CGI::Header - Adapter for CGI::header() function
use CGI::Header; # CGI.pm-compatible HTTP header properties my $header = { -attachment => 'foo.gif', -charset => 'utf-7', -cookie => [ $cookie1, $cookie2 ], # CGI::Cookie objects -expires => '+3d', -nph => 1, -p3p => [qw/CAO DSP LAW CURa/], -target => 'ResultsWindow', -type => 'image/gif' }; # create a CGI::Header object my $h = CGI::Header->new( $header ); # update $header $h->set( 'Content-Length' => 3002 ); $h->delete( 'Content-Disposition' ); $h->clear; $h->header; # same reference as $header
This document referes to CGI::Header version 0.19.
This module is a utility class to manipulate a hash reference received by the header() function provided by CGI.pm. This class is, so to speak, a subclass of Hash, while Perl5 doesn't provide a built-in class called Hash.
header()
This module isn't the replacement of the function. Although this class implements as_string() method, the function should stringify the reference in most cases.
as_string()
This module can be used in the following situation:
For example, CGI::Application implements header_add() method which can be used to add CGI.pm-compatible HTTP header properties. Instances of CGI applications often hold those properties.
header_add()
my $header = { -type => 'text/plain' };
Since property names are case-insensitive, application developers have to normalize them manually when they specify header properties. CGI::Header normalizes them automatically.
use CGI::Header; my $h = CGI::Header->new( $header ); $h->set( 'Content-Length' => 3002 ); # add Content-Length header $header; # => { # -type => 'text/plain', # -content_length => '3002', # }
use CGI; print CGI::header( $header ); # Content-length: 3002 # Content-Type: text/plain; charset=ISO-8859-1 #
header() function just stringifies given header properties. This module can be used to generate PSGI-compatible header array references. See "EXAMPLES".
Given a header hash reference, returns a CGI::Header object which holds a reference to the original given argument:
my $header = { -type => 'text/plain' }; my $h = CGI::Header->new( $header ); $h->header; # same reference as $header
The object updates the reference when called write methods like set(), delete() or clear():
set()
delete()
clear()
# updates $header $h->set( 'Content-Length' => 3002 ); $h->delete( 'Content-Disposition' ); $h->clear;
You can also pass the reference to the hash which contains your current environment, preceded by the header hash reference:
my $h = CGI::Header->new( $header, \%ENV ); $h->env; # => \%ENV
NOTE: In this case, new() doesn't check whether property names of $header are normalized or not at all, and so you have to rehash() the header hash reference explicitly when you aren't sure that they are normalized.
new()
$header
rehash()
It's roughly equivalent to:
my $h = CGI::Header->new({ -type => 'text/plain', ... })->rehash;
Unlike rehash(), if a property name is duplicated, that property will be overwritten silently:
my $h = CGI::Header->new( -Type => 'text/plain', Content_Type => 'text/html' ); $h->header->{-type}; # => "text/html"
In addition to CGI.pm-compatible HTTP header properties, you can specify '-env' property which represents your current environment:
my $h = CGI::Header->new( -type => 'text/plain', -env => \%ENV, ); $h->header; # => { -type => 'text/plain' } $h->env; # => \%ENV
A shortcut for:
my $header = CGI::Header->new({ -type => $media_type });
Returns the reference to the hash which contains your current environment. env() defaults to \%ENV. This module depends on the following elements of env():
env()
\%ENV
SERVER_PROTOCOL SERVER_SOFTWARE
Returns the header hash reference associated with this CGI::Header object. You can always pass the header hash to CGI::header() function to generate CGI response headers:
CGI::header()
print CGI::header( $header->header );
Rebuilds the header hash to normalize parameter names without changing the reference. Returns this object itself. If parameter names aren't normalized, the methods listed below won't work as you expect.
my $h1 = $header->header; # => { # '-content_type' => 'text/plain', # 'Set-Cookie' => 'ID=123456; path=/', # 'expires' => '+3d', # '-target' => 'ResultsWindow', # '-content-length' => '3002' # } $header->rehash; my $h2 = $header->header; # same reference as $h1 # => { # '-type' => 'text/plain', # '-cookie' => 'ID=123456; path=/', # '-expires' => '+3d', # '-target' => 'ResultsWindow', # '-content_length' => '3002' # }
Normalized parameter names are:
'Content-Length' -> 'content-length'
'content-length' -> '-content-length'
'-content-length' -> '-content_length'
CGI::header() also accepts aliases of parameter names. This module converts them as follows:
'-content_type' -> '-type' '-set_cookie' -> '-cookie' '-cookies' -> '-cookie' '-window_target' -> '-target' '-uri' -> '-location' '-url' -> '-location'
If a property name is duplicated, throws an exception:
$header->header; # => { # -Type => 'text/plain', # Content_Type => 'text/html', # } $header->rehash; # die "Property '-type' already exists"
Get or set the value of the header field. The header field name ($field) is not case sensitive. You can use underscores as a replacement for dashes in header names.
