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// Copyright 2021-2023 The Connect Authors
//
// 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.
package connect_test
import (
"context"
"net/http"
"strconv"
connect "connectrpc.com/connect"
pingv1 "connectrpc.com/connect/internal/gen/connect/ping/v1"
"connectrpc.com/connect/internal/gen/connect/ping/v1/pingv1connect"
)
// ExampleCachingServer is an example of how servers can take advantage the
// Connect protocol's support for HTTP-level caching. The Protobuf
// definition for this API is in proto/connect/ping/v1/ping.proto.
type ExampleCachingPingServer struct {
pingv1connect.UnimplementedPingServiceHandler
}
// Ping is idempotent and free of side effects (and the Protobuf schema
// indicates this), so clients using the Connect protocol may call it with HTTP
// GET requests. This implementation uses Etags to manage client-side caching.
func (*ExampleCachingPingServer) Ping(
_ context.Context,
req *connect.Request[pingv1.PingRequest],
) (*connect.Response[pingv1.PingResponse], error) {
resp := connect.NewResponse(&pingv1.PingResponse{
Number: req.Msg.GetNumber(),
})
// Our hashing logic is simple: we use the number in the PingResponse.
hash := strconv.FormatInt(resp.Msg.GetNumber(), 10)
// If the request was an HTTP GET, we'll need to check if the client already
// has the response cached.
if req.HTTPMethod() == http.MethodGet && req.Header().Get("If-None-Match") == hash {
return nil, connect.NewNotModifiedError(http.Header{
"Etag": []string{hash},
})
}
resp.Header().Set("Etag", hash)
return resp, nil
}
func ExampleNewNotModifiedError() {
mux := http.NewServeMux()
mux.Handle(pingv1connect.NewPingServiceHandler(&ExampleCachingPingServer{}))
_ = http.ListenAndServe("localhost:8080", mux)
}
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