3.8 KiB
@improbable-eng/grpc-web
Library for making gRPC-Web requests from a browser
This library is intended for both JavaScript and TypeScript usage from a web browser or NodeJS (see Usage with NodeJS).
Note: This only works if the server supports gRPC-Web
A Golang gRPC-Web middleware and a Golang-based gRPC-Web proxy are available here.
Please see the full gRPC-Web README for known limitations.
Installation
@improbable-eng/grpc-web
has peer dependencies of google-protobuf
and @types/google-protobuf
.
npm install google-protobuf @types/google-protobuf @improbable-eng/grpc-web --save
Example Project
There is an example project available here
Usage Overview
- Use
ts-protoc-gen
withprotoc
to generate.js
and.d.ts
files for your request and response classes.ts-protoc-gen
can also generate gRPC service definitions with theservice=true
argument. - Make a request using
unary()
,invoke()
orclient()
import {grpc} from "@improbable-eng/grpc-web";
// Import code-generated data structures.
import {BookService} from "./generated/proto/examplecom/library/book_service_pb_service";
import {GetBookRequest} from "./generated/proto/examplecom/library/book_service_pb";
const getBookRequest = new GetBookRequest();
getBookRequest.setIsbn(60929871);
grpc.unary(BookService.GetBook, {
request: getBookRequest,
host: host,
onEnd: res => {
const { status, statusMessage, headers, message, trailers } = res;
if (status === grpc.Code.OK && message) {
console.log("all ok. got book: ", message.toObject());
}
}
});
- Requests can be aborted/cancelled before they complete:
const request = grpc.unary(BookService.GetBook, { ... });
request.cancel();
Available Request Functions
There are three functions for making gRPC requests:
grpc.unary
This is a convenience function for making requests that consist of a single request message and single response message. It can only be used with unary methods.
rpc GetBook(GetBookRequest) returns (Book) {}
grpc.invoke
This is a convenience function for making requests that consist of a single request message and a stream of response messages (server-streaming). It can also be used with unary methods.
rpc GetBook(GetBookRequest) returns (Book) {}
rpc QueryBooks(QueryBooksRequest) returns (stream Book) {}
grpc.client
grpc.client
returns a client. Dependant upon transport compatibility this client is capable of sending multiple request messages (client-streaming) and receiving multiple response messages (server-streaming). It can be used with any type of method, but will enforce limiting the sending of messages for unary methods.
rpc GetBook(GetBookRequest) returns (Book) {}
rpc QueryBooks(QueryBooksRequest) returns (stream Book) {}
rpc LogReadPages(stream PageRead) returns (google.protobuf.Empty) {}
rpc ListenForBooks(stream QueryBooksRequest) returns (stream Book) {}
Usage with NodeJS
Refer to grpc-web-node-http-transport.