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package proto
import (
"context"
"errors"
"net/http"
httptransport "github.com/go-kit/kit/transport/http"
"google.golang.org/protobuf/proto"
)
// EncodeProtoResponse is an EncodeResponseFunc that serializes the response as Protobuf.
// Many Proto-over-HTTP services can use it as a sensible default. If the response
// implements Headerer, the provided headers will be applied to the response. If the
// response implements StatusCoder, the provided StatusCode will be used instead of 200.
func EncodeProtoResponse(ctx context.Context, w http.ResponseWriter, pres interface{}) error {
res, ok := pres.(proto.Message)
if !ok {
return errors.New("response does not implement proto.Message")
}
w.Header().Set("Content-Type", "application/x-protobuf")
if headerer, ok := w.(httptransport.Headerer); ok {
for k := range headerer.Headers() {
w.Header().Set(k, headerer.Headers().Get(k))
}
}
code := http.StatusOK
if sc, ok := pres.(httptransport.StatusCoder); ok {
code = sc.StatusCode()
}
w.WriteHeader(code)
if code == http.StatusNoContent {
return nil
}
if res == nil {
return nil
}
b, err := proto.Marshal(res)
if err != nil {
return err
}
_, err = w.Write(b)
if err != nil {
return err
}
return nil
}
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