first comit

venv/lib/python3.10/site-packages/django/contrib/messages/__init__.py

@@ -0,0 +1,3 @@
+from django.contrib.messages.api import *  # NOQA
+from django.contrib.messages.constants import *  # NOQA
+from django.contrib.messages.storage.base import Message  # NOQA

venv/lib/python3.10/site-packages/django/contrib/messages/api.py

@@ -0,0 +1,127 @@
+from django.contrib.messages import constants
+from django.contrib.messages.storage import default_storage
+
+__all__ = (
+    "add_message",
+    "get_messages",
+    "get_level",
+    "set_level",
+    "debug",
+    "info",
+    "success",
+    "warning",
+    "error",
+    "MessageFailure",
+)
+
+
+class MessageFailure(Exception):
+    pass
+
+
+def add_message(request, level, message, extra_tags="", fail_silently=False):
+    """
+    Attempt to add a message to the request using the 'messages' app.
+    """
+    try:
+        messages = request._messages
+    except AttributeError:
+        if not hasattr(request, "META"):
+            raise TypeError(
+                "add_message() argument must be an HttpRequest object, not "
+                "'%s'." % request.__class__.__name__
+            )
+        if not fail_silently:
+            raise MessageFailure(
+                "You cannot add messages without installing "
+                "django.contrib.messages.middleware.MessageMiddleware"
+            )
+    else:
+        return messages.add(level, message, extra_tags)
+
+
+def get_messages(request):
+    """
+    Return the message storage on the request if it exists, otherwise return
+    an empty list.
+    """
+    return getattr(request, "_messages", [])
+
+
+def get_level(request):
+    """
+    Return the minimum level of messages to be recorded.
+
+    The default level is the ``MESSAGE_LEVEL`` setting. If this is not found,
+    use the ``INFO`` level.
+    """
+    storage = getattr(request, "_messages", default_storage(request))
+    return storage.level
+
+
+def set_level(request, level):
+    """
+    Set the minimum level of messages to be recorded, and return ``True`` if
+    the level was recorded successfully.
+
+    If set to ``None``, use the default level (see the get_level() function).
+    """
+    if not hasattr(request, "_messages"):
+        return False
+    request._messages.level = level
+    return True
+
+
+def debug(request, message, extra_tags="", fail_silently=False):
+    """Add a message with the ``DEBUG`` level."""
+    add_message(
+        request,
+        constants.DEBUG,
+        message,
+        extra_tags=extra_tags,
+        fail_silently=fail_silently,
+    )
+
+
+def info(request, message, extra_tags="", fail_silently=False):
+    """Add a message with the ``INFO`` level."""
+    add_message(
+        request,
+        constants.INFO,
+        message,
+        extra_tags=extra_tags,
+        fail_silently=fail_silently,
+    )
+
+
+def success(request, message, extra_tags="", fail_silently=False):
+    """Add a message with the ``SUCCESS`` level."""
+    add_message(
+        request,
+        constants.SUCCESS,
+        message,
+        extra_tags=extra_tags,
+        fail_silently=fail_silently,
+    )
+
+
+def warning(request, message, extra_tags="", fail_silently=False):
+    """Add a message with the ``WARNING`` level."""
+    add_message(
+        request,
+        constants.WARNING,
+        message,
+        extra_tags=extra_tags,
+        fail_silently=fail_silently,
+    )
+
+
+def error(request, message, extra_tags="", fail_silently=False):
+    """Add a message with the ``ERROR`` level."""
+    add_message(
+        request,
+        constants.ERROR,
+        message,
+        extra_tags=extra_tags,
+        fail_silently=fail_silently,
+    )

venv/lib/python3.10/site-packages/django/contrib/messages/apps.py

@@ -0,0 +1,19 @@
+from django.apps import AppConfig
+from django.contrib.messages.storage import base
+from django.contrib.messages.utils import get_level_tags
+from django.core.signals import setting_changed
+from django.utils.functional import SimpleLazyObject
+from django.utils.translation import gettext_lazy as _
+
+
+def update_level_tags(setting, **kwargs):
+    if setting == "MESSAGE_TAGS":
+        base.LEVEL_TAGS = SimpleLazyObject(get_level_tags)
+
+
+class MessagesConfig(AppConfig):
+    name = "django.contrib.messages"
+    verbose_name = _("Messages")
+
+    def ready(self):
+        setting_changed.connect(update_level_tags)

