Effect CommunityEC
Effect Community•4mo ago
Guilherme Guerreiro

Integrating CORS with Effect HttpApi using a Layer

Hello all! I'm trying to build some handlers for Better-Auth in my Effect HttpApi and the solution I ended up with for my handlers is the example bellow. The problem for me is having to setup the CORS. I have a CorsLive Layer that already does this for me on every endpoint of my api but it fails on this specific group. Is there a better way to do this? 

const authHandler = Effect.gen(function* () {
  const repository = yield* AuthRepository;
  const envVars = yield* EnvVars;

  const request = yield* HttpServerRequest.HttpServerRequest;
  const nodeRequest = NodeHttpServerRequest.toIncomingMessage(request);
  const nodeResponse = NodeHttpServerRequest.toServerResponse(request);

  const appUrl = envVars.APP_URL;

  nodeResponse.setHeader("Access-Control-Allow-Origin", appUrl);
  nodeResponse.setHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS");
  nodeResponse.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");
  nodeResponse.setHeader("Access-Control-Max-Age", "600");
  nodeResponse.setHeader("Access-Control-Allow-Credentials", "true");

  // Handle preflight requests
  if (nodeRequest.method === "OPTIONS") {
    nodeResponse.statusCode = 200;
    nodeResponse.end();
    return nodeResponse;
  }

  yield* Effect.tryPromise({
    try: () => toNodeHandler(repository.handler)(nodeRequest, nodeResponse),
    catch: (error) => {
      return new BetterAuthApiError({ error });
    },
  });

  return nodeResponse;
}).pipe(Effect.provide([AuthRepository.Default]));

const CorsLive = Layer.unwrapEffect(
  EnvVars.pipe(
    Effect.map((envVars) =>
      HttpApiBuilder.middlewareCors({
        allowedOrigins: [envVars.APP_URL],
        allowedMethods: ["GET", "POST", "PUT", "DELETE", "PATCH"],
        allowedHeaders: ["Content-Type", "Authorization", "B3", "traceparent"],
        credentials: true,
      }),
    ),
  ),
);
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