unable to use session variables outside view function - flask

Question

I have login page where the user inputs the username and password. I have made the username as session variable in the /login view function and would like to use this variable outside the view function in the main body of the code in a if-else block.
session['username'] = request.form['username'].lower()
How do I do this?
Here is part of the code for this:
import os
import csv
import pymysql
import pymysql.cursors
from datetime import date
import calendar
import ssl
from ldap3 import Connection, Server, ANONYMOUS, SIMPLE, SYNC, ASYNC,ALL
from flask import Flask, make_response,render_template,url_for,redirect,request,session,escape
from validusers import users
app = Flask(__name__)
IT = pymysql.connect(host='xx.xx.xx.xx', user='xxxxx', password='xxxxx',
db='xxxx')#Connect to the IT database
Others = pymysql.connect(host='xxxxx', user='xxxxxx', password='xxxxxx',
db='xxxxx')#Connect to the non IT database
a=IT.cursor() # Open Cursor for IT database
b=Others.cursor()#Open Cursor for non-IT database
**#app.route('/')
#app.route('/login',methods=['GET', 'POST'])
def login():
error=None
if request.method =='POST':
#if not request.form['username']:
#error='You forgot to enter "Username", please try again'
#return render_template('login.html',error=error)
if request.form['username'].lower() not in users:
error='You are not authorized to view this page !!'
return render_template('login.html',error=error)
#if not request.form['password']:
#error='You forgot to enter "Password", please try again'
#return render_template('login.html',error=error)
#else:
#s = Server('appauth.corp.domain.com:636', use_ssl=True, get_info=ALL)
#c = Connection(s,user=request.form['username'],password=request.form['password'],check_names=True, lazy=False,raise_exceptions=False)
#c.open()
#c.bind()
#if (c.bind() != True) is True:
#error='Invalid credentials. Please try again'
#else:
#session['username'] = request.form['username'].lower()
#return redirect(url_for('index'))
return render_template('login.html',error=error)**
#app.route('/index',methods=['GET','POST'])
def index():
if 'username' in session:
return render_template('index.html')
Filename = os.getenv("HOMEDRIVE") + os.getenv("HOMEPATH") + "\\Desktop\RosterUnified.csv" # Create/write a CSV file in the user's desktop
Filename1=os.getenv("HOMEDRIVE") + os.getenv("HOMEPATH") + "\\Desktop\RosterCurrentMonth.csv"
d=open(Filename, 'w',newline='\n') #Format for CSV input
c = csv.writer(d)
c.writerow(["Manager NT ID"," Vertical Org","Employee ID" ]+ dayssl)# Write the header list of strings in the first row
for row in result_IT:
c.writerow(row)#Write output for IT to csv
d.close()
#result_IT and result_Oters part of code is ommitted
e=open(Filename, 'a',newline='\n')
f= csv.writer(e)
for row in result_Others:
f.writerow(row)# Append to the existing CSV file with non IT data
e.close()
x=session['username']
sql="select verticalorg from tbl_employeedetails where empntid=(%s)"
args=x
a.execute(sql,args)
b.execute(sql,args)
c=a.fetchall()
d1=b.fetchall()
s=c+d1
q=[x[0] for x in s]
sql1="select role from tbl_employeedetails where empntid=(%s)"
a.execute(sql1,args)
b.execute(sql1,args)
c1=a.fetchall()
d2=b.fetchall()
Role=c1+d2
r=[x[0] for x in Role]
if r=='O':
if q==27:
f1=open(Filename,'r',newline='\n')
f2=open(Filename1,'w',newline='\n')
reader = csv.DictReader(f1)
writer = csv.writer(f2)
writer.writerow(["Manager NT ID"," Vertical Org","Employee ID" ]+ dayssl)
rows = [row for row in reader if row['Vertical Org'] == 'HR']
writer.writerow[row in rows]
elif q==2:
f1=open(Filename,'r',newline='\n')
f2=open(Filename1,'w',newline='\n')
reader = csv.DictReader(f1)
writer = csv.writer(f2)
writer.writerow(["Manager NT ID"," Vertical Org","Employee ID" ]+ dayssl)
f2.close()
z=open(Filename1)
with z as f:
p = f.read()
else:
z=open(Filename)
with z as f:
p = f.read()
#app.route('/csv/')
def download_csv():
csv = p
response = make_response(csv)
cd = 'attachment; filename=RosterCurrentMonth.csv'
response.headers['Content-Disposition'] = cd
response.mimetype='text/csv'
return response
z.close()
os.remove(Filename)
#app.route('/logout')
def logout():
# remove the username from the session if it's there
session.pop('username', None)
return redirect(url_for('login'))
app.secret_key ='secret key generated'
if __name__=='__main__':
context=('RosterWeb.crt','RosterWeb.key')
app.run(ssl_context=context, threaded=True, debug=True)
getting the error:
Traceback (most recent call last):
File "roster.py", line 175, in <module>
x=session['username']
File "C:\Users\dasa17\Envs\r_web\lib\site-packages\werkzeug\local.py", line 37
3, in <lambda>
__getitem__ = lambda x, i: x._get_current_object()[i]
File "C:\Users\dasa17\Envs\r_web\lib\site-packages\werkzeug\local.py", line 30
2, in _get_current_object
return self.__local()
File "C:\Users\dasa17\Envs\r_web\lib\site-packages\flask\globals.py", line 37,
in _lookup_req_object
raise RuntimeError(_request_ctx_err_msg)
RuntimeError: Working outside of request context.
This typically means that you attempted to use functionality that needed
an active HTTP request. Consult the documentation on testing for
information about how to avoid this problem.

Answer 1

You need to place the code you want to run before any routing is done in a function and use the before_first_request decorator on it. It will be executed before your first request is done and you can make use of your session variable from there.
#app.route('/')
def index():
# ... index route here ...
pass
#app.before_first_request
def init_app():
# ... do some preparation here ...
session['username'] = 'me'