package reflect import ( "errors" "fmt" "net/url" "reflect" "regexp" "strings" "time" ) // ErrInvalidParam specifies invalid url query params var ErrInvalidParam = errors.New("invalid url query param provided") var bracketSplitter = regexp.MustCompile(`\[|\]`) var timeKind = reflect.TypeOf(time.Time{}).Kind() type StructField struct { Field reflect.StructField Value reflect.Value } func StructFieldByTag(src interface{}, tkey string, tval string) (interface{}, error) { sv := reflect.ValueOf(src) if sv.Kind() == reflect.Ptr { sv = sv.Elem() } if sv.Kind() != reflect.Struct { return nil, ErrInvalidStruct } typ := sv.Type() for idx := 0; idx < typ.NumField(); idx++ { fld := typ.Field(idx) val := sv.Field(idx) if !val.CanSet() || len(fld.PkgPath) != 0 { continue } if ts, ok := fld.Tag.Lookup(tkey); ok { for _, p := range strings.Split(ts, ",") { if p == tval { if val.Kind() != reflect.Ptr && val.CanAddr() { val = val.Addr() } return val.Interface(), nil } } } switch val.Kind() { case reflect.Ptr: if val = val.Elem(); val.Kind() == reflect.Struct { if iface, err := StructFieldByTag(val.Interface(), tkey, tval); err == nil { return iface, nil } } case reflect.Struct: if iface, err := StructFieldByTag(val.Interface(), tkey, tval); err == nil { return iface, nil } } } return nil, ErrNotFound } func StructFieldByName(src interface{}, tkey string) (interface{}, error) { sv := reflect.ValueOf(src) if sv.Kind() == reflect.Ptr { sv = sv.Elem() } if sv.Kind() != reflect.Struct { return nil, ErrInvalidStruct } typ := sv.Type() for idx := 0; idx < typ.NumField(); idx++ { fld := typ.Field(idx) val := sv.Field(idx) if !val.CanSet() || len(fld.PkgPath) != 0 { continue } if fld.Name == tkey { if val.Kind() != reflect.Ptr && val.CanAddr() { val = val.Addr() } return val.Interface(), nil } switch val.Kind() { case reflect.Ptr: if val = val.Elem(); val.Kind() == reflect.Struct { if iface, err := StructFieldByName(val.Interface(), tkey); err == nil { return iface, nil } } case reflect.Struct: if iface, err := StructFieldByName(val.Interface(), tkey); err == nil { return iface, nil } } } return nil, ErrNotFound } // StructFields returns slice of struct fields func StructFields(src interface{}) ([]StructField, error) { var fields []StructField sv := reflect.ValueOf(src) if sv.Kind() == reflect.Ptr { sv = sv.Elem() } if sv.Kind() != reflect.Struct { return nil, ErrInvalidStruct } typ := sv.Type() for idx := 0; idx < typ.NumField(); idx++ { fld := typ.Field(idx) val := sv.Field(idx) if !val.CanSet() || len(fld.PkgPath) != 0 { continue } switch val.Kind() { case timeKind: fields = append(fields, StructField{Field: fld, Value: val}) case reflect.Struct: infields, err := StructFields(val.Interface()) if err != nil { return nil, err } fields = append(fields, infields...) default: fields = append(fields, StructField{Field: fld, Value: val}) } } return fields, nil } // CopyDefaults for a from b // a and b should be pointers to the same kind of struct func CopyDefaults(a, b interface{}) { pt := reflect.TypeOf(a) t := pt.Elem() va := reflect.ValueOf(a).Elem() vb := reflect.ValueOf(b).Elem() for i := 0; i < t.NumField(); i++ { aField := va.Field(i) if aField.CanSet() { bField := vb.Field(i) aField.Set(bField) } } } // CopyFrom sets the public members of a from b // a and b should be pointers to structs // a can be a different type from b // Only the Fields which have the same name and assignable type on a // and b will be set. func CopyFrom(a, b interface{}) { ta := reflect.TypeOf(a).Elem() tb := reflect.TypeOf(b).Elem() va := reflect.ValueOf(a).Elem() vb := reflect.ValueOf(b).Elem() for i := 0; i < tb.NumField(); i++ { bField := vb.Field(i) tbField := tb.Field(i) name := tbField.Name