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What i want to do is just display the firstevent from one API. The variable is called “firstevent” and the value should display on the webpage. But firstevent is inside a def, so i change it into a global variable and hope it can be used across different functions. But it shows “NameError: global name 'firstevent' is not defined”. This is what I am doing:

define a global variable 

global firstevent

send this variable a random value, it supposed to be events['items'][1]['end']

firstevent = 1

displaying firstevent’s value on website. 

@app.route("/")
def index():
    return 'User %s' % firstevent

I am not sure what’s happening now, maybe it’s a scope issue? I have check many answers online but still cannot find the solution.

Here are the details(not the whole code)

import os

# Retrieve Flask, our framework
# request module gives access to incoming request data
import argparse
import httplib2
import os
import sys
import json

from flask import Flask, request
from apiclient import discovery
from oauth2client import file
from oauth2client import client
from oauth2client import tools

from apiclient.discovery import build
from oauth2client.client import OAuth2WebServerFlow

import httplib2

global firstevent  
app = Flask(__name__)

def main(argv):
  # Parse the command-line flags.
  flags = parser.parse_args(argv[1:])

  # If the credentials don't exist or are invalid run through the native client
  # flow. The Storage object will ensure that if successful the good
  # credentials will get written back to the file.
  storage = file.Storage('sample.dat')
  credentials = storage.get()
  if credentials is None or credentials.invalid:
    credentials = tools.run_flow(FLOW, storage, flags)

  # Create an httplib2.Http object to handle our HTTP requests and authorize it
  # with our good Credentials.
  http = httplib2.Http()
  http = credentials.authorize(http)

  # Construct the service object for the interacting with the Calendar API.
  calendar = discovery.build('calendar', 'v3', http=http)
  created_event = calendar.events().quickAdd(calendarId='XXXX@gmail.com', text='Appointment at Somewhere on June 3rd 10am-10:25am').execute()
  events = calendar.events().list(calendarId='XXXX@gmail.com').execute()
  #firstevent = events['items'][1]['end']

  firstevent = 1
  #print events['items'][1]['end']

 # Main Page Route
@app.route("/")
def index():
    return 'User %s' % firstevent


# Second Page Route
@app.route("/page2")
def page2():
  return """<html><body>
  <h2>Welcome to page 2</h2>
    <p>This is just amazing!</p>
    </body></html>"""


# start the webserver
if __name__ == "__main__":
    app.debug = True
    app.run()
user2592038
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  • Keep in mind that global variables in this context are not process safe. See https://stackoverflow.com/a/32825482/4108726 – frainfreeze Apr 05 '21 at 17:01

1 Answers1

29

Yep, it's a scope problem. In the beginning of your main() function, add this:

global firstevent

That should done it. Any variable that is not defined inside a function, is a global. You can access it straightly from any function. However, to modify the variable you'll need to write global var in your function.

Example

This creates a local variable "firstevent" on the function:

firstevent = 0
def modify():
    firstevent = 1

And this modifies the global variable 'firstevent'

firstevent = 0
def modify():
    global firstevent
    firstevent = 1
aIKid
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