commands: add FilterBodyPrefix method to command type

This call is used for removing "routine" responses that get sent in
the body of a response rather than the status. Otherwise, it is the same
as the FilterPrefix function.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

internal/commands/response.go

@@ -1,6 +1,7 @@
 package commands
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -156,6 +157,18 @@ func (r Response) FilterSuffix(s string) Response {
 	return r
 }
 
+// FilterBodyPrefix sets the body value equivalent to an empty string if the
+// body value contains the given prefix string.
+func (r Response) FilterBodyPrefix(p string) Response {
+	if !r.Ok() {
+		return r
+	}
+	if bytes.HasPrefix(r.body, []byte(p)) {
+		return Response{[]byte(""), r.status, r.err}
+	}
+	return r
+}
+
 // FilterDeprecated removes deprecation warnings from the response status.
 // Use it when checking the response from calls that may be deprecated in ceph
 // if you want those calls to continue working if the warning is present.