningAndDeleteThemAtTheEnd( context: Context<Partial<ContextState>, AppState>, next: NextFn, ): Promise<void> { context.state.userID = 123; // ^? number | undefined context.state.sessionID = 456; // ^? number | undefined await next(); // Wait for subsequent middleware to finish delete context.state.userID; delete context.state.sessionID; }

function setEndpointNotFound( context: RouterContextStrongerState<"/(.*)", AppState, Partial<ContextState>>, ): void { context.response.status = 404; context.response.body = "Endpoint not available!"; }

function idsAreSet<T extends { state: Partial<ContextState> }>( contextWithPartialState: T, ): contextWithPartialState is T & { state: T["state"] & Required<Pick<T["state"], "sessionID" | "userID">>; } { return ( typeof contextWithPartialState.state.sessionID === "number" && typeof contextWithPartialState.state.userID === "number" ); } async function someOtherMiddleware( context: Context<Partial<ContextState>, AppState>, next: NextFn, ): Promise<void> { // In the main scope of the function: context.state.userID; // ^? number | undefined context.state.sessionID; // ^? number | undefined if (idsAreSet(context)) { // After the type guard is used, in the `true` path scope: context.state.userID; // ^? number context.state.sessionID; // ^? number } else { // After the type guard is used, in the `false` path scope: context.state.userID; // ^? number | undefined context.state.sessionID; // ^? number | undefined } await next(); }

import { Application, type Context, type RouteParams, Router, type RouterContext, type State as AnyOakState, } from "https://deno.land/x/oak@v10.6.0/mod.ts"; type EmptyObject = Record<never, never>; type AppState = EmptyObject; const app = new Application<AppState>({ state: {} }); type ContextState = { userID: number; sessionID: number; }; interface RouterContextStrongerState< R extends string, AS extends AnyOakState = EmptyObject, S extends AS = AS, P extends RouteParams<R> = RouteParams<R>, > extends Context<S, AS> { captures: string[]; matched?: Exclude<RouterContext<R, P, S>["matched"], undefined>; params: P; routeName?: string; router: Router; routerPath?: string; } type NextFn = () => Promise<unknown>; async function assignContextStateValuesAtTheBeginningAndDeleteThemAtTheEnd( context: Context<Partial<ContextState>, AppState>, next: NextFn, ): Promise<void> { context.state.userID = 123; context.state.sessionID = 456; await next(); delete context.state.userID; delete context.state.sessionID; } function setEndpointNotFound( context: RouterContextStrongerState<"/(.*)", AppState, Partial<ContextState>>, ): void { context.response.status = 404; context.response.body = "Endpoint not available!"; } const router = new Router<Partial<ContextState>>(); router.use(assignContextStateValuesAtTheBeginningAndDeleteThemAtTheEnd); router.get("/(.*)", setEndpointNotFound); app.use(router.routes(), router.allowedMethods()); // This is not necessary, but is potentially helpful to see in the console function printStartupMessage({ hostname, port, secure }: { hostname: string; port: number; secure?: boolean; }): void { if (!hostname || hostname === "0.0.0.0") hostname = "localhost"; const address = new URL(`http${secure ? "s" : ""}://${hostname}:${port}/`).href; console.log(`Listening at ${address}`); console.log("Use ctrl+c to stop"); } app.addEventListener("listen", printStartupMessage); await app.listen({ port: 8080 });

Typescript 如何在 deno 中强类型化 Oak 上下文状态对象

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