$field
# field names are case-insensitive $header->get( 'Content-Length' ); $header->get( 'content-length' );
The $value argument may be a plain string or a reference to an array of CGI::Cookie objects for the Set-Cookie header.
$value
$header->set( 'Content-Length' => 3002 ); my $length = $header->get( 'Content-Length' ); # => 3002 # $cookie1 and $cookie2 are CGI::Cookie objects $header->set( 'Set-Cookie' => [$cookie1, $cookie2] ); my $cookies = $header->get( 'Set-Cookie' ); # => [ $cookie1, $cookie2 ]
Returns a Boolean value telling whether the specified field exists.
if ( $header->exists('ETag') ) { ... }
Deletes the specified field form CGI response headers. Returns the value of the deleted field.
my $value = $header->delete( 'Content-Disposition' ); # => 'inline'
This will remove all header fields.
Returns true if the header contains no key-value pairs.
$header->clear; if ( $header->is_empty ) { # true ... }
Returns a copy of this CGI::Header object. It's identical to:
my %copy = %{ $header->header }; # shallow copy my $clone = CGI::Header->new( \%copy, $header->env );
Can be used to turn the page into an attachment. Represents suggested name for the saved file.
$header->attachment( 'genome.jpg' ); my $filename = $header->attachment; # => "genome.jpg"
In this case, the outgoing header will be formatted as:
Content-Disposition: attachment; filename="genome.jpg"
Represents P3P tags. The parameter can be an array or a space-delimited string. Returns a list of P3P tags. (In scalar context, returns the number of P3P tags.)
$header->p3p_tags(qw/CAO DSP LAW CURa/); # or $header->p3p_tags( 'CAO DSP LAW CURa' ); my @tags = $header->p3p_tags; # => ("CAO", "DSP", "LAW", "CURa") my $size = $header->p3p_tags; # => 4
P3P: policyref="/w3c/p3p.xml", CP="CAO DSP LAW CURa"
The Expires header gives the date and time after which the entity should be considered stale. You can specify an absolute or relative expiration interval. The following forms are all valid for this field:
$header->expires( '+30s' ); # 30 seconds from now $header->expires( '+10m' ); # ten minutes from now $header->expires( '+1h' ); # one hour from now $header->expires( 'now' ); # immediately $header->expires( '+3M' ); # in three months $header->expires( '+10y' ); # in ten years time # at the indicated time & date $header->expires( 'Thu, 25 Apr 1999 00:40:33 GMT' );
If set to a true value, will issue the correct headers to work with a NPH (no-parse-header) script.
$header->nph( 1 ); my $nph = $header->nph; # => 1
Returns the list of distinct field names present in the header in a random order. The field names have case as returned by CGI::header().
my @fields = $header->field_names; # => ( 'Set-Cookie', 'Content-length', 'Content-Type' )
Apply a subroutine to each header field in turn. The callback routine is called with two parameters; the name of the field and a value. If the Set-Cookie header is multi-valued, then the routine is called once for each value. Any return values of the callback routine are ignored.
my @lines; $header->each(sub { my ( $field, $value ) = @_; push @lines, "$field: $value"; }); print join @lines, "\n"; # Content-length: 3002 # Content-Type: text/plain
Returns pairs of fields and values.
# $cookie1 and $cookie2 are CGI::Cookie objects my $header = CGI::Header->new( -cookie => [$cookie1, $cookie2] ); $header->flatten; # => ( # "Set-Cookie" => "$cookie1", # "Set-Cookie" => "$cookie2", # ... # ) $header->flatten(1); # => ( # "Set-Cookie" => $cookie1, # "Set-Cookie" => $cookie2, # ... # ) $header->flatten(0); # => ( # "Set-Cookie" => [$cookie1, $cookie2], # ... # )
Returns the header fields as a formatted MIME header. The optional $eol parameter specifies the line ending sequence to use. The default is \015\012.