venv/lib/python3.10/site-packages/django/contrib/messages/constants.py

@@ -0,0 +1,21 @@
+DEBUG = 10
+INFO = 20
+SUCCESS = 25
+WARNING = 30
+ERROR = 40
+
+DEFAULT_TAGS = {
+    DEBUG: "debug",
+    INFO: "info",
+    SUCCESS: "success",
+    WARNING: "warning",
+    ERROR: "error",
+}
+
+DEFAULT_LEVELS = {
+    "DEBUG": DEBUG,
+    "INFO": INFO,
+    "SUCCESS": SUCCESS,
+    "WARNING": WARNING,
+    "ERROR": ERROR,
+}

venv/lib/python3.10/site-packages/django/contrib/messages/context_processors.py

@@ -0,0 +1,13 @@
+from django.contrib.messages.api import get_messages
+from django.contrib.messages.constants import DEFAULT_LEVELS
+
+
+def messages(request):
+    """
+    Return a lazy 'messages' context variable as well as
+    'DEFAULT_MESSAGE_LEVELS'.
+    """
+    return {
+        "messages": get_messages(request),
+        "DEFAULT_MESSAGE_LEVELS": DEFAULT_LEVELS,
+    }

venv/lib/python3.10/site-packages/django/contrib/messages/middleware.py

@@ -0,0 +1,26 @@
+from django.conf import settings
+from django.contrib.messages.storage import default_storage
+from django.utils.deprecation import MiddlewareMixin
+
+
+class MessageMiddleware(MiddlewareMixin):
+    """
+    Middleware that handles temporary messages.
+    """
+
+    def process_request(self, request):
+        request._messages = default_storage(request)
+
+    def process_response(self, request, response):
+        """
+        Update the storage backend (i.e., save the messages).
+
+        Raise ValueError if not all messages could be stored and DEBUG is True.
+        """
+        # A higher middleware layer may return a request which does not contain
+        # messages storage, so make no assumption that it will be there.
+        if hasattr(request, "_messages"):
+            unstored_messages = request._messages.update(response)
+            if unstored_messages and settings.DEBUG:
+                raise ValueError("Not all temporary messages could be stored.")
+        return response

venv/lib/python3.10/site-packages/django/contrib/messages/storage/__init__.py

@@ -0,0 +1,12 @@
+from django.conf import settings
+from django.utils.module_loading import import_string
+
+
+def default_storage(request):
+    """
+    Callable with the same interface as the storage classes.
+
+    This isn't just default_storage = import_string(settings.MESSAGE_STORAGE)
+    to avoid accessing the settings at the module level.
+    """
+    return import_string(settings.MESSAGE_STORAGE)(request)

