Flask-SimpleLDAP

Flask-SimpleLDAP provides LDAP authentication for Flask and is compatible with and tested on Python 3.10+.

Quickstart

First, install Flask-SimpleLDAP:

pip install flask-simpleldap

Flask-SimpleLDAP depends, and will install for you, a recent version of Flask (2.3.3 or later) and python-ldap. Please consult the python-ldap installation instructions if you get an error during installation.

Next, add an LDAP instance to your code and at least the three required configuration options. The complete sample from examples/basic_auth/app.py looks like this:

from flask import Flask, g
from flask_simpleldap import LDAP

app = Flask(__name__)
# app.config["LDAP_HOST"] = "ldap.example.org"  # defaults to localhost
app.config["LDAP_BASE_DN"] = "OU=users,dc=example,dc=org"
app.config["LDAP_USERNAME"] = "CN=user,OU=Users,DC=example,DC=org"
app.config["LDAP_PASSWORD"] = "password"

ldap = LDAP(app)

@app.route("/")
@ldap.basic_auth_required
def index():
    return f"Welcome, {g.ldap_username}!"

if __name__ == "__main__":
    app.run()

When the user visits the protected URL, the browser will prompt for the login and password via the built-in HTTP authentication window. Note that with the default value of LDAP_USER_OBJECT_FILTER the login is expected to match the userPrincipalName attribute of the LDAP user, e.g. me@mydomain.com.

Once you get the basic example working, check out the more complex ones:

• examples/groups demonstrates using:
  • @ldap.login_required for form/cookie-based auth, instead of basic HTTP authentication.
  • @ldap.group_required() to restrict access to pages based on the user's LDAP groups.
• examples/blueprints implements the same functionality, but uses Flask's application factories and blueprints.

OpenLDAP

Add the LDAP instance to your code and depending on your OpenLDAP configuration, add the following at least LDAP_USER_OBJECT_FILTER and LDAP_USER_OBJECT_FILTER.

from flask import Flask, g
from flask_simpleldap import LDAP

app = Flask(__name__)

# Base
app.config["LDAP_REALM_NAME"] = "OpenLDAP Authentication"
app.config["LDAP_HOST"] = "openldap.example.org"
app.config["LDAP_BASE_DN"] = "dc=users,dc=openldap,dc=org"
app.config["LDAP_USERNAME"] = "cn=user,ou=servauth-users,dc=users,dc=openldap,dc=org"
app.config["LDAP_PASSWORD"] = "password"

# OpenLDAP
app.config["LDAP_OBJECTS_DN"] = "dn"
app.config["LDAP_OPENLDAP"] = True
app.config["LDAP_USER_OBJECT_FILTER"] = "(&(objectclass=inetOrgPerson)(uid=%s))"

# Groups
app.config["LDAP_GROUP_MEMBERS_FIELD"] = "uniquemember"
app.config["LDAP_GROUP_OBJECT_FILTER"] = "(&(objectclass=groupOfUniqueNames)(cn=%s))"
app.config["LDAP_GROUP_MEMBER_FILTER"] = "(&(cn=*)(objectclass=groupOfUniqueNames)(uniquemember=%s))"
app.config["LDAP_GROUP_MEMBER_FILTER_FIELD"] = "cn"

ldap = LDAP(app)

@app.route("/")
@ldap.basic_auth_required
def index():
    return f"Welcome, {g.ldap_username}!"

if __name__ == "__main__":
    app.run()

Configuration