How to manage groups and permission sources¶
Overview
It’s possible for you to manage your groups and permissions under a source-independent API and here you will learn how to do it.
Source adapters enable you to
retrieve information from your groups and
permissions, as well as manage them, under an API
absolutely independent of the source type. You may take advantage
of this functionality to manage your sources from your own application or to
write an application-independent front-end to manage groups and permissions
in arbitrary WSGI applications using repoze.what
.
This functionality will also enable you to switch from one back-end to another with no need to update your code (except for the part where you instance the source adapter).
Managing your sources¶
Sources are managed from their respective adapters. For example, to manage the groups defined in a database, you can use:
from repoze.what.plugins.sql import SqlGroupsAdapter
from your_model import User, Group, DBSession
groups = SqlGroupsAdapter(Group, User, DBSession)
Or to manage the permissions defined in an XML file, you could use:
from repoze.what.plugins.xml import XMLGroupsAdapter
permissions = XMLGroupsAdapter('/path/to/permissions.xml')
Tip
As of v1.0.1, you can re-use the same adapters used by repoze.what
to control access. You will find them in the WSGI environment:
# This is where repoze.what adapters are kept:
adapters = environ['repoze.what.adapters']
# Now let's extract the group and permission adapters:
group_adapters = adapters['groups']
permission_adapters = adapters['permissions']
Retrieving all the available sections from a source¶
To get all the groups from the group source above, you may use the code below, which will return a dictionary whose keys are the name of the groups and the items are the username of the users that belong to such groups:
>>> groups.get_all_sections()
{u'admins': set([u'gustavo', u'adolfo']), u'developers': set([u'narea'])}
And to get all the permissions from the permission source above, you may use the code below, which will return a dictionary whose keys are the name of the permissions and the items are the name of the groups that are granted such permissions:
>>> permissions.get_all_sections()
{u'upload-images': set([u'admins', u'developers']), u'write-post': set()}
Retrieving all the items from a given section¶
To get all the users that belong to a given group in the group source above, you may use:
>>> groups.get_section_items(u'admins')
set([u'gustavo', u'adolfo'])
And to get all the groups that are granted a given permission in the permission source above:
>>> permissions.get_section_items(u'upload-images')
set([u'admins', u'developers'])
Setting the items of a given section¶
To set the members of a given group in the group source above, you may use:
>>> groups.set_section_items(u'admins', [u'rms', u'guido'])
And to set the groups that are granted a given permission in the permission source above:
>>> permissions.set_section_items(u'write-post', [u'admins'])
Warning
set_section_items
will override the previous set of items. See, for
example:
>>> groups.get_all_sections()
{u'admins': set([u'gustavo', u'adolfo']), u'developers': set([u'narea'])}
>>> groups.set_section_items(u'admins', [u'rms', u'guido'])
>>> groups.get_all_sections()
{u'admins': set([u'rms', u'guido']), u'developers': set([u'narea'])}
Including items in a section¶
To add one the item to a given group of the group source above, you may use:
>>> groups.include_item(u'admins', u'rms')
Or to include many users at once:
>>> groups.include_items(u'admins', [u'rms', u'guido'])
And to grant a given permission to one group in the permission source above:
>>> permissions.include_item(u'write-post', u'admins')
Or to grant the same permission to many groups at once:
>>> permissions.include_items(u'write-post', [u'admins', u'developers'])
Excluding items from a section¶
To remove one the items from a given group of the group source above, you may use:
>>> groups.exclude_item(u'admins', u'gustavo')
Or to exclude many items at once:
>>> groups.exclude_items(u'admins', [u'gustavo', u'adolfo'])
And to deny a given permission to one group in the permission source above:
>>> permissions.exclude_item(u'upload-images', u'developers')
Or to grant the same permission to many groups at once:
>>> permissions.exclude_items(u'upload-images', [u'admins', u'developers'])
Adding a section to a source¶
To create a group in the group source above, you may use:
>>> groups.create_section(u'designers')
And to create a permission in the permission source above:
>>> permissions.create_section(u'edit-post')
Renaming a section¶
To rename a group in the group source above, you may use:
>>> groups.edit_section(u'designers', u'graphic-designers')
And to rename a permission in the permission source above:
>>> permissions.edit_section(u'write-post', u'create-post')
Removing a section from a source¶
To remove a group from the group source above, you may use:
>>> groups.delete_section(u'developers')
And to remove a permission from the permission source above:
>>> permissions.delete_section(u'write-post')
Checking whether the source is writable¶
Some adapters may not support writting the source, or some source types may
be read-only (e.g., a source served over HTTP), or some source types may be
writable but the current source itself may be read-only (e.g., a read-only
file). For this reason, you should check whether you can write to the source
– You will get a SourceError
exception if you try to write to a
read-only source.
