Frontend
The frontend service translates various owncloud related HTTP APIs to CS3 requests.
Endpoints Overview
Currently, the frontend service handles requests for three functionalities, which are appprovider, archiver, datagateway and ocs.
appprovider
The appprovider endpoint, by default /app, forwards HTTP requests to the CS3 App Registry API
archiver
The archiver endpoint, by default /archiver, implements zip and tar download for collections of files. It will internally use the CS3 API to initiate downloads and then stream the individual files as part of a compressed file.
datagateway
The datagateway endpoint, by default /data, forwards file up- and download requests to the correct CS3 data provider. OCIS starts a dataprovider as part of the storage-* services. The routing happens based on the JWT that was created by a storage provider in response to an InitiateFileDownload or InitiateFileUpload request.
ocs
The ocs endpoint, by default /ocs, implements the ownCloud 10 Open Collaboration Services API by translating it into CS3 API requests. It can handle users, groups, capabilities and also implements the files sharing functionality on top of CS3. The /ocs/v[12].php/cloud/user/signing-key is currently handled by the dedicated ocs service.
Scalability
While the frontend service does not persist any data it does cache Stat() responses and user information. Therefore, multiple instances of this service can be spawned in a bigger deployment like when using container orchestration with Kubernetes, when configuring FRONTEND_OCS_RESOURCE_INFO_CACHE_TYPE=redis and the related config options.
Define Read-Only Attributes
A lot of user management is made via the standardized libregraph API. Depending on how the system is configured, there might be some user attributes that an ocis instance admin can't change because of properties coming from an external LDAP server, or similar. This can be the case when the ocis admin is not the LDAP admin. To ease life for admins, there are hints as capabilites telling the frontend which attributes are read-only to enable a different optical representation like being grayed out. To configure these hints, use the environment variable FRONTEND_READONLY_USER_ATTRIBUTES, which takes a comma separated list of attributes, see the envvar for supported values.
You can find more details regarding available attributes at the libre-graph-api openapi-spec and on owncloud.dev.