NAME

       Plack::Middleware::AccessLog - Logs requests like Apache's log format

SYNOPSIS

         # in app.psgi
         use Plack::Builder;

         builder {
             enable "Plack::Middleware::AccessLog", format => "combined";
             $app;
         };

DESCRIPTION

       Plack::Middleware::AccessLog forwards the request to the given app and logs request and
       response details to the logger callback. The format can be specified using Apache-like
       format strings (or "combined" or "common" for the default formats). If none is specified
       "combined" is used.

       This middleware uses calculable Content-Length by checking body type, and cannot log the
       time taken to serve requests. It also logs the request before the response is actually
       sent to the client. Use Plack::Middleware::AccessLog::Timed if you want to log details
       after the response is transmitted (more like a real web server) to the client.

       This middleware is enabled by default when you run plackup as a default "development"
       environment.

CONFIGURATION

       format
             enable "Plack::Middleware::AccessLog",
                 format => '%h %l %u %t "%r" %>s %b "%{Referer}i" "%{User-agent}i"';

           Takes a format string (or a preset template "combined" or "custom") to specify the log
           format. This middleware uses Apache::LogFormat::Compiler to generate access_log lines.
           See more details on perldoc Apache::LogFormat::Compiler

              %%    a percent sign
              %h    REMOTE_ADDR from the PSGI environment, or -
              %l    remote logname not implemented (currently always -)
              %u    REMOTE_USER from the PSGI environment, or -
              %t    [local timestamp, in default format]
              %r    REQUEST_METHOD, REQUEST_URI and SERVER_PROTOCOL from the PSGI environment
              %s    the HTTP status code of the response
              %b    content length of the response
              %T    custom field for handling times in subclasses
              %D    custom field for handling sub-second times in subclasses
              %v    SERVER_NAME from the PSGI environment, or -
              %V    HTTP_HOST or SERVER_NAME from the PSGI environment, or -
              %p    SERVER_PORT from the PSGI environment
              %P    the worker's process id
              %m    REQUEST_METHOD from the PSGI environment
              %U    PATH_INFO from the PSGI environment
              %q    QUERY_STRING from the PSGI environment
              %H    SERVER_PROTOCOL from the PSGI environment

           Some of these format fields are only supported by middleware that subclasses
           "AccessLog".

           In addition, custom values can be referenced, using "%{name}", with one of the
           mandatory modifier flags "i", "o" or "t":

              %{variable-name}i    HTTP_VARIABLE_NAME value from the PSGI environment
              %{header-name}o      header-name header in the response
              %{time-format]t      localtime in the specified strftime format

       logger
             my $logger = Log::Dispatch->new(...);
             enable "Plack::Middleware::AccessLog",
                 logger => sub { $logger->log(level => 'debug', message => @_) };

           Sets a callback to print log message to. It prints to the "psgi.errors" output stream
           by default.

       char_handlers
             my $handlers = {
                 'z' => sub {
                     my ($env,$req) = @_;
                     return $env->{HTTP_X_FORWARDED_FOR};
                 }
             };

             enable "Plack::Middleware::AccessLog",
                 format => '%z %{HTTP_X_FORWARDED_FOR|REMOTE_ADDR}Z',
                 char_handlers => $handlers;

           Takes a hash reference and passes it to the underlying Apache::LogFormat::Compiler's
           "char_handlers".  For more details see "ADD CUSTOM FORMAT STRING" in
           Apache::LogFormat::Compiler.

       block_handlers
             my $handlers = {
                 'Z' => sub {
                     my ($block,$env,$req) = @_;
                     # block eq 'HTTP_X_FORWARDED_FOR|REMOTE_ADDR'
                     my ($main, $alt) = split('\|', $args);
                     return exists $env->{$main} ? $env->{$main} : $env->{$alt};
                 }
             };

             enable "Plack::Middleware::AccessLog",
                 format => '%z %{HTTP_X_FORWARDED_FOR|REMOTE_ADDR}Z',
                 block_handlers => $handlers;

           Takes a hash reference and passes it to the underlying Apache::LogFormat::Compiler's
           "block_handlers".  For more details see "ADD CUSTOM FORMAT STRING" in
           Apache::LogFormat::Compiler.

AUTHORS

       Tatsuhiko Miyagawa

       Masahiro Nagano

SEE ALSO

       Apache::LogFormat::Compiler, <http://httpd.apache.org/docs/2.2/mod/mod_log_config.html>
       Rack::CustomLogger