Customizing Views
*****************

Flask-Security bootstraps your application with various views for
handling its configured features to get you up and running as quickly
as possible. However, you'll probably want to change the way these
views look to be more in line with your application's visual design.


Views
=====

Flask-Security is packaged with a default template for each view it
presents to a user. Templates are located within a subfolder named
"security". The following is a list of view templates:

* *security/forgot_password.html*

* *security/login_user.html*

* *security/register_user.html*

* *security/reset_password.html*

* *security/change_password.html*

* *security/send_confirmation.html*

* *security/send_login.html*

Overriding these templates is simple:

1. Create a folder named "security" within your application's
   templates folder

2. Create a template with the same name for the template you wish to
   override

You can also specify custom template file paths in the configuration.

Each template is passed a template context object that includes the
following, including the objects/values that are passed to the
template by the main Flask application context processor:

* "<template_name>_form": A form object for the view

* "security": The Flask-Security extension object

To add more values to the template context, you can specify a context
processor for all views or a specific view. For example:

   security = Security(app, user_datastore)

   # This processor is added to all templates
   @security.context_processor
   def security_context_processor():
       return dict(hello="world")

   # This processor is added to only the register view
   @security.register_context_processor
   def security_register_processor():
       return dict(something="else")

The following is a list of all the available context processor
decorators:

* "context_processor": All views

* "forgot_password_context_processor": Forgot password view

* "login_context_processor": Login view

* "register_context_processor": Register view

* "reset_password_context_processor": Reset password view

* "change_password_context_processor": Change password view

* "send_confirmation_context_processor": Send confirmation view

* "send_login_context_processor": Send login view


Forms
=====

All forms can be overridden. For each form used, you can specify a
replacement class. This allows you to add extra fields to the register
form or override validators:

   from flask_security.forms import RegisterForm

   class ExtendedRegisterForm(RegisterForm):
       first_name = StringField('First Name', [Required()])
       last_name = StringField('Last Name', [Required()])

   security = Security(app, user_datastore,
            register_form=ExtendedRegisterForm)

For the "register_form" and "confirm_register_form", each field is
passed to the user model (as kwargs) when a user is created. In the
above case, the "first_name" and "last_name" fields are passed
directly to the model, so the model should look like:

   class User(db.Model, UserMixin):
       id = db.Column(db.Integer, primary_key=True)
       email = db.Column(db.String(255), unique=True)
       password = db.Column(db.String(255))
       first_name = db.Column(db.String(255))
       last_name = db.Column(db.String(255))

The following is a list of all the available form overrides:

* "login_form": Login form

* "confirm_register_form": Confirmable register form

* "register_form": Register form

* "forgot_password_form": Forgot password form

* "reset_password_form": Reset password form

* "change_password_form": Change password form

* "send_confirmation_form": Send confirmation form

* "passwordless_login_form": Passwordless login form


Emails
======

Flask-Security is also packaged with a default template for each email
that it may send. Templates are located within the subfolder named
"security/email". The following is a list of email templates:

* *security/email/confirmation_instructions.html*

* *security/email/confirmation_instructions.txt*

* *security/email/login_instructions.html*

* *security/email/login_instructions.txt*

* *security/email/reset_instructions.html*

* *security/email/reset_instructions.txt*

* *security/email/reset_notice.html*

* *security/email/change_notice.txt*

* *security/email/change_notice.html*

* *security/email/reset_notice.txt*

* *security/email/welcome.html*

* *security/email/welcome.txt*

Overriding these templates is simple:

1. Create a folder named "security" within your application's
   templates folder

2. Create a folder named "email" within the "security" folder

3. Create a template with the same name for the template you wish to
   override

Each template is passed a template context object that includes values
for any links that are required in the email. If you require more
values in the templates, you can specify an email context processor
with the "mail_context_processor" decorator. For example:

   security = Security(app, user_datastore)

   # This processor is added to all emails
   @security.mail_context_processor
   def security_mail_processor():
       return dict(hello="world")


Emails with Celery
==================

Sometimes it makes sense to send emails via a task queue, such as
Celery. To delay the sending of emails, you can use the
"@security.send_mail_task" decorator like so:

   # Setup the task
   @celery.task
   def send_security_email(msg):
       # Use the Flask-Mail extension instance to send the incoming ``msg`` parameter
       # which is an instance of `flask_mail.Message`
       mail.send(msg)

   @security.send_mail_task
   def delay_security_email(msg):
       send_security_email.delay(msg)

If factory method is going to be used for initialization, use
"_SecurityState" object returned by "init_app" method to initialize
Celery tasks intead of using "security.send_mail_task" directly like
so:

   from flask import Flask
   from flask_mail import Mail
   from flask_security import Security, SQLAlchemyUserDatastore
   from celery import Celery

   mail = Mail()
   security = Security()
   celery = Celery()

   def create_app(config):
       """Initialize Flask instance."""

       app = Flask(__name__)
       app.config.from_object(config)

       @celery.task
       def send_flask_mail(msg):
           mail.send(msg)

       mail.init_app(app)
       datastore = SQLAlchemyUserDatastore(db, User, Role)
       security_ctx = security.init_app(app, datastore)

       # Flexible way for defining custom mail sending task.
       @security_ctx.send_mail_task
       def delay_flask_security_mail(msg):
           send_flask_mail.delay(msg)

       # A shortcurt.
       security_ctx.send_mail_task(send_flask_mail.delay)

       return app

Note that "flask_mail.Message" may not be serialized as an argument
passed to Celery. The practical way with custom serialization may look
like so:

   @celery.task
   def send_flask_mail(**kwargs):
           mail.send(Message(**kwargs))

   @security_ctx.send_mail_task
   def delay_flask_security_mail(msg):
       send_flask_mail.delay(subject=msg.subject, sender=msg.sender,
                             recipients=msg.recipients, body=msg.body,
                             html=msg.html)