venv/lib/python3.10/site-packages/django/contrib/messages/storage/base.py

@@ -0,0 +1,183 @@
+from django.conf import settings
+from django.contrib.messages import constants, utils
+from django.utils.functional import SimpleLazyObject
+
+LEVEL_TAGS = SimpleLazyObject(utils.get_level_tags)
+
+
+class Message:
+    """
+    Represent an actual message that can be stored in any of the supported
+    storage classes (typically session- or cookie-based) and rendered in a view
+    or template.
+    """
+
+    def __init__(self, level, message, extra_tags=None):
+        self.level = int(level)
+        self.message = message
+        self.extra_tags = extra_tags
+
+    def _prepare(self):
+        """
+        Prepare the message for serialization by forcing the ``message``
+        and ``extra_tags`` to str in case they are lazy translations.
+        """
+        self.message = str(self.message)
+        self.extra_tags = str(self.extra_tags) if self.extra_tags is not None else None
+
+    def __eq__(self, other):
+        if not isinstance(other, Message):
+            return NotImplemented
+        return self.level == other.level and self.message == other.message
+
+    def __str__(self):
+        return str(self.message)
+
+    def __repr__(self):
+        extra_tags = f", extra_tags={self.extra_tags!r}" if self.extra_tags else ""
+        return f"Message(level={self.level}, message={self.message!r}{extra_tags})"
+
+    @property
+    def tags(self):
+        return " ".join(tag for tag in [self.extra_tags, self.level_tag] if tag)
+
+    @property
+    def level_tag(self):
+        return LEVEL_TAGS.get(self.level, "")
+
+
+class BaseStorage:
+    """
+    This is the base backend for temporary message storage.
+
+    This is not a complete class; to be a usable storage backend, it must be
+    subclassed and the two methods ``_get`` and ``_store`` overridden.
+    """
+
+    def __init__(self, request, *args, **kwargs):
+        self.request = request
+        self._queued_messages = []
+        self.used = False
+        self.added_new = False
+        super().__init__(*args, **kwargs)
+
+    def __len__(self):
+        return len(self._loaded_messages) + len(self._queued_messages)
+
+    def __iter__(self):
+        self.used = True
+        if self._queued_messages:
+            self._loaded_messages.extend(self._queued_messages)
+            self._queued_messages = []
+        return iter(self._loaded_messages)
+
+    def __contains__(self, item):
+        return item in self._loaded_messages or item in self._queued_messages
+
+    def __repr__(self):
+        return f"<{self.__class__.__qualname__}: request={self.request!r}>"
+
+    @property
+    def _loaded_messages(self):
+        """
+        Return a list of loaded messages, retrieving them first if they have
+        not been loaded yet.
+        """
+        if not hasattr(self, "_loaded_data"):
+            messages, all_retrieved = self._get()
+            self._loaded_data = messages or []
+        return self._loaded_data
+
+    def _get(self, *args, **kwargs):
+        """
+        Retrieve a list of stored messages. Return a tuple of the messages
+        and a flag indicating whether or not all the messages originally
+        intended to be stored in this storage were, in fact, stored and
+        retrieved; e.g., ``(messages, all_retrieved)``.
+
+        **This method must be implemented by a subclass.**
+
+        If it is possible to tell if the backend was not used (as opposed to
+        just containing no messages) then ``None`` should be returned in
+        place of ``messages``.
+        """
+        raise NotImplementedError(
+            "subclasses of BaseStorage must provide a _get() method"
+        )
+
+    def _store(self, messages, response, *args, **kwargs):
+        """
+        Store a list of messages and return a list of any messages which could
+        not be stored.
+
+        One type of object must be able to be stored, ``Message``.
+
+        **This method must be implemented by a subclass.**
+        """
+        raise NotImplementedError(
+            "subclasses of BaseStorage must provide a _store() method"
+        )
+
+    def _prepare_messages(self, messages):
+        """
+        Prepare a list of messages for storage.
+        """
+        for message in messages:
+            message._prepare()
+
+    def update(self, response):
+        """
+        Store all unread messages.
+
+        If the backend has yet to be iterated, store previously stored messages
+        again. Otherwise, only store messages added after the last iteration.
+        """
+        self._prepare_messages(self._queued_messages)
+        if self.used:
+            return self._store(self._queued_messages, response)
+        elif self.added_new:
+            messages = self._loaded_messages + self._queued_messages
+            return self._store(messages, response)
+
+    def add(self, level, message, extra_tags=""):
+        """
+        Queue a message to be stored.
+
+        The message is only queued if it contained something and its level is
+        not less than the recording level (``self.level``).
+        """
+        if not message:
+            return
+        # Check that the message level is not less than the recording level.
+        level = int(level)
+        if level < self.level:
+            return
+        # Add the message.
+        self.added_new = True
+        message = Message(level, message, extra_tags=extra_tags)
+        self._queued_messages.append(message)
+
+    def _get_level(self):
+        """
+        Return the minimum recorded level.
+
+        The default level is the ``MESSAGE_LEVEL`` setting. If this is
+        not found, the ``INFO`` level is used.
+        """
+        if not hasattr(self, "_level"):
+            self._level = getattr(settings, "MESSAGE_LEVEL", constants.INFO)
+        return self._level
+
+    def _set_level(self, value=None):
+        """
+        Set a custom minimum recorded level.
+
+        If set to ``None``, the default level will be used (see the
+        ``_get_level`` method).
+        """
+        if value is None and hasattr(self, "_level"):
+            del self._level
+        else:
+            self._level = int(value)
+
+    level = property(_get_level, _set_level, _set_level)