To check whether the group source above is writable, you may use:
>>> groups.is_writable
True
And to check whether the permission source above is writable:
>>> permissions.is_writable
False
Possible problems¶
While dealing with an adapter, the following exceptions may be raised if an error occurs:
Writing your own source adapters¶
Note
It’s very unlikely that you’ll want to write a source adapter, so if you get bored reading this section, it’s absolutely safe for you to skip it and come back later if you ever need to create an adapter.
Both group and permission
adapters must extend the abstract class
BaseSourceAdapter
:
Sample source adapters¶
The following class illustrates how a group adapter may look like:
from repoze.what.adapters import BaseSourceAdapter
class FakeGroupSourceAdapter(BaseSourceAdapter):
"""Mock group source adapter"""
def __init__(self, *args, **kwargs):
super(FakeGroupSourceAdapter, self).__init__(*args, **kwargs)
self.fake_sections = {
u'admins': set([u'rms']),
u'developers': set([u'rms', u'linus']),
u'trolls': set([u'sballmer']),
u'python': set(),
u'php': set()
}
def _get_all_sections(self):
return self.fake_sections
def _get_section_items(self, section):
return self.fake_sections[section]
def _find_sections(self, credentials):
username = credentials['repoze.what.userid']
return set([n for (n, g) in self.fake_sections.items()
if username in g])
def _include_items(self, section, items):
self.fake_sections[section] |= items
def _exclude_items(self, section, items):
for item in items:
self.fake_sections[section].remove(item)
def _item_is_included(self, section, item):
return item in self.fake_sections[section]
def _create_section(self, section):
self.fake_sections[section] = set()
def _edit_section(self, section, new_section):
self.fake_sections[new_section] = self.fake_sections[section]
del self.fake_sections[section]
def _delete_section(self, section):
del self.fake_sections[section]
def _section_exists(self, section):
return self.fake_sections.has_key(section)
And the following class illustrates how a permission adapter may look like:
from repoze.what.adapters import BaseSourceAdapter
class FakePermissionSourceAdapter(BaseSourceAdapter):
"""Mock permissions source adapter"""
def __init__(self, *args, **kwargs):
super(FakePermissionSourceAdapter, self).__init__(*args, **kwargs)
self.fake_sections = {
u'see-site': set([u'trolls']),
u'edit-site': set([u'admins', u'developers']),
u'commit': set([u'developers'])
}
def _get_all_sections(self):
return self.fake_sections
def _get_section_items(self, section):
return self.fake_sections[section]
def _find_sections(self, group_name):
return set([n for (n, p) in self.fake_sections.items()
if group_name in p])
def _include_items(self, section, items):
self.fake_sections[section] |= items
def _exclude_items(self, section, items):
for item in items:
self.fake_sections[section].remove(item)
def _item_is_included(self, section, item):
return item in self.fake_sections[section]
def _create_section(self, section):
self.fake_sections[section] = set()
def _edit_section(self, section, new_section):
self.fake_sections[new_section] = self.fake_sections[section]
del self.fake_sections[section]
def _delete_section(self, section):
del self.fake_sections[section]
def _section_exists(self, section):
return self.fake_sections.has_key(section)
Testing your source adapters with testutil
¶
repoze.what
provides convenient utilities to automate the verification
of your adapters. This utility is the repoze.what.adapters.testutil
module, made up four test cases, which when extended must define the adapter
(as self.adapter
) in the setup, as well as call this class’ setUp()
method:
Attention
repoze.what.adapters.testutil
is not a full replacement for a test
suite, so you are still highly encouraged to write the relevant/missing
tests to lead the code coverage of your adapters to 100%.