PoC for running Connect on Next.js

[[...connect]].ts

// place this file in pages/api/[[...connect]].ts


// Copyright 2021-2023 Buf Technologies, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import {compressionBrotli, compressionGzip,} from "@bufbuild/connect-node"
import routes from "../../connect";
import {nextJsApiRouter} from "../../connect-nextjs-adapter";

// TODO check out cors middle ware https://github.com/vercel/next.js/blob/canary/examples/api-routes-cors/pages/api/cors.ts

const {handler, config} = nextJsApiRouter({
    routes,
})

export {handler as default, config};

connect-nextjs-adapter.ts

// Copyright 2021-2023 Buf Technologies, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import {ConnectRouter, createConnectRouter, ConnectRouterOptions} from "@bufbuild/connect";
import { UniversalHandler } from "@bufbuild/connect/protocol";
import {
   compressionBrotli,
   compressionGzip,
   universalRequestFromNodeRequest,
   universalResponseToNodeResponse
} from "@bufbuild/connect-node";
import {NextApiRequest, NextApiResponse} from "next";

type NextApiHandler<T = any> = (req: NextApiRequest, res: NextApiResponse<T>) => unknown | Promise<unknown>;

interface NextJsApiRouterOptions extends ConnectRouterOptions {
   /**
    * Route definitions. We recommend the following pattern:
    *
    * Create a file `connect.ts` with a default export such as this:
    *
    * ```ts
    * import {ConnectRouter} from "@bufbuild/connect";
    *
    * export default (router: ConnectRouter) => {
    *   router.service(ElizaService, {});
    * }
    * ```
    *
    * Then pass this function here.
    */
   routes: (router: ConnectRouter) => void;

   /**
    * Serve all handlers under this prefix. For example, the prefix "/something"
    * will serve the RPC foo.FooService/Bar under "/something/foo.FooService/Bar".
    *
    * This is `/api` by default for Next.js.
    */
   prefix?: string;
}

export function nextJsApiRouter(options: NextJsApiRouterOptions): ApiRoute {
   if (options.acceptCompression === undefined) {
      options.acceptCompression = [compressionGzip, compressionBrotli];
   }
   const router = createConnectRouter(options);
   options.routes(router);
   const prefix = options.prefix ?? "/api";
   const paths = new Map<string, UniversalHandler>();
   for (const uHandler of router.handlers) {
      paths.set(prefix + uHandler.requestPath, uHandler);
   }
   async function handler(req: NextApiRequest, res: NextApiResponse) {
      const requestPath = req.url ?? "";
      const uHandler = paths.get(requestPath);
      if (!uHandler) {
         res.writeHead(404);
         res.end();
         return;
      }
      const uRes = await uHandler(universalRequestFromNodeRequest(req, req.body));
      await universalResponseToNodeResponse(uRes, res);
   }
   return {
      handler,
      config: {
         api: {
            bodyParser: false,
         },
      }
   };
}


interface ApiRoute {
   handler: NextApiHandler;
   config: {
      api: {
         bodyParser: false, // body-parser stumbles over connect+json server-streaming RPC
      },
   }
}