49 lines
1.5 KiB
Go
49 lines
1.5 KiB
Go
package json
|
|
|
|
import (
|
|
"reflect"
|
|
|
|
"github.com/hashicorp/go-msgpack/codec"
|
|
)
|
|
|
|
// extendFunc is a mapping from one struct to another, to change the shape of the encoded JSON
|
|
type extendFunc func(interface{}) interface{}
|
|
|
|
var (
|
|
// extendedTypes is a mapping of extended types to their extension function
|
|
extendedTypes = map[reflect.Type]extendFunc{}
|
|
)
|
|
|
|
// registerExtension registers an extension function against a particular type
|
|
func registerExtension(tpe reflect.Type, ext extendFunc) {
|
|
extendedTypes[tpe] = ext
|
|
}
|
|
|
|
// nomadJsonEncodingExtensions is a catch-all go-msgpack extension
|
|
// it looks up the types in the list of registered extension functions and applies it
|
|
type nomadJsonEncodingExtensions struct{}
|
|
|
|
// ConvertExt calls the registered conversions functions
|
|
func (n nomadJsonEncodingExtensions) ConvertExt(v interface{}) interface{} {
|
|
if fn, ok := extendedTypes[reflect.TypeOf(v)]; ok {
|
|
return fn(v)
|
|
} else {
|
|
// shouldn't get here, but returning v will probably result in an infinite loop
|
|
// return nil and erase this field
|
|
return nil
|
|
}
|
|
}
|
|
|
|
// UpdateExt is required by go-msgpack, but not used by us
|
|
func (n nomadJsonEncodingExtensions) UpdateExt(_ interface{}, _ interface{}) {}
|
|
|
|
// NomadJsonEncodingExtensions registers all extension functions against the
|
|
// provided JsonHandle.
|
|
// It should be called on any JsonHandle which is used by the API HTTP server.
|
|
func NomadJsonEncodingExtensions(h *codec.JsonHandle) *codec.JsonHandle {
|
|
for tpe := range extendedTypes {
|
|
h.SetInterfaceExt(tpe, 1, nomadJsonEncodingExtensions{})
|
|
}
|
|
return h
|
|
}
|