The aim of this package is to provide a set of functions to interact with CERN’s LDAP servers, allowing to lookup users by login and full name and the membership of user groups. The output is normally displayed in read-only buffers. Below you can find a list of variables that can be customised and also the commands that this package provides. It’s recommended though to read the documentation of each variable and function as this document typically contains only summaries and brief explanations.

Even though it’s obviously tailored to the CERN context and hence with a rather small audience, this package might also serve as inspiration for others learning how to talk to LDAP servers using Emacs.

Licence

See COPYING.

Disclaimer

This Emacs package has no affiliation whatsoever with CERN or the CERN IT department and it’s hence not maintained as part of any CERN project.

However, the current maintainer (who turns out to be working for CERN at the moment) will be happy to discuss changes and give a helping hand but please note that developing cern-ldap.el is not part of his paid job.

Download and installation

The source code is available in Sourcehut and automatically mirrored to Github for convenience:

• Sourcehut: https://git.sr.ht/~nbarrientos/cern-ldap.el
• Github (mirror): https://github.com/nbarrientos/cern-ldap.el

Manual installation

From MELPA

The latest version (current master) of this software can be installed directly from MELPA. Firstly, configure MELPA (upstream instructions). Then, refresh the local package list and install cern-ldap.

M-x package-refresh-contents RET
M-x package-install RET cern-ldap RET

With use-package

From MELPA

See above for instructions on how to setup MELPA first.

(use-package cern-ldap
  :ensure t
  :custom
  (cern-ldap-buffer-name-format "*LDAP (%t) %l*")
  (cern-ldap-user-full-name-matching-type 'strict))

From sources

Example installation with use-package using a local copy:

(use-package cern-ldap
  :ensure nil
  :load-path "~/.emacs.d/local-packages/cern-ldap.el"
  :custom
  (cern-ldap-server-url "ldap://localhost:1389"))

Don’t forget to clone the source code into the load path specified above (or any other of your choice).

Doom Emacs

• Add the following to ~/.doom.d/packages.el:

(package! cern-ldap)

• Include your customisations in ~/.doom.d/config.el, for example:

(use-package! cern-ldap
  :custom
  (cern-ldap-buffer-name-format "*LDAP (%t) %l*")
  (cern-ldap-user-full-name-matching-type 'strict))

Contributing

Send patches and/or comments to the mailing list.

Customisation options

The package allows the user to customise the behaviour of the code in several ways. Here’s just a list of the customisation variables for quick reference:

• cern-ldap-server-url
• cern-ldap-buffer-name-format
• cern-ldap-finish-hook
• cern-ldap-user-lookup-location-key
• cern-ldap-user-lookup-login-key
• cern-ldap-user-lookup-full-name-key
• cern-ldap-user-full-name-matching-type
• cern-ldap-user-displayed-attributes
• cern-ldap-user-group-membership-filter
• cern-ldap-user-sort-key

For more information just run M-x customize-group cern-ldap or read the documentation of each of the variables listed above, for example by running M-x describe-variable cern-ldap-server-url.

User interface

With explicit input

These commands will always prompt for user input using the minibuffer.

• cern-ldap-user-by-location: Lookup a user (or several) by physical location. With prefix argument, return more information. Only primary accounts will be listed.
• cern-ldap-user-by-login: Lookup a user by login. With prefix argument, return more information.
• cern-ldap-user-by-full-name: Lookup a user (or several) by full name. The search query is enclosed in * by default, making the search query more greedy (see cern-ldap-user-full-name-matching-type).
• cern-ldap-group: Lookup the members of a group by name. With prefix argument, do it non-recursive.

Please refer to the built-in help of each function for further information.

With implicit input

The following commands fish the required input from the current buffer, either from the active region or from the word/line at point. The word is collected with superword-mode enabled so for instance groups with dashes are picked up.

• cern-ldap-user-by-login-dwim
• cern-ldap-user-by-location-dwim
• cern-ldap-user-by-full-name-dwim
• cern-ldap-group-dwim

Please refer to the built-in help of each function for further information.

Keybindings

No keybindings, keymaps or global minor modes are provided. It’s up to the user to configure them to their liking.

Combining with transient

It might be a good idea to pack these commands in a transient menu, for example:

(transient-define-prefix my/cern-ldap-dispatch ()
  "Dispatch CERN LDAP related commands."
  [["LDAP user (by login)"
    ("U" "Dwim" cern-ldap-user-by-login-dwim)
    ("u" "Ask" cern-ldap-user-by-login)]
   ["LDAP user (by full name)"
    ("F" "Dwim" cern-ldap-user-by-full-name-dwim)
    ("f" "Ask" cern-ldap-user-by-full-name)]
   ["LDAP user (by location)"
    ("L" "Dwim" cern-ldap-user-by-location-dwim)
    ("l" "Ask" cern-ldap-user-by-location)]
   ["LDAP group"
    ("G" "Dwim" cern-ldap-group-dwim)
    ("g" "Ask" cern-ldap-group)]])

Limitations

1. Support for paginated LDAP results is limited in Emacs so, at the moment, it’s not possible to discover the membership of groups for which the server decides to split the results. The CERN LDAP servers start enforcing pagination when there are more than 1500 results returned. For the time being groups this big will be signalled as “empty”.