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Configuration: placeholders

This page lists placeholder variables that can be used in KDL directives for routing, proxying, conditions, and logging.

Placeholders

Ferron supports the following placeholders for header values, subconditions, reverse proxying, and redirect destinations:

  • {path} - the request URI with path (for example, /index.html)
  • {path_and_query} - the request URI with path and query string (for example, /index.html?param=value)
  • {method} - the request method
  • {version} - the HTTP version of the request
  • {header:<header_name>} - the value of a header with the specified name (<header_name> is replaced with the name of the header, for example, Content-Type)
  • {scheme} - the scheme of the request URI (http or https), applicable only for subconditions, reverse proxying and redirect destinations.
  • {client_ip} - the client IP address, applicable only for subconditions, reverse proxying and redirect destinations.
  • {client_port} - the client port number, applicable only for subconditions, reverse proxying and redirect destinations.
  • {client_ip_canonical} (Ferron 2.3.0 or newer) - the client IP address in canonical form (IPv4-mapped IPv6 addresses, like ::ffff:127.0.0.1, are converted to IPv4, like 127.0.0.1), applicable only for subconditions, reverse proxying and redirect destinations.
  • {server_ip} - the server IP address, applicable only for subconditions, reverse proxying and redirect destinations.
  • {server_port} - the server port number, applicable only for subconditions, reverse proxying and redirect destinations.
  • {server_ip_canonical} (Ferron 2.3.0 or newer) - the server IP address in canonical form (IPv4-mapped IPv6 addresses, like ::ffff:127.0.0.1, are converted to IPv4, like 127.0.0.1), applicable only for subconditions, reverse proxying and redirect destinations.

Log placeholders

Ferron 2.0.0 and newer supports the following placeholders for access logs:

  • {path} - the request URI with path (for example, /index.html)
  • {path_and_query} - the request URI with path and query string (for example, /index.html?param=value)
  • {method} - the request method
  • {version} - the HTTP version of the request
  • {header:<header_name>} - the value of a header with the specified name (<header_name> is replaced with the name of the header, for example, Content-Type; -, if header is missing)
  • {scheme} - the scheme of the request URI (http or https).
  • {client_ip} - the client IP address.
  • {client_port} - the client port number.
  • {client_ip_canonical} (Ferron 2.3.0 or newer) - the client IP address in canonical form (IPv4-mapped IPv6 addresses, like ::ffff:127.0.0.1, are converted to IPv4, like 127.0.0.1).
  • {server_ip} - the server IP address.
  • {server_port} - the server port number.
  • {server_ip_canonical} (Ferron 2.3.0 or newer) - the server IP address in canonical form (IPv4-mapped IPv6 addresses, like ::ffff:127.0.0.1, are converted to IPv4, like 127.0.0.1).
  • {auth_user} - the username of the authenticated user (-, if not authenticated)
  • {timestamp} - the formatted timestamp of the entry
  • {status_code} - the HTTP status code of the response
  • {content_length} - the content length of the response (-, if not available)

These placeholders can be used both in log_format and in log_json additional property templates.