}
				sset.Add(kv.Key)
			}
			e.Encode(kvs)
		}
	}
	return &buf, d.Err()
}

// parsePostPolicyForm - Parse JSON policy string into typed PostPolicyForm structure.
func parsePostPolicyForm(r io.Reader) (PostPolicyForm, error) {
	reader, err := sanitizePolicy(r)
	if err != nil {
		return PostPolicyForm{}, err
	}

	d := json.NewDecoder(reader)

			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
			return
		}
	}

	// Handle policy if it is set.
	if len(policyBytes) > 0 {
		postPolicyForm, err := parsePostPolicyForm(bytes.NewReader(policyBytes))
		if err != nil {
			errAPI := errorCodes.ToAPIErr(ErrPostPolicyConditionInvalidFormat)
			errAPI.Description = fmt.Sprintf("%s '(%s)'", errAPI.Description, err)