14287: Refactor controller to use strong types in API handlers.

[arvados.git] / sdk / go / arvados / resource_list.go

diff --git a/sdk/go/arvados/resource_list.go b/sdk/go/arvados/resource_list.go
index 14ce098cfc1a54f0f0de74aa9cf60ca8274a693e..505ba51ec531387cffe71c8f7b179f436a6d9b75 100644 (file)
--- a/sdk/go/arvados/resource_list.go
+++ b/sdk/go/arvados/resource_list.go
@@ -4,7 +4,10 @@
 
 package arvados
 
-import "encoding/json"
+import (
+       "encoding/json"
+       "fmt"
+)
 
 // ResourceListParams expresses which results are requested in a
 // list/index API.
@@ -27,7 +30,35 @@ type Filter struct {
        Operand  interface{}
 }
 
-// MarshalJSON encodes a Filter in the form expected by the API.
+// MarshalJSON encodes a Filter to a JSON array.
 func (f *Filter) MarshalJSON() ([]byte, error) {
        return json.Marshal([]interface{}{f.Attr, f.Operator, f.Operand})
 }
+
+// UnmarshalJSON decodes a JSON array to a Filter.
+func (f *Filter) UnmarshalJSON(data []byte) error {
+       var elements []interface{}
+       err := json.Unmarshal(data, &elements)
+       if err != nil {
+               return err
+       }
+       if len(elements) != 3 {
+               return fmt.Errorf("invalid filter %q: must have 3 elements", data)
+       }
+       attr, ok := elements[0].(string)
+       if !ok {
+               return fmt.Errorf("invalid filter attr %q", elements[0])
+       }
+       op, ok := elements[1].(string)
+       if !ok {
+               return fmt.Errorf("invalid filter operator %q", elements[1])
+       }
+       operand := elements[2]
+       switch operand.(type) {
+       case string, float64, []interface{}:
+       default:
+               return fmt.Errorf("invalid filter operand %q", elements[2])
+       }
+       *f = Filter{attr, op, operand}
+       return nil
+}