The Authorization System

weppy includes an useful authorization system, based on the once available on web2py, which automatically creates required database tables, and generate forms to add access control in your application writing just a few lines.

So how do you use it? Let's find out with an example:

from weppy import App, DAL
from import Auth
from weppy.sessions import SessionCookieManager

app = App(__name__)
app.config.db.uri = "sqlite://storage.sqlite"

db = DAL(app)
auth = Auth(app, db)

app.common_handlers = [

def account(f, k):
    form = auth(f, k)
    return dict(form=form)

That's it. Write a template page for the account function including the returned form and open in your browser. weppy should redirect you to the login page and showing you the relative form.

Note: weppy's auth module requires session handling and a DAL instance activated on your application to work properly.

As you've figured out, the exposed account function will be responsible of the authorization flow in your app. The Auth module of weppy exposes (with the default settings):

  • http://.../{baseurl}/login
  • http://.../{baseurl}/logout
  • http://.../{baseurl}/register
  • http://.../{baseurl}/verify_email
  • http://.../{baseurl}/retrieve_username
  • http://.../{baseurl}/retrieve_password
  • http://.../{baseurl}/reset_password
  • http://.../{baseurl}/request_reset_password
  • http://.../{baseurl}/change_password
  • http://.../{baseurl}/profile

and it also creates all the database tables needed, from users to groups and memberships ones.

You can obviously change the routing url for the authorization function:

def accunt(f, k):
    # code

and even change the name of the exposed function, but if you do that, you mast tell to the Auth module to use it to generate urls:

auth = Auth(app, db, base_url='mycontrol')

def mycontrol(f, k):
    form = auth(f, k)
    return dict(form=form)

otherwise the authorization module won't work properly.

Disable specific actions

You may want to disable some actions exposed by the authorization module, let's say for example you don't want the retrieve_username functionality. To do that, just edit your application configuration:

app.config.auth.actions_disabled = ["retrieve_username"]

Add custom actions

You can also define custom actions to be routed by your application. Let's say you want to route "/account/facebook" on your "/account" exposed function:

def myfbfunction():
    # code

auth.register_action("facebook", myfbfunction)

and that's it.

Access control with "requires"

One of the advantages of the authorization module is the simple way you can introduce access controls over your application. Let's say, for example, that you need to allow access to a specific zone only to logged users. In weppy you can do that in just a line of code:

from import requires

@requires(auth.is_logged_in, url('unauthorized_page'))
def myprotected_page():
    #some code

As you probably figured out, the requires helper will check the condition passed as the first parameter and if the request doesn't met the requirement, it will redirect the client on the url passed as second parameter.

You can also pass a function to be invoked as second parameter, for example:

def not_auth():

@requires(lambda: auth.has_membership('administrator'), not_auth)
def admin():
    # code

to return an HTTP 403 error.

Note: when you need to evaluate the condition during the request, if the first argument passed to requires is not a callable you should use a lambda function.

Sometimes you may need to return specific contents on missing authorization, for example you can write:

from import service

def not_auth():
    return dict(error="Not authorized")

@requires(auth.is_logged_in, not_auth)
def protected():
    return dict(data="Some data here")

so the client will receive a JSON object also on authorization error.

– Ok dude. What if I want to protect an entire application module with access control?

You can use the RequireHandler instead of decorating any function of your module:

from weppy import AppModule
from weppy.handlers import RequireHandler

mymodule = AppModule(app, "mymodule", __name__)
mymodule.common_handlers = [RequireHandler(some_condition, otherwise)]

just remember to not add access control over your authorization exposed function, otherwise your user won't be able to login.

Authorization models

New in version 0.4

The Auth module define five models (and obviously the five related database tables) under default behavior:

  • AuthUser
  • AuthGroup
  • AuthMembership
  • AuthPermission
  • AuthEvent

Now, you can customize the models subclassing them, and the first you want to is the one referred to the user, on which you can add your fields, for example an avatar. You will define your User model:

from weppy.dal import Field
from import AuthUser

class User(AuthUser):
    avatar = Field("upload", uploadfolder="uploads")

    form_profile_rw = {
        "avatar": True

and pass it to the Auth instance:

from import Auth
auth = Auth(app, db, usermodel=User)

As you can see, defining your user model subclassing AuthUser is quite the same as for a Model, except that the fields you define will be the additional fields you want to add to the user table, and instead of the form_rw attribute you have form_profile_rw and form_registration_rw to treat separately the field access during user registration and when the user edits its own profile. As the default visibility is set to False for any extra field you have defined, in the above example the client will be able to upload an avatar for its account only with the profile function and not during the registration.

The default fields included in the AuthUser model are:

  • email
  • password
  • first_name
  • last_name

plus some other columns need by the system and hidden to the users.

If you don't want to have the first_name and last_name fields inside your user model (they are set to be not-null), you can subclass the AuthUserBasic model instead, available under which doesn't include them.

Before seeing how to customize the remaining auth models, let's see which relations are available as default.

Auth relations

The default Auth configuration gives you the ability to use these has_many relations on the AuthUser model (and any model subclassing it):

user = db.AuthUser(id=1)
# referring membership records
# referring group records
# referring permission records
# referring event records

The AuthGroup model has these has_many relations:

group = db.AuthGroup(id=1)
# referring user records
# referring permission records

Consequentially, AuthMembership, AuthPermission and AuthEvent have the inverse belongs_to relations:

membership = db.AuthMembership(id=1)
# referred user record
# referred group record

permission = db.AuthPermission(id=1)
# referred group record

event = db.AuthEvent(id=1)
# referred user record

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Customizing auth models

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Users management

Thanks to the models and relations defined by the Auth module, you can easily manage the users in your application. Let's say, for example, you want to add a group of administrators:

admins = auth.add_group('administrators')

then you can add users to the administrators' group easily:

admin = db.User(id=42)
# 1st way:
auth.add_membership(admins, admin)
# 2nd way:
auth.add_membership('administrators', admin)
# 3rd way:
# 4th way:

Once you have added groups and memberships, you can use the has_membership helper of the Auth model (that we've already seen before in the requires paragraph):

# on the logged user:
# specifying a user:
auth.has_membership('administrator', user)

and you can obviously get all the groups user has membership with using relation:


But weppy's Auth module also have a finer management for users, considering permissions:

auth.add_permission(admins, 'ban_users')

As you got from the example, this allows you to bind specific permissions to groups, and then checks for them both on groups and users:

# on the logged user:
# on specific user:
auth.has_permission('ban_users', user=admin)
# on specific group:
auth.has_permission('ban_users', group=admins)

weppy's Auth permissions also support more details, like a model name and a record:

maintenance = db.Preference(name='maintenance').first()
auth.add_permission(admins, 'write', 'Setting',
# then you will check
auth.has_permission('write', 'Setting',

Auth module configuration

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Additional login methods

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