aField := va.FieldByName(name) taField, found := ta.FieldByName(name) if found && aField.IsValid() && bField.IsValid() && aField.CanSet() && tbField.Type.AssignableTo(taField.Type) { aField.Set(bField) } } } func StructURLValues(src interface{}, pref string, tags []string) (url.Values, error) { data := url.Values{} sv := reflect.ValueOf(src) if sv.Kind() == reflect.Ptr { sv = sv.Elem() } if sv.Kind() != reflect.Struct { return nil, ErrInvalidStruct } typ := sv.Type() for idx := 0; idx < typ.NumField(); idx++ { fld := typ.Field(idx) val := sv.Field(idx) if !val.CanSet() || len(fld.PkgPath) != 0 || !val.IsValid() { continue } var t *tag for _, tn := range tags { ts, ok := fld.Tag.Lookup(tn) if !ok { continue } tp := strings.Split(ts, ",") // special switch tn { case "protobuf": // special t = &tag{key: tn, name: tp[3][5:], opts: append(tp[:3], tp[4:]...)} default: t = &tag{key: tn, name: tp[0], opts: tp[1:]} } if t.name != "" { break } } if t.name == "" { // fallback to lowercase t.name = strings.ToLower(fld.Name) } if pref != "" { t.name = pref + "." + t.name } if !val.IsValid() || val.IsZero() { continue } switch val.Kind() { case reflect.Struct, reflect.Ptr: if val.IsNil() { continue } ndata, err := StructURLValues(val.Interface(), t.name, tags) if err != nil { return ndata, err } for k, v := range ndata { data[k] = v } default: switch val.Kind() { case reflect.Slice: for i := 0; i < val.Len(); i++ { va := val.Index(i) // if va.Type().Elem().Kind() != reflect.Ptr { if va.Kind() != reflect.Ptr { data.Set(t.name, fmt.Sprintf("%v", va.Interface())) continue } switch va.Type().Elem().String() { case "wrapperspb.BoolValue", "wrapperspb.BytesValue", "wrapperspb.StringValue": if eva := reflect.Indirect(va).FieldByName("Value"); eva.IsValid() { data.Add(t.name, fmt.Sprintf("%v", eva.Interface())) } case "wrapperspb.DoubleValue", "wrapperspb.FloatValue": if eva := reflect.Indirect(va).FieldByName("Value"); eva.IsValid() { data.Add(t.name, fmt.Sprintf("%v", eva.Interface())) } case "wrapperspb.Int32Value", "wrapperspb.Int64Value": if eva := reflect.Indirect(va).FieldByName("Value"); eva.IsValid() { data.Add(t.name, fmt.Sprintf("%v", eva.Interface())) } case "wrapperspb.UInt32Value", "wrapperspb.UInt64Value": if eva := reflect.Indirect(va).FieldByName("Value"); eva.IsValid() { data.Add(t.name, fmt.Sprintf("%v", eva.Interface())) } default: data.Add(t.name, fmt.Sprintf("%v", val.Index(i).Interface())) } } default: data.Set(t.name, fmt.Sprintf("%v", val.Interface())) } } } return data, nil } // URLMap returns map of url query params func URLMap(query string) (map[string]interface{}, error) { var mp interface{} = make(map[string]interface{}) params := strings.Split(query, "&") for _, part := range params { tm, err := queryToMap(part) if err != nil { return nil, err } mp = merge(mp, tm) } return mp.(map[string]interface{}), nil } // FlattenMap expand key.subkey to nested map func FlattenMap(a map[string]interface{}) map[string]interface{} { // preprocess map nb := make(map[string]interface{}, len(a)) for k, v := range a { ps := strings.Split(k, ".") if len(ps) == 1 { nb[k] = v continue } em := make(map[string]interface{}) em[ps[len(ps)-1]] = v for i := len(ps) - 2; i > 0; i-- { nm := make(map[string]interface{}) nm[ps[i]] = em em = nm } if vm, ok := nb[ps[0]]; ok { // nested map nm := vm.