Merge pull request #188 from nyaruka/perms

Refactor permissions code

smartmin/__init__.py

@@ -1,3 +1 @@
-from __future__ import unicode_literals
-
 __version__ = "5.0.2"

smartmin/management/__init__.py

@@ -1,168 +0,0 @@
-import sys
-
-from django.apps import apps
-from django.conf import settings
-from django.contrib.auth.models import Group, Permission
-from django.contrib.contenttypes.models import ContentType
-from django.core.exceptions import ObjectDoesNotExist
-from django.db.models.signals import post_migrate
-
-from smartmin.perms import assign_perm, remove_perm
-
-permissions_app_name = None
-
-
-def get_permissions_app_name():
-    """
-    Gets the app after which smartmin permissions should be installed. This can be specified by PERMISSIONS_APP in the
-    Django settings or defaults to the last app with models
-    """
-    global permissions_app_name
-
-    if not permissions_app_name:
-        permissions_app_name = getattr(settings, "PERMISSIONS_APP", None)
-
-        if not permissions_app_name:
-            app_names_with_models = [a.name for a in apps.get_app_configs() if a.models_module is not None]
-            if app_names_with_models:
-                permissions_app_name = app_names_with_models[-1]
-
-    return permissions_app_name
-
-
-def is_permissions_app(app_config):
-    """
-    Returns whether this is the app after which permissions should be installed.
-    """
-    return app_config.name == get_permissions_app_name()
-
-
-def check_role_permissions(role, permissions, current_permissions):
-    """
-    Checks the the passed in role (can be user, group or AnonymousUser)  has all the passed
-    in permissions, granting them if necessary.
-    """
-    role_permissions = []
-
-    # get all the current permissions, we'll remove these as we verify they should still be granted
-    for permission in permissions:
-        splits = permission.split(".")
-        if len(splits) != 2 and len(splits) != 3:
-            sys.stderr.write("  invalid permission %s, ignoring\n" % permission)
-            continue
-
-        app = splits[0]
-        codenames = []
-
-        if len(splits) == 2:
-            codenames.append(splits[1])
-        else:
-            (object, action) = splits[1:]
-
-            # if this is a wildcard, then query our database for all the permissions that exist on this object
-            if action == "*":
-                for perm in Permission.objects.filter(codename__startswith="%s_" % object, content_type__app_label=app):
-                    codenames.append(perm.codename)
-            # otherwise, this is an error, continue
-            else:
-                sys.stderr.write("  invalid permission %s, ignoring\n" % permission)
-                continue
-
-        if len(codenames) == 0:
-            continue
-
-        for codename in codenames:
-            # the full codename for this permission
-            full_codename = "%s.%s" % (app, codename)
-
-            # this marks all the permissions which should remain
-            role_permissions.append(full_codename)
-
-            try:
-                assign_perm(full_codename, role)
-            except ObjectDoesNotExist:
-                pass
-                # sys.stderr.write("  unknown permission %s, ignoring\n" % permission)
-
-    # remove any that are extra
-    for permission in current_permissions:
-        if isinstance(permission, str):
-            key = permission
-        else:
-            key = "%s.%s" % (permission.content_type.app_label, permission.codename)
-
-        if key not in role_permissions:
-            remove_perm(key, role)
-
-
-def check_all_group_permissions(sender, **kwargs):
-    """
-    Checks that all the permissions specified in our settings.py are set for our groups.
-    """
-    if not is_permissions_app(sender):
-        return
-
-    config = getattr(settings, "GROUP_PERMISSIONS", dict())
-
-    # for each of our items
-    for name, permissions in config.items():
-        # get or create the group
-        (group, created) = Group.objects.get_or_create(name=name)
-        if created:
-            pass
-
-        check_role_permissions(group, permissions, group.permissions.all())
-
-
-def add_permission(content_type, permission):
-    """
-    Adds the passed in permission to that content type.  Note that the permission passed
-    in should be a single word, or verb.  The proper 'codename' will be generated from that.
-    """
-    # build our permission slug
-    codename = "%s_%s" % (content_type.model, permission)
-
-    # sys.stderr.write("Checking %s permission for %s\n" % (permission, content_type.name))
-
-    # does it already exist
-    if not Permission.objects.filter(content_type=content_type, codename=codename):
-        Permission.objects.create(
-            content_type=content_type, codename=codename, name="Can %s %s" % (permission, content_type.name)
-        )
-        # sys.stderr.write("Added %s permission for %s\n" % (permission, content_type.name))
-
-
-def check_all_permissions(sender, **kwargs):
-    """
-    This syncdb checks our PERMISSIONS setting in settings.py and makes sure all those permissions
-    actually exit.
-    """
-    if not is_permissions_app(sender):
-        return
-
-    config = getattr(settings, "PERMISSIONS", dict())
-
-    # for each of our items
-    for natural_key, permissions in config.items():
-        # if the natural key '*' then that means add to all objects
-        if natural_key == "*":
-            # for each of our content types
-            for content_type in ContentType.objects.all():
-                for permission in permissions:
-                    add_permission(content_type, permission)
-
-        # otherwise, this is on a specific content type, add for each of those
-        else:
-            app, model = natural_key.split(".")
-            try:
-                content_type = ContentType.objects.get_by_natural_key(app, model)
-            except ContentType.DoesNotExist:
-                continue
-
-            # add each permission
-            for permission in permissions:
-                add_permission(content_type, permission)
-
-
-post_migrate.connect(check_all_permissions)
-post_migrate.connect(check_all_group_permissions)

smartmin/models.py

@@ -8,8 +8,13 @@
 
 from django.conf import settings
 from django.db import models
+from django.db.models.signals import post_migrate
 from django.utils import timezone
 
