Technical discussion on the Community Solid Server (CSS)

by Maria Dimou (CERN), Ruben Verborgh (University of Gent)


Why this meeting:

Maria Dimou, CERN-Solid collaboration manager, proposed, via this policy document, the deployment of an in-house  CSS instance into production.
Reasons: CSS is open source and recently released. Therefore it has best chances to be up-to-date with the evolution of the specifications.
So far, the understanding and usage of the  CERN CSS instance  is not smooth.
This meeting is about agreeing with CSS developers on a collaboration that will unblock the situation towards a CERN endorsement of Solid in general and CSS, in particular.


Ruben Verborgh, Joachim Van Herwegen (CSS), Theo Meyer, Alain Bourgeois (SolidOS), Jan Schill, Maria Dimou (CERN).

Summary and Decisions:

  1. About ID Provider (IDP) and CSS:
    CSS comes with an IDP  and one can change it.
    The Solid OIDC is different from the standard OIDC. This is because it builds on top of it and returns extra values needed from Solid. Therefore it doesn't work with the CERN SSO or any other. Between (1) extending CSS to work with SSO or (2) using the Digita keycloak proxy, Ruben prefers (1), a solution that empowers CSS for the future.
    **ACTION** Joachim to look into this. Theo to create an issue, by taking the existing one on login method - and expand it into make CSS  compatible with SSO  systems in general.
  2. Discussion on the UI:
    Maria said is unusable for both inexperienced and very demanding users, mainly due to the lack of UI. Ruben said that no Solid server should have a UI for pods. The UI is the business of applications interfacing with the server. In the SolidOS development team Alain, Jeff, TimBL and especially Timea work on the UI. According to Ruben, the culture of navigating in one's filesystem is changing. Today a file finder doesn't exist on a smartphone. It is the application that gets what it needs from the file system. When discussing UIs the use case is important. Developers should build an application according to the Solid specifications. It will have its UI and will work with the Solid server.
    What is very important for successful apps is that they make no assumptions on where things are, in the solid apps i.e. MediaKraken assumes movies in a given directory, this is bad design.

    Some additional info from the agenda, not discussed:
    1. Currently there is no "account management" page in CSS but is actually being working on, should be available soon. Add / delete pod is also in the plan for css.
    2. Theo Meyer reports that using a CSS pod with a external WebID is not stable yet. It is not a problem coming from CSS, but a more general to Solid, in the sense that this kind of configuration is not well defined yet. Discussion. This point was not extensibly discussed at this meeting. Nevertheless, the fact is that CSS is highly customisable.

  3. Maria asked Ruben what the Flanders' government commits to exactly with their 7M euros. There will be several posts for application development and Solid awareness raising in Flanders.
  4. Conceptual issues are more at the centre of CSS project leadership interest. This appears in Ruben's blog and articles, the PhD position announcement and the Solid World interventions on Consent and Access to Knowledge. Nevertheless, in operational environments, a theory/practice compromise must be found. By facilitating the CSS introduction to CERN, with its  40+K impatient users, we would all gain and the project as well. Maria proposed a collaboration in one of the funded posts. Ruben was very positive. This will be discussed offline.

Please contact Maria Dimou for further information on the CERN-Solid collaboration.

Organized by

Maria Dimou