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django-permissions-1.0 / permissions / utils.py

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# django imports
from django.db import IntegrityError
from django.contrib.auth.models import User
from django.contrib.contenttypes.models import ContentType
from django.core.exceptions import ObjectDoesNotExist

# permissions imports
from permissions.models import ObjectPermission
from permissions.models import ObjectPermissionInheritanceBlock
from permissions.models import Permission
from permissions.models import PrincipalRoleRelation
from permissions.models import Role

# Roles ######################################################################

def add_role(principal, role):
    """Adds a global role to a principal.

    **Parameters:**

    principal
        The principal (user or group) which gets the role added.

    role
        The role which is assigned.
    """
    if isinstance(principal, User):
        try:
            ppr = PrincipalRoleRelation.objects.get(user=principal, role=role, content_id=None, content_type=None)
        except PrincipalRoleRelation.DoesNotExist:
            PrincipalRoleRelation.objects.create(user=principal, role=role)
            return True
    else:
        try:
            ppr = PrincipalRoleRelation.objects.get(group=principal, role=role, content_id=None, content_type=None)
        except PrincipalRoleRelation.DoesNotExist:
            PrincipalRoleRelation.objects.create(group=principal, role=role)
            return True

    return False

def add_local_role(obj, principal, role):
    """Adds a local role to a principal.

    **Parameters:**

    obj
        The object for which the principal gets the role.

    principal
        The principal (user or group) which gets the role.

    role
        The role which is assigned.
    """
    ctype = ContentType.objects.get_for_model(obj)
    if isinstance(principal, User):
        try:
            ppr = PrincipalRoleRelation.objects.get(user=principal, role=role, content_id=obj.id, content_type=ctype)
        except PrincipalRoleRelation.DoesNotExist:
            PrincipalRoleRelation.objects.create(user=principal, role=role, content=obj)
            return True
    else:
        try:
            ppr = PrincipalRoleRelation.objects.get(group=principal, role=role, content_id=obj.id, content_type=ctype)
        except PrincipalRoleRelation.DoesNotExist:
            PrincipalRoleRelation.objects.create(group=principal, role=role, content=obj)
            return True

    return False

def remove_role(principal, role):
    """Removes role from passed principal.

    **Parameters:**

    principal
        The principal (user or group) from which the role is removed.

    role
        The role which is removed.
    """
    try:
        if isinstance(principal, User):
            ppr = PrincipalRoleRelation.objects.get(
                    user=principal, role=role, content_id=None, content_type=None)
        else:
            ppr = PrincipalRoleRelation.objects.get(
                    group=principal, role=role, content_id=None, content_type=None)

    except PrincipalRoleRelation.DoesNotExist:
        return False
    else:
        ppr.delete()

    return True

def remove_local_role(obj, principal, role):
    """Removes role from obj and principle.

    **Parameters:**

    obj
        The object from which the role is removed.

    principal
        The principal (user or group) from which the role is removed.

    role
        The role which is assigned.
    """
    try:
        ctype = ContentType.objects.get_for_model(obj)

        if isinstance(principal, User):
            ppr = PrincipalRoleRelation.objects.get(
                user=principal, role=role, content_id=obj.id, content_type=ctype)
        else:
            ppr = PrincipalRoleRelation.objects.get(
                group=principal, role=role, content_id=obj.id, content_type=ctype)

    except PrincipalRoleRelation.DoesNotExist:
        return False
    else:
        ppr.delete()

    return True

def remove_roles(principal):
    """Removes all local roles from passed object and principal (user or
    group).

    **Parameters:**

    principal
        The principal (user or group) from which all roles are removed.
    """
    try:
        if obj is None:
            if isinstance(principal, User):
                ppr = PrincipalRoleRelation.objects.filter(
                    user=principal, content_id=None, content_type=None)
            else:
                ppr = PrincipalRoleRelation.objects.filter(
                    group=principal, content_id=None, content_type=None)

        else:
            ctype = ContentType.objects.get_for_model(obj)

            if isinstance(principal, User):
                ppr = PrincipalRoleRelation.objects.filter(
                    user=principal, content_id=obj.id, content_type=ctype)
            else:
                ppr = PrincipalRoleRelation.objects.filter(
                    group=principal, content_id=obj.id, content_type=ctype)

    except PrincipalRoleRelation.DoesNotExist:
        return False
    else:
        ppr.delete()

    return True

def remove_local_roles(obj, principal):
    """Removes all local roles from passed object and principal (user or
    group).

