Initial implementation of a generic json_reader function and download…

…_JSON method

DESCRIPTION

@@ -121,4 +121,4 @@ Encoding: UTF-8
 Language: en-gb
 LazyData: true
 Roxygen: list(markdown = TRUE)
-RoxygenNote: 7.1.1
+RoxygenNote: 7.1.2

NAMESPACE

@@ -79,6 +79,7 @@ importFrom(httr,GET)
 importFrom(httr,POST)
 importFrom(httr,content)
 importFrom(httr,status_code)
+importFrom(jsonlite,fromJSON)
 importFrom(lifecycle,deprecate_warn)
 importFrom(lifecycle,deprecated)
 importFrom(lifecycle,is_present)

R/shared-methods.R

@@ -302,6 +302,20 @@ DataClass <- R6::R6Class(
       )
     },
 
+    #' @description Download raw data from `data_urls`, stores a named list
+    #' of the `data_url` name and the corresponding raw data table in
+    #' `data$raw`. Designed as a drop-in replacement for `download` so
+    #' it can be used in sub-classes.
+    #' @importFrom purrr map
+    download_JSON = function() {
+      if (length(self$data_urls) == 0) {
+        stop("No data to download as data_urls is empty")
+      }
+      self$data$raw <- map(self$data_urls, json_reader,
+        verbose = self$verbose
+      )
+    },
+
     #' @description Cleans raw data (corrects format, converts column types,
     #' etc). Works on raw data and so should be called after
     #' \href{#method-download}{\code{download()}}

R/utils.R

@@ -53,6 +53,30 @@ csv_reader <- function(file, verbose = FALSE, guess_max = 1000, ...) {
   return(tibble(data))
 }
 
+#' Custom JSON reading function
+#'
+#' @description Checks for use of memoise and then uses vroom::vroom.
+#' @param file A URL or filepath to a JSON
+#' @param ... extra parameters to be passed to jsonlite::fromJSON
+#' @inheritParams message_verbose
+#' @return A data table
+#' @importFrom tibble tibble
+#' @importFrom jsonlite fromJSON
+#' @concept utility
+json_reader <- function(file, verbose = FALSE, ...) {
+  if (verbose) {
+    message("Downloading data from ", file)
+    data <- fromJSON(file, ...)
+  } else {
+    data <- suppressWarnings(
+      suppressMessages(
+        fromJSON(file, ...)
+      )
+    )
+  }
+  return(tibble(data))
+}
+
 #' Wrapper for message
 #'
 #' @description A wrapper for `message` that only prints output when