fix(cmd/protoc-gen-go-http): support opaque protobuf API for named body and response_body fields

cmd/protoc-gen-go-http/http.go

@@ -161,13 +161,15 @@ func buildHTTPRule(g *protogen.GeneratedFile, service *protogen.Service, m *prot
 	} else if body != "" {
 		md.HasBody = true
 		md.Body = "." + camelCaseVars(body)
+		md.BodyProtoName = body
 	} else {
 		md.HasBody = false
 	}
 	if responseBody == "*" {
 		md.ResponseBody = ""
 	} else if responseBody != "" {
 		md.ResponseBody = "." + camelCaseVars(responseBody)
+		md.ResponseBodyProtoName = responseBody
 	}
 	return md
 }
@@ -259,6 +261,23 @@ func replacePath(name string, value string, path string) string {
 	return path
 }
 
+// toGetterAccessor converts a CamelCase field accessor like ".Payload" or ".User.Profile"
+// into a chained getter call like ".GetPayload()" or ".GetUser().GetProfile()".
+// This is compatible with both open and opaque protobuf Go API styles.
+func toGetterAccessor(camelCaseBody string) string {
+	if camelCaseBody == "" {
+		return ""
+	}
+	parts := strings.Split(camelCaseBody[1:], ".") // strip leading dot, split segments
+	var result strings.Builder
+	for _, part := range parts {
+		result.WriteString(".Get")
+		result.WriteString(part)
+		result.WriteString("()")
+	}
+	return result.String()
+}
+
 func camelCaseVars(s string) string {
 	subs := strings.Split(s, ".")
 	vars := make([]string, 0, len(subs))

cmd/protoc-gen-go-http/httpTemplate.tpl

@@ -26,9 +26,15 @@ func _{{$svrType}}_{{.Name}}{{.Num}}_HTTP_Handler(srv {{$svrType}}HTTPServer) fu
 	return func(ctx http.Context) error {
 		var in {{.Request}}
 		{{- if .HasBody}}
-		if err := ctx.Bind(&in{{.Body}}); err != nil {
+		{{- if .BodyProtoName}}
+		if err := ctx.Bind(in.ProtoReflect().Mutable(in.ProtoReflect().Descriptor().Fields().ByName("{{.BodyProtoName}}")).Message().Interface()); err != nil {
 			return err
 		}
+		{{- else}}
+		if err := ctx.Bind(&in); err != nil {
+			return err
+		}
+		{{- end}}
 		{{- end}}
 		if err := ctx.BindQuery(&in); err != nil {
 			return err
@@ -47,7 +53,11 @@ func _{{$svrType}}_{{.Name}}{{.Num}}_HTTP_Handler(srv {{$svrType}}HTTPServer) fu
 			return err
 		}
 		reply := out.(*{{.Reply}})
+		{{- if .ResponseBodyProtoName}}
+		return ctx.Result(200, reply{{getterAccessor .ResponseBody}})
+		{{- else}}
 		return ctx.Result(200, reply{{.ResponseBody}})
+		{{- end}}
 	}
 }
 {{end}}
@@ -79,11 +89,15 @@ func (c *{{$svrType}}HTTPClientImpl) {{.Name}}(ctx context.Context, in *{{.Reque
 	path := binding.EncodeURL(pattern, in, {{not .HasBody}})
 	opts = append(opts, http.Operation(Operation{{$svrType}}{{.OriginalName}}))
 	opts = append(opts, http.PathTemplate(pattern))
-	{{if .HasBody -}}
-	err := c.cc.Invoke(ctx, "{{.Method}}", path, in{{.Body}}, &out{{.ResponseBody}}, opts...)
-	{{else -}}
-	err := c.cc.Invoke(ctx, "{{.Method}}", path, nil, &out{{.ResponseBody}}, opts...)
-	{{end -}}
+	{{- if .HasBody}}
+	{{- if .BodyProtoName}}
+	err := c.cc.Invoke(ctx, "{{.Method}}", path, in{{getterAccessor .Body}}, {{if .ResponseBodyProtoName}}out.ProtoReflect().Mutable(out.ProtoReflect().Descriptor().Fields().ByName("{{.ResponseBodyProtoName}}")).Message().Interface(){{else}}&out{{.ResponseBody}}{{end}}, opts...)
+	{{- else}}
+	err := c.cc.Invoke(ctx, "{{.Method}}", path, in{{.Body}}, {{if .ResponseBodyProtoName}}out.ProtoReflect().Mutable(out.ProtoReflect().Descriptor().Fields().ByName("{{.ResponseBodyProtoName}}")).Message().Interface(){{else}}&out{{.ResponseBody}}{{end}}, opts...)
+	{{- end}}
+	{{- else}}
+	err := c.cc.Invoke(ctx, "{{.Method}}", path, nil, {{if .ResponseBodyProtoName}}out.ProtoReflect().Mutable(out.ProtoReflect().Descriptor().Fields().ByName("{{.ResponseBodyProtoName}}")).Message().Interface(){{else}}&out{{.ResponseBody}}{{end}}, opts...)
+	{{- end}}
 	if err != nil {
 		return nil, err
 	}

cmd/protoc-gen-go-http/http_test.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"reflect"
+	"strings"
 	"testing"
 )
 
