Getting started with repoze.what
¶
Overview
This document describes the basics of repoze.what
, including its
terminology and how to configure authentication and authorization easily.
Terminology¶
As explained previously, repoze.what
’s base authorization pattern
is based on the groups to which the user belongs and the permissions granted
to such groups, and such groups and permissions can be stored in different
types of sources – because of that, repoze.what
uses a generic
terminology when it deals with those sources:
- source
- Where authorization data (groups and/or permissions) is stored. It may be a database or a file (an Htgroups file, an Ini file, etc), for example.
- group source
- A source that stores groups. For example, an Htgroups file or an Ini file.
- permission source
- A source that stores permissions. For example, an Ini file.
- source adapter
- An object that manages a given type of source to add, edit and delete entries under an API independent of the source type.
- group adapter
- An adapter that deals with one group source.
- permission adapter
- An adapter that deals with one permission source.
- section
- Sections are the compound elements that make up a source – this is, in a permission source, the sections are the permissions, and in a group source, the sections are the groups.
- item
- The elements that are contained in a section. In a permission source, the items are the groups that are granted the permission represented in their parent section; likewise, in a group source, the items are the Ids of the users that belong to the group represented in the parent section.
The authentication framework (repoze.who
) only deals with the
sources that handle your users’ credentials, while the
authorization framework (repoze.what
) deals with both the
sources that handle your groups and those that handle your
permissions.
Sample sources¶
Below are the contents of a mock .htgroups
file that defines the groups of
an application. In other words, such a file is a group source of
type htgroups
:
developers: rms, linus, guido
admins: rms, linus
users: gustavo, maribel
It has three sections and five items: “developers” (made up of the items “rms”, “linus” and “guido”), “admins” (made up of the items “rms” and “linus”) and “users (made up of the items “gustavo” and “maribel”).
And below are the contents of a mock .ini
file that defines the permissions
of the groups in an application. In other words, such a file is a
permission source of type Ini
:
[manage-site]
admins
[release-software]
admins
developers
[contact-us]
users
It has three sections and three items: “manage-site” (made up one item, “admins”), “release-software” (made up of the items “admins” and “developers”) and “contact-us” (made up of the item “users”).
If you use a database to store your users, groups and permissions, then such a database is both the group and permission source:
- The tables where you store your groups and users are the sections and the section items, respectively, of the
group source
.- The tables where you store your permissions and groups are the sections and the section items, respectively, of the
permission source
.
Setting up authentication and authorization¶
Note
If you are using a web framework and it already configures
repoze.what
, you may want to skip this section.
To enable authorization in your Web application, you need to add some
WSGI middleware to your application, which is automatically done for you if
you are using the quickstart
.
When you enable authorization with repoze.what
, authentication
with repoze.who
is automatically enabled.
Warning
Do not try to configure repoze.who
directly – if you want
authorization to work, you have to configure it through repoze.what
.
Using authentication and authorization without the quickstart¶
If you’re not using the quickstart, then you have to add the required middleware in your application. This gives you more flexibility, such as being able not to use a database to store your users’ credentials, your groups and/or your permissions.
You are highly encouraged to add such a middleware with a function defined in,
say, {yourproject}.config.middleware
and called, say, add_auth
. Then
that function may look like this:
def add_auth(app):
"""
Add authentication and authorization middleware to the ``app``.
:param app: The WSGI application.
:return: The same WSGI application, with authentication and
authorization middleware.
People will login using HTTP Authentication and their credentials are
kept in an ``Htpasswd`` file. For authorization through repoze.what,
we load our groups stored in an ``Htgroups`` file and our permissions
stored in an ``.ini`` file.
"""
from repoze.who.plugins.basicauth import BasicAuthPlugin
from repoze.who.plugins.htpasswd import HTPasswdPlugin, crypt_check
from repoze.what.middleware import setup_auth
from repoze.what.plugins.ini import INIPermissionsAdapter
# Please note that the Htgroups plugins has not been created yet; want
# to jump in?
from repoze.what.plugins.htgroups import HtgroupsAdapter
# Defining the group adapters; you may add as much as you need:
groups = {'all_groups': HtgroupsAdapter('/path/to/groups.htgroups')}
# Defining the permission adapters; you may add as much as you need:
permissions = {'all_perms': INIPermissionsAdapter('/path/to/perms.ini')}
# repoze.who identifiers; you may add as much as you need:
basicauth = BasicAuthPlugin('Private web site')
identifiers = [('basicauth', basicauth)]
# repoze.who authenticators; you may add as much as you need:
htpasswd_auth = HTPasswdPlugin('/path/to/users.htpasswd', crypt_check)
authenticators = [('htpasswd', htpasswd_auth)]
# repoze.who challengers; you may add as much as you need:
challengers = [('basicauth', basicauth)]
app_with_auth = setup_auth(
app,
groups,
permissions,
identifiers=identifiers,
authenticators=authenticators,
challengers=challengers)
return app_with_auth
Of course, there are other things you may customize, such as adding
repoze.who
identifiers, more authenticators, challengers and metadata
providers (read repoze.what.middleware.setup_auth()
for more information).
What’s next?¶
Now you are ready to control authorization in your application with
predicates
!