venv/lib/python3.10/site-packages/django/contrib/messages/storage/cookie.py

@@ -0,0 +1,248 @@
+import binascii
+import json
+
+from django.conf import settings
+from django.contrib.messages.storage.base import BaseStorage, Message
+from django.core import signing
+from django.http import SimpleCookie
+from django.utils.safestring import SafeData, mark_safe
+
+
+class MessageEncoder(json.JSONEncoder):
+    """
+    Compactly serialize instances of the ``Message`` class as JSON.
+    """
+
+    message_key = "__json_message"
+
+    def default(self, obj):
+        if isinstance(obj, Message):
+            # Using 0/1 here instead of False/True to produce more compact json
+            is_safedata = 1 if isinstance(obj.message, SafeData) else 0
+            message = [self.message_key, is_safedata, obj.level, obj.message]
+            if obj.extra_tags is not None:
+                message.append(obj.extra_tags)
+            return message
+        return super().default(obj)
+
+
+class MessageDecoder(json.JSONDecoder):
+    """
+    Decode JSON that includes serialized ``Message`` instances.
+    """
+
+    def process_messages(self, obj):
+        if isinstance(obj, list) and obj:
+            if obj[0] == MessageEncoder.message_key:
+                if obj[1]:
+                    obj[3] = mark_safe(obj[3])
+                return Message(*obj[2:])
+            return [self.process_messages(item) for item in obj]
+        if isinstance(obj, dict):
+            return {key: self.process_messages(value) for key, value in obj.items()}
+        return obj
+
+    def decode(self, s, **kwargs):
+        decoded = super().decode(s, **kwargs)
+        return self.process_messages(decoded)
+
+
+class MessagePartSerializer:
+    def dumps(self, obj):
+        return [
+            json.dumps(
+                o,
+                separators=(",", ":"),
+                cls=MessageEncoder,
+            )
+            for o in obj
+        ]
+
+
+class MessagePartGatherSerializer:
+    def dumps(self, obj):
+        """
+        The parameter is an already serialized list of Message objects. No need
+        to serialize it again, only join the list together and encode it.
+        """
+        return ("[" + ",".join(obj) + "]").encode("latin-1")
+
+
+class MessageSerializer:
+    def loads(self, data):
+        return json.loads(data.decode("latin-1"), cls=MessageDecoder)
+
+
+class CookieStorage(BaseStorage):
+    """
+    Store messages in a cookie.
+    """
+
+    cookie_name = "messages"
+    # uwsgi's default configuration enforces a maximum size of 4kb for all the
+    # HTTP headers. In order to leave some room for other cookies and headers,
+    # restrict the session cookie to 1/2 of 4kb. See #18781.
+    max_cookie_size = 2048
+    not_finished = "__messagesnotfinished__"
+    not_finished_json = json.dumps("__messagesnotfinished__")
+    key_salt = "django.contrib.messages"
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.signer = signing.get_cookie_signer(salt=self.key_salt)
+
+    def _get(self, *args, **kwargs):
+        """
+        Retrieve a list of messages from the messages cookie. If the
+        not_finished sentinel value is found at the end of the message list,
+        remove it and return a result indicating that not all messages were
+        retrieved by this storage.
+        """
+        data = self.request.COOKIES.get(self.cookie_name)
+        messages = self._decode(data)
+        all_retrieved = not (messages and messages[-1] == self.not_finished)
+        if messages and not all_retrieved:
+            # remove the sentinel value
+            messages.pop()
+        return messages, all_retrieved
+
+    def _update_cookie(self, encoded_data, response):
+        """
+        Either set the cookie with the encoded data if there is any data to
+        store, or delete the cookie.
+        """
+        if encoded_data:
+            response.set_cookie(
+                self.cookie_name,
+                encoded_data,
+                domain=settings.SESSION_COOKIE_DOMAIN,
+                secure=settings.SESSION_COOKIE_SECURE or None,
+                httponly=settings.SESSION_COOKIE_HTTPONLY or None,
+                samesite=settings.SESSION_COOKIE_SAMESITE,
+            )
+        else:
+            response.delete_cookie(
+                self.cookie_name,
+                domain=settings.SESSION_COOKIE_DOMAIN,
+                samesite=settings.SESSION_COOKIE_SAMESITE,
