77 lines
1.8 KiB
Go
77 lines
1.8 KiB
Go
package utils
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import (
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"reflect"
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"strconv"
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"strings"
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"github.com/pkg/errors"
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)
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// ValueAtPath will get struct attribute value by recursive
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func ValueAtPath(v interface{}, path string) (interface{}, error) {
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components := strings.Split(path, ".")
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rv := reflect.ValueOf(v)
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for rv.Kind() == reflect.Ptr {
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if rv.IsNil() {
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return nil, errors.Errorf("object %#v is nil", v)
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}
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rv = rv.Elem()
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}
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if rv.Kind() == reflect.Slice || rv.Kind() == reflect.Array {
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i, err := strconv.Atoi(components[0])
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if err != nil {
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return nil, errors.Errorf("path %s is invalid at index of array", path)
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}
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length := rv.Len()
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if i >= length {
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return nil, errors.Errorf("path %s is invalid, array has length %v, but got %v", path, length, i)
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}
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itemV := rv.Index(i)
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if !itemV.IsValid() {
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return nil, errors.Errorf("path %s is invalid for map", path)
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}
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if len(components) > 1 {
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return ValueAtPath(itemV.Interface(), strings.Join(components[1:], "."))
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}
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return itemV.Interface(), nil
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}
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if rv.Kind() == reflect.Map && !rv.IsNil() {
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itemV := rv.MapIndex(reflect.ValueOf(components[0]))
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if !itemV.IsValid() {
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return nil, errors.Errorf("path %s is invalid for map", path)
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}
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if len(components) > 1 {
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return ValueAtPath(itemV.Interface(), strings.Join(components[1:], "."))
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}
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return itemV.Interface(), nil
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}
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if rv.Kind() == reflect.Struct {
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itemV := rv.FieldByNameFunc(func(s string) bool {
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return strings.ToLower(s) == strings.ToLower(components[0])
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})
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if !itemV.IsValid() {
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return nil, errors.Errorf("path %s is invalid for struct", path)
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}
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if len(components) > 1 {
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return ValueAtPath(itemV.Interface(), strings.Join(components[1:], "."))
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}
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return itemV.Interface(), nil
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}
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return nil, errors.Errorf("object %#v is invalid, need map or struct", v)
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}
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