fix(get_hydrometrie_observations_tr): Error on empty response

Fix #13

R/doApiQuery.R

@@ -88,8 +88,10 @@ doApiQuery <- function(api,
       if (as.numeric(l$count) > 20000) {
         stop(
           "The request reach the API limitation of 20000 records.\n",
-          "Use filter arguments to reduce the number of records of your request."
+          "Use filter arguments to reduce the number of records of your query."
         )
+      } else if(as.numeric(l$count) == 0) {
+        return(NULL)
       }
       data <- c(data, l$data)
       if (resp$status_code == 206) {

R/get_hydrometrie_observations_tr.R

@@ -6,6 +6,8 @@
 #' @param entities 1-[character] string filtering the rows of the returned value, possible values are: "station" for filtering on station rows, "site" for filtering on site rows, "both" for keeping all the rows
 #'
 #' @return a [tibble::tibble] with all available parameters in columns and one row by time step and by station.
+#' If the query returns no records then the returned value is [NULL].
+#'
 #' @export
 #'
 #' @examples
@@ -16,27 +18,33 @@ get_hydrometrie_observations_tr  <- function(params,
                                              entities = "station",
                                              cfg = config::get(file = system.file("config.yml",
                                                         package = "hubeau"))) {
+  # Checks
+  if(!entities %in% c("station", "site", "both")) {
+    stop("Argument 'entities' must be one of these values: 'station', 'site', 'both'")
+  }
+
   l <- doApiQuery(
     api = "hydrometrie",
     operation = "observations_tr",
     params = params,
     cfg = cfg
   )
-  l <- lapply(l, function(x) {
-    x$geometry <- NULL
-    if (entities == "station") {
-      if (is.null(x$code_station)) {
-        return(NULL)
-      }
-    } else if (entities == "site") {
-      if (!is.null(x$code_station)) {
-        return(NULL)
+  if(!is.null(l)) {
+    l <- lapply(l, function(x) {
+      x$geometry <- NULL
+      if (entities == "station") {
+        if (is.null(x$code_station)) {
+          return(NULL)
+        }
+      } else if (entities == "site") {
+        if (!is.null(x$code_station)) {
+          return(NULL)
+        }
       }
-    } else if (entities != "both") {
-      stop("Argument 'entities' must be one of these values: 'station', 'site', 'both'")
-    }
-    return(x)
-  })
-  l[sapply(l, is.null)] <- NULL
-  convert_list_to_tibble(l)
+      return(x)
+    })
+    l[sapply(l, is.null)] <- NULL
+    l <- convert_list_to_tibble(l)
+  }
+  return(l)
 }

tests/testthat/test-get_hydrometrie_observations_tr.R

-params <- list(code_entite = "H0203020",
+params <- list(bbox = "1.6,47.79,1.8,47.99",
                date_debut_obs = format(Sys.Date()-3),
                grandeur_hydro = "Q")
 
@@ -9,7 +9,6 @@ test_that("entities not in ('station', 'site', 'both') should throw an error", {
   )
 })
 
-
 test_that("`entities = 'station'` => 'code_station' must be always not NA", {
   skip_on_cran()
   df <- get_hydrometrie_observations_tr(params, entities = "station")