(map[string]interface{}) for vk, vv := range em { nm[vk] = vv } nb[ps[0]] = nm } else { nb[ps[0]] = em } } return nb } /* case reflect.String: fn := func(c rune) bool { return c == ',' || c == ';' || c == ' ' } slice := strings.FieldsFunc(vb.String(), fn) if va.IsNil() { va.Set(reflect.MakeSlice(va.Type(), len(slice), len(slice))) } */ func btSplitter(str string) []string { r := bracketSplitter.Split(str, -1) for idx, s := range r { if len(s) == 0 { if len(r) > idx+1 { copy(r[idx:], r[idx+1:]) r = r[:len(r)-1] } } } return r } // queryToMap turns something like a[b][c]=4 into // map[string]interface{}{ // "a": map[string]interface{}{ // "b": map[string]interface{}{ // "c": 4, // }, // }, // } func queryToMap(param string) (map[string]interface{}, error) { rawKey, rawValue, err := splitKeyAndValue(param) if err != nil { return nil, err } rawValue, err = url.QueryUnescape(rawValue) if err != nil { return nil, err } rawKey, err = url.QueryUnescape(rawKey) if err != nil { return nil, err } pieces := btSplitter(rawKey) key := pieces[0] // If len==1 then rawKey has no [] chars and we can just // decode this as key=value into {key: value} if len(pieces) == 1 { return map[string]interface{}{ key: rawValue, }, nil } // If len > 1 then we have something like a[b][c]=2 // so we need to turn this into {"a": {"b": {"c": 2}}} // To do this we break our key into two pieces: // a and b[c] // and then we set {"a": queryToMap("b[c]", value)} ret := make(map[string]interface{}) ret[key], err = queryToMap(buildNewKey(rawKey) + "=" + rawValue) if err != nil { return nil, err } // When URL params have a set of empty brackets (eg a[]=1) // it is assumed to be an array. This will get us the // correct value for the array item and return it as an // []interface{} so that it can be merged properly. if pieces[1] == "" { temp := ret[key].(map[string]interface{}) ret[key] = []interface{}{temp[""]} } return ret, nil } // buildNewKey will take something like: // origKey = "bar[one][two]" // pieces = [bar one two ] // and return "one[two]" func buildNewKey(origKey string) string { pieces := btSplitter(origKey) ret := origKey[len(pieces[0])+1:] ret = ret[:len(pieces[1])] + ret[len(pieces[1])+1:] return ret } // splitKeyAndValue splits a URL param at the last equal // sign and returns the two strings. If no equal sign is // found, the ErrInvalidParam error is returned. func splitKeyAndValue(param string) (string, string, error) { li := strings.LastIndex(param, "=") if li == -1 { return "", "", ErrInvalidParam } return param[:li], param[li+1:], nil } // merge merges a with b if they are either both slices // or map[string]interface{} types. Otherwise it returns b. func merge(a interface{}, b interface{}) interface{} { if av, aok := a.(map[string]interface{}); aok { if bv, bok := b.(map[string]interface{}); bok { return mergeMapIface(av, bv) } } if av, aok := a.([]interface{}); aok { if bv, bok := b.([]interface{}); bok { return mergeSliceIface(av, bv) } } va := reflect.ValueOf(a) vb := reflect.ValueOf(b) if (va.Type().Kind() == reflect.Slice) && (va.Type().Elem().Kind() == vb.Type().Kind() || vb.Type().ConvertibleTo(va.Type().Elem())) { va = reflect.Append(va, vb.Convert(va.Type().Elem())) return va.Interface() } return b } // mergeMap merges a with b, attempting to merge any nested // values in nested maps but eventually overwriting anything // in a that can't be merged with whatever is in b. func mergeMapIface(a map[string]interface{}, b map[string]interface{}) map[string]interface{} { for bK, bV := range b { if aV, ok := a[bK]; ok { if (reflect.ValueOf(aV).Type().Kind() == reflect.ValueOf(bV).Type().Kind()) || ((reflect.ValueOf(aV).Type().Kind() == reflect.Slice) && reflect.ValueOf(aV).Type().Elem().Kind() == reflect.ValueOf(bV).Type().Kind()) { nV := []interface{}{aV, bV} a[bK] = nV } else { a[bK] = merge(a[bK], bV) } } else { a[bK] = bV } } return a } // mergeSlice merges a with b and returns the result. func mergeSliceIface(a []interface{}, b []interface{}) []interface{} { a = append(a, b...) return a } type tag struct { key string name string opts []string }