R/define-searchrequest-flag.R

In mRpostman: An IMAP Client for R

#' Define flag search request
#' @param name A string containing one or more flags to search for. Use
#'   \href{#method-list_flags}{\code{ImapCon$list_flags()}} to list the flags
#'   in a selected mail folder.
#' @param negate If \code{TRUE}, negates the search and seeks for "NOT SEARCH
#'   CRITERIA". Default is \code{FALSE}.
#' @param use_uid Default is \code{FALSE}. In this case, results will be
#'   presented as message's sequence numbers. A message sequence number is a
#'   message's relative position to the oldest message in the mailbox. It may
#'   change after deleting or moving messages. If a message is deleted, sequence
#'   numbers are reordered to fill the gap. If \code{TRUE}, the command will be
#'   performed using the \code{"UID"} or unique identifier, and results are
#'   presented as such. UIDs are always the same during the life cycle of a message.
#' @param esearch A logical. Default is \code{FALSE}. If the IMAP server has
#'   \code{ESEARCH} capability, it can be used to optimize search results. It
#'   will condense the results: instead of writing down the whole sequences of messages'
#'   ids, such as \code{\{1 2 3 4 5\}}, it will be presented as \code{\{1:5\}},
#'   which decreases transmission costs. This argument can be used along with
#'   \code{buffersize} to avoid results stripping. Check if your IMAP server
#'   supports \code{ESEARCH} with
#'   \href{#method-list_server_capabilities}{\code{ImapCon$list_server_capabilities()}}.
#' @param handle A curl handle object.
#' @noRd
define_searchrequest_flag <- function(name, negate, use_uid, esearch, handle) {

  # esearch
  if (isTRUE(esearch)) {
    esearch_string = "RETURN () "
  } else {
    esearch_string = NULL
  }

  # flag/name (especial)
  # if (!is.null(flag)) {
  flag_string <- paste(name, collapse = " ") #v0.9.0 (for more than one flag passed)
  flag_string = paste0(flag_string, "") # different here because flag is the main parameter of search
  # } else {
  #   flag_string = NULL
  # }

  # use_uid
  if (isTRUE(use_uid)) {
    use_uid_string = "UID "
  } else {
    use_uid_string = NULL
  }

  # negate
  if (isTRUE(negate)) {
    negate_string = "NOT "
  } else {
    negate_string = NULL
  }

  customrequest <- paste0(use_uid_string, "SEARCH ", esearch_string, negate_string,
                          flag_string)

  tryCatch({
    curl::handle_setopt(
      handle = handle,
      customrequest = customrequest)
  }, error = function(e){
    stop("The connection handle is dead. Please, configure a new IMAP connection with ImapCon$new().")
  })

  return(c(handle = handle, customrequest = customrequest))
}