more robust parameter handling

Author: Ryan Patrick Kyle

R/dash.R

@@ -647,11 +647,15 @@ Dash <- R6::R6Class(
       }
 
       getServerParam <- function(value, type, default) {
+        if (type %in% c("double", "integer") && value < 0)
+          return(default)
         if (!is.null(value) && toupper(value) %in% c("TRUE", "FALSE"))
           value <- as.logical(toupper(value))
-        if (type == "numeric")
-          value <- as.numeric(value)
-        if (value != "" && length(value) != 0 && mode(value) == type && !is.na(value)) {
+        if (type == "integer")
+          value <- as.integer(value)
+        if (type == "double")
+          value <- as.double(value)        
+        if (value != "" && length(value) != 0 && typeof(value) == type && !is.na(value)) {
           return(value)
         } else {
           return(default)
@@ -662,7 +666,7 @@ Dash <- R6::R6Class(
       private$debug <- debug
 
       self$server$host <- getServerParam(host, "character", "127.0.0.1")
-      self$server$port <- getServerParam(as.integer(port), "numeric", 8050)
+      self$server$port <- getServerParam(as.integer(port), "integer", 8050)
 
       dev_tools_ui <- getServerParam(dev_tools_ui, "logical", debug)
       dev_tools_props_check <- getServerParam(dev_tools_props_check, "logical", debug)
@@ -686,9 +690,9 @@ Dash <- R6::R6Class(
 
       if (dev_tools_hot_reload) {
         hot_reload <- TRUE
-        hot_reload_interval <- getServerParam(dev_tools_hot_reload_interval, "numeric", 3)
-        hot_reload_watch_interval <- getServerParam(dev_tools_hot_reload_watch_interval, "numeric", 0.5)
-        hot_reload_max_retry <- getServerParam(as.integer(dev_tools_hot_reload_max_retry), "numeric", 8)
+        hot_reload_interval <- getServerParam(dev_tools_hot_reload_interval, "double", 3)
+        hot_reload_watch_interval <- getServerParam(dev_tools_hot_reload_watch_interval, "double", 0.5)
+        hot_reload_max_retry <- getServerParam(as.integer(dev_tools_hot_reload_max_retry), "integer", 8)
         # convert from seconds to msec as used by js `setInterval`
         self$config$hot_reload <- list(interval = hot_reload_watch_interval * 1000, max_retry = hot_reload_max_retry)
       } else {