Plack::Util(3pm) User Contributed Perl Documentation Plack::Util(3pm)
NAME
Plack::Util - Utility subroutines for Plack server and framework developers
FUNCTIONS
TRUE, FALSE
my $true = Plack::Util::TRUE;
my $false = Plack::Util::FALSE;
Utility constants to include when you specify boolean variables in $env hash (e.g. "psgi.multithread").
load_class
my $class = Plack::Util::load_class($class [, $prefix ]);
Constructs a class name and "require" the class. Throws an exception if the .pm file for the class is not found, just with the built-in
"require".
If $prefix is set, the class name is prepended to the $class unless $class begins with "+" sign, which means the class name is already
fully qualified.
my $class = Plack::Util::load_class("Foo"); # Foo
my $class = Plack::Util::load_class("Baz", "Foo::Bar"); # Foo::Bar::Baz
my $class = Plack::Util::load_class("+XYZ::ZZZ", "Foo::Bar"); # XYZ::ZZZ
is_real_fh
if ( Plack::Util::is_real_fh($fh) ) { }
returns true if a given $fh is a real file handle that has a file descriptor. It returns false if $fh is PerlIO handle that is not
really related to the underlying file etc.
content_length
my $cl = Plack::Util::content_length($body);
Returns the length of content from body if it can be calculated. If $body is an array ref it's a sum of length of each chunk, if $body
is a real filehandle it's a remaining size of the filehandle, otherwise returns undef.
set_io_path
Plack::Util::set_io_path($fh, "/path/to/foobar.txt");
Sets the (absolute) file path to $fh filehandle object, so you can call "$fh->path" on it. As a side effect $fh is blessed to an
internal package but it can still be treated as a normal file handle.
This module doesn't normalize or absolutize the given path, and is intended to be used from Server or Middleware implementations. See
also IO::File::WithPath.
foreach
Plack::Util::foreach($body, $cb);
Iterate through $body which is an array reference or IO::Handle-like object and pass each line (which is NOT really guaranteed to be a
line) to the callback function.
It internally sets the buffer length $/ to 65536 in case it reads the binary file, unless otherwise set in the caller's code.
load_psgi
my $app = Plack::Util::load_psgi $psgi_file_or_class;
Load "app.psgi" file or a class name (like "MyApp::PSGI") and require the file to get PSGI application handler. If the file can't be
loaded (e.g. file doesn't exist or has a perl syntax error), it will throw an exception.
Security: If you give this function a class name or module name that is loadable from your system, it will load the module. This could
lead to a security hole:
my $psgi = ...; # user-input: consider "Moose.pm"
$app = Plack::Util::load_psgi($psgi); # this does 'require "Moose.pm"'!
Generally speaking, passing an external input to this function is considered very insecure. But if you really want to do that, be sure
to validate the argument passed to this function. Also, if you do not want to accept an arbitrary class name but only load from a file
path, make sure that the argument $psgi_file_or_class begins with "/" so that Perl's built-in do function won't search the include
path.
run_app
my $res = Plack::Util::run_app $app, $env;
Runs the $app by wrapping errors with eval and if an error is found, logs it to "$env->{'psgi.errors'}" and returns the template 500
Error response.
header_get, header_exists, header_set, header_push, header_remove
my $hdrs = [ 'Content-Type' => 'text/plain' ];
my $v = Plack::Util::header_get($hdrs, $key); # First found only
my @v = Plack::Util::header_get($hdrs, $key);
my $bool = Plack::Util::header_exists($hdrs, $key);
Plack::Util::header_set($hdrs, $key, $val); # overwrites existent header
Plack::Util::header_push($hdrs, $key, $val);
Plack::Util::header_remove($hdrs, $key);
Utility functions to manipulate PSGI response headers array reference. The methods that read existent header value handles header name
as case insensitive.
my $hdrs = [ 'Content-Type' => 'text/plain' ];
my $v = Plack::Util::header_get($hdrs, 'content-type'); # 'text/plain'
headers
my $headers = [ 'Content-Type' => 'text/plain' ];
my $h = Plack::Util::headers($headers);
$h->get($key);
if ($h->exists($key)) { ... }
$h->set($key => $val);
$h->push($key => $val);
$h->remove($key);
$h->headers; # same reference as $headers
Given a header array reference, returns a convenient object that has an instance methods to access "header_*" functions with an OO
interface. The object holds a reference to the original given $headers argument and updates the reference accordingly when called write
methods like "set", "push" or "remove". It also has "headers" method that would return the same reference.
status_with_no_entity_body
if (status_with_no_entity_body($res->[0])) { }
Returns true if the given status code doesn't have any Entity body in HTTP response, i.e. it's 100, 101, 204 or 304.
inline_object
my $o = Plack::Util::inline_object(
write => sub { $h->push_write(@_) },
close => sub { $h->push_shutdown },
);
$o->write(@stuff);
$o->close;
Creates an instant object that can react to methods passed in the constructor. Handy to create when you need to create an IO stream
object for input or errors.
response_cb
See "RESPONSE CALLBACK" in Plack::Middleware for details.
perl v5.14.2 2011-11-02 Plack::Util(3pm)