chore: factor out findRandomPort() and validate user input

rstudio · Jan 13, 2025 · 8b0c288 · 8b0c288
1 parent 6afb174
commit 8b0c288
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Showing 2 changed files with 51 additions and 22 deletions.
diff --git a/R/find-port.R b/R/find-port.R
@@ -14,34 +14,55 @@ getRandomPort <- function(){
   port
 }
 
-#' Find a port either using the assigned port or randomly search 10 times for an available
-#' port. If a port was manually assigned, just return it and assume it will work.
-#' @noRd
-findPort <- function(port){
-  if (missing(port) || is.null(port)){
-    if (!is.null(.globals$port)){
-      # Start by trying the .globals$port
-      port <- .globals$port
-    } else {
-      port <- getRandomPort()
-    }
+findRandomPort <- function() {
+  port <- if (!is.null(.globals$port)) {
+    # Start by trying the .globals$port
+    .globals$port
+  } else {
+    getRandomPort()
+  }
 
-    for (i in 1:10){
-      tryCatch(srv <- httpuv::startServer("127.0.0.1", port, list(), quiet = TRUE), error=function(e){
+  for (i in 1:10) {
+    tryCatch(
+      srv <- httpuv::startServer("127.0.0.1", port, list(), quiet = TRUE),
+      error = function(e) {
         port <<- 0
-      })
-      if (port != 0){
-        # Stop the temporary server, and retain this port number.
-        httpuv::stopServer(srv)
-        .globals$port <- port
-        break
       }
-      port <- getRandomPort()
+    )
+    if (port != 0) {
+      # Stop the temporary server, and retain this port number.
+      httpuv::stopServer(srv)
+      .globals$port <- port
+      break
     }
+    port <- getRandomPort()
+  }
+
+  if (port == 0) {
+    stop(
+      "Unable to start a Plumber server. We were unable to find a free port in 10 tries."
+    )
+  }
+
+  as.integer(port)
+}
+
+#' Find a port either using the assigned port or randomly search 10 times for an available
+#' port. If a port was manually assigned, just return it and assume it will work.
+#' @noRd
+findPort <- function(port) {
+  if (missing(port) || is.null(port)) {
+    return(findRandomPort())
+  }
+
+  port_og <- port
+
+  if (rlang::is_character(port)) {
+    port <- suppressWarnings(as.integer(port))
   }
 
-  if (port == 0){
-    stop("Unable to start a Plumber server. Either the port specified was unavailable or we were unable to find a free port.")
+  if (!rlang::is_integerish(port, n = 1, finite = TRUE) || port != port_og) {
+    stop("Port must be an integer value, not '", port_og, "'.")
   }
 
   as.integer(port)

diff --git a/tests/testthat/test-find-port.R b/tests/testthat/test-find-port.R
@@ -23,6 +23,14 @@ test_that("global port used if available", {
 
 test_that("integer type is returned", {
   expect_type(findPort(), "integer")
+  expect_equal(findPort("8000"), 8000L)
+  expect_equal(findPort(8000.00000), 8000L)
+})
+
+test_that("throws if provided non-integerish port", {
+  expect_error(findPort("blue"))
+  expect_error(findPort(8000.0001))
+  expect_error(findPort(8000:8002))
 })
 
 test_that("finds a good port and persists it", {