Migrating from gRPC-Web to connect-web

Bareun's web client has moved from the earlier gRPC-Web to connect-web. connect-web is a lightweight RPC client that lets a browser call the Bareun server directly without a separate proxy.

This document summarizes what changes when you move a web frontend from gRPC-Web to connect-web.

Why migrate

The Bareun server is implemented with connect-go, so it accepts Connect-RPC, gRPC, and REST at the same time. In a browser, you can combine @connectrpc/connect, @connectrpc/connect-web, and @bufbuild/protobuf to call it cleanly with the standard fetch.

Replacing packages

# Remove the previous (gRPC-Web) dependencies,
npm remove grpc-web google-protobuf

# and install the connect-web stack.
npm install @connectrpc/connect @connectrpc/connect-web @bufbuild/protobuf

Client code comparison

import { createConnectTransport } from "@connectrpc/connect-web";
import { createClient } from "@connectrpc/connect";
import { LanguageService } from "./gen/language_service_connect";

// Create the transport layer to the Bareun server.
const transport = createConnectTransport({
  baseUrl: "https://api.bareun.ai",
});
const client = createClient(LanguageService, transport);

// Call AnalyzeSyntax
const res = await client.analyzeSyntax({
  document: { content: "오늘 날씨가 좋네요.", language: "ko_KR" },
  encodingType: "UTF16",
});

import { LanguageServiceClient } from "./gen/Language_serviceServiceClientPb";
import { AnalyzeSyntaxRequest, Document } from "./gen/language_service_pb";

const client = new LanguageServiceClient("https://...:5656");
const req = new AnalyzeSyntaxRequest();
const doc = new Document();
doc.setContent("오늘 날씨가 좋네요.");
doc.setLanguage("ko_KR");
req.setDocument(doc);
client.analyzeSyntax(req, {}, (err, res) => { /* ... */ });

Migration checklist

• Remove grpc-web and google-protobuf, and install the three connect-web packages
• Switch proto code generation to the buf-based connect plugin
• Replace the client creation code with createConnectTransport + createClient
• Clean up endpoints: connect-web calls the Bareun server directly, without a separate Envoy proxy
• Check the request field names (document, encodingType, customDictNames, etc.)

Frequently asked questions

Q. If I switch to connect-web, do I have to change the server too?

No. The Bareun server is implemented with connect-go and accepts connect-web requests as is. You call the same LanguageService, so you only replace the client, with no server change.

Q. Which packages does connect-web use?

It uses @connectrpc/connect, @connectrpc/connect-web, and @bufbuild/protobuf for message serialization. Remove the existing grpc-web and google-protobuf.

Q. Does the structure of the analysis result change too?

The response message structure (sentence, eojeol (space-delimited word unit), morpheme, TextSpan position) is the same. What changes is the transport and the client code; the analysis result itself is the same.