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

NAME SYNOPSIS DESCRIPTION CONFIGURATION AUTHORS SEE ALSO

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;
};

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