Merge branch 'function-otp-connect'

Author: marcusyoung

DESCRIPTION

@@ -13,4 +13,8 @@ Description: An interface for Open Trip Planner <http://www.opentripplanner.org/
 License: GPL-3
 Encoding: UTF-8
 LazyData: true
+Imports:
+    checkmate,
+    httr
 RoxygenNote: 6.0.1
+Suggests: testthat

NAMESPACE

@@ -1,3 +1,4 @@
 # Generated by roxygen2: do not edit by hand
 
 export(hello)
+export(otp_connect)

R/otp-connect.R

@@ -0,0 +1,117 @@
+#' Set up and confirm a connection to an OTP instance.
+#'
+#' Defines the parameters required to connect to a router on an OTP instance and,
+#' if required, confirms that the instance and router are queryable.
+#'
+#' @param hostname A string, e.g. "ec2-34-217-73-26.us-west-2.compute.amazonaws.com".
+#'     Optional, default is "localhost".
+#' @param router A string, e.g. "UK2018". Optional, default is "default".
+#' @param port A positive integer. Optional, default is 8080.
+#' @param ssl Logical, indicates whether to use https. Optional, default is FALSE.
+#' @param check Logical. If TRUE connection object is only returned if OTP
+#'     instance and router are confirmed reachable. Optional, default is TRUE.
+#' @return Returns an S3 object of class otpconnect. If \code{check} is TRUE
+#'     and the router is not reachable the object is not returned.
+#' @examples
+#' otpcon <- otp_connect()
+#' otpcon <- otp_connect(router = "UK2018",
+#'                       ssl = TRUE)
+#' otpcon <- otp_connect(hostname = "ec2.us-west-2.compute.amazonaws.com",
+#'                       router = "UK2018",
+#'                       port = 8888,
+#'                       ssl = TRUE)
+
+#' @export
+otp_connect <- function(hostname = "localhost",
+                        router = "default",
+                        port = 8080,
+                        ssl = FALSE,
+                        check = TRUE)
+{
+  # argument checks
+
+  coll <- checkmate::makeAssertCollection()
+  checkmate::assert_string(hostname, add = coll)
+  checkmate::assert_string(router, add = coll)
+  checkmate::assert_int(port, lower = 1, add = coll)
+  checkmate::assert_logical(ssl, add = coll)
+  checkmate::assert_logical(check, add = coll)
+  checkmate::reportAssertions(coll)
+
+  otpcon <- list(
+    hostname = hostname,
+    router = router,
+    port = port,
+    ssl = ssl
+  )
+
+  # Set the name for the class
+  class(otpcon) <- append(class(otpcon), "otpconnect")
+
+
+  # If check then confirm router is queryable
+
+  if (isTRUE(check)) {
+    if (check_router(otpcon) == 200) {
+      message("Router ", make_url(otpcon), " exists")
+      return(otpcon)
+    } else {
+      stop("Router ", make_url(otpcon),  " does not exist")
+    }
+  } else {
+    return(otpcon)
+  }
+}
+
+# otpconnect class method to generate baseurl
+
+make_url <- function(x)
+{
+  UseMethod("make_url", x)
+}
+
+make_url.default <- function(x)
+{
+  warning(
+    "make_url does not know how to handle objects of class ",
+    class(x),
+    ", and can only be used on the class otpconnect"
+  )
+  return(NULL)
+}
+
+make_url.otpconnect <- function(x)
+{
+  url <- paste0(
+    ifelse(isTRUE(x$ssl), 'https://', 'http://'),
+    x$hostname,
+    ':',
+    x$port,
+    '/otp/routers/',
+    x$router
+  )
+  return(url)
+}
+
+# otpconnect method to check if router exists
+
+check_router <- function(x)
+{
+  UseMethod("check_router", x)
+}
+
+check_router.default <- function(x)
+{
+  warning(
+    "check_router does not know how to handle objects of class ",
+    class(x),
+    ", and can only be used on the class otpconnect"
+  )
+  return(NULL)
+}
+
+check_router.otpconnect <- function(x)
+{
+  check <- httr::GET(make_url(x))
+  return(check$status_code)
+}

man/otp_connect.Rd

@@ -0,0 +1,4 @@
+library(testthat)
+library(opentripplanner)
+
+test_check("opentripplanner")

tests/testthat.R

@@ -0,0 +1,31 @@
+
+
+context("Test the otp_connect function")
+
+test_that("default object is created and make_url method works", {
+  otpcon <- otp_connect(check = FALSE)
+  expect_is(otpcon, "otpconnect")
+  expect_match(make_url(otpcon), "http://localhost:8080/otp/routers/default")
+})
+
+# the following tests require an OTP instance at http://localhost:8080/otp with "default" router
+
+test_that("object returned when check is TRUE and router exists", {
+  otpcon <- otp_connect()
+  expect_is(otpcon, "otpconnect")
+})
+
+test_that("correct message when check is TRUE and router exists", {
+  expect_message(otp_connect(), "Router http://localhost:8080/otp/routers/default exists")
+})
+
+
+test_that("object is not returned when check is TRUE and router does not exist", {
+  #otpcon <- otp_connect(router = "test")
+  expect_false(exists("otpcon"))
+})
+
+test_that("correct error when check is TRUE and router does not exist", {
+  expect_error(otp_connect(router = "test"), "Router http://localhost:8080/otp/routers/test does not exist")
+})
+