    **Parameters:**

    obj
        The object from which the roles are removed.

    principal
        The principal (user or group) from which the roles are removed.
    """
    try:
        ctype = ContentType.objects.get_for_model(obj)

        if isinstance(principal, User):
            ppr = PrincipalRoleRelation.objects.filter(
                user=principal, content_id=obj.id, content_type=ctype)
        else:
            ppr = PrincipalRoleRelation.objects.filter(
                group=principal, content_id=obj.id, content_type=ctype)

    except PrincipalRoleRelation.DoesNotExist:
        return False
    else:
        ppr.delete()

    return True

def get_roles(principal, obj=None):
    """Returns all roles of passed user for passed content object. This takes
    global and local roles into account

    **Parameters:**

    obj
        The object from which the roles are removed.

    principal
        The principal (user or group) from which the roles are removed.
    """
    roles = get_global_roles(principal)

    if obj is not None:
        roles.extend(get_local_roles(obj, principal))

    if isinstance(principal, User):
        for group in principal.groups.all():
            roles.extend(get_local_roles(obj, group))

    return roles

def get_global_roles(principal):
    """Returns global roles of passed principal (user or group).
    """
    if isinstance(principal, User):
        return [prr.role for prr in PrincipalRoleRelation.objects.filter(
            user=principal, content_id=None, content_type=None)]
    else:
        return [prr.role for prr in PrincipalRoleRelation.objects.filter(
            group=principal, content_id=None, content_type=None)]

def get_local_roles(obj, principal):
    """Returns local for passed user and content object.
    """
    ctype = ContentType.objects.get_for_model(obj)

    if isinstance(principal, User):
        return [prr.role for prr in PrincipalRoleRelation.objects.filter(
            user=principal, content_id=obj.id, content_type=ctype)]
    else:
        return [prr.role for prr in PrincipalRoleRelation.objects.filter(
            group=principal, content_id=obj.id, content_type=ctype)]

# Permissions ################################################################

def grant_permission(obj, permission, role):
    """Adds passed permission to passed group and object. Returns True if the
    permission was able to be added, otherwise False.

    **Parameters:**

    obj
        The content object for which the permission should be granted.

    permission
        The permission which should be granted. Either a permission
        object or the codename of a permission.

    role
        The role for which the permission should be granted.
    """
    if not isinstance(permission, Permission):
        try:
            permission = Permission.objects.get(codename = permission)
        except Permission.DoesNotExist:
            return False

    ct = ContentType.objects.get_for_model(obj)
    try:
        ObjectPermission.objects.get(role=role, content_type = ct, content_id=obj.id, permission=permission)
    except ObjectPermission.DoesNotExist:
        try:
            result = ObjectPermission.objects.create(role=role, content=obj, permission=permission)
        except IntegrityError:
            return False

    return True

def remove_permission(obj, permission, role):
    """Removes passed permission from passed role and object. Returns True if
    the permission has been removed.

    **Parameters:**

    obj
        The content object for which a permission should be removed.

    permission
        The permission which should be removed. Either a permission object
        or the codename of a permission.

    role
        The role for which a permission should be removed.
    """
    if not isinstance(permission, Permission):
        try:
            permission = Permission.objects.get(codename = permission)
        except Permission.DoesNotExist:
            return False

    ct = ContentType.objects.get_for_model(obj)

    try:
        op = ObjectPermission.objects.get(role=role, content_type = ct, content_id=obj.id, permission = permission)
    except ObjectPermission.DoesNotExist:
        return False

    op.delete()
    return True

def has_permission(obj, codename, user, roles=[]):
    """Checks whether the passed user has passed permission for passed object.

    **Parameters:**

    obj
        The object for which the permission should be checked.

    codename
        The permission's codename which should be checked.

    user
        The user for which the permission should be checked.

    groups
        If given these groups will be assigned to the user temporarily before
        the permissions are checked. If you don't know why this is need you
        can safely ignore it.
    """
    if user.is_superuser:
        return True

    if user.is_anonymous():
        user = None
    else:
        roles.extend(get_roles(user, obj))

    ct = ContentType.objects.get_for_model(obj)

    while obj is not None:
        p = ObjectPermission.objects.filter(
            content_type=ct, content_id=obj.id, role__in=roles, permission__codename = codename)

        if p.count() > 0:
            return True

        if is_inherited(obj, codename) == False:
            return False

        try:
            obj = obj.get_parent_for_permissions()
            ct = ContentType.objects.get_for_model(obj)
        except AttributeError:
            return False

    return False

# Inheritance ################################################################

def add_inheritance_block(obj, permission):
    """Adds an inheritance for the passed permission on the passed obj.

