authentik/website/docs/expressions/index.md

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Expressions

Expressions allow you to write custom logic using Python code.

Expressions are used in different places throughout authentik, and can do different things.

:::info These functions/objects are available wherever expressions are used. For more specific information, see Expression Policies and Property Mappings :::

Global objects

  • ak_logger: structlog BoundLogger. (ref)
  • requests: requests Session object. (ref)

Generally available functions

regex_match(value: Any, regex: str) -> bool

Check if value matches Regular Expression regex.

Example:

return regex_match(request.user.username, '.*admin.*')

regex_replace(value: Any, regex: str, repl: str) -> str

Replace anything matching regex within value with repl and return it.

Example:

user_email_local = regex_replace(request.user.email, '(.+)@.+', '')

ak_is_group_member(user: User, **group_filters) -> bool

Check if user is member of a group matching **group_filters.

Example:

return ak_is_group_member(request.user, name="test_group")

ak_user_by(**filters) -> Optional[User]

Fetch a user matching **filters. Returns "None" if no user was found.

Example:

other_user = ak_user_by(username="other_user")

Comparing IP Addresses

To compare IP Addresses or check if an IP Address is within a given subnet, you can use the functions ip_address('192.0.2.1') and ip_network('192.0.2.0/24'). With these objects you can do arithmetic operations.

You can also check if an IP Address is within a subnet by writing the following:

ip_address('192.0.2.1') in ip_network('192.0.2.0/24')
# evaluates to True