Alphavantage getQuote batch discontinued

[helgasoft]

Description

It seems Alphavantage's API has changed and they do not have batch quotes anymore. Only single quote, like this.     So current getQuote.av does not work anymore. Related to #213

Expected behavior

Being able to get quotes from Alphavantage anytime with personal API key.

Minimal, reproducible example

getQuote(c('IBM','F'), src='av', api.key='yourOwn')   # No data for symbols: IBM, F

Proposed patch

getQuote.av <- function (Symbols='A;B;F', api.key, verbose=FALSE) {
  # get latest daily quotes from AV, they dont have batch quotes anymore as of Feb 2020
  importDefaults("getQuote.av")
  if (!hasArg("api.key")) {
    stop("getQuote.av: An API key is required (api.key). Free registration,", 
         " at https://www.alphavantage.co/.", call. = FALSE)
  }
  if (length(Symbols) > 1 && is.character(Symbols))  # accept vector too
    Symbols <- paste(Symbols, collapse = ";")
  Symbols <- unique(unlist(strsplit(Symbols, ";")))
  length.of.symbols <- length(unlist(strsplit(Symbols, ";")))
  if (length.of.symbols==0) 
    stop('no symbols provided', call. = FALSE)
  if (verbose) cat('\n getting quotes: ')
  qdf <- data.frame()
  for (i in 1:length.of.symbols) {
    Sys.sleep(0.5)
    if (verbose) cat(Symbols[i], " ")
    url <- paste0('https://www.alphavantage.co/query?function=GLOBAL_QUOTE&symbol=',Symbols[i],'&apikey=',api.key)
    dd <- jsonlite::fromJSON(url)
    if (names(dd[1])=="Error Message") next   # skip invalid symbols
    dd <- dd[[1]]  # dd$`Global Quote`
    dd[2:6] <- sapply(dd[2:6], as.numeric)
    tmpdf <- data.frame(symbol = toupper(Symbols[i]), 
                        date = as.Date(dd$`07. latest trading day`),
                        open = if (is.null(dd$`02. open`)) 0 else dd$`02. open`, 
                        high = if (is.null(dd$`03. high`)) 0 else dd$`03. high`, 
                        low =  if (is.null(dd$`04. low`))  0 else dd$`04. low`, 
                        close = dd$`05. price`,
                        volume=if (is.null(dd$`06. volume`)) 0 else dd$`06. volume` )
    qdf <- rbind(qdf, tmpdf)
  }
  if (verbose) cat('done.\n')
  rownames(qdf) <- qdf$symbol
  qdf$symbol <- NULL
  qdf
}