structs/structure.go

52 lines
1.2 KiB
Go

// Package structure contains various utilities functions to work with structs.
package structure
import (
"errors"
"reflect"
)
// ErrNotStruct is returned when the passed value is not a struct
var ErrNotStruct = errors.New("not struct")
// ToMap converts a struct to a map[string]interface{}. The default map key
// string is the struct fieldname but this can be changed by defining a
// "structure" tag key if needed. Note that only exported fields of a struct
// can be accessed, non exported fields will be neglected.
func ToMap(in interface{}) (map[string]interface{}, error) {
out := make(map[string]interface{})
t := reflect.TypeOf(in)
v := reflect.ValueOf(in)
// if pointer get the underlying element≤
if t.Kind() == reflect.Ptr {
t = t.Elem()
v = v.Elem()
}
if t.Kind() != reflect.Struct {
return nil, ErrNotStruct
}
for i := 0; i < t.NumField(); i++ {
field := t.Field(i)
// we can't access the value of unexported fields
if field.PkgPath != "" {
continue
}
name := field.Name
// override if the user passed a structure tag
if tag := field.Tag.Get("structure"); tag != "" {
name = tag
}
out[name] = v.Field(i).Interface()
}
return out, nil
}