Add `limit` argument to `fetch_` functions

Provider Data:
#' Fetch Provider Data as Tibble or Download CSV
#'
#' @family Provider Data
#'
#' @seealso \code{\link[healthyR.data]{get_provider_meta_data}}
#'
#' @description
#' This function retrieves provider data from the provided link and returns it as a tibble
#' with cleaned names or downloads the data as a CSV file if the link ends in .csv. 
#' This function is intended to be used with the CMS provider data API.
#'
#' @param .data_link A character string containing the URL to fetch data from.
#' @param .limit An integer specifying the maximum number of rows to fetch. 
#' Default is 500. If set to 0, all records will be returned.
#'
#' @return A tibble containing the fetched data with cleaned names, or downloads 
#' a CSV file to the user-selected directory. If an error occurs, returns `NULL`.
#'
#' @details
#' The function sends a request to the provided URL using `httr2::request` and
#' `httr2::req_perform`. If the response status is not 200, it stops with an
#' error message indicating the failure. If the URL ends in .csv, it uses `utils::download.file`
#' to download the CSV file to a directory chosen by the user. Otherwise, the 
#' response body is parsed as JSON and converted into a tibble using 
#' `dplyr::as_tibble`. The column names are cleaned using `janitor::clean_names`, 
#' and any character columns are stripped of leading and trailing whitespace 
#' using `stringr::str_squish`. The default limit for a return on records is 500. 
#' If the limit is set to 0, all records will be returned.
#'
#' @examples
#' library(dplyr)
#'
#' # Example usage:
#' data_url <- "069d-826b"
#'
#' df_tbl <- fetch_provider_data(data_url, .limit = 1)
#'
#' df_tbl |>
#'  glimpse()
#'
#' @name fetch_provider_data
NULL
#'
#' @export
#' @rdname fetch_provider_data
fetch_provider_data <- function(.data_link, .limit = 500) {
  data_link <- .data_link
  limit <- as.integer(.limit)

  # Check if the URL is valid
  url_valid <- is_valid_url(data_link)

  # If the link does not end with .csv AND does not start with
  # https://data.cms.gov AND is not a valid url then it is should be treated
  # as an identifier and then construct the API query URL
  if (
    (
      !grepl("\\.csv$", data_link) &
      !grepl("^https://data.cms.gov", data_link) &
      !url_valid
    )
  ) {
    data_link <- paste0(
      "https://data.cms.gov/provider-data/api/1/datastore/query/",
      data_link,
      "/0?limit=", limit
    )
  }

  # Check if the URL starts with the required prefix and is a valid URL
  if (!is.character(data_link) ||
      length(data_link) != 1 ||
      !grepl("^https://data.cms.gov/provider-data", data_link) ||
      !is_valid_url(data_link)
  ) {
    rlang::abort(
      message = "The provided data link is not valid or does not start with
            'https://data.cms.gov/provider-data'. Please first pull an
            appropriate data link from the CMS provider data API using the
            get_provider_meta_data() function.",
      use_cli_format = TRUE
    )
  }

  # If the link ends with .csv, download the file
  if (grepl("\\.csv$", data_link)) {
    tryCatch({
      dir_path <- utils::choose.dir()
      if (is.na(dir_path)) {
        stop("No directory selected.")
      }
      file_path <- file.path(dir_path, basename(data_link))
      utils::download.file(data_link, file_path)
      message("File downloaded to ", file_path)
      return(NULL)
    }, error = function(e) {
      message("An error occurred while downloading the file: ", e$message)
      return(NULL)
    })
  }

  # Otherwise, fetch and process the JSON data
  tryCatch({
    response <- httr2::request(data_link) |>
      httr2::req_perform()
    if (httr2::resp_status(response) != 200) {
      stop("Failed to retrieve data: HTTP status ", httr2::resp_status(response))
    }
    json_data <- httr2::resp_body_json(
      response, check_type = FALSE, simplifyVector = TRUE
    )
    json_data[["results"]] |>
      dplyr::as_tibble() |>
      janitor::clean_names() |>
      dplyr::mutate(dplyr::across(dplyr::where(is.character), stringr::str_squish))
  }, error = function(e) {
    message("An error occurred: ", e$message)
    return(NULL)
  })
}
spsanderson / healthyR.data

Add `limit` argument to `fetch_` functions #107
