Use Apache Feather for API object transfer instead of RDS

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: etn
 Title: Access Data from the European Tracking Network
-Version: 2.3.0
+Version: 2.3.1.9000
 Authors@R: c(
     person("Peter", "Desmet", email = "[email protected]",
            role = c("aut", "cre"), comment =  c(ORCID = "0000-0002-8442-8025")),
@@ -19,8 +19,9 @@ License: MIT + file LICENSE
 URL: https://github.com/inbo/etn, https://inbo.github.io/etn
 BugReports: https://github.com/inbo/etn/issues
 Depends:
-    R (>= 3.4.0)
+    R (>= 4.0)
 Imports:
+    arrow,
     askpass,
     assertthat,
     DBI,

NEWS.md

@@ -1,3 +1,7 @@
+# etn (development version)
+* API functions now use the `arrow` package to transfer data.frames, which should allow for greater amounts of detections to be transferred without crashing (#323, #327). This will also reduce memory usage for large objects, an should generally result in a speedup.
+* etn now requires an R version of at least 4, this is a consequence of the usage of the `arrow` package.
+
 # etn 2.3.0
 
 * **The etn package can now be used on your computer!** It connects to the ETN database with an API provided by the [etnservice](https://github.com/inbo/etnservice) package. All functions make use of this API by default, which may result in **slower response times**. To use the previous method of directly connecting to the database (only possible when working on the [LifeWatch RStudio Server](https://rstudio.lifewatch.be/)), set `api = false` in all functions (#280).

R/utils.R

@@ -162,19 +162,17 @@ get_val <- function(temp_key, api_domain = "https://opencpu.lifewatch.be") {
     verb = "GET",
     url = glue::glue(
       "{api_domain}",
-      "tmp/{temp_key}/R/.val/rds",
+      # I'm passing an argument to arrow::write_feather() via OpenCPU, this
+      # feature is currenlty only documented in the NEWS file. Not in the
+      # official documentation of OPENCPU
+      'tmp/{temp_key}/R/.val/feather?compression="lz4"',
       .sep = "/"
     ),
     times = 5
   ) %>%
-    httr::content(as = "raw") %>%
-    rawConnection()
+    httr::content(as = "raw")
   # read connection
-  api_response <- response_connection %>%
-    gzcon() %>%
-    readRDS()
-  # close connection
-  close(response_connection)
+  api_response <- arrow::read_feather(response_connection)
   # Return OpenCPU return object
   return(api_response)
 }