route/vendor/github.com/grpc-ecosystem/grpc-gateway/runtime/query.go

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2017-01-26 15:51:44 +00:00
package runtime
import (
"fmt"
"net/url"
"reflect"
"strings"
"time"
"github.com/golang/protobuf/proto"
"github.com/grpc-ecosystem/grpc-gateway/utilities"
"google.golang.org/grpc/grpclog"
)
// PopulateQueryParameters populates "values" into "msg".
// A value is ignored if its key starts with one of the elements in "filter".
func PopulateQueryParameters(msg proto.Message, values url.Values, filter *utilities.DoubleArray) error {
for key, values := range values {
fieldPath := strings.Split(key, ".")
if filter.HasCommonPrefix(fieldPath) {
continue
}
if err := populateFieldValueFromPath(msg, fieldPath, values); err != nil {
return err
}
}
return nil
}
// PopulateFieldFromPath sets a value in a nested Protobuf structure.
// It instantiates missing protobuf fields as it goes.
func PopulateFieldFromPath(msg proto.Message, fieldPathString string, value string) error {
fieldPath := strings.Split(fieldPathString, ".")
return populateFieldValueFromPath(msg, fieldPath, []string{value})
}
func populateFieldValueFromPath(msg proto.Message, fieldPath []string, values []string) error {
m := reflect.ValueOf(msg)
if m.Kind() != reflect.Ptr {
return fmt.Errorf("unexpected type %T: %v", msg, msg)
}
m = m.Elem()
for i, fieldName := range fieldPath {
isLast := i == len(fieldPath)-1
if !isLast && m.Kind() != reflect.Struct {
return fmt.Errorf("non-aggregate type in the mid of path: %s", strings.Join(fieldPath, "."))
}
f := fieldByProtoName(m, fieldName)
if !f.IsValid() {
grpclog.Printf("field not found in %T: %s", msg, strings.Join(fieldPath, "."))
return nil
}
switch f.Kind() {
case reflect.Bool, reflect.Float32, reflect.Float64, reflect.Int32, reflect.Int64, reflect.String, reflect.Uint32, reflect.Uint64:
m = f
case reflect.Slice:
// TODO(yugui) Support []byte
if !isLast {
return fmt.Errorf("unexpected repeated field in %s", strings.Join(fieldPath, "."))
}
return populateRepeatedField(f, values)
case reflect.Ptr:
if f.IsNil() {
m = reflect.New(f.Type().Elem())
f.Set(m.Convert(f.Type()))
}
m = f.Elem()
continue
case reflect.Struct:
m = f
continue
default:
return fmt.Errorf("unexpected type %s in %T", f.Type(), msg)
}
}
switch len(values) {
case 0:
return fmt.Errorf("no value of field: %s", strings.Join(fieldPath, "."))
case 1:
default:
grpclog.Printf("too many field values: %s", strings.Join(fieldPath, "."))
}
return populateField(m, values[0])
}
// fieldByProtoName looks up a field whose corresponding protobuf field name is "name".
// "m" must be a struct value. It returns zero reflect.Value if no such field found.
func fieldByProtoName(m reflect.Value, name string) reflect.Value {
props := proto.GetProperties(m.Type())
for _, p := range props.Prop {
if p.OrigName == name {
return m.FieldByName(p.Name)
}
}
return reflect.Value{}
}
func populateRepeatedField(f reflect.Value, values []string) error {
elemType := f.Type().Elem()
conv, ok := convFromType[elemType.Kind()]
if !ok {
return fmt.Errorf("unsupported field type %s", elemType)
}
f.Set(reflect.MakeSlice(f.Type(), len(values), len(values)).Convert(f.Type()))
for i, v := range values {
result := conv.Call([]reflect.Value{reflect.ValueOf(v)})
if err := result[1].Interface(); err != nil {
return err.(error)
}
f.Index(i).Set(result[0].Convert(f.Index(i).Type()))
}
return nil
}
func populateField(f reflect.Value, value string) error {
// Handle well known type
type wkt interface {
XXX_WellKnownType() string
}
if wkt, ok := f.Addr().Interface().(wkt); ok {
switch wkt.XXX_WellKnownType() {
case "Timestamp":
if value == "null" {
f.Field(0).SetInt(0)
f.Field(1).SetInt(0)
return nil
}
t, err := time.Parse(time.RFC3339Nano, value)
if err != nil {
return fmt.Errorf("bad Timestamp: %v", err)
}
f.Field(0).SetInt(int64(t.Unix()))
f.Field(1).SetInt(int64(t.Nanosecond()))
return nil
}
}
conv, ok := convFromType[f.Kind()]
if !ok {
return fmt.Errorf("unsupported field type %T", f)
}
result := conv.Call([]reflect.Value{reflect.ValueOf(value)})
if err := result[1].Interface(); err != nil {
return err.(error)
}
f.Set(result[0].Convert(f.Type()))
return nil
}
var (
convFromType = map[reflect.Kind]reflect.Value{
reflect.String: reflect.ValueOf(String),
reflect.Bool: reflect.ValueOf(Bool),
reflect.Float64: reflect.ValueOf(Float64),
reflect.Float32: reflect.ValueOf(Float32),
reflect.Int64: reflect.ValueOf(Int64),
reflect.Int32: reflect.ValueOf(Int32),
reflect.Uint64: reflect.ValueOf(Uint64),
reflect.Uint32: reflect.ValueOf(Uint32),
// TODO(yugui) Support []byte
}
)