What can cause MultiValueDictKeyError in Django?

Question

i almost finished my register form, but something went wrong and i totally don't know what. It is a little difficult to describe but i will try.

So, as you can see here is login form:

login.html

 <h1>login page</h1>


 <table>
        <tr><a href="register.html">return to register page</a><br> </tr>
        <tr><a href="index.html">return to home page</a> </tr>
    </table>
<br>
<div>
        <form method="post">
            {% csrf_token %}
            <div>
                <div><label>Login/Email </label><input type="text" name="login_name" placeholder="Login/Email"></div>
                <div><label>Password </label><input type="password" name="login_password" placeholder="enter password"></div>
                <div><input type="submit" value="Login"></div>
            </div>
        </form>
    </div>

and here is register form: register.html

<h1>Register page</h1>
    <table>
        <tr><a href="login.html">return to login page</a> <br></tr>
        <tr><a href="index.html">return to home page</a> </tr>
    </table>
    <br>
<div>
        <form method="POST">
            {% csrf_token %}
            <div>
                <div><label>Name </label><input type="text" name="registerFrom_name" placeholder="Enter the name"></div>
                <div><label>Surname </label><input type="text" name="registerFrom_surname" placeholder="Enter the surname"></div>
                <div><label>Login/Email </label><input type="text" name="registerFrom_login" placeholder="Login/Email"></div>
                <div><label>Password </label><input type="registerForm_password" name="registerFrom_password" placeholder="Enter password"></div>
                <div><label>Email  </label><input type="text" name="registerForm_email"></div>
                <div><input type="submit" value="Register"> </div>
            </div>
        </form>
    </div>

Bellow my own backend to handle froms:

view.html

# BACKEND

from django.shortcuts import render
from django.views import View
from . import ValidateUser, RegisterUser

# Create your views here.

CSRF_COOKIE_SECURE = True


class WebServiceView(View):


    # INDEX - MAIN PAGE
    def indexPage(self, request):
        return render(request, "index.html")

    def register(self, request):

        res = RegisterUser.RegisterUser("user", "user", "login", "test", "emai@email")
        res.createUser()

        return render(request, "register.html")

    def login(self, request):
        print("Login function")
        res = ValidateUser.ValidateUser('/config/dbConfig.ini', '127.0.0.1') # Connection to mysql database
        formParametr = request.POST

        print(formParametr)
        login = formParametr['register_name']
        password = formParametr['register_password']

        res.checkUser(login, password.encode("utf8"))

        return render(request, "login.html")

Problem rise when i first open register.html and then i will go to the login.html page. Django throw MultiValueDictKeyError at /shop/login.html. I completely don't understand why. As you can see, a key "name" has 'register_name' already. So what can cause problem ?

Below Full error:

'register_name'

Request Method:     GET
Request URL:    http://127.0.0.1:8000/shop/login.html
Django Version:     2.2.5
Exception Type:     MultiValueDictKeyError
Exception Value:    

'register_name'

Exception Location:     /usr/local/lib/python3.7/dist-packages/django/utils/datastructures.py in __getitem__, line 80
Python Executable:  /usr/bin/python3.7
Python Version:     3.7.4
Python Path:    

['/home/reg3x/PycharmProjects/lovLevelMusic',
 '/usr/lib/python37.zip',
 '/usr/lib/python3.7',
 '/usr/lib/python3.7/lib-dynload',
 '/usr/local/lib/python3.7/dist-packages',
 '/usr/lib/python3/dist-packages',
 '/usr/lib/python3.7/dist-packages']

Answer 1

It's a KeyError. It's telling you that you don't have a key for register_name in your POST dictionary. And that's because you used login_name in the template.

Really, you should be using Django forms for this, which would a) take care of outputting the fields in the template with the correct names and b) ensure the data was valid and fully populated before you accessed it in the view.

(There are other things in your code that make me very concerned as well. Why have you got login and register methods within a view class? That's not how class-based views work. And why is your URL ending in .html? That's not how Django URLs work. And, most importantly, what is ValidateUser and RegisterUser? Why are you connecting to your database explicitly in each view? Why do you have those classes? That is not how you work with the database in Django. Why are you doing any of this?)