Force error handler to serialize with unboxed json serializer

NEWS.md

@@ -1,6 +1,10 @@
 plumber 1.0.0.9999 Development version
 --------------------------------------------------------------------------------
 
+### Breaking changes
+
+* Force json serialization of endpoint error responses instead of using endpoint serializer. (@meztez, #689)
+
 ### New features
 
 * Passing `edit = TRUE` to `plumb_api()` will open the API source file (#699)
@@ -9,10 +13,11 @@ plumber 1.0.0.9999 Development version
 
 ### Bug fixes
 
-* When calling `Plumber$handle()` and defining a new `PlumberEndpoint`, `...` will be checked for invalid names #677
+* When calling `Plumber$handle()` and defining a new `PlumberEndpoint`, `...` will be checked for invalid names (@meztez, #677)
 
 * `/__swagger__/` now always redirect to `/__docs__/`, even when Swagger isn't the selected interface. Use `options(plumber.legacyRedirects = FALSE)` to disable this behavior (@blairj09 #694)
 
+
 plumber 1.0.0
 --------------------------------------------------------------------------------
 

R/default-handlers.R

@@ -6,6 +6,7 @@ default404Handler <- function(req, res){
     return(list(error = "405 - Method Not Allowed"))
   }
   res$status <- 404
+  res$serializer <- serializer_unboxed_json()
   list(error="404 - Resource Not Found")
 }
 
@@ -20,6 +21,7 @@ defaultErrorHandler <- function(){
       # It's possible, however, than a handler set a 40x and then wants to use this function to
       # render an error, though.
       res$status <- 500
+      res$serializer <- serializer_unboxed_json()
       li$error <- "500 - Internal server error"
     } else {
       li$error <- "Internal error"

tests/testthat/helper-mock-request.R

@@ -1,5 +1,5 @@
 
-make_req <- function(verb = "GET", path = "/", qs="", body="", args = c(), ...){
+make_req <- function(verb = "GET", path = "/", qs="", body="", args = c(), pr = NULL, ...){
   req <- as.environment(list(...))
   req$REQUEST_METHOD <- toupper(verb)
   req$PATH_INFO <- path
@@ -13,5 +13,6 @@ make_req <- function(verb = "GET", path = "/", qs="", body="", args = c(), ...){
                          read = function(){ body },
                          rewind = function(){ length(body) })
   req$bodyRaw <- body
+  req$pr <- pr
   req
 }

tests/testthat/test-async.R

@@ -237,6 +237,9 @@ test_that("async hooks change value being passed through",  {
 context("Promise - errors are handled")
 
 expect_route_error <- function(response, txt) {
+  if (!is.list(response$body)) {
+    response$body <- jsonlite::parse_json(response$body, simplifyVector = TRUE)
+  }
   expect_equal(response$body$error, "500 - Internal server error")
   expect_true(grepl(txt, response$body$message))
 }

tests/testthat/test-endpoint-aroundexec.R

@@ -135,9 +135,12 @@ test_that("not producing an image produces an error", {
   })
 
   expect_output(
-    result <- root$call(make_req("GET", "/no_plot")),
+    result <- root$call(make_req("GET", "/no_plot", pr = root)),
     "device output file is missing"
   )
   expect_equal(result$status, 500)
+  if (!is.list(result$body)) {
+    result$body <- jsonlite::parse_json(result$body, simplifyVector = TRUE)
+  }
   expect_true(grepl("device output file is missing", result$body$message))
 })

tests/testthat/test-serializer-feather.R

@@ -29,3 +29,12 @@ test_that("Errors call error handler", {
   serializer_feather()(parse(text="hi"), data.frame(), PlumberResponse$new("csv"), errorHandler = errHandler)
   expect_equal(errors, 1)
 })
+
+test_that("Errors are rendered correctly with debug TRUE", {
+  skip_if_not_installed("feather")
+
+  pr <- pr() %>% pr_get("/", function() stop("myerror"), serializer = serializer_feather()) %>% pr_set_debug(TRUE)
+  capture.output(res <- pr$serve(make_req(pr = pr), PlumberResponse$new("csv")))
+
+  expect_match(res$body, "Error in (function () : myerror", fixed = TRUE)
+})