+            )
+
+    def _store(self, messages, response, remove_oldest=True, *args, **kwargs):
+        """
+        Store the messages to a cookie and return a list of any messages which
+        could not be stored.
+
+        If the encoded data is larger than ``max_cookie_size``, remove
+        messages until the data fits (these are the messages which are
+        returned), and add the not_finished sentinel value to indicate as much.
+        """
+        unstored_messages = []
+        serialized_messages = MessagePartSerializer().dumps(messages)
+        encoded_data = self._encode_parts(serialized_messages)
+        if self.max_cookie_size:
+            # data is going to be stored eventually by SimpleCookie, which
+            # adds its own overhead, which we must account for.
+            cookie = SimpleCookie()  # create outside the loop
+
+            def is_too_large_for_cookie(data):
+                return data and len(cookie.value_encode(data)[1]) > self.max_cookie_size
+
+            def compute_msg(some_serialized_msg):
+                return self._encode_parts(
+                    some_serialized_msg + [self.not_finished_json],
+                    encode_empty=True,
+                )
+
+            if is_too_large_for_cookie(encoded_data):
+                if remove_oldest:
+                    idx = bisect_keep_right(
+                        serialized_messages,
+                        fn=lambda m: is_too_large_for_cookie(compute_msg(m)),
+                    )
+                    unstored_messages = messages[:idx]
+                    encoded_data = compute_msg(serialized_messages[idx:])
+                else:
+                    idx = bisect_keep_left(
+                        serialized_messages,
+                        fn=lambda m: is_too_large_for_cookie(compute_msg(m)),
+                    )
+                    unstored_messages = messages[idx:]
+                    encoded_data = compute_msg(serialized_messages[:idx])
+
+        self._update_cookie(encoded_data, response)
+        return unstored_messages
+
+    def _encode_parts(self, messages, encode_empty=False):
+        """
+        Return an encoded version of the serialized messages list which can be
+        stored as plain text.
+
+        Since the data will be retrieved from the client-side, the encoded data
+        also contains a hash to ensure that the data was not tampered with.
+        """
+        if messages or encode_empty:
+            return self.signer.sign_object(
+                messages, serializer=MessagePartGatherSerializer, compress=True
+            )
+
+    def _encode(self, messages, encode_empty=False):
+        """
+        Return an encoded version of the messages list which can be stored as
+        plain text.
+
+        Proxies MessagePartSerializer.dumps and _encoded_parts.
+        """
+        serialized_messages = MessagePartSerializer().dumps(messages)
+        return self._encode_parts(serialized_messages, encode_empty=encode_empty)
+
+    def _decode(self, data):
+        """
+        Safely decode an encoded text stream back into a list of messages.
+
+        If the encoded text stream contained an invalid hash or was in an
+        invalid format, return None.
+        """
+        if not data:
+            return None
+        try:
+            return self.signer.unsign_object(data, serializer=MessageSerializer)
+        except (signing.BadSignature, binascii.Error, json.JSONDecodeError):
+            pass
+        # Mark the data as used (so it gets removed) since something was wrong
+        # with the data.
+        self.used = True
+        return None
+
+
+def bisect_keep_left(a, fn):
+    """
+    Find the index of the first element from the start of the array that
+    verifies the given condition.
+    The function is applied from the start of the array to the pivot.
+    """
+    lo = 0
+    hi = len(a)
+    while lo < hi:
+        mid = (lo + hi) // 2
+        if fn(a[: mid + 1]):
+            hi = mid
+        else:
+            lo = mid + 1
+    return lo
+
+
+def bisect_keep_right(a, fn):
+    """
+    Find the index of the first element from the end of the array that verifies
+    the given condition.
+    The function is applied from the pivot to the end of array.
+    """
+    lo = 0
+    hi = len(a)
+    while lo < hi:
+        mid = (lo + hi) // 2
+        if fn(a[mid:]):
+            lo = mid + 1
+        else:
+            hi = mid
+    return lo

