So I'm making a program where I need a user to log in or register. The registered account goes to a .txt file from which I'm supposed to read the data to log in again.
I managed to get the basics working. I can register a new account to the file and I can log in with every account I've created, but I can't seem to get 2 important elements working. The first one is for when the user inserts an inexistent username/ password (in this case the program just does nothing as I can't figure out a condition to make it go back to asking the username and password), and the second one is for when I insert a username and password that don't match. Here the program goes back and asks for them again but then keeps asking, even if I put them correctly.
Here's my function if anyone's interested in having a look at it:
def ent():
util = False
ppass = False
login = False
while not login:
n_util = input("Introduce your username: ")
password = input("Introduce your password: ")
with open("dadoscontas.txt", "r") as f:
while not util:
vski = 0
for line in f:
vski += 1
if vski == 1:
if line.strip() == n_util:
util = True
else:
break
if vski == 2:
if line.strip() == password and user:
ppass = True
if user and ppass:
login = True
print("Logged in")
I've spent my whole afternoon trying different things to see if I can get these 2 things to work, but I can't. As I said, the function above is the part that kinda works, and if anyone could give any suggestions / point me in the right direction it would be really helpful. Thank you in advance.
Does this code cover your needs?
def ent():
util = False
login = False
while not login:
n_util = input("Introduce your username: ")
password = input("Introduce your password: ")
with open("some_test.txt", "r") as f:
vski = 0
for line in f:
vski += 1
if vski%2:
if line.strip() == n_util:
util = True
elif util:
if line.strip() == password:
login = True
else:
util = False
print("Logged in")
Or you even could exit the function with return in if line.strip() == password: block.
But i would recommend you to store the file content to dictionaries (user_name:passwor),
because you are parsing the whole file again and again while login=False:
def ent():
login = False
name=""
my_data = {}
with open("some_test.txt", "r") as f:
index = 0
for line in f:
index += 1
if index%2:
name = line.strip()
else:
my_data[name] = line.strip()
while not login:
n_util = input("Introduce your username: ")
password = input("Introduce your password: ")
if n_util in my_data and my_data[n_util] == password:
login = True
print("Logged in")
If you use python2 you can use .get() or try instead of n_util in my_data for better performance.
Related
import json
def write_json(data, file='users.json'):
with open(file, 'w') as f:
json.dump(data, f, indent=4)
while True:
user = {'name':[], 'password':[]}
choice = int(input('1) Register, 2) Login\n>> '))
if choice == 1:
username = input('Enter username: ')
password = input('Enter password: ')
user['name'] = username
user['password'] = password
print('Registered successfully')
with open('users.json') as json_file:
data = json.load(json_file)
users = data['users']
for user in users:
if user['name'] == username:
print(f'User "{username}" already exists')
break
new_user = user
users.append(new_user)
write_json(data)
if choice == 2:
username = input('Enter username: ')
password = input('Enter password: ')
with open('users.json', 'r') as f:
data = json.load(f)
for user in data['users']:
if user['name'] == username and user['password'] == password:
print('Logged in succesfully')
I am trying to make a simple login/register system, but when the user registers for the 2nd time, its gets overridden by the 1st key/value every time, I tried user.clear() but it doesnt seem to have an effect
The issue is that you are using a single dict item for all your users. The way you've set it up only allows for one user to exist.
You need to restructure your dict. You could do a list of dict items, but I would suggest using the username as the key in your dict. Since usernames are supposed to be unique, this makes sense IMHO.
In case you want to use the simpler list of dict items metioned above, you would structure it as follows:
[
{'Edo': 'mypassword'},
{'Iso': 'yourpassword'}
]
I've added some comments on the adjusted code below...
