expand response payload processing (#399)

In contrast to other server-vendors, SMC does not return the task id in
the Location header of the response to a firmware upload. In BMC version
1.05.03 (Redfish version 1.14.0) the payload format changes from a
TaskAccepted message to a Redfish task, which breaks task id detection.
This change adds an attempt to deserialize the task structure before
falling back to the earlier TaskAccepted message type.

This also corrects the startUpdateURI.

internal/redfishwrapper/firmware.go

@@ -16,6 +16,7 @@ import (
 	"time"
 
 	"github.com/pkg/errors"
+	"github.com/stmcginnis/gofish/redfish"
 
 	"github.com/bmc-toolbox/bmclib/v2/constants"
 	bmclibErrs "github.com/bmc-toolbox/bmclib/v2/errors"
@@ -31,7 +32,7 @@ const (
 var (
 	// the URI for starting a firmware update via StartUpdate is defined in the Redfish Resource and
 	// Schema Guide (2024.1)
-	startUpdateURI = "redfish/v1/UpdateService/Actions/UpdateService.StartUpdate"
+	startUpdateURI = "/redfish/v1/UpdateService/Actions/UpdateService.StartUpdate"
 )
 
 var (
@@ -112,6 +113,16 @@ func (c *Client) FirmwareUpload(ctx context.Context, updateFile *os.File, params
 		return taskIDFromLocationHeader(location)
 	}
 
+	rfTask := &redfish.Task{}
+	if err := rfTask.UnmarshalJSON(response); err != nil {
+		// we got invalid JSON
+		return "", fmt.Errorf("unmarshaling redfish response: %w", err)
+	}
+	// it's possible to get well-formed JSON that isn't a Task (thanks SMC). Test that we have something sensible.
+	if strings.Contains(rfTask.ODataType, "Task") {
+		return rfTask.ID, nil
+	}
+
 	return taskIDFromResponseBody(response)
 }
 
@@ -146,6 +157,15 @@ func (c *Client) StartUpdateForUploadedFirmware(ctx context.Context) (taskID str
 		return taskIDFromLocationHeader(location)
 	}
 
+	rfTask := &redfish.Task{}
+	if err := rfTask.UnmarshalJSON(response); err != nil {
+		// we got invalid JSON
+		return "", fmt.Errorf("unmarshaling redfish response: %w", err)
+	}
+	if strings.Contains(rfTask.ODataType, "Task") {
+		return rfTask.ID, nil
+	}
+
 	return taskIDFromResponseBody(response)
 }