Some format specifiers take a mandatory key, enclosed in curly braces between percent sign and the actual specifier. CLF means "common log format", if a value is zero, a '-' is used instead.
table(table table-striped).
|_. specifier |_. description |
| %% | Percent sign itself |
| %a | Remote IP-address |
| %A | Local IP-address|
| %b | Size of response in bytes, excluding HTTP headers (CLF) |
| %B | Size of response in bytes, excluding HTTP headers |
| %{foobar}C | (*not implemented yet*) Contents of cookie @foobar@ of the request |
| %D | Time taken to serve the request in microseconds |
| %{foobar}e | Contents of the request environment variable @foobar@ |
| %f | Path to physical file |
| %h | Remote IP-address (same as @%a@) |
| %{foobar}i | Contents of request header @foobar@ |
| %m | Request method (GET, POST, etc) |
| %{foobar}o | Contents of response header @foobar@ |
| %p | Local port |
| %q | Querystring |
| %r | First line of request (GET /foo.html?bar HTTP/1.1) |
| %s | Response status code |
| %t | Time/date the request was received in standard english format |
| %T | Time taken to serve the request in seconds |
| %u | Authed user (from mod_auth). Same as @%{REMOTE_USER}e@ |
| %U | Request path (not including querystring) |
| %v | Server name as set through the @server.name@ option or the request hostname of @server.name@ is not set |
| %V | Request hostname |
| %X | Connection status after response: "X" if aborted before completed, "+" if keepalive, "-" if no keepalive |
| %I | Bytes received including HTTP headers and request body |
| %O | Bytes sent including HTTP headers and response body |
Modifiers right after the percent sign like Apache provides them, are not supported. "<" or ">" are ignored, everything else results in a parse error. Specifiers supported by Apache but not lighty: %l, %n, %P