venv/lib/python3.10/site-packages/django/contrib/messages/storage/fallback.py

@@ -0,0 +1,56 @@
+from django.contrib.messages.storage.base import BaseStorage
+from django.contrib.messages.storage.cookie import CookieStorage
+from django.contrib.messages.storage.session import SessionStorage
+
+
+class FallbackStorage(BaseStorage):
+    """
+    Try to store all messages in the first backend. Store any unstored
+    messages in each subsequent backend.
+    """
+
+    storage_classes = (CookieStorage, SessionStorage)
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.storages = [
+            storage_class(*args, **kwargs) for storage_class in self.storage_classes
+        ]
+        self._used_storages = set()
+
+    def _get(self, *args, **kwargs):
+        """
+        Get a single list of messages from all storage backends.
+        """
+        all_messages = []
+        for storage in self.storages:
+            messages, all_retrieved = storage._get()
+            # If the backend hasn't been used, no more retrieval is necessary.
+            if messages is None:
+                break
+            if messages:
+                self._used_storages.add(storage)
+            all_messages.extend(messages)
+            # If this storage class contained all the messages, no further
+            # retrieval is necessary
+            if all_retrieved:
+                break
+        return all_messages, all_retrieved
+
+    def _store(self, messages, response, *args, **kwargs):
+        """
+        Store the messages and return any unstored messages after trying all
+        backends.
+
+        For each storage backend, any messages not stored are passed on to the
+        next backend.
+        """
+        for storage in self.storages:
+            if messages:
+                messages = storage._store(messages, response, remove_oldest=False)
+            # Even if there are no more messages, continue iterating to ensure
+            # storages which contained messages are flushed.
+            elif storage in self._used_storages:
+                storage._store([], response)
+                self._used_storages.remove(storage)
+        return messages

venv/lib/python3.10/site-packages/django/contrib/messages/storage/session.py

@@ -0,0 +1,52 @@
+import json
+
+from django.contrib.messages.storage.base import BaseStorage
+from django.contrib.messages.storage.cookie import MessageDecoder, MessageEncoder
+from django.core.exceptions import ImproperlyConfigured
+
+
+class SessionStorage(BaseStorage):
+    """
+    Store messages in the session (that is, django.contrib.sessions).
+    """
+
+    session_key = "_messages"
+
+    def __init__(self, request, *args, **kwargs):
+        if not hasattr(request, "session"):
+            raise ImproperlyConfigured(
+                "The session-based temporary message storage requires session "
+                "middleware to be installed, and come before the message "
+                "middleware in the MIDDLEWARE list."
+            )
+        super().__init__(request, *args, **kwargs)
+
+    def _get(self, *args, **kwargs):
+        """
+        Retrieve a list of messages from the request's session. This storage
+        always stores everything it is given, so return True for the
+        all_retrieved flag.
+        """
+        return (
+            self.deserialize_messages(self.request.session.get(self.session_key)),
+            True,
+        )
+
+    def _store(self, messages, response, *args, **kwargs):
+        """
+        Store a list of messages to the request's session.
+        """
+        if messages:
+            self.request.session[self.session_key] = self.serialize_messages(messages)
+        else:
+            self.request.session.pop(self.session_key, None)
+        return []
+
+    def serialize_messages(self, messages):
+        encoder = MessageEncoder()
+        return encoder.encode(messages)
+
+    def deserialize_messages(self, data):
+        if data and isinstance(data, str):
+            return json.loads(data, cls=MessageDecoder)
+        return data

venv/lib/python3.10/site-packages/django/contrib/messages/test.py

@@ -0,0 +1,8 @@
+from .api import get_messages
+
+
+class MessagesTestMixin:
+    def assertMessages(self, response, expected_messages, *, ordered=True):
+        request_messages = list(get_messages(response.wsgi_request))
+        assertion = self.assertEqual if ordered else self.assertCountEqual
+        assertion(request_messages, expected_messages)

venv/lib/python3.10/site-packages/django/contrib/messages/utils.py

@@ -0,0 +1,12 @@
+from django.conf import settings
+from django.contrib.messages import constants
+
+
+def get_level_tags():
+    """
+    Return the message level tags.
+    """
+    return {
+        **constants.DEFAULT_TAGS,
+        **getattr(settings, "MESSAGE_TAGS", {}),
+    }

venv/lib/python3.10/site-packages/django/contrib/messages/views.py

@@ -0,0 +1,19 @@
+from django.contrib import messages
+
+
+class SuccessMessageMixin:
+    """
+    Add a success message on successful form submission.
+    """
+
+    success_message = ""
+
+    def form_valid(self, form):
+        response = super().form_valid(form)
+        success_message = self.get_success_message(form.cleaned_data)
+        if success_message:
+            messages.success(self.request, success_message)
+        return response
+
+    def get_success_message(self, cleaned_data):
+        return self.success_message % cleaned_data