How does updateEvent emit boolean when there is a new bar on BarDataList?

[nicholashoyy]

Hi guys,

I am browsing through source codes for eventkit and ib_async, but still couldn't figure out the relevant codes for returning True value when there is a new bar on a BarDataList (updated by reqHistoricalData with keepUpToDate = True).

In the below example provided by blog AlgoTrading101, there is a callback function on_new_bar to which boolean value & BarDataList are emitted. I wonder how this boolean value is generated after new bar is received. I have looked through wrapper.HistoricalDataUpdate, ib.reqHistoriclaData, ib.reqHistoricalDataAsync. Still no clues. May I have your kind help?

from ib_insync import *
ib = IB()
ib.connect()

def place_order(direction, qty, df, tp, sl):
bracket_order = ib.bracketOrder(direction, qty, limitPrice=df.close.iloc[-1], takeProfitPrice=tp, stopLossPrice=sl)

for ord in bracket_order:
ib.placeOrder(contract, ord)

def on_new_bar(bars: BarDataList, has_new_bar: bool):
if has_new_bar:
df = util.df(data)
sma = df.close.tail(50).mean()
std_dev = df.close.tail(50).std() * 3

if contract not in [i.contract for i in ib.positions()]:
if df.close.iloc[-1] > sma + std_dev:
place_order('SELL', 1, df, sma, sma +std_dev * 2

elif df.close.iloc[-1] < sma - std_dev:
place_order('BUY', 1, df, sma, sma+std_dev * 2)

contract = ContFuture('HE', 'GLOBEX')
ib.qualifyContracts(contract)

data = ib.reqHistoricalData(
contract,
endDateTime='',
durationStr='2 D',
barSizeSetting='15 mins',
whatToShow='MIDPOINT',
useRTH=True,
keepUpToDate=True,
)

data.updateEvent += on_new_bar

ib.run()

[jjlinares]

It's in wrapper.realtimeBar

[nicholashoyy]

Thank you very much