Storage Backends

With version 1.0, the concept of Storage Backend was introduced to let developers choose how messages are persisted. Django Stored Messages provides a pool of backends out of the box and developers can extend the app providing their own implementation of a Storage Backend.

STORAGE_BACKEND settings parameter contains a string representing the backend class to use. If not specified, it defaults to the default backend.

Here follows a list of supported backends.

Default backend: Django ORM

'STORAGE_BACKEND': 'stored_messages.backends.DefaultBackend'

This is the default backend, it stores messages on the configured database using plain old Django models; it doesn’t need any additional configuration.

Redis backend

'STORAGE_BACKEND': 'stored_messages.backends.redis'

Users’ inbox and archives are persisted on a Redis instance. Keys are in the form user:<userid>:notifications user:<userid>:archive and values are lists. This backend needs the REDIS_URL settings to be specified, for example:

STORED_MESSAGES={
    'REDIS_URL': 'redis://username:password@localhost:6379/0',
}

Implementing your own backend

Custom backends should derive from StoredMessagesBackend class and implement all the methods:

class stored_messages.backends.base.StoredMessagesBackend

archive_list(user)

Retrieve all the messages in user‘s archive.

Params:

user: Django User instance

Return:

An iterable containing Message instances

archive_store(users, msg_instance)

Store a Message instance in the archive for a list of users.

Params:

users: a list or iterable containing Django User instances msg_instance: Message instance to persist in archive

Return:

None

Raise:

MessageTypeNotSupported if msg_instance cannot be managed by current backend

can_handle(msg_instance)

Determine if this backend can handle messages of the same type of msg_instance.

Params:

msg_instance: Message instance

Return:

True if type is correct, False otherwise

create_message(level, msg_text, extra_tags, date=None)

Create and return a Message instance. Instance types depend on backends implementation.

Params:

level: message level (see django.contrib.messages) msg_text: what you think it is extra_tags: see django.contrib.messages date: a DateTime (optional)

Return:

Message instance

expired_messages_cleanup()

Remove messages that have been expired.

Params:

None

Return:

None

inbox_delete(user, msg_id)

Remove a Message instance from user‘s inbox.

Params:

user: Django User instance msg_id: Message identifier

Return:

None

Raise:

MessageDoesNotExist if msg_id was not found

inbox_get(user, msg_id)

Retrieve a Message instance from user‘s inbox.

Params:

user: Django User instance msg_id: Message identifier

Return:

A Message instance

Raise:

MessageDoesNotExist if msg_id was not found

inbox_list(user)

Retrieve all the messages in user‘s Inbox.

Params:

user: Django User instance

Return:

An iterable containing Message instances

inbox_purge(user)

Delete all the messages in user‘s Inbox.

Params:

user: Django User instance

Return:

None

inbox_store(users, msg_instance)

Store a Message instance in the inbox for a list of users.

Params:

users: a list or iterable containing Django User instances msg_instance: Message instance to persist in inbox

Return:

None

Raise:

MessageTypeNotSupported if msg_instance cannot be managed by current backend