StoragesService::getStorages() will check the visibility of the backend
and auth mechanism for the storage, and if either are not visible to the
user (aka disabled by admin) then the storage will be filtered out. The
original method StoragesService::getAllStorages() still exists in case
such storages need to be detected, but its use is discouraged.
Failure to prepare the storage during backend or auth mechanism
manipulation will throw an InsufficientDataForMeaningfulAnswerException,
which is propagated to StorageNotAvailableException in the filesystem
layer via the FailedStorage helper class.
When a storage is unavailable not due to failure, but due to
insufficient data being available, a special 'indeterminate' status is
returned to the configuration UI.
A backend can now specify generic authentication schemes that it
supports, instead of specifying the parameters for its authentication
method directly. This allows multiple authentication mechanisms to be
implemented for a single scheme, providing altered functionality.
This commit introduces the backend framework for this feature, and so at
this point the UI will be broken as the frontend does not specify the
required information.
Terminology:
- authentication scheme
Parameter interface for the authentication method. A backend
supporting the 'password' scheme accepts two parameters, 'user' and
'password'.
- authentication mechanism
Specific mechanism implementing a scheme. Basic mechanisms may
forward configuration options directly to the backend, more advanced
ones may lookup parameters or retrieve them from the session
New dropdown selector for external storage configurations to select the
authentication mechanism to be used.
Authentication mechanisms can have visibilities, just like backends.
The API was extended too to make it easier to add/remove visibilities.
In addition, the concept of 'allowed visibility' has been introduced, so
a backend/auth mechanism can force a maximum visibility level (e.g.
Local storage type) that cannot be overridden by configuration in the
web UI.
An authentication mechanism is a fully instantiated implementation. This
allows an implementation to have dependencies injected into it, e.g. an
\OCP\IDB for database operations.
When a StorageConfig is being prepared for mounting, the authentication
mechanism implementation has manipulateStorage() called,
which inserts the relevant authentication method options into the
storage ready for mounting.
UserGlobalStoragesService reads the global storage configuration,
cherry-picking storages applicable to a user. Writing storages through
this service is forbidden, on punishment of throwing an exception.
Storage IDs may also be config hashes when retrieved from this service,
as it is unable to update the storages with real IDs.
As UserGlobalStoragesService and UserStoragesService share a bit of code
relating to users, that has been split into UserTrait. UserTrait also
allows for the user set to be overridden, rather than using the user
from IUserSession.
Config\ConfigAdapter has been reworked to use UserStoragesService and
UserGlobalStoragesService instead of
OC_Mount_Config::getAbsoluteMountPoints(), further reducing dependance
on that horrible static class.
Backends are registered to the BackendService through new data
structures:
Backends are concrete classes, deriving from
\OCA\Files_External\Lib\Backend\Backend. During construction, the
various configuration parameters of the Backend can be set, in a design
similar to Symfony Console.
DefinitionParameter stores a parameter configuration for an external
storage: name of parameter, human-readable name, type of parameter
(text, password, hidden, checkbox), flags (optional or not).
Storages in the StoragesController now get their parameters validated
server-side (fixes a TODO).
