[Python] Flask Waitress Webapp

PS C:\Users\****\OneDrive\Projects> python appv2.0.py
python : ERROR:appv2.0:Exception on / [POST]
At line:1 char:1
+ python appv2.0.py
+ ~~~~~~~~~~~~~~~~~
+ CategoryInfo : NotSpecified: (ERROR:appv2.0:Exception on / [POST]:String) [], RemoteException
+ FullyQualifiedErrorId : NativeCommandError

Traceback (most recent call last):
File "C:\Users\****\AppData\Local\Programs\Python\Python37\lib\site-packages\flask\app.py", line 2525, in wsgi_app
response = self.full_dispatch_request()
File "C:\Users\****\AppData\Local\Programs\Python\Python37\lib\site-packages\flask\app.py", line 1823, in full_dispatch_request
return self.finalize_request(rv)
File "C:\Users\****\AppData\Local\Programs\Python\Python37\lib\site-packages\flask\app.py", line 1842, in finalize_request
response = self.make_response(rv)
File "C:\Users\****\AppData\Local\Programs\Python\Python37\lib\site-packages\flask\app.py", line 2135, in make_response
f"The view function for {request.endpoint!r} did not"
TypeError: The view function for 'json' did not return a valid response. The function either returned None or ended without a return statement.
ERROR:appv2.0:Exception on / [POST]


# import main Flask class and request object
from flask import Flask, request
from waitress import serve
import os
import json as jsons

# create the Flask app
app = Flask(__name__)

def log(mode, d):
os.chdir("C:/Users/****/Desktop")
if mode == "o":
with open('Trend.txt', 'r+') as f:
firstLine = f.readline().rstrip('\r\n')
flDict = jsons.loads(firstLine)
if d["t"] != flDict["t"]:
ds = "{'sym': '" + d['sym'] + "', 't': '" + d['t'] + "', 'i': " + str(d['i']) + ", 'tt': " + str(d['tt']) + ", 'tc': " + str(d['tc']) + "}"
ds = ds.replace("'", '"')
f.seek(0, 0)
f.write(ds.rstrip('\r\n') + '\n' + firstLine)
f.truncate()
with open('Alert.txt', 'r+') as f:
firstLine = f.readline().rstrip('\r\n')
flDict = jsons.loads(firstLine)
if d["t"] != flDict["t"]:
d = str(d)
d = d.replace("'", '"')
f.seek(0, 0)
f.write(d.rstrip('\r\n'))
f.truncate()
with open('Alert_History.txt', 'r+') as f:
content = f.read()
f.seek(0, 0)
f.write(firstLine + '\n' + content)

elif mode == "t":
with open('Trend.txt', 'r+') as f:
firstLine = f.readline().rstrip('\r\n')
flDict = jsons.loads(firstLine)
if d["t"] != flDict["t"]:
d = str(d)
d = d.replace("'", '"')
f.seek(0, 0)
f.write(d.rstrip('\r\n') + '\n' + firstLine)
f.truncate()
elif mode == "m":
with open('MACD.txt', 'r+') as f:
firstLine = f.readline().rstrip('\r\n')
flDict = jsons.loads(firstLine)
if d["t"] != flDict["t"]:
d = str(d)
d = d.replace("'", '"')
f.seek(0, 0)
f.write(d.rstrip('\r\n') + '\n' + firstLine)
f.truncate()
elif mode == "ham":
with open('HA-MACD.txt', 'r+') as f:
firstLine = f.readline().rstrip('\r\n')
flDict = jsons.loads(firstLine)
if d["t"] != flDict["t"]:
d = str(d)
d = d.replace("'", '"')
f.seek(0, 0)
f.write(d.rstrip('\r\n') + '\n' + firstLine)
f.truncate()
elif mode == "rza":
with open('RZ-Alert.txt', 'r+') as f:
firstLine = f.readline().rstrip('\r\n')
flDict = jsons.loads(firstLine)
if d["t"] != flDict["t"]:
d = str(d)
d = d.replace("'", '"')
f.seek(0, 0)
f.write(d.rstrip('\r\n') + '\n' + firstLine)
f.truncate()

@app.route('/', methods=['POST'])
def json():
request_data = request.get_json()
print(request_data)
if request_data["ty"] == "o":
log("o", request_data["d"])

ticker = request_data["d"]["sym"]
time = request_data["d"]["t"]
interval = request_data["d"]["i"]
buy = request_data["d"]["b"]
sell = request_data["d"]["s"]
strong_buy = request_data["d"]["sb"]
strong_sell = request_data["d"]["ss"]

return "{}, {}, interval: {}, buy: {}, sell: {}, strong buy: {}, strong sell: {}.".format(ticker, time, interval, buy, sell, strong_buy, strong_sell)
elif request_data["ty"] == "t":
log("t", request_data["d"])

ticker = request_data["d"]["sym"]
time = request_data["d"]["t"]
interval = request_data["d"]["i"]
trend_tracer = request_data["d"]["tt"]
trend_catcher = request_data["d"]["tc"]

return "{}, {}, interval: {}, trend tracer: {}, trend catcher: {}.".format(ticker, time, interval, trend_tracer, trend_catcher)
elif request_data["ty"] == "m":
log("m", request_data["d"])

ticker = request_data["d"]["sym"]
time = request_data["d"]["t"]
interval = request_data["d"]["i"]
histogram = request_data["d"]["h"]
umacd = request_data["d"]["m"]
signal = request_data["d"]["s"]

return "{}, {}, interval: {}, histogram: {}, umacd: {}, signal: {}.".format(ticker, time, interval, histogram, umacd, signal)
elif request_data["ty"] == "ham":
log("ham", request_data["d"])

ticker = request_data["d"]["sym"]
time = request_data["d"]["t"]
interval = request_data["d"]["i"]
histogram = request_data["d"]["h"]
umacd = request_data["d"]["m"]
signal = request_data["d"]["s"]

return "{}, {}, interval: {}, histogram: {}, umacd: {}, signal: {}.".format(ticker, time, interval, histogram, umacd, signal)
elif request_data["ty"] == "rza":
log("rza", request_data["d"])

ticker = request_data["d"]["sym"]
time = request_data["d"]["t"]
interval = request_data["d"]["i"]
buy = request_data["d"]["b"]
sell = request_data["d"]["s"]

return "{}, {}, interval: {}, buy: {}, sell: {}.".format(ticker, time, interval, buy, sell)

#if __name__ == '__main__':
# run app in debug mode on port 8080
#app.run(debug=True, port=8080)

serve(app, host='127.0.0.1', port=8080, threads=2)


I attempted to execute the code via Powershell and this is the error I was given. Please help me figure this one out. I built a webapp using flask and waitress in 2023 and it has been a while since I have updated. It could be a matter of updating some package dependencies but I am not sure. I am a bit rusty with my coding so please excuse me if I am not up to date.

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