import json
def write_json(data, file="users.json"):
with open(file, "w") as outfile:
json.dump(data, outfile, indent=4)
def load_json(file="users.json"):
# try block in case file doesn't exist
try:
with open(file) as infile:
result = json.load(infile)
return result
except Exception as e:
# just printing out the error
print(e)
# should only be file not found error
# returning an empty dict
return {}
while True:
# you need to load before actually doing anything.
# if you don't you might overwrite the file
userlist = load_json()
# newlines for each option
choice = int(input("1) Register\n2) Login\n>> "))
if choice == 1:
username = input("Enter username: ")
# check if user already exists before requesting password
# since usernames are supposed to be unique, you can just
# create a dict with the key being username.
# you could use the value directly for password, but
# if you need to store more values for a user, I advice
# you use another dict as the value.
if username in userlist:
print(f"User {username} already exists")
# do some other magic here to handle this scenario
# continue makes the while loop go to the next iteration
continue
password = input("Enter password: ")
userlist[username] = {"password": password, "someotheruserdate": "dunno?"}
write_json(userlist)
# only print the success **after** you've actually
# completed all relevant logic.
print("Registered successfully")
# change this to elif instead of a second if statement
elif choice == 2:
username = input("Enter username: ")
password = input("Enter password: ")
if username in userlist and userlist[username]["password"] == password:
print("Logged in succesfully")
else:
# handle wrong username/password
# here you need to check after getting both username&password
print("Incorrect username/password combination")
I have some code that makes a login system that retrieves the accounts from a text file. The account format goes like this: Username:Password:ID, (1 is admin anything else is guest)
my current list:
Admin:Admin!:1
Guest:Password:0
test:test:0
but for some strange reason if I write in the admin credentials it lets me in but anything else fails here is my code:
import sys
username = raw_input("Username: ")
password = raw_input("Password: ")
createLogin = file("login.txt", "a")
with open("login.txt", "r") as login:
lines = login.readlines()
while True:
for line in lines:
if line.split(":")[0] == username and line.split(":")[1] == password:
print("Welcome back %s" % (username))
while True:
message = raw_input("")
else:
sys.exit()
I would appreciate it if someone could modify or tell me what to add to the code. Thanks.
So your issue is that you check the first line of the 'login.txt' file, and exit if it doesn't match. You could do something like this:
for line in lines:
if line.split(":")[0] == username and line.split(":")[1] == password:
print("Welcome back %s" % (username))
while True:
message = raw_input("")
else:
sys.exit()
By moving the else one indent back, you create a for/else loop, which will run the else code if no lines in the file matched.
I am trying to make a login system that is looped basically and whenever I try to enter the correct details that are even stored in the .csv file, it outputs as incorrect username/password no matter what I put. This code works for python 3.6 but I need it to work for python 3.2.3.
loop1 = False #for this bit of code (logging in)
loop2 = False #for next bit of code
while loop1 == False:
choice = input("Login/SignUp [TYPE 'L' OR 'S']: ").lower()
if choice == "l":
username = input("Username: ")
password = input("Password: ")
f = open("usernamepassword.csv","r")
for line in f:
details = line.split(",")
if username == details[0] and password == details[1]:
print("Welcome")
break
#this whole bit of code is meant to read from the csv and check if the login details are correct
else:
print("Username/Password [INCORRECT]")
Allow me to refactor your code:
def login(username, password):
with open("usernamepassword.csv", "r") as csv:
all_details =
[[attr.strip() for attr in line.split(",")]
for line in csv]
return any(
username == details[0]
and password == details[1]
for details in all_details)
def login_action():
username = input("Username: ")
password = input("Password: ")
if not login(username, password):
raise ValueError("Username/Password [INCORRECT]")
return True
_USER_ACTIONS = {
'l': login_action
}
def main():
while True:
choice = input("Login/SignUp [TYPE 'L' or 'S']: ").lower()
action = _USER_ACTIONS[choice]
try:
if action():
break
except Exception as err:
print(err.message)
I think your unexpected behavior comes from not stripping the values you get after splitting by ,
Solved by replacing:
if username == details[0] and password == details[1]:
With:
if username == details[0] and (password+"\n") == details[1]:
You may have a bug in line.split(','), try line.strip().split(',')
TL; DR: posted a proper solution there : https://github.com/cgte/stackoverflow-issues/tree/master/47207293-csv-dict
I'll stuff up my answer later if needed.
Furthermore you have a poor code design here, and find yourself debugging in the middle of a loop.
So first of all : load the data file, store content to a dict.
f = open("usernamepassword.csv","r")
for line in f:
details = line.split(",")
if username == details[0] and password == details[1]:
print("Welcome")
break
Should become
user_pass = {}
f = open("usernamepassword.csv","r")
for line in f:
user, password = line.strip().split(",")
user_pass[user] = password
f.close()
or better
with open("usernamepassword.csv","r") as f:
for line in f.readlines():
user, password = line.split().split(",")
user_pass[user] = password
eventually run python -i yourfile.py and type "user_pass" to see what is actually stored when correct go on further code.
