Make reqContractDetails always working when R API invokes remote TWS

[diegoperoni]

Description

I noticed that when reqContractDetails requests many contracts (ex. option chain) and R invokes a remote TWS (not in the same machine) it doesn't work (socket error).

Expected behavior

I fixed the problem adding a small delay during the iteration. It works very well for me. Hope it is useful!

Minimal, reproducible example

reqContractDetails <-
  function(conn, Contract, reqId="1", verbose=FALSE,
           eventWrapper=eWrapper(), CALLBACK=twsCALLBACK, ...) {
    
    .reqContractDetails(conn, Contract, reqId)
    
    if(is.null(CALLBACK))
      invisible(return(NULL))
    
    # create an internal eWrapper to *only* handle contract request data,
    # all else is discarded.
    eW <- eWrapper(NULL)
    eW$contractDetails <- function(curMsg, msg, timestamp, file, ...) {
      # custom contractData function called from processMsg
      twsContractDetails(version=msg[1],
                         #reqId=msg[2],
                         contract=twsContract(conId=msg[12+1],
                                              symbol=msg[3],
                                              sectype=msg[4],
                                              expiry=msg[5],  
                                              primary=msg[21],
                                              strike=msg[5+1],
                                              right=msg[6+1],
                                              exch=msg[7+1],
                                              currency=msg[8+1],
                                              multiplier=msg[14+1],
                                              include_expired=Contract$include_expired,
                                              combo_legs_desc="", comboleg="",
                                              local=msg[9+1]),
                         marketName=msg[10+1],
                         tradingClass=msg[11+1],
                         conId=msg[12+1],
                         minTick=msg[13+1],
                         orderTypes=unlist(strsplit(msg[15+1],",")),
                         validExchanges=unlist(strsplit(msg[16+1],",")),
                         priceMagnifier=msg[17+1],
                         underConId=msg[18+1],
                         longName=msg[19+1],
                         contractMonth=msg[22],
                         industry=msg[23],
                         category=msg[24],
                         subcategory=msg[25],
                         timeZoneId=msg[26],
                         tradingHours=msg[27],
                         liquidHours=msg[28])
    }
    
    contracts <- list()
    con <- conn[[1]]
    while (TRUE) {
      socketSelect(list(con), FALSE, NULL) 
      curMsg <- readBin(con, character(), 1)
      if(curMsg != .twsIncomingMSG$CONTRACT_DATA) {
        if(curMsg == .twsIncomingMSG$ERR_MSG) {
          if(!errorHandler(con,verbose,OK=c(165,300,366,2104,2106,2107))){
            warning("error in contract details")
            break
          }
        } else {
          processMsg(curMsg, con, eW, timestamp, file)
          if(curMsg == .twsIncomingMSG$CONTRACT_DATA_END)
            break      
        }
      }
      if(curMsg == .twsIncomingMSG$CONTRACT_DATA) {
        contracts[[length(contracts)+1]] <-
          processMsg(curMsg, con, eW, timestamp, file)
      }
      
       Sys.sleep(0.01) # NEW CODE
    }
    return(contracts)
  }