    **Parameters:**

        permission
            The permission for which an inheritance block should be added.
            Either a permission object or the codename of a permission.
        obj
            The content object for which an inheritance block should be added.
    """
    if not isinstance(permission, Permission):
        try:
            permission = Permission.objects.get(codename = permission)
        except Permission.DoesNotExist:
            return False

    ct = ContentType.objects.get_for_model(obj)
    try:
        ObjectPermissionInheritanceBlock.objects.get(content_type = ct, content_id=obj.id, permission=permission)
    except ObjectPermissionInheritanceBlock.DoesNotExist:
        try:
            result = ObjectPermissionInheritanceBlock.objects.create(content=obj, permission=permission)
        except IntegrityError:
            return False
    return True

def remove_inheritance_block(obj, permission):
    """Removes a inheritance block for the passed permission from the passed
    object.

    **Parameters:**

        obj
            The content object for which an inheritance block should be added.

        permission
            The permission for which an inheritance block should be removed.
            Either a permission object or the codename of a permission.
    """
    if not isinstance(permission, Permission):
        try:
            permission = Permission.objects.get(codename = permission)
        except Permission.DoesNotExist:
            return False

    ct = ContentType.objects.get_for_model(obj)
    try:
        opi = ObjectPermissionInheritanceBlock.objects.get(content_type = ct, content_id=obj.id, permission=permission)
    except ObjectPermissionInheritanceBlock.DoesNotExist:
        return False

    opi.delete()
    return True

def is_inherited(obj, codename):
    """Returns True if the passed permission is inherited for passed object.

    **Parameters:**

        obj
            The content object for which the permission should be checked.

        codename
            The permission which should be checked. Must be the codename of
            the permission.
    """
    ct = ContentType.objects.get_for_model(obj)
    try:
        ObjectPermissionInheritanceBlock.objects.get(
            content_type=ct, content_id=obj.id, permission__codename = codename)
    except ObjectDoesNotExist:
        return True
    else:
        return False

def get_role(name):
    """Returns the role with given name or None if it doesn't exit.
    """
    try:
        return Role.objects.get(name=name)
    except Role.DoesNotExist:
        return None

def reset(obj):
    """Resets all permissions and inheritance blocks of passed object.
    """
    ctype = ContentType.objects.get_for_model(obj)
    ObjectPermissionInheritanceBlock.objects.filter(content_id=obj.id, content_type=ctype).delete()
    ObjectPermission.objects.filter(content_id=obj.id, content_type=ctype).delete()

# Registering ################################################################

def register_permission(name, codename, ctypes=[]):
    """Registers a permission to the framework. Returns the permission if the
    registration was successfully, otherwise False.

    **Parameters:**

        name
            The unique name of the permission. This is displayed to the
            customer.
        codename
            The unique codename of the permission. This is used internally to
            identify the permission.
        content_types
            The content type for which the permission is active. This can be
            used to display only reasonable permissions for an object.
    """
    try:
        p = Permission.objects.create(name=name, codename=codename)
        p.content_types = ctypes
        p.save()
    except IntegrityError:
        return False
    return p

def unregister_permission(codename):
    """Unregisters a permission from the framework

    **Parameters:**

        codename
            The unique codename of the permission.
    """
    try:
        permission = Permission.objects.get(codename=codename)
    except Permission.DoesNotExist:
        return False
    permission.delete()
    return True

def register_role(name):
    """Registers a group with passed name to the framework. Returns the new
    role if the registration was successfully, otherwise False.

    **Parameters:**

    name
        The unique group name.
    """
    try:
        role = Role.objects.create(name=name)
    except IntegrityError:
        return False
    return role

def unregister_role(name):
    """Unregisters the role with passed name.

    **Parameters:**

        name
            The unique role name.
    """
    try:
        role = Role.objects.get(name=name)
    except Role.DoesNotExist:
        return False

    role.delete()
    return True