R/shalla_cat.R

In themains/rdomains: Get the Category of Content Hosted by a Domain

#' Get Category from Shallalist
#'
#' Fetches category of content hosted by a domain according to Shalla. 
#' The function checks if path to the shalla file is provided by the user. 
#' If not, it looks for \code{shalla_domain_category.csv} in the working directory. 
#'
#' @param domains vector of domain names
#' @param use_file path to the latest shallalist file downloaded using \code{\link{get_shalla_data}}
#' 
#' @return data.frame with original list and content category of the domain
#' 
#' @export
#' @examples \dontrun{
#' shalla_cat(domains = "http://www.google.com")
#' }

shalla_cat <- function(domains = NULL, use_file = NULL) {

  # Nuke leading and trailing spaces
  c_domains  <- gsub("^ *| *$", "", domains)

  # nuke leading http://
  c_domains  <- gsub("^http://", "", c_domains)

  # nuke leading www.
  c_domains  <- gsub("^www.", "", c_domains)

  # Initialize results df
  shalla <- NA
  domain_cat <- data.frame(domain_name = c_domains, shalla_category = NA)

  if (is.character(use_file)) {

    if (!file.exists(use_file)) stop("Please provide correct path to the file.
                                     Or download it using get_shalla_data().")
    shalla <- read.csv(use_file, stringsAsFactors = FALSE)
  } else {

    if (!file.exists("shalla_domain_category.csv")) {
      stop("Please provide path to the shallalist file.
            Or download it using get_shalla_data().")
    }
    shalla <- read.csv("shalla_domain_category.csv", stringsAsFactors = FALSE)
  }

  # Match
  domain_cat$shalla_category <-
      shalla$category[match(c_domains, shalla$domains)]

  domain_cat
}