Merge pull request #51 from ijlyttle/master

Pagination, thanks to Ian Lyttle!

DESCRIPTION

@@ -31,6 +31,7 @@ Imports:
 Suggests:
     testthat,
     knitr,
-    rmarkdown
+    rmarkdown,
+    purrr
 VignetteBuilder: knitr
 RoxygenNote: 5.0.1

R/boxr_misc.R

@@ -1,6 +1,8 @@
 #' Obtain a data.frame describing the contents of a box.com folder
 #' 
 #' @param dir_id The box.com id for the folder that you'd like to query
+#' @param limit  Maximum number of entries to retrieve per query-page
+#' @param max    Maximum number of entries to retrieve in total
 #' 
 #' @return A data.frame describing the contents of the the folder specified by 
 #'   \code{dir_id}. Non recursive.
@@ -13,26 +15,75 @@
 #'   examining the contents of local directories.
 #'   
 #' @export
-box_ls <- function(dir_id = box_getwd()) {
+box_ls <- function(dir_id = box_getwd(), limit = 100, max = Inf) {
+
+  # maybe some logic here to check that limit <= 1000
 
   checkAuth()
 
-  req <- httr::GET(
-    paste0(
-      "https://api.box.com/2.0/folders/",
-      box_id(dir_id), 
-      "/items?fields=modified_at,content_modified_at,name,id,type,sha1,size,",
-      "owned_by,path_collection,description&limit=1000"
-    ),
-    httr::config(token = getOption("boxr.token"))
+  url_root <- "https://api.box.com/2.0"
+
+  url <- httr::parse_url(
+    paste(url_root, "folders", box_id(dir_id), "items", sep = "/")
   )
+
+  fields <- c("modified_at" ,"content_modified_at", "name", "id", "type",
+              "sha1" ,"size", "owned_by", "path_collection", "description")
+
+  url$query <- list(
+    fields = paste(fields, collapse = ","),
+    limit = limit
+  )
+
+  out <- box_pagination(url, max = max)
 
-  out <- httr::content(req)$entries
   class(out) <- "boxr_object_list"
   return(out)
 }
 
 
+#' @keywords internal
+box_pagination <- function(url, max = 200) {
+
+  out       <- list()
+  next_page <- TRUE
+  page      <- 1
+  n_so_far  <- 0
+
+  while (next_page) {
+
+    limit <- url$query$limit
+
+    url$query$offset <- (page - 1) * limit
+
+    req      <- httr::GET(
+      url, 
+      httr::config(token = getOption("boxr.token"))
+    )
+
+    if (req$status_code == 404) {
+      message("box.com indicates that no results were found")
+      return()
+    }
+
+    httr::stop_for_status(req)
+
+    resp     <- httr::content(req)
+    n_req    <- length(resp$entries)
+    n_so_far <- n_so_far + n_req
+    total    <- resp$total_count
+
+    if (!n_so_far < total | n_so_far >= max)
+      next_page <- FALSE
+
+    out     <- c(out, resp$entries)
+    page    <- page + 1
+  }
+
+  return(out)
+}
+
+
 #' Get/Set Default box.com directory/folder
 #' 
 #' @description Providing analgous functionality for the jbase \bold{\code{R}}

tests/testthat/test_12_ls.R

@@ -0,0 +1,70 @@
+context("Listing remote files")
+
+# function to create a file in a local directory
+#
+# @param x    numeric, number of the file
+# @param dir  character, name of the directory
+#
+fn_create <- function(x, dir){
+
+  name <- paste0("file_", formatC(x, width = 4, flag = "0"), ".txt")
+  filename <- file.path(dir_ls, name)
+
+  writeLines("test file", filename)
+}
+
+# given a boxr_object_list, return a vector of names
+#
+# @param b boxr_object_list
+#
+get_filenames <- function(b){
+  b %>%
+    as.data.frame() %>%
+    dplyr::arrange(name) %>%
+    `[[`("name")
+}
+
+test_that("file listing works", {
+
+  skip_on_cran()
+  boxr:::skip_on_travis()
+
+  # (Re)create local dir structure
+  boxr:::create_test_dir()
+
+  # create ls directory
+  dir_ls <- file.path("test_dir", "ls")
+  dir.create(dir_ls)
+
+  # create files in the ls directory
+  purrr::walk(seq_len(10), fn_create, dir_ls)
+
+  files_local <- list.files(dir_ls)
+
+  # push the local directory
+  box_push(0, "test_dir", overwrite = TRUE, delete = TRUE)
+
+  # get the id of the remote ld directory
+  id_ls <- 
+    box_ls(0) %>%
+    as.data.frame() %>%
+    dplyr::filter(name == "ls") %>%
+    dplyr::select(id) %>%
+    `[[`(1) %>%
+    as.numeric()
+
+  # get the listing without pagination
+  files_box <- 
+    box_ls(id_ls) %>% 
+    get_filenames()
+
+  # get the listing with pagination
+  files_box_page <-
+    box_ls(id_ls, limit = 5) %>%
+    get_filenames()
+
+  # test
+  expect_identical(files_box, files_local)
+  expect_identical(files_box_page, files_local)
+
+})