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版本：10.x

响应缓存

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以下示例使用 Vercel 的边缘缓存 以最快速度向用户提供数据。

信息

使用缓存时务必谨慎——尤其是在处理个人信息时。

 
由于默认启用了批处理，建议在 responseMeta 函数中设置缓存头部，并确保没有可能包含个人数据的并发调用——或者当存在认证头或 cookie 时完全省略缓存头部。

 
你也可以使用 splitLink 来区分公共请求和需要保持私有且不缓存的请求。

应用缓存​

若在应用中启用 SSR，可能会发现应用在 Vercel 等平台加载缓慢，实际上无需 SSG 也能静态渲染整个应用；参阅此 Twitter 讨论串获取更多洞见。

示例代码​

utils/trpc.tsx
tsx
import { httpBatchLink } from '@trpc/client';
import { createTRPCNext } from '@trpc/next';
import type { AppRouter } from '../server/routers/_app';
export const trpc = createTRPCNext<AppRouter>({
  config(config) {
    if (typeof window !== 'undefined') {
      return {
        links: [
          httpBatchLink({
            url: '/api/trpc',
          }),
        ],
      };
    }
    const url = process.env.VERCEL_URL
      ? `https://${process.env.VERCEL_URL}/api/trpc`
      : 'http://localhost:3000/api/trpc';
    return {
      links: {
        http: httpBatchLink({
          url,
        }),
      },
    };
  },
  ssr: true,
  responseMeta(opts) {
    const { clientErrors } = opts;
    if (clientErrors.length) {
      // propagate http first error from API calls
      return {
        status: clientErrors[0].data?.httpStatus ?? 500,
      };
    }
    // cache request for 1 day + revalidate once every second
    const ONE_DAY_IN_SECONDS = 60 * 60 * 24;
    return {
      headers: {
        'cache-control': `s-maxage=1, stale-while-revalidate=${ONE_DAY_IN_SECONDS}`,
      },
    };
  },
});
utils/trpc.tsx
tsx
import { httpBatchLink } from '@trpc/client';
import { createTRPCNext } from '@trpc/next';
import type { AppRouter } from '../server/routers/_app';
export const trpc = createTRPCNext<AppRouter>({
  config(config) {
    if (typeof window !== 'undefined') {
      return {
        links: [
          httpBatchLink({
            url: '/api/trpc',
          }),
        ],
      };
    }
    const url = process.env.VERCEL_URL
      ? `https://${process.env.VERCEL_URL}/api/trpc`
      : 'http://localhost:3000/api/trpc';
    return {
      links: {
        http: httpBatchLink({
          url,
        }),
      },
    };
  },
  ssr: true,
  responseMeta(opts) {
    const { clientErrors } = opts;
    if (clientErrors.length) {
      // propagate http first error from API calls
      return {
        status: clientErrors[0].data?.httpStatus ?? 500,
      };
    }
    // cache request for 1 day + revalidate once every second
    const ONE_DAY_IN_SECONDS = 60 * 60 * 24;
    return {
      headers: {
        'cache-control': `s-maxage=1, stale-while-revalidate=${ONE_DAY_IN_SECONDS}`,
      },
    };
  },
});

API 响应缓存​

由于所有查询都是标准的 HTTP GET 请求，我们可以使用常规 HTTP 头部缓存响应，从而加速响应、减轻数据库压力，并轻松将 API 扩展到海量用户。

使用 responseMeta 缓存响应​

假设你将 API 部署在支持处理 stale-while-revalidate 缓存头的地方（例如 Vercel）。

server.ts
tsx
import { initTRPC } from '@trpc/server';
import * as trpcNext from '@trpc/server/adapters/next';
export const createContext = async ({
  req,
  res,
}: trpcNext.CreateNextContextOptions) => {
  return {
    req,
    res,
    prisma,
  };
};
type Context = Awaited<ReturnType<typeof createContext>>;
export const t = initTRPC.context<Context>().create();
const waitFor = async (ms: number) =>
  new Promise((resolve) => setTimeout(resolve, ms));
export const appRouter = t.router({
  public: t.router({
    slowQueryCached: t.procedure.query(async (opts) => {
      await waitFor(5000); // wait for 5s
      return {
        lastUpdated: new Date().toJSON(),
      };
    }),
  }),
});
// Exporting type _type_ AppRouter only exposes types that can be used for inference
// https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-8.html#type-only-imports-and-export
export type AppRouter = typeof appRouter;
// export API handler
export default trpcNext.createNextApiHandler({
  router: appRouter,
  createContext,
  responseMeta(opts) {
    const { ctx, paths, errors, type } = opts;
    // assuming you have all your public routes with the keyword `public` in them
    const allPublic = paths && paths.every((path) => path.includes('public'));
    // checking that no procedures errored
    const allOk = errors.length === 0;
    // checking we're doing a query request
    const isQuery = type === 'query';
    if (ctx?.res && allPublic && allOk && isQuery) {
      // cache request for 1 day + revalidate once every second
      const ONE_DAY_IN_SECONDS = 60 * 60 * 24;
      return {
        headers: {
          'cache-control': `s-maxage=1, stale-while-revalidate=${ONE_DAY_IN_SECONDS}`,
        },
      };
    }
    return {};
  },
});
server.ts
tsx
import { initTRPC } from '@trpc/server';
import * as trpcNext from '@trpc/server/adapters/next';
export const createContext = async ({
  req,
  res,
}: trpcNext.CreateNextContextOptions) => {
  return {
    req,
    res,
    prisma,
  };
};
type Context = Awaited<ReturnType<typeof createContext>>;
export const t = initTRPC.context<Context>().create();
const waitFor = async (ms: number) =>
  new Promise((resolve) => setTimeout(resolve, ms));
export const appRouter = t.router({
  public: t.router({
    slowQueryCached: t.procedure.query(async (opts) => {
      await waitFor(5000); // wait for 5s
      return {
        lastUpdated: new Date().toJSON(),
      };
    }),
  }),
});
// Exporting type _type_ AppRouter only exposes types that can be used for inference
// https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-8.html#type-only-imports-and-export
export type AppRouter = typeof appRouter;
// export API handler
export default trpcNext.createNextApiHandler({
  router: appRouter,
  createContext,
  responseMeta(opts) {
    const { ctx, paths, errors, type } = opts;
    // assuming you have all your public routes with the keyword `public` in them
    const allPublic = paths && paths.every((path) => path.includes('public'));
    // checking that no procedures errored
    const allOk = errors.length === 0;
    // checking we're doing a query request
    const isQuery = type === 'query';
    if (ctx?.res && allPublic && allOk && isQuery) {
      // cache request for 1 day + revalidate once every second
      const ONE_DAY_IN_SECONDS = 60 * 60 * 24;
      return {
        headers: {
          'cache-control': `s-maxage=1, stale-while-revalidate=${ONE_DAY_IN_SECONDS}`,
        },
      };
    }
    return {};
  },
});