@@ -98,3 +99,90 @@ func TestReplaceBoundary(t *testing.T) {
 		t.Fatal(`"/test/{message.namespace=*}/name/{message.name=*}" should be "/test/{message.namespace:.*}/name/{message.name:.*}"`)
 	}
 }
+
+func TestGetterAccessor(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"", ""},
+		{".Payload", ".GetPayload()"},
+		{".UserProfile", ".GetUserProfile()"},
+		{".User.Profile", ".GetUser().GetProfile()"},
+	}
+	for _, tt := range tests {
+		got := toGetterAccessor(tt.input)
+		if got != tt.expected {
+			t.Fatalf("toGetterAccessor(%q) = %q, want %q", tt.input, got, tt.expected)
+		}
+	}
+}
+
+func TestTemplateBodyNamedField(t *testing.T) {
+	sd := &serviceDesc{
+		ServiceType: "TestSvc",
+		ServiceName: "test.v1.TestSvc",
+		Metadata:    "test/v1/test.proto",
+		Methods: []*methodDesc{
+			{
+				Name:          "BotHandler",
+				OriginalName: "BotHandler",
+				Num:           0,
+				Request:       "BotHandlerRequest",
+				Reply:         "emptypb.Empty",
+				Path:          "/api/v1/bot",
+				Method:        "POST",
+				HasBody:       true,
+				Body:          ".Payload",
+				BodyProtoName: "payload",
+			},
+		},
+	}
+	output := sd.execute()
+
+	// Server handler should use proto reflection for named body field
+	if !strings.Contains(output, `in.ProtoReflect().Mutable(in.ProtoReflect().Descriptor().Fields().ByName("payload")).Message().Interface()`) {
+		t.Fatal("server handler should use ProtoReflect().Mutable() for named body field")
+	}
+	if strings.Contains(output, "&in.Payload") {
+		t.Fatal("server handler should NOT use direct field access &in.Payload")
+	}
+
+	// Client should use getter for named body field
+	if !strings.Contains(output, "in.GetPayload()") {
+		t.Fatal("client should use getter in.GetPayload() for named body field")
+	}
+	if strings.Contains(output, "in.Payload") && !strings.Contains(output, "in.GetPayload()") {
+		t.Fatal("client should NOT use direct field access in.Payload")
+	}
+}
+
+func TestTemplateBodyStar(t *testing.T) {
+	sd := &serviceDesc{
+		ServiceType: "TestSvc",
+		ServiceName: "test.v1.TestSvc",
+		Metadata:    "test/v1/test.proto",
+		Methods: []*methodDesc{
+			{
+				Name:         "Create",
+				OriginalName: "Create",
+				Num:          0,
+				Request:      "CreateRequest",
+				Reply:        "CreateReply",
+				Path:         "/api/v1/create",
+				Method:       "POST",
+				HasBody:      true,
+				Body:         "",
+			},
+		},
+	}
+	output := sd.execute()
+
+	// body="*" should use &in for server bind and in for client
+	if !strings.Contains(output, "ctx.Bind(&in)") {
+		t.Fatal("body=* should use ctx.Bind(&in)")
+	}
+	if strings.Contains(output, "ProtoReflect") {
+		t.Fatal("body=* should NOT use ProtoReflect")
+	}
+}

cmd/protoc-gen-go-http/template.go

@@ -27,12 +27,14 @@ type methodDesc struct {
 	Reply        string
 	Comment      string
 	// http_rule
-	Path         string
-	Method       string
-	HasVars      bool
-	HasBody      bool
-	Body         string
-	ResponseBody string
+	Path                  string
+	Method                string
+	HasVars               bool
+	HasBody               bool
+	Body                  string
+	BodyProtoName         string // proto field name for named body (empty when body is "*")
+	ResponseBody          string
+	ResponseBodyProtoName string // proto field name for named response_body (empty when "*")
 }
 
 func (s *serviceDesc) execute() string {
@@ -41,7 +43,9 @@ func (s *serviceDesc) execute() string {
 		s.MethodSets[m.Name] = m
 	}
 	buf := new(bytes.Buffer)
-	tmpl, err := template.New("http").Parse(strings.TrimSpace(httpTemplate))
+	tmpl, err := template.New("http").Funcs(template.FuncMap{
+		"getterAccessor": toGetterAccessor,
+	}).Parse(strings.TrimSpace(httpTemplate))
 	if err != nil {
 		panic(err)
 	}

cmd/protoc-gen-go-http/version.go

@@ -1,4 +1,4 @@
 package main
 
 // release is the current protoc-gen-go-http version.
-const release = "v2.9.2"
+const release = "v2.9.3"