Support gRPC transcoding dot notation syntax in path template

gengokit/httptransport/embeddable_funcs.go

@@ -1,6 +1,7 @@
 package httptransport
 
 import (
+	"encoding/json"
 	"fmt"
 	"strings"
 )
@@ -69,3 +70,39 @@ func RemoveBraces(val string) string {
 	val = strings.Replace(val, "}", "", -1)
 	return val
 }
+
+// encodePathParams encodes `mux.Vars()` with dot notations into JSON objects
+// to be unmarshaled into non-basetype fields.
+// e.g. {"book.name": "books/1"} -> {"book": {"name": "books/1"}}
+func encodePathParams(vars map[string]string) map[string]string {
+	var recur func(path, value string, data map[string]interface{})
+	recur = func(path, value string, data map[string]interface{}) {
+		parts := strings.SplitN(path, ".", 2)
+		key := parts[0]
+		if len(parts) == 1 {
+			data[key] = value
+		} else {
+			if _, ok := data[key]; !ok {
+				data[key] = make(map[string]interface{})
+			}
+			recur(parts[1], value, data[key].(map[string]interface{}))
+		}
+	}
+
+	data := make(map[string]interface{})
+	for key, val := range vars {
+		recur(key, val, data)
+	}
+
+	ret := make(map[string]string)
+	for key, val := range data {
+		switch val := val.(type) {
+		case string:
+			ret[key] = val
+		case map[string]interface{}:
+			m, _ := json.Marshal(val)
+			ret[key] = string(m)
+		}
+	}
+	return ret
+}

gengokit/httptransport/embeddable_funcs_test.go

@@ -0,0 +1,69 @@
+package httptransport
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestEncodePathParams(t *testing.T) {
+	tests := []struct {
+		name string
+		vars map[string]string
+		want map[string]string
+	}{
+		{
+			name: "simple",
+			vars: map[string]string{
+				"parent": "shelves/shelf1",
+			},
+			want: map[string]string{
+				"parent": "shelves/shelf1",
+			},
+		},
+		{
+			name: "dot notation - single value",
+			vars: map[string]string{
+				"book.name": "shelves/shelf1/books/book1",
+			},
+			want: map[string]string{
+				"book": `{"name":"shelves/shelf1/books/book1"}`,
+			},
+		},
+		{
+			name: "dot notation - multiple values",
+			vars: map[string]string{
+				"book.name":    "shelves/shelf1/books/book1",
+				"book.version": "v1",
+			},
+			want: map[string]string{
+				"book": `{"name":"shelves/shelf1/books/book1","version":"v1"}`,
+			},
+		},
+		{
+			name: "dot notation - multiple levels",
+			vars: map[string]string{
+				"book.version.name": "versions/v1",
+			},
+			want: map[string]string{
+				"book": `{"version":{"name":"versions/v1"}}`,
+			},
+		},
+		{
+			name: "dot notation - multiple values in multiple levels",
+			vars: map[string]string{
+				"book.name":         "shelves/shelf1/books/book1",
+				"book.version.name": "versions/v1",
+			},
+			want: map[string]string{
+				"book": `{"name":"shelves/shelf1/books/book1","version":{"name":"versions/v1"}}`,
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := encodePathParams(tt.vars); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("encodePathParams() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

gengokit/httptransport/httptransport.go

@@ -191,7 +191,11 @@ func GenServerTemplate(exec interface{}) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	code = FormatCode(code)
+	encodeFuncSource, err := FuncSourceCode(encodePathParams)
+	if err != nil {
+		return "", err
+	}
+	code = FormatCode(code + encodeFuncSource)
 	return code, nil
 }
 
