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import requests
import json
"""
Given the parameters,
fetches the data for the corresponding chart using yahoo finance.
If bad request, returns the previous chart.
"""
def fetch_chart_data(ticker, period='1y', interval='1d'):
params = {
'interval' : interval, # 1m, 2m, 5m, 15m, 30m, 60m, 90m, 1h, 4h, 1d, 5d, 1wk, 1mo, 3mo
'range' : period, # "1d","5d","1mo","3mo","6mo","1y","2y","5y","10y","ytd","max"
'events' : 'div|split|earn',
'includePrePost' : 'false' }
headers = {'User-agent' : 'fin-backtesting-proj'}
r = requests.get("https://query2.finance.yahoo.com/v8/finance/chart/" + ticker, headers=headers, params=params)
print(r.url)
print("status_code:\t", r.status_code)
# decode the JSON response data into a Python object
try:
r.raise_for_status() # raises if error before parsing
except:
last_data = pull_last_from_file()
last_data['error'] = True
return last_data
data_obj = r.json()
# get the specific data we want
timestamps = data_obj['chart']['result'][0]['timestamp']
close_prices = data_obj['chart']['result'][0]['indicators']['quote'][0]['close']
# clean out null's and 0s from the data
i = 0
while i < len(timestamps):
if close_prices[i] == None or close_prices[i] == 0:
del close_prices[i]
del timestamps[i]
i -= 1
i += 1
name = data_obj['chart']['result'][0]['meta']['longName']
data = {'timestamps': timestamps, 'prices': close_prices, 'name': name, 'error': False}
update_last_file(data)
# save data to file in case necessary
return data
# helper function to pull most recent chart data on failure
def pull_last_from_file():
fd = open('last_chart_data.json', 'r')
d = json.loads(fd.read())
fd.close()
return d
def update_last_file(data):
fd = open('last_chart_data.json', 'w')
fd.truncate(0)
fd.write(json.dumps(data))
fd.close()
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