Use a version for question_submission events. Add boxes to quiz questions

NEWS.md

@@ -23,6 +23,8 @@ learnr 0.10.0 (unreleased)
 
 * When questions are tried again, the existing answer will remain, not forcing the user to restart from scratch. ([#270](https://github.com/rstudio/learnr/issues/270))
 
+* A version number has been added to `question_submission` events.  This will help when using custom storage methods. ([#291](https://github.com/rstudio/learnr/pull/291))
+
 
 ## Bug fixes
 

R/storage.R

@@ -5,6 +5,7 @@ save_question_submission <- function(session, label, question, answer) {
     session = session,
     object_id = label,
     tutorial_object("question_submission", list(
+      version = 1,
       question = question,
       answer = answer
     ))
@@ -103,17 +104,6 @@ get_all_state_objects <- function(session, exercise_output = TRUE) {
         object$data["output"] <- list(NULL)
       }
     }
-    if (object$type == "question_submission") {
-      if (!is.null(object$data$answers)) {
-        # as of v0.10.0...
-        # upgrade from old storage format to new storage format
-        # rename answers -> answer
-        object$data$answer <- object$data$answers
-        object$data$answers <- NULL
-        # do not record correct information
-        object$data$correct <- NULL
-      }
-    }
     object
   })
 
@@ -205,18 +195,41 @@ save_object <- function(session, object_id, data) {
   tutorial_storage(session)$save_object(tutorial_id, tutorial_version, user_id, object_id, data)
 }
 
+
+update_object <- function(object) {
+  if (object$type == "question_submission") {
+    version <- object$data$version
+    if (!is.null(version)) {
+      if (identical(version, 1)) {
+        # do nothing
+      } else {
+        # as of v0.10.0...
+        # upgrade from old storage format to new storage format
+        # rename answers -> answer
+        object$data$answer <- object$data$answers
+        object$data$answers <- NULL
+        # do not record correct information
+        object$data$correct <- NULL
+      }
+    }
+  }
+  object
+}
+
 get_object <- function(session, object_id) {
   tutorial_id <- read_request(session, "tutorial.tutorial_id")
   tutorial_version <- read_request(session, "tutorial.tutorial_version")
   user_id <- read_request(session, "tutorial.user_id")
-  tutorial_storage(session)$get_object(tutorial_id, tutorial_version, user_id, object_id)
+  object <- tutorial_storage(session)$get_object(tutorial_id, tutorial_version, user_id, object_id)
+  update_object(object)
 }
 
 get_objects <- function(session) {
   tutorial_id <- read_request(session, "tutorial.tutorial_id")
   tutorial_version <- read_request(session, "tutorial.tutorial_version")
   user_id <- read_request(session, "tutorial.user_id")
-  tutorial_storage(session)$get_objects(tutorial_id, tutorial_version, user_id)
+  objects <- tutorial_storage(session)$get_objects(tutorial_id, tutorial_version, user_id)
+  lapply(objects, update_object)
 }
 
 remove_all_objects <- function(session) {