@@ -258,13 +262,19 @@ func (b *Binding) PathSections() []string {
 	parts := strings.Split(path, "/")
 	for _, part := range parts {
 		if len(part) > 2 && part[0] == '{' && part[len(part)-1] == '}' {
-			name := RemoveBraces(part)
-			if _, ok := isEnum[gogen.CamelCase(name)]; ok {
-				convert := fmt.Sprintf("fmt.Sprintf(\"%%d\", req.%v)", gogen.CamelCase(name))
+			name := part[1 : len(part)-1]
+			parts := strings.Split(name, ".")
+			for idx, part := range parts {
+				parts[idx] = gogen.CamelCase(part)
+			}
+			camelName := strings.Join(parts, ".")
+
+			if _, ok := isEnum[camelName]; ok {
+				convert := fmt.Sprintf("fmt.Sprintf(\"%%d\", req.%v)", camelName)
 				rv = append(rv, convert)
 				continue
 			}
-			convert := fmt.Sprintf("fmt.Sprint(req.%v)", gogen.CamelCase(name))
+			convert := fmt.Sprintf("fmt.Sprint(req.%v)", camelName)
 			rv = append(rv, convert)
 		} else {
 			// Add quotes around things which'll be embeded as string literals,
@@ -291,7 +301,7 @@ if {{.LocalName}}StrArr, ok := {{.Location}}Params["{{.QueryParamName}}"]; ok {
 if err != nil {
 	return nil, errors.Wrap(err, fmt.Sprintf("Error while extracting {{.LocalName}} from {{.Location}}, {{.Location}}Params: %v", {{.Location}}Params))
 }{{end}}
-req.{{.CamelName}} = {{.TypeConversion}}
+{{if or .Repeated .IsBaseType .IsEnum}}req.{{.CamelName}} = {{.TypeConversion}}{{end}}
 `
 	mergedLogic := queryParamLogic + genericLogic + "}"
 	if f.Location == "path" {
@@ -389,9 +399,7 @@ func createDecodeConvertFunc(f Field) (string, bool) {
 		// pointer as well. So we special case args of a single custom message
 		// type so that the variable LocalName is declared as a pointer.
 		singleCustomTypeUnmarshalTmpl := `
-var {{.LocalName}} *{{.GoType}}
-{{.LocalName}} = &{{.GoType}}{}
-err = json.Unmarshal([]byte({{.LocalName}}Str), {{.LocalName}})`
+err = json.Unmarshal([]byte({{.LocalName}}Str), req.{{.CamelName}})`
 
 		errorCheckingTmpl := `
 if err != nil {

gengokit/httptransport/httptransport_test.go

@@ -251,6 +251,15 @@ func TestBinding_PathSections(t *testing.T) {
 				`"books"`,
 			},
 		},
+		{
+			name:         "dot notation",
+			pathTemplate: `/v1/{book.name:shelves/[^/]+/books/[^/]+}`,
+			want: []string{
+				`""`,
+				`"v1"`,
+				"fmt.Sprint(req.Book.Name)",
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

gengokit/httptransport/templates/server.go

@@ -31,7 +31,7 @@ var ServerDecodeTemplate = `
 			}
 		}
 
-		pathParams := mux.Vars(r)
+		pathParams := encodePathParams(mux.Vars(r))
 		_ = pathParams
 
 		queryParams := r.URL.Query()

gengokit/httptransport/templates_test.go

@@ -180,7 +180,7 @@ func DecodeHTTPSumZeroRequest(_ context.Context, r *http.Request) (interface{},
 		}
 	}
 
-	pathParams := mux.Vars(r)
+	pathParams := encodePathParams(mux.Vars(r))
 	_ = pathParams
 
 	queryParams := r.URL.Query()

go.mod

@@ -5,6 +5,7 @@ go 1.13
 require (
 	github.com/davecgh/go-spew v1.1.1
 	github.com/gogo/protobuf v1.2.2-0.20190601103108-21df5aa0e680
+	github.com/kevinburke/go-bindata v3.22.0+incompatible // indirect
 	github.com/kr/pretty v0.1.0 // indirect
 	github.com/pkg/errors v0.8.1
 	github.com/pmezard/go-difflib v1.0.0

go.sum

@@ -3,6 +3,8 @@ github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/gogo/protobuf v1.2.2-0.20190601103108-21df5aa0e680 h1:C0sYRtvp5PUPDdevTvhGWbyiRrLM1ci+tHfyJymCNzM=
 github.com/gogo/protobuf v1.2.2-0.20190601103108-21df5aa0e680/go.mod h1:hp+jE20tsWTFYpLwKvXlhS1hjn+gTNwPg2I6zVXpSg4=
+github.com/kevinburke/go-bindata v3.22.0+incompatible h1:/JmqEhIWQ7GRScV0WjX/0tqBrC5D21ALg0H0U/KZ/ts=
+github.com/kevinburke/go-bindata v3.22.0+incompatible/go.mod h1:/pEEZ72flUW2p0yi30bslSp9YqD9pysLxunQDdb2CPM=
 github.com/kisielk/errcheck v1.1.0/go.mod h1:EZBBE59ingxPouuu3KfxchcWSUPOHkagtvWXihfKN4Q=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1 h1:mweAR1A6xJ3oS2pRaGiHgQ4OO8tzTaLawm8vnODuwDk=