R/download_prices.R

In vschaftenaar/crypto: Download crypto prices

get.price=function(coin='BTC',value='USD',time.frame=NULL){
  time.frame=tolower(time.frame)

  options(warn=-1)
  if(length(coin)==1){
  #single coin

    if(length(time.frame)==0){
      #current price

      lnk=paste0('https://min-api.cryptocompare.com/data/price?fsym=',coin,'&tsyms=',paste0(value,collapse = ','))
      x=jsonlite::fromJSON(readLines(lnk))


    }else{
      #historical price

      if(time.frame %in% c('minute','hour','day')){
            lnk=paste0('https://min-api.cryptocompare.com/data/v2/histo',time.frame,'?fsym=',coin,'&tsym=',value,'&limit=2000')
            x=jsonlite::fromJSON(readLines(lnk))
            x=data.table::data.table(x$Data$Data)
            x=data.table::data.table(
              t= as.POSIXct(x$time,origin='1970-01-01'),
              h= x$high,
              l= x$low,
              o= x$open,
              c= x$clos,
              vol= x$volumeto)
      }else{
        stop('please make sure the time.frame is either: minute, hour, or day')
      }
    }


  }else{
  #multiple ocins
    if(!is.null(time.frame))message('no historical day available for multiple coins...')
    lnk=paste0('https://min-api.cryptocompare.com/data/pricemulti?fsyms=',paste0(coin,collapse = ','),'&tsyms=',paste0(value,collapse = ','))
    x=jsonlite::fromJSON(readLines(lnk))
  }


  options(warn=0)
  return(x)

}

get.market.cap <- function(n=100,value='USD'){
  options(warn = -1)
  
  steps <- ceiling(n/100)-1
  dbOut <- data.table()
  
  for(page in 0:steps){
      lnk <-  paste0('https://min-api.cryptocompare.com/data/top/mktcapfull?limit=100&tsym=',value,'&page=',page)
      x   <- jsonlite::fromJSON(readLines(lnk))$Data
      
      # x.raw <- as.data.table(x$RAW)[,c(6,38,39)]
      x.raw <- as.data.table(x$RAW[[value]])
      x.raw <- x.raw[,.(PRICE,SUPPLY,MKTCAP)]
      names(x.raw) <- c('price','supply','marketcap')

      selection <- data.table(
        name       = as.data.table(x$CoinInfo)$FullName,
        ticker     = as.data.table(x$CoinInfo)$Name,
        type       = as.data.table(x$CoinInfo)$ProofType,
        algo       = as.data.table(x$CoinInfo)$Algorithm,
        max.supply = as.data.table(x$CoinInfo)$MaxSupply
        )
      
      selection <- cbind(
        selection,
        x.raw
      )
      dbOut <- rbind(dbOut,selection)
  }
  
  dbOut[,rank:=1:nrow(dbOut)]
  dbOut[,value:=value]
    
  dbOut=data.table(dbOut[,c('rank','name','ticker','type','algo','price','value','supply','marketcap','max.supply')])
  dbOut=head(dbOut,n)
  options(warn=0)
  return(dbOut)
}