$eol
\015\012
When valid multi-line headers are included, this method will always output them back as a single line, according to the folding rules of RFC 2616: the newlines will be removed, while the white space remains.
Unlike CGI.pm, when invalid newlines are included, this module removes them instead of throwing exceptions.
If $header->nph is true, the Status-Line will be added to the beginning of response headers automatically.
$header->nph
$header->nph(1); $header->as_string; # HTTP/1.1 200 OK # Server: Apache/1.3.27 (Unix) # ...
use CGI::Header; my $header = { -type => 'text/plain' }; tie my %header => 'CGI::Header' => $header; # update $header $header{'Content-Length'} = 3002; delete $header{'Content-Disposition'}; %header = (); tied( %header )->header; # same reference as $header
Above methods are aliased as follows:
TIEHASH -> new FETCH -> get STORE -> set DELETE -> delete CLEAR -> clear EXISTS -> exists SCALAR -> !is_empty
You can also iterate through the tied hash:
my @fields = keys %header; my @values = values %header; my ( $field, $value ) = each %header;
See also perltie.
use CGI::Header; use HTTP::Headers; my @header_props = ( -type => 'text/plain', ... ); my $h = HTTP::Headers->new( CGI::Header->new(@header_props)->flatten ); $h->header( 'Content-Type' ); # => "text/plain"
use parent 'CGI::PSGI'; use CGI::Header; use Plack::Util; sub psgi_header { my $self = shift; my @args = ref $_[0] eq 'HASH' ? %{ $_[0] } : @_; my $header = CGI::Header->new( -charset => $self->charset, @args, -env => $self->env, ); $header->set( 'Pragma' => 'no-cache' ) if $self->cache; my $status = $header->delete('Status') || '200 OK'; $status =~ s/\D*$//; if ( Plack::Util::status_with_no_entity_body($status) ) { $header->delete( $_ ) for qw( Content-Type Content-Length ); } my @headers = $header->flatten; # remove the Server header splice @headers, 0, 2 if $header->nph; $status, \@headers; }
See also CGI::Emulate::PSGI, CGI::PSGI.
This module is compatible with CGI.pm 3.51 or higher.
Since the following strings conflict with property names, you can't use them as field names ($field):
"Attachment" "Charset" "Cookie" "Cookies" "NPH" "Target" "Type"
You can set the Content-Type header to neither undef nor an empty:
# wrong $header->set( 'Content-Type' => undef ); $header->set( 'Content-Type' => q{} );
Use delete() instead:
$header->delete('Content-Type');
If one of the following conditions is met, the Date header will be set automatically, and also the header field will become read-only:
if ( $header->nph or $header->get('Set-Cookie') or $header->expires ) { my $date = $header->get('Date'); # => HTTP-Date (current time) $header->set( 'Date' => 'Thu, 25 Apr 1999 00:40:33 GMT' ); # wrong $header->delete('Date'); # wrong }
You can't assign to the Expires header directly because the following behavior will surprise us:
# wrong $header->set( 'Expires' => '+3d' ); my $value = $header->get('Expires'); # => "Thu, 25 Apr 1999 00:40:33 GMT" (not "+3d")
Use expires() instead:
$header->expires('+3d');
You can't assign to the P3P header directly:
# wrong $header->set( 'P3P' => '/path/to/p3p.xml' );
CGI::header() restricts where the policy-reference file is located, and so you can't modify the location (/w3c/p3p.xml). You're allowed to set P3P tags using p3p_tags().
/w3c/p3p.xml
p3p_tags()
If the following condition is met, the Server header will be set automatically, and also the header field will become read-only:
if ( $header->nph ) { my $server = $header->get('Server'); # => $header->env->{SERVER_SOFTWARE} $header->set( 'Server' => 'Apache/1.3.27 (Unix)' ); # wrong $header->delete( 'Server' ); # wrong }
CGI, Plack::Util::headers(), HTTP::Headers
There are no known bugs in this module. Please report problems to ANAZAWA (anazawa@cpan.org). Patches are welcome.
Ryo Anazawa (anazawa@cpan.org)
This module is free software; you can redistibute it and/or modify it under the same terms as Perl itself. See perlartistic.
To install CGI::Header, copy and paste the appropriate command in to your terminal.
cpanm
cpanm CGI::Header
CPAN shell
perl -MCPAN -e shell install CGI::Header
For more information on module installation, please visit the detailed CPAN module installation guide.