Switch covidcast_meta to request CSVs as well

Author: capnrefsmmat

R-packages/covidcast/R/covidcast.R

@@ -429,17 +429,15 @@ covidcast_signals <- function(data_source, signal,
 #'
 #' @export
 covidcast_meta <- function() {
-  meta <- jsonlite::fromJSON(.request(
+  meta <- .request(
     list(source = "covidcast_meta",
-         cached = "true")))
+         format = "csv"))
 
-  if (meta$message != "success") {
-    abort(paste0("Failed to obtain metadata: ", meta$message, "."),
-          err_msg = meta$message,
-          class = "covidcast_meta_fetch_failed")
+  if (nchar(meta) == 0) {
+    abort("Failed to obtain metadata", class = "covidcast_meta_fetch_failed")
   }
 
-  meta <- meta$epidata %>%
+  meta <- read.csv(textConnection(meta), stringsAsFactors = FALSE) %>%
     dplyr::mutate(min_time = api_to_date(.data$min_time),
                   max_time = api_to_date(.data$max_time),
                   max_issue = api_to_date(.data$max_issue))

R-packages/covidcast/tests/testthat/api.covidcast.cmu.edu/epidata/api.php-d2e163.json

@@ -0,0 +1,3 @@
+data_source,signal,time_type,geo_type,min_time,max_time,min_value,max_value,max_issue
+foo,bar,day,county,20200101,20200102,0,10,20200404
+foo,bar,day,county,20201002,20201003,0,10,20201101

R-packages/covidcast/tests/testthat/api.covidcast.cmu.edu/epidata/api.php-dd024f.csv

@@ -13,8 +13,10 @@ library(dplyr)
 # types of errors.
 #
 # 2. Once you've written a test, it can be difficult to find the file storing
-# the JSON needed for that test. We hence store the filename in comments
-# adjacent to every call.
+# the JSON or CSV needed for that test. We hence store the filename in comments
+# adjacent to every call. (Note that we request CSVs from the API for
+# covidcast_signal, and httptest suggests filenames ending in .json by default.
+# You can use .csv instead and httptest will correctly locate those files.)
 #
 # 3. covidcast_signal() calls covidcast_meta() unconditionally. We hence need a
 # single meta file that suffices for all tests that call covidcast_signal().
@@ -38,29 +40,28 @@ library(dplyr)
 
 with_mock_api({
   test_that("covidcast_meta formats result correctly", {
-    # api.php-d2e163.json
+    # api.php-dd024f.csv
     expect_equal(covidcast_meta(),
                  structure(
                    data.frame(
                      data_source = "foo",
                      signal = c("bar", "bar2"),
                      min_time = as.Date(c("2020-01-01", "2020-10-02")),
                      max_time = as.Date(c("2020-01-02", "2020-10-03")),
-                     max_issue = as.Date(c("2020-04-04", "2020-11-01")),
                      min_value = 0,
                      max_value = 10,
                      num_locations = 100,
                      time_type = "day",
-                     geo_type = "county"
+                     geo_type = "county",
+                     max_issue = as.Date(c("2020-04-04", "2020-11-01"))
                    ),
                    class = c("covidcast_meta", "data.frame")
                  ))
   })
 })
 
 test_that("covidcast_meta raises error when API signals one", {
-  stub(covidcast_meta, ".request",
-       "{\"message\": \"argle-bargle\"}")
+  stub(covidcast_meta, ".request", "")
 
   expect_error(covidcast_meta(),
                class = "covidcast_meta_fetch_failed")