guard_basic: Basic authentication guard

In fireproof: Authentication and Authorization for 'fiery' Servers

Basic authentication guard

Description

Basic authentication is a HTTP scheme that sends username and password as a : separated, base64 encoded string in the authorization header. Because it is effectively send in plain text (base64 encoding can easily be decoded) this should only ever be used along with other security measures such as https/ssl to avoid username and passwords being snooped from the request.

Usage

guard_basic(validate, user_info = NULL, realm = "private", name = "BasicAuth")

Arguments

validate	A function that will be called with the arguments username, password, realm, request, and response and returns TRUE if the user is valid, and FALSE otherwise. If the function returns a character vector it is considered to be authenticated and the return value will be understood as scopes the user is granted.
user_info	A function to extract user information from the username. It is called with a single argument: user which is the username used for the successful authentication. The function should return a new user_info list.
realm	The realm this authentication corresponds to. Will be returned to the client on a failed authentication attempt to inform them of the credentials required, though most often these days it is kept from the user.
name	The name of the guard

Details

This guard will use a user-provided function to test a username/password pair. It is up to the server implementation to handle the storage and testing of the passwords in a sensible and responsible way. See sodium::password_store() for a good first step towards responsible design.

Value

A GuardBasic R6 object

User information

guard_basic() automatically adds user information after authentication. By default it will set the provider field to "local" and the id field to the username used for logging in. Further, it will set the scopes field to any scopes returned by the authenticator function.

References

Basic authentication RFC

Examples

# Create a guard of dubious quality
basic <- guard_basic(
  validate = function(user, password) {
    user == "thomas" && password == "pedersen"
  },
  user_info = function(user) {
    new_user_info(
      name_given = "Thomas",
      name_middle = "Lin",
      name_family = "Pedersen"
    )
  }
)

# Add it to a fireproof plugin
fp <- Fireproof$new()
fp$add_guard(basic, "basic_auth")

# Use it in an endpoint
fp$add_auth("get", "/*", basic_auth)

fireproof documentation built on Dec. 17, 2025, 5:09 p.m.