R/crypto_list.R

In heguevel/Crypto: Cryptocurrency Market Data

#' Retrieves name, symbol, slug and rank for all tokens
#'
#' List all of the crypto currencies that have existed on CoinMarketCap
#' and use this to populate the URL base for scraping historical market
#' data. It retrieves name, slug, symbol and rank of crypto currencies from
#' CoinMarketCap and creates URLS for \code{scraper()} to use.
#'
#' @param coin Name, symbol or slug of crypto currency
#' @param start_date Start date to retrieve data from, format yyyymmdd
#' @param end_date Start date to retrieve data from, format yyyymmdd
#' @param coin_list 'api', 'static' or NULL
#'
#' @return Crypto currency historic OHLC market data in a dataframe:
#'   \item{symbol}{Coin symbol (not-unique)}
#'   \item{name}{Coin name}
#'   \item{slug}{Coin URL slug (unique)}
#'   \item{rank}{Current rank by market cap}
#'   \item{exchange_url}{Exchange market tables urls for scraping}
#'   \item{history_url}{Historical market tables urls for scraping}
#'
#' Required dependency that is used in function call \code{getCoins()}.
#' @importFrom tibble tibble
#' @importFrom lubridate today
#'
#' @examples
#' \dontrun{
#' coin <- 'kin'
#' coins <- crypto_list(coin)
#'
#' # return all coins
#' coin_list <- crypto_list()
#' }
#'
#' @name crypto_list
#'
#' @export
#'
crypto_list <- function(coin = NULL, start_date = NULL, end_date = NULL, coin_list = NULL) {
  if (is.null(coin_list)) {
    json <- "https://s2.coinmarketcap.com/generated/search/quick_search.json"
    coins <- safely_read_json(json)
  } else {
    ifelse(coin_list == "api", coins <- get_coinlist_api(), coins <- get_coinlist_static())
  }
  
  if (!is.null(coin)) {
    name <- coins$name
    slug <- coins$slug
    symbol <- coins$symbol
    c1 <- subset(coins, toupper(name) %in% toupper(coin))
    c2 <- subset(coins, symbol %in% toupper(coin))
    c3 <- subset(coins, slug %in% tolower(coin))
    coins <- tibble::tibble()
    if (nrow(c1) > 0) {
      coins <- rbind(coins, c1)
    }
    if (nrow(c2) > 0) {
      coins <- rbind(coins, c2)
    }
    if (nrow(c3) > 0) {
      coins <- rbind(coins, c3)
    }
    if (nrow(coins) > 1L) {
      coins <- unique(coins)
    }
  }
  coins <- tibble::tibble(symbol = coins$symbol, name = coins$name, slug = coins$slug, 
    rank = coins$rank)
  if (is.null(start_date)) {
    start_date <- "20130428"
  }
  if (is.null(end_date)) {
    end_date <- gsub("-", "", lubridate::today())
  }
  exchangeurl <- paste0("https://coinmarketcap.com/currencies/", coins$slug, "/#markets")
  historyurl <- paste0("https://coinmarketcap.com/currencies/", coins$slug, "/historical-data/?start=", 
    start_date, "&end=", end_date)
  exchange_url <- c(exchangeurl)
  history_url <- c(historyurl)
  coins$symbol <- as.character(toupper(coins$symbol))
  coins$name <- as.character(coins$name)
  coins$slug <- as.character(coins$slug)
  coins$exchange_url <- as.character(exchange_url)
  coins$history_url <- as.character(history_url)
  coins$rank <- as.numeric(coins$rank)
  return(coins)
}