flask routes not playing well with bootstrap modal forms, generating form undefined error

Question

When testing the "failed login" error message portion of my page I constantly get a form undefined jinja error. I'm very new to coding with Python/Flask and using bootstrap modals and forms so I'm sure it's something simple I am over looking. Because I am using modals, I needed to add the commands to each page route in the python code and I feel like the error is in the nested If's I'm using there.

I've tried moving the Flask code around so that the Login portion runs first but no matter what I try I get the same error. I am able to login with known, good username/passwords and I can register new usernames with no problem. I apologize if this too much information, I've not posted here before but I have used SO frequently for troubleshooting so I have a good feeling the community here can spot what I'm doing wrong.

Here is the Python

#Define routes
@app.route('/home', methods=['GET', 'POST'])
def index():
    #Allow registry from page
    form = RegisterForm(request.form)
    if request.method == 'POST' and form.validate():
        name = form.name.data
        email = form.email.data
        username = form.username.data
        password = sha256_crypt.encrypt(str(form.password.data))

        # Execute query
        engine.execute("INSERT INTO users(name, email, username, password) VALUES(?, ?, ?, ?)", (name, email, username, password))
        # Changes Auto Commit so there is no need for opening a session or running a commit line.

        flash('You are now registered and can log in', 'success')

        return redirect(url_for('index'))
    else:
         #Allow login from page
        if request.method == 'POST':
            # Get Form Fields
            username = request.form['username']
            password_candidate = request.form['password']
            # Get user by username
            result = engine.execute("SELECT Username, Password FROM users WHERE username = ?", [username])

            # Get stored hash
            data = result.fetchone()
            if data is None:
                error = 'Username not found'
                return render_template('home.html', error=error)

            password = data['Password']

            # Compare Passwords
            if sha256_crypt.verify(password_candidate, password):
                # Passed
                session['logged_in'] = True
                session['username'] = username

                flash('You are now logged in', 'success')

                return redirect(url_for('dashboard'))
            else:
                error = 'Invalid login'
            return render_template('home.html', error=error)
    return render_template('home.html', form=form)

Here is the HTML



    
  
    {% if session.logged_in %}
    
      
        
           Home (current)
        
        
           About Us
        
        
           Articles
        
        
          
            Dropdown
          
          
            Action
            Another action
            
            Something else here
          
        
      
      {% else %}
      
          
            
               Home (current)
            
            
               About Us
            
          
      {% endif %}
      
      {% if session.logged_in %}
      
     
           Dashboard 
      

      
  
       Logout 
      
      
        
          
            
              Log out?
              
            
            
              Are you sure you want to logout?
            
            
              
              
            
          
        
      
    
    
      
      
    
  

        {% else %}
        
        
        
          
          
            
              
                
                  Let's get registered!
                  
                
                
                    Register
                    {% from "includes/_formhelpers.html" import render_field %}
                    
                      
                        {{render_field(form.name, class_="form-control")}}
                      
                      
                        {{render_field(form.email, class_="form-control")}}
                      
                      
                        {{render_field(form.username, class_="form-control")}}
                      
                      
                        {{render_field(form.password, class_="form-control")}}
                        Your Password is required to be 6 characters long, a strong password is suggested. Please see the example below
                        Ex: Th1s1s@cceptabl3!
                      
                      
                        {{render_field(form.confirm, class_="form-control")}}
                      
                      
                      
                    
                
                
                     Already a member?   Sign in here!
              
            
          

        

          
          
            
            
              
                
                  
                    Ready to log in?
                    
                  
                  
                      
                          
                            Username
                            
                          
                          
                            Password
                            
                          
                          
                          
                        
                  
                  
                     Not a member?   Sign up here!
                  
                
              
            
          
      {% endif %}

And here is the error I get:

jinja2.exceptions.UndefinedError
jinja2.exceptions.UndefinedError: 'form' is undefined

Traceback (most recent call last)
File "C:\ProgramData\CooperConda\lib\site-packages\flask\app.py", line 2463, in __call__
return self.wsgi_app(environ, start_response)
File "C:\ProgramData\CooperConda\lib\site-packages\flask\app.py", line 2449, in wsgi_app
response = self.handle_exception(e)
File "C:\ProgramData\CooperConda\lib\site-packages\flask\app.py", line 1866, in handle_exception
reraise(exc_type, exc_value, tb)
File "C:\ProgramData\CooperConda\lib\site-packages\flask\_compat.py", line 39, in reraise
raise value
File "C:\ProgramData\CooperConda\lib\site-packages\flask\app.py", line 2446, in wsgi_app
response = self.full_dispatch_request()
File "C:\ProgramData\CooperConda\lib\site-packages\flask\app.py", line 1951, in full_dispatch_request
rv = self.handle_user_exception(e)
File "C:\ProgramData\CooperConda\lib\site-packages\flask\app.py", line 1820, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "C:\ProgramData\CooperConda\lib\site-packages\flask\_compat.py", line 39, in reraise
raise value
File "C:\ProgramData\CooperConda\lib\site-packages\flask\app.py", line 1949, in full_dispatch_request
rv = self.dispatch_request()
File "C:\ProgramData\CooperConda\lib\site-packages\flask\app.py", line 1935, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "C:\Users	lquickl\devel\MyFlaskApp\app.py", line 61, in index
return render_template('home.html', error=error)
File "C:\ProgramData\CooperConda\lib\site-packages\flask	emplating.py", line 140, in render_template
ctx.app,
File "C:\ProgramData\CooperConda\lib\site-packages\flask	emplating.py", line 120, in _render
rv = template.render(context)
File "C:\ProgramData\CooperConda\lib\site-packages\jinja2\asyncsupport.py", line 76, in render
return original_render(self, *args, **kwargs)
File "C:\ProgramData\CooperConda\lib\site-packages\jinja2\environment.py", line 1008, in render
return self.environment.handle_exception(exc_info, True)
File "C:\ProgramData\CooperConda\lib\site-packages\jinja2\environment.py", line 780, in handle_exception
reraise(exc_type, exc_value, tb)
File "C:\ProgramData\CooperConda\lib\site-packages\jinja2\_compat.py", line 37, in reraise
raise value.with_traceback(tb)
File "C:\Users	lquickl\devel\MyFlaskApp	emplates\home.html", line 1, in top-level template code
{% extends 'layout.html' %}

{% block body %}
  
    
        Welcome to My FlaskApp
File "C:\Users	lquickl\devel\MyFlaskApp	emplates\layout.html", line 23, in top-level template code

    

    {% include 'includes/_navbar.html' %}
    
        {% include 'includes/_messages.html' %}
        {% block body %}{% endblock %}

Terry Quickle · Accepted Answer

Big thanks to NemoMeMeliorEst!

I changed my code to the below and now it's working! (Minus the **, added those for emphasis to change)

 # Get stored hash
            data = result.fetchone()
            if data is None:
                error = 'Username not found'
                return render_template('home.html', error=error, ***form=form***)
            password = data['Password']
            # Compare Passwords
            if sha256_crypt.verify(password_candidate, password):
                # Passed
                session['logged_in'] = True
                session['username'] = username
                flash('You are now logged in', 'success')
                return redirect(url_for('dashboard'))
            else:
                error = 'Invalid login'
            return render_template('home.html', error=error, ***form=form***)
    return render_template('home.html', form=form)

flask routes not playing well with bootstrap modal forms, generating form undefined error

Answers (1)

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