+from .perms import sync_permissions
+
+post_migrate.connect(sync_permissions)
+
 
 class SmartImportRowError(Exception):
     def __init__(self, message):

smartmin/perms.py

@@ -1,35 +1,136 @@
-from django.contrib.auth.models import Permission
+import re
 
+from django.apps import apps
+from django.conf import settings
+from django.contrib.auth.models import Group, Permission
+from django.contrib.contenttypes.models import ContentType
 
-def assign_perm(perm, group):
+permissions_app_name = None
+perm_desc_regex = re.compile(r"(?P<app>\w+)\.(?P<codename>\w+)(?P<wild>\.\*)?")
+
+
+def get_permissions_app_name():
+    """
+    Gets the app after which smartmin permissions should be installed. This can be specified by PERMISSIONS_APP in the
+    Django settings or defaults to the last app with models
+    """
+    global permissions_app_name
+
+    if not permissions_app_name:
+        permissions_app_name = getattr(settings, "PERMISSIONS_APP", None)
+
+        if not permissions_app_name:
+            app_names_with_models = [a.name for a in apps.get_app_configs() if a.models_module is not None]
+            if app_names_with_models:
+                permissions_app_name = app_names_with_models[-1]
+
+    return permissions_app_name
+
+
+def is_permissions_app(app_config):
+    """
+    Returns whether this is the app after which permissions should be installed.
+    """
+    return app_config.name == get_permissions_app_name()
+
+
+def update_group_permissions(group, permissions: list):
+    """
+    Checks the the passed in role (can be user, group or AnonymousUser)  has all the passed
+    in permissions, granting them if necessary.
+    """
+
+    new_permissions = []
+
+    for perm_desc in permissions:
+        app_label, codename, wild = _parse_perm_desc(perm_desc)
+
+        if wild:
+            codenames = Permission.objects.filter(
+                content_type__app_label=app_label, codename__startswith=f"{codename}_"
+            ).values_list("codename", flat=True)
+        else:
+            codenames = [codename]
+
+        perms = []
+        for codename in codenames:
+            try:
+                perms.append(Permission.objects.get(content_type__app_label=app_label, codename=codename))
+            except Permission.DoesNotExist:
+                raise ValueError(f"Cannot grant permission {app_label}.{codename} as it does not exist.")
+
+            new_permissions.append((app_label, codename))
+
+        group.permissions.add(*perms)
+
+    # remove any that are extra
+    for perm in group.permissions.select_related("content_type").all():
+        if (perm.content_type.app_label, perm.codename) not in new_permissions:
+            group.permissions.remove(perm)
+
+
+def sync_permissions(sender, **kwargs):
+    """
+    1. Ensures all permissions decribed by the PERMISSIONS setting exist in the database.
+    2. Ensures all permissions granted by the GROUP_PERMISSIONS setting are granted to the appropriate groups.
+    """
+
+    if not is_permissions_app(sender):
+        return
+
+    # for each of our items
+    for natural_key, permissions in getattr(settings, "PERMISSIONS", {}).items():
+        # if the natural key '*' then that means add to all objects
+        if natural_key == "*":
+            # for each of our content types
+            for content_type in ContentType.objects.all():
+                for permission in permissions:
+                    _ensure_permission_exists(content_type, permission)
+
+        # otherwise, this is on a specific content type, add for each of those
+        else:
+            app, model = natural_key.split(".")
+            try:
+                content_type = ContentType.objects.get_by_natural_key(app, model)
+            except ContentType.DoesNotExist:
+                continue
+
+            # add each permission
+            for permission in permissions:
+                _ensure_permission_exists(content_type, permission)
+
+    # for each of our items
+    for name, permissions in getattr(settings, "GROUP_PERMISSIONS", {}).items():
+        # get or create the group
+        (group, created) = Group.objects.get_or_create(name=name)
+        if created:
+            pass
+
+        update_group_permissions(group, permissions)
+
+
+def _parse_perm_desc(desc: str) -> tuple:
     """
-    Assigns a permission to a group
+    Parses a permission descriptor into its app_label, model and permission parts, e.g.
+        app.model.*      => app, model, True
+        app.model_perm   => app, model_perm, False
     """
-    if not isinstance(perm, Permission):
-        try:
-            app_label, codename = perm.split(".", 1)
-        except ValueError:
-            raise ValueError(
-                "For global permissions, first argument must be in" " format: 'app_label.codename' (is %r)" % perm
-            )
-        perm = Permission.objects.get(content_type__app_label=app_label, codename=codename)
 
-    group.permissions.add(perm)
-    return perm
+    match = perm_desc_regex.match(desc)
+    if not match:
+        raise ValueError(f"Invalid permission descriptor: {desc}")
 
+    return match.group("app"), match.group("codename"), bool(match.group("wild"))
 
-def remove_perm(perm, group):
+
+def _ensure_permission_exists(content_type: str, permission: str):
     """
-    Removes a permission from a group
+    Adds the passed in permission to that content type.  Note that the permission passed
+    in should be a single word, or verb.  The proper 'codename' will be generated from that.
     """
-    if not isinstance(perm, Permission):
-        try:
-            app_label, codename = perm.split(".", 1)
-        except ValueError:
-            raise ValueError(
-                "For global permissions, first argument must be in" " format: 'app_label.codename' (is %r)" % perm
-            )
-        perm = Permission.objects.get(content_type__app_label=app_label, codename=codename)
 
-    group.permissions.remove(perm)
-    return
+    codename = f"{content_type.model}_{permission}"  # build our permission slug
+
+    Permission.objects.get_or_create(
+        content_type=content_type, codename=codename, defaults={"name": f"Can {permission} {content_type.name}"}
+    )