EPrints User Group 2015-01-13

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Access Control Layer

John Salter and John Beaman, University of Leeds


  • Hello: we're John Salter and John Beaman from the University of Leeds.
  • We've spent some time trying to write an Access Control system for EPrints. It's been a horror.
  • One of our use-cases is for Research Data, but it could be used on other repository types.

Out of the box User Access Control

  • EPrints (you all know what this is, right..?) has basic control at the document level - the 'security' field:
    • public (Open Access)
    • validuser (anyone who's got an account on that EPrints instance)
    • staffonly (Repository editors/admins)
  • This doesn't cover the requirements for some repositories...


  • Control access to EPrints, Documents
  • Control access based on:
    • User attributes (e.g. signed-in via Shibboleth)
    • Location / IP address (e.g. on-campus)
  • Simple interface to assign restrictions

EPACL: EPrints Access Control Layer

Modular Design

  • Doesn't overwrite any existing 'security' specified on documents.
  • Will be available as a standard EPrints Plugin (EPM package) via the EPrints Bazaar
  • ACL Authority modules governing different methods of Authentication (see later) can be developed separately
  • These modules can simply be 'dropped in' to the existing framework as required

ACL Objects

  • ACL Authority
    • Corresponds to a method of authentication (e.g. Shibboleth, LDAP etc.)
  • ACL Role
    • Authorised by an ACL Authority with zero or more 'filters' applied
    • Filters act as additional requirements (e.g. ACL_Authority='LDAP', Filter='dc=leeds.ac.uk')
  • ACL Group
    • Each ACL Group consists of one or more ACL Roles
    • The ACL Roles are combined within an ACL Group by being 'OR'ed or 'AND'ed together
    • One or more ACL Groups are applied to EPrints data objects (e.g. eprints, documents)
    • The ACL Groups applied to EPrints data objects are 'OR'ed or 'AND'ed together

Request vs User

  • Two basic steps to authorise access - request and user
  • First EPrints checks if the request has appropriate access rights
  • If so, any additional user requirements are also checked
  • If not, the request is denied (since the user's credentials are irrelevant at that point)

Dealing with rejection

  • What happens when someone is denied access?
    • Document landing pages
    • Restricted summary pages
    • Contact details to request access?

Summary Page citation style

  • How do we deal with rejected requests (i.e. what do we show)?
  • We can define different citation styles depending on whether the request is allowed or denied
  • 'Restricted' citations may be required (e.g. to satisfy the minimum metadata requirements of a DOI)

Document-level landing pages

  • Partly born out of DOI requirements
  • Individual documents may have their own DOI, so ideally need their own 'landing page'
  • Document landing pages should contain at least the mandatory metadata fields if linked from a DOI

The horrors (and the solutions)

  • The out-of-the-box document security is deep within EPrints (we learnt about doing some really cranky Perl-fu)
  • Documents don't use the SummaryPage - again this is deep in the code (we learnt lots about Eprints Triggers)
  • Apache 2.2 and 2.4 differ in the way they handle IP addresses (Seb did some patching of EPrints code - but this hasn't been released - may be in 3.3.13?)
  • All sorts of crazy inheritance complexities
  • EPrints doesn't use 'sessions' in the same way as most other web software. Sessions are only created when a user logs in (we think user accounts need to be automatically created - is this right? It would be useful for tracking re-use)
  • EPrints documentation is *ahem* offering room for improvement */ahem*...

Homeless thoughts

  • Summary Page citation style
  • Access logging
  • Login sources: login screen with multiple routes (tabs) / LDAP as additional route rather than default route
  • Modular design
  • Request vs User
  • Describe ACL_Group, ACL_Role, ACL_Authority
  • DOIs at Doc level = landing page citation style
  • Objects and SubObjects
  • Viewing (downloading for a document)