gRPC-Webの統合
gRPC-Webプロキシを使用して、Webブラウザーから直接gRPC通信を行えるようにする方法を学習します。
「gRPC-Webの統合」はCoddyKit上の無料gRPC & High Performance APIsレッスンです。 これはレッスン1/4です。 下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。 これはgRPC & High Performance APIs学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 gRPC & High Performance APIsコースには全4レッスンが含まれています。
このレッスンの一部はまだ翻訳されておらず、英語で表示されています。
Bridging Browsers to gRPC
Welcome to gRPC-Web Integration!
You've learned about gRPC's power for high-performance communication. But what if you want your web browser applications to talk to gRPC services directly? That's where gRPC-Web comes in.
This lesson explores how gRPC-Web enables browser-based clients to interact with gRPC backends.
Why Browsers Need gRPC-Web
Modern browsers don't fully expose the low-level HTTP/2 features that native gRPC relies on, especially for advanced streaming capabilities.
- No full HTTP/2 control: Browsers abstract away direct HTTP/2 frame manipulation.
- CORS restrictions: Cross-Origin Resource Sharing (CORS) policies can complicate direct gRPC connections.
- Limited header access: Some gRPC-specific headers might not be accessible or modifiable.
These limitations prevent a standard gRPC client from running directly in a browser.
Introducing the gRPC-Web Proxy
The core idea behind gRPC-Web is to use a proxy. This proxy sits between your browser client and your gRPC server.
- The browser client sends requests in a gRPC-Web compatible format (often HTTP/1.1 or a restricted HTTP/2).
- The gRPC-Web proxy translates these requests into native gRPC (full HTTP/2) and forwards them to your gRPC server.
- It also translates the gRPC server's responses back into a format the browser client understands.
Think of it as a translator for your browser to speak gRPC.
Common Proxy Solutions
While you could write your own, several robust proxies are available:
- Envoy Proxy: A popular, high-performance open-source edge and service proxy. It has built-in support for gRPC-Web.
grpcwebproxy: A dedicated proxy written in Go, specifically designed for gRPC-Web.
These tools handle the complex translation layer, allowing your gRPC server to remain a standard gRPC server.
The Communication Flow
Here's a simplified view of how a gRPC-Web call works:
- Browser Client: Makes an HTTP/1.1 (or restricted HTTP/2) request to the proxy.
- gRPC-Web Proxy: Receives the request, converts it to a standard HTTP/2 gRPC request.
- gRPC Server: Processes the native gRPC request and sends back a native gRPC response.
- gRPC-Web Proxy: Receives the gRPC response, converts it back to an HTTP/1.1 (or restricted HTTP/2) response.
- Browser Client: Receives and processes the converted response.
Protobuf for Web Clients
Just like with regular gRPC, you define your service and messages using Protocol Buffers (Protobuf).
To generate client-side code for browsers, you use a special Protobuf plugin, typically protoc-gen-grpc-web. This generates JavaScript or TypeScript code that works with browser environments.
This generated code knows how to format requests for the gRPC-Web proxy and parse its responses.
Example: Web Client Call
After generating your client stubs, making a gRPC-Web call from JavaScript/TypeScript looks familiar. Here's a conceptual snippet for a GreeterService:
(Note: This code is illustrative and not runnable without a full gRPC-Web setup including proto compilation, a running proxy, and server.)
import {HelloRequest} from './helloworld_pb';
import {GreeterClient} from './HelloworldServiceClientPb';
const client = new GreeterClient(
'http://localhost:8080', // Proxy address
null, null
);
const request = new HelloRequest();
request.setName('CoddyKit User');
client.sayHello(request, {}, (err, response) => {
if (err) {
console.error(err.code, err.message);
return;
}
console.log(response.getMessage());
});Server-Side Remains Standard
One of the great advantages of gRPC-Web is that your gRPC server doesn't need to know anything about it!
The server simply receives standard gRPC requests (HTTP/2) from the proxy and sends back standard gRPC responses. This means you don't need to change your existing gRPC service implementations to support browser clients.
This separation of concerns simplifies development and maintenance.
Streaming Limitations in gRPC-Web
While gRPC-Web is powerful, it has some limitations compared to native gRPC:
- Unary RPCs: Fully supported (request-response).
- Server Streaming: Generally supported (server sends multiple responses to one request).
- Client Streaming: Not typically supported due to browser limitations on streaming requests.
- Bidirectional Streaming: Not typically supported for the same reason.
For applications heavily relying on client or bidirectional streaming, native gRPC clients (e.g., in Node.js, mobile apps) are usually required.
Quick Check: gRPC-Web Purpose
Which of the following statements accurately describe the primary purpose or characteristics of gRPC-Web?
Recap: Bridging Browsers & gRPC
You've successfully learned about gRPC-Web!
- It's a solution to enable web browser clients to interact with gRPC services.
- It works by using a proxy (like Envoy or
grpcwebproxy) to translate requests and responses. - Your gRPC server remains standard, unaware of the gRPC-Web layer.
- While it supports unary and server streaming, client and bidirectional streaming are typically not supported.
This powerful tool bridges the gap, bringing the benefits of gRPC to your web applications!
よくある質問
「gRPC-Webの統合」レッスンは無料ですか？
はい。「gRPC-Webの統合」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、gRPC & High Performance APIsコースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 gRPC & High Performance APIsコースには全4レッスンが含まれています。
「gRPC-Webの統合」で何を学びますか？
gRPC-Webプロキシを使用して、Webブラウザーから直接gRPC通信を行えるようにする方法を学習します。 ブラウザで直接実行するハンズオンコードでgRPC & High Performance APIsを演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。
gRPC & High Performance APIsを始めるのに経験は必要ですか？
事前経験は必要ありません。CoddyKitのgRPC & High Performance APIsは初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。 これはレッスン1/4です。
「gRPC-Webの統合」レッスンにはどのくらい時間がかかりますか？
ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。
このgRPC & High Performance APIsレッスンでコードを書いて実行できますか？
はい。すべてのgRPC & High Performance APIsレッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。