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OpenPaaS supports LemonLDAP authentication. If this is the first time you hear about LemonLDAP, check their website to explore that awesome software.

LemonLDAP protects OpenPaaS behind a proxy. OpenPaaS then authenticates users by reading HTTP trusted-headers forwarded from LemonLDAP. See more about it here.

When the user logs in to OpenPaaS, the following steps happen:

  1. The user goes to OpenPaaS and is redirected to login page of LemonLDAP
  2. The user enters credentials to log in and is redirected back to OpenPaaS
  3. OpenPaaS reads the trusted-headers forwarded from LemonLDAP, converts it to OpenPaaS user
  4. If the user is found in trusted-headers, OpenPaaS makes the user authenticated. It then stores the user object in database on first login or updates the existing user in database on next logins

Getting started

Install LemonLDAP::NG software

First, you need to install LemonLDAP::NG software. Have a look here.

Install LemonLDAP awesome module

Clone the repository:

git clone

Go into the module directory and install module dependencies

npm install --production

Next, you need to enable LemonLDAP awesome module for OpenPaaS. To do it, create a symbol link of this module in modules directory of OpenPaaS ESN then enable it in local configuration:

"modules": [
  "linagora.esn.lemonldap" // add this line

Once enabled, this module will be loaded with OpenPaaS and ready to work. The next step is to configure LemonLDAP virtualhost to protect OpenPaaS.

Configure LemonLDAP

To configure LemonLDAP, you must login to LemonLDAP manager page.

Add virtual host

LemonLDAP::NG configuration is built around Apache or Nginx virtual hosts. Each virtual host is a protected resource, with access rules, headers, POST data and options.

Access Rule

In LemonLDAP Manager page, go to Virtual Hosts » <your virtualhost> » Access Rule, click on New rule, then fill:

Commments: Protect home page
Regular expressions: ^/$
Rules: accept

In the same page, change the Default rule to unprotect to allow other resources of OpenPaaS to be accessible normaly from outside.

User provision

This module provisions users automatically on their first login. It converts the authenticated user information in trusted-headers to OpenPaaS user and creates a user instance on the storage layer (MongoDB).

The converter needs a mapping to know which field in headers is corresponding to the user attribute in OpenPaaS. You can configure this mapping in global configuration.

The configuration is applied for the whole application so it must be platform-wide configuration:

"domain_id" : null,
"modules": [{
  "name": "core",
  "configurations": [...]
}, {
  "name": "linagora.esn.lemonldap",
  "configurations": [{
    "name": "mapping",
    "value": {
      "ll-auth-user": "auth-user", // required, mapping for unique username (usually email)
      "ll-auth-domain": "auth-domain",  // required, mapping for user domain
      "lastname": "auth-name",
      "main_phone": "auth-phone",
  }, {


When the user logs out from OpenPaaS, he should be logged out from LemonLDAP and vice versa, when the user logs out from LemonLDAP, he should be logged out from OpenPaaS.

Logout from OpenPaaS then LemonLDAP

To achieve this behaviour, OpenPaaS redirects the user to a logout endpoint of LemonLDAP after his logout from OpenPaaS, hence the user is fully logged out from both services.

You can configure the logout endpoint in platform-wide configuration, it looks like:

"domain_id" : null,
"modules": [{
  "name": "core",
  "configurations": [...]
}, {
  "name": "linagora.esn.lemonldap",
  "configurations": [{
    "name": "logoutUrl",
    "value": ""
  }, {

That logout endpoint is something like depending on your LemonLDAP setup.

Logout from LemonLDAP then OpenPaaS

Once the user logs out from LemonLDAP, it then forwards the logout to other applications to close their sessions. LemonLDAP has a logout forward mechanism, that will add a step in logout process, to send logout requests (indeed, GET requests on application logout URL) inside hidden iframes.

In LemonLDAP Manager page, go to General parameters » Advanced parameters » Logout forward and click on Add a key, then fill:

Key: application name, e.g. OpenPaaS
Value: OpenPaaS logout URL, e.g.

Note that the request on logout URL will be sent after user is disconnected, so you should unprotect this URL if it is protected by a LemonLDAP Handler. Forturnately, this is done above by setting the Default rule to unprotect.