R/common.R

In beykuet/ROandaAPI: R wrapper for the [OANDA REST API](http://developer.oanda.com/rest-live/introduction/)

header <- function(token, headers=NULL)
{
  headers <- c(headers, "Authorization"=paste0("Bearer ", token))
  add_headers(.headers = headers)
}

domain <- function(account_type)
{
  if(account_type == "trade"){
    list(rest="api-fxtrade.oanda.com", streaming="stream-fxtrade.oanda.com")
  } else {
    list(rest="api-fxpractice.oanda.com", streaming="stream-fxpractice.oanda.com")
  }
}

is_empty <- function(x){x == "" || is.null(x)}

POST <- function(oanda, endpoint, params)
{
  url <- paste0("https://", oanda$domain$rest, endpoint)
  body <- Filter(Negate(is_empty), params$body)
  httr::POST(url, config=header(oanda$token, params$headers), body=body, encode="form")
}

PATCH <- function(oanda, endpoint, params)
{
  url <- paste0("https://", oanda$domain$rest, endpoint)
  body <- Filter(Negate(is_empty), params$body)
  httr::PATCH(url, config=header(oanda$token, params$headers), body=body, encode="form")
}

DELETE <- function(oanda, endpoint, params)
{
  url <- paste0("https://", oanda$domain$rest, endpoint)
  httr::DELETE(url, config=header(oanda$token, params$headers), encode="form")
}

GET <- function(oanda, endpoint, params)
{
  url <- paste0("https://", oanda$domain$rest, endpoint)
  query <- Filter(Negate(is_empty), params$query)
  httr::GET(url, header(oanda$token), query=query)
}

request <- function(oanda, endpoint, method=GET, params=list(body=NULL, query=NULL))
{
  response <- method(oanda, endpoint, params)

  status <- http_status(response)

  to_df(httr::content(response, "text", encoding="utf-8"))
}


tidy_string <- function(x)
{
  x <- str_replace_all(x, "[:upper:]", '_\\0')
  x <- str_replace_all(x, ".+\\.", "")
  tolower(x)
}

tidy_df <- function(df)
{
  colnames(df) <- tidy_string(colnames(df))
  #Convert time
  if("time" %in% colnames(df)){
    df$time <- lubridate::ymd_hms(df$time)
  }
  df
}

json_to_df <- function(json)
{
  list_to_df(fromJSON(json))
}

list_to_df <- function(x)
{
  as.data.frame(t(unlist(x)), stringsAsFactors=FALSE)
}

to_df <- function(content)
{
  x <- fromJSON(content, flatten=TRUE)
  if(is.null(unlist(x))){return(NULL)}

  df <- if(is.data.frame(x)){
    x
  } else{
    is_dfs <- sapply(x, is.data.frame)
    if(any(is_dfs)){
      # Include data.frame as an element
      indexes <- which(is_dfs)
      tmp <- dplyr::bind_rows(x[indexes])
      if(length(x[-indexes]) == 0){
        tmp
      } else{
        cbind(tmp, dplyr::bind_cols(x[-indexes]))
      }
    } else{
      list_to_df(x)
    }
  }
  #Change column names
  tidy_df(df)
}

account_id_inner <- function(oanda, account_id)
{
  if(is.null(account_id)){oanda$account_id}else{account_id}
}

to_cs_string <- function(x){paste(x, collapse=",")}