proto: add convert function for protobuf/types.Struct

Co-authored-by: Paul Banks <banks@banksco.de>
This commit is contained in:
Daniel Nephin 2020-09-18 15:36:12 -04:00
parent 450540af33
commit b4c48d4417
1 changed files with 278 additions and 0 deletions

View File

@ -0,0 +1,278 @@
package pbservice
import (
fmt "fmt"
"reflect"
types "github.com/gogo/protobuf/types"
)
// ProtobufTypesStructToMapStringInterface converts a protobuf/types.Struct into a
// map[string]interface{}.
func ProtobufTypesStructToMapStringInterface(s *types.Struct) map[string]interface{} {
if s == nil {
return nil
}
m := make(map[string]interface{}, len(s.Fields))
for k, v := range s.Fields {
m[k] = interfaceFromPBValue(v)
}
return m
}
// interfaceFromPBValue converts a protobuf Value into an interface{}
func interfaceFromPBValue(v *types.Value) interface{} {
if v == nil {
return nil
}
switch k := v.Kind.(type) {
case *types.Value_NullValue:
return nil
case *types.Value_NumberValue:
return k.NumberValue
case *types.Value_StringValue:
return k.StringValue
case *types.Value_BoolValue:
return k.BoolValue
case *types.Value_StructValue:
return ProtobufTypesStructToMapStringInterface(k.StructValue)
case *types.Value_ListValue:
s := make([]interface{}, len(k.ListValue.Values))
for i, e := range k.ListValue.Values {
s[i] = interfaceFromPBValue(e)
}
return s
default:
panic("unknown kind")
}
}
// MapStringInterfaceToProtobufTypesStruct converts a map[string]interface{} into a proto.Struct
func MapStringInterfaceToProtobufTypesStruct(m map[string]interface{}) *types.Struct {
if len(m) == 0 {
return nil
}
fields := make(map[string]*types.Value, len(m))
for k, v := range m {
fields[k] = interfaceToPBValue(v)
}
return &types.Struct{Fields: fields}
}
// SliceToPBListValue converts a []interface{} into a proto.ListValue. It's used
// internally by MapStringInterfaceToProtobufTypesStruct when it encouters slices.
func SliceToPBListValue(s []interface{}) *types.ListValue {
if len(s) == 0 {
return nil
}
vals := make([]*types.Value, len(s))
for i, v := range s {
vals[i] = interfaceToPBValue(v)
}
return &types.ListValue{Values: vals}
}
// interfaceToPBValue converts a interface{} into a proto.Value. It attempts to
// do so by type switch and simple casts where possible but falls back to
// reflection if necessary.
func interfaceToPBValue(v interface{}) *types.Value {
switch v := v.(type) {
case nil:
return nil
case int:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: float64(v),
},
}
case int8:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: float64(v),
},
}
case int32:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: float64(v),
},
}
case int64:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: float64(v),
},
}
case uint:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: float64(v),
},
}
case uint8:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: float64(v),
},
}
case uint32:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: float64(v),
},
}
case uint64:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: float64(v),
},
}
case float32:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: float64(v),
},
}
case float64:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: v,
},
}
case string:
return &types.Value{
Kind: &types.Value_StringValue{
StringValue: v,
},
}
case error:
return &types.Value{
Kind: &types.Value_StringValue{
StringValue: v.Error(),
},
}
case map[string]interface{}:
return &types.Value{
Kind: &types.Value_StructValue{
StructValue: MapStringInterfaceToProtobufTypesStruct(v),
},
}
case []interface{}:
return &types.Value{
Kind: &types.Value_ListValue{
ListValue: SliceToPBListValue(v),
},
}
default:
return interfaceToPBValueReflect(reflect.ValueOf(v))
}
}
// interfaceToPBValueReflect converts a interface{} into a proto.Value using
// reflection.
func interfaceToPBValueReflect(v reflect.Value) *types.Value {
switch v.Kind() {
case reflect.Interface:
return interfaceToPBValue(v.Interface())
case reflect.Bool:
return &types.Value{
Kind: &types.Value_BoolValue{
BoolValue: v.Bool(),
},
}
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: float64(v.Int()),
},
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: float64(v.Uint()),
},
}
case reflect.Float32, reflect.Float64:
return &types.Value{
Kind: &types.Value_NumberValue{
NumberValue: v.Float(),
},
}
case reflect.Ptr:
if v.IsNil() {
return nil
}
return interfaceToPBValueReflect(reflect.Indirect(v))
case reflect.Array, reflect.Slice:
size := v.Len()
if size == 0 {
return nil
}
values := make([]*types.Value, size)
for i := 0; i < size; i++ {
values[i] = interfaceToPBValue(v.Index(i))
}
return &types.Value{
Kind: &types.Value_ListValue{
ListValue: &types.ListValue{
Values: values,
},
},
}
case reflect.Struct:
t := v.Type()
size := v.NumField()
if size == 0 {
return nil
}
fields := make(map[string]*types.Value, size)
for i := 0; i < size; i++ {
name := t.Field(i).Name
// Only include public fields. There may be a better way with struct tags
// but this works for now.
if len(name) > 0 && 'A' <= name[0] && name[0] <= 'Z' {
fields[name] = interfaceToPBValue(v.Field(i))
}
}
if len(fields) == 0 {
return nil
}
return &types.Value{
Kind: &types.Value_StructValue{
StructValue: &types.Struct{
Fields: fields,
},
},
}
case reflect.Map:
keys := v.MapKeys()
if len(keys) == 0 {
return nil
}
fields := make(map[string]*types.Value, len(keys))
for _, k := range keys {
if k.Kind() == reflect.String {
fields[k.String()] = interfaceToPBValue(v.MapIndex(k))
}
}
if len(fields) == 0 {
return nil
}
return &types.Value{
Kind: &types.Value_StructValue{
StructValue: &types.Struct{
Fields: fields,
},
},
}
default:
// Last resort
return &types.Value{
Kind: &types.Value_StringValue{
StringValue: fmt.Sprint(v),
},
}
}
}