Think of using the csv module : https://docs.python.org/3/library/csv.html
Then get username and password from input and check:
if login in user_pass and user_pass[login] = password:
# or better `if user_pass.get(login, None) == password:`
do_stuff()
import csv
def login():
global student
student = []
file = open("student.csv","r")
data = csv.reader(file)
UsernameVerified = False
PasswordVerified = False
while UsernameVerified == False:
username = input("Username: ")
for row in data:
user = []
student.append(row)
print(UsernameVerified)
for multi in row[5:6]:
if username in multi:
print("found")
UsernameVerified = True
print(UsernameVerified)
This is the current code I am using. However when I run this code and put in the correct user name, it finds the user 3 times which it shouldn't be doing.
Also when I put in the wrong user then the right user, it cannot find the user at all.
I am doing this for a school project and have had 2 teachers look into this, so far no progress was made.
Output when I input the correct User first
Output when I input the wrong User first, then the Correct one
New code
——————
import csv
def login():
global student
student = []
UsernameVerified = False
PasswordVerified = False
while UsernameVerified == False:
file = open("student.csv","r")
data = csv.reader(file)
username = input("Username: ")
for row in data:
user = []
student.append(row)
print(UsernameVerified)
for user in row[5:6]:
if username in user:
print("found")
UsernameVerified = True
print(UsernameVerified)
while PasswordVerified == False:
file = open("student.csv","r")
data = csv.reader(file)
password = input("Password: ")
for row in data:
user = []
student.append(row)
print(PasswordVerified)
for pass1 in row[4:5]:
if password in pass1:
print("found")
PasswordVerified = True
print(PasswordVerified)
For the first question: it returns 3 times because the while loop only stops and the end of for loop. if you want a quick fix use "break" inside for loop when you log in the user
For the second question that happens because "data" variable is pointed to the end of file. Basically you open the file, read it until the end when you enter the wrong user, and it stays there. try opening the file only after the "input" using a "with" statement
I'm writing a program that will verify a username:
def user_login():
""" Login and create a username, maybe """
with open('username.txt', 'r') as f:
if f.readline() is "":
username = raw_input("First login, enter a username to use: ")
with open('username.txt', 'a+') as user:
user.write(username)
else:
login_id = raw_input("Enter username: ")
if login_id == str(f.readline()):
return True
else:
print "Invalid username."
return False
if __name__ == '__main__':
if user_login() is not True:
print "Failed to verify"
Everytime I run this it outputs the following:
Enter username: tperkins91
Invalid username.
Failed to verify
How do I compare user input to reading from a file?
Opening the same file again in another nested context is not a good idea. Instead, open the file once in append mode, and use f.seek(0) to return to the start whenever you need to:
def user_login():
""" Login and create a username, maybe """
with open('username.txt', 'a+') as f:
if f.readline() is "":
username = raw_input("First login, enter a username to use: ")
f.seek(0)
f.write(username)
# return True/False --> make the function return a bool in this branch
else:
login_id = raw_input("Enter username: ")
f.seek(0)
if login_id == f.readline():
return True
else:
print "Invalid username."
return False
if __name__ == '__main__':
if user_login() is not True:
print "Failed to verify"
Returning a bool value in the if branch is something you may want to consider so the return type of your function is consistent as bool, and not None as in the current case.
When you use readline() the first time the current file position is moved past the first record. A better way to find if the file is empty is to test it's size:
import os.path
import sys
def user_login():
fname = 'username.txt'
""" Login and create a username, maybe """
if os.path.getsize(fname) == 0:
with open(fname, 'w') as f:
username = raw_input("First login, enter a username to use: ")
f.write(username)
return True #/False --> make the function return a bool in this branch
else:
with open(fname, 'r') as f:
login_id = raw_input("Enter username: ")
if login_id == f.readline().rstrip():
return True
else:
print >>sys.stderr, "Invalid username."
return False
if __name__ == '__main__':
if user_login() is not True:
print "Failed to verify"
f.readline() will include a trailing newline, if there is one in the file, whereas raw_input() will not. While we don't explicitly write one, someone might edit the file and add a newline unintentionally, hence the addition of the rstrip() as a defensive precaution.