CGI::Header - Handle CGI.pm-compatible HTTP header properties
use CGI;
use CGI::Header;
my $query = CGI->new;
# 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 => $header,
query => $query
);
# update $header
$h->set( 'Content-Length' => 3002 ); # overwrite
$h->delete('Content-Disposition'); # => 3002
$h->clear; # => $self
$h->header; # same reference as $header
This document refers to CGI::Header version 0.44.
This module is compatible with CGI.pm 3.51 or higher.
This module is a utility class to manipulate a hash reference received by CGI.pm's header() method.
This module isn't the replacement of the CGI::header() function, but complements CGI.pm.
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.
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 => $header );
$h->set( 'Content-Length' => 3002 ); # add Content-Length header
$header;
# => {
# 'type' => 'text/plain',
# 'content-length' => '3002',
# }
use CGI; print CGI::header( $header ); # Content-length: 3002 # Content-Type: text/plain; charset=ISO-8859-1 #
header() function just stringifies given header properties. This module can be used to generate PSGI-compatible header array references. See CGI::Header::PSGI.
Returns your current query object. This attribute defaults to the Singleton instance of CGI.pm ($CGI::Q) which is shared by functions exported by the module.
Works like CGI::Application's header_type method. This method can be used to declare that you are setting a redirection header. This attribute defaults to header.
$header->handler('redirect')->as_string; # invokes $header->query->redirect
Returns the header hash reference associated with this CGI::Header object. This attribute defaults to a reference to an empty hash. You can always pass the header hash to CGI::header() function to generate CGI response headers:
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 property names are:
'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' 'cookies' -> 'cookie' 'set-cookie' -> 'cookie' 'uri' -> 'location' 'url' -> 'location' 'window-target' -> 'target'
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.
# field names are case-insensitive
$header->get('Content-Length');
$header->get('content-length');
The $value argument must be a plain string:
$header->set( 'Content-Length' => 3002 );
my $length = $header->get('Content-Length'); # => 3002
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 a copy of this CGI::Header object. It's identical to:
my %copy = %{ $header->header }; # shallow copy
my $clone = CGI::Header->new( \%copy, $header->query );
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", # ... # )
If $header->handler is set to header, it's identical to:
$header->query->header( $header->header );
If $header->handler is set to redirect, it's identical to:
$header->query->redirect( $header->header );
If $header->handler is set to none, returns an empty string.
The following methods were named after property names recognized by CGI.pm's header method. Most of these methods can both be used to read and to set the value of a property.
If you pass an argument to the method, the property value will be set, and also the current object itself will be returned; therefore you can chain methods as follows:
$header->type('text/html')->charset('utf-8');
If no argument is supplied, the property value will returned. If the given property doesn't exist, undef will be returned.
Get or set the attachment property. Can be used to turn the page into an attachment. Represents suggested name for the saved file.
$header->attachment('genome.jpg');
In this case, the outgoing header will be formatted as:
Content-Disposition: attachment; filename="genome.jpg"
Get or set the charset property. Represents the character set sent to the browser.
Get or set the cookie property. The parameter can be a list of CGI::Cookie objects.
Given a list of CGI::Cookie objects, appends them to the cookie property.
Get or set the expires property. 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' );
Get or set the Location header.
$header->location('http://somewhere.else/in/movie/land');
Get or set the nph property. If set to a true value, will issue the correct headers to work with a NPH (no-parse-header) script.
$header->nph(1);
Get or set the p3p property. 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(qw/CAO DSP LAW CURa/);
# or
$header->p3p( 'CAO DSP LAW CURa' );
my @tags = $header->p3p; # => ("CAO", "DSP", "LAW", "CURa")
my $size = $header->p3p; # => 4
In this case, the outgoing header will be formatted as:
P3P: policyref="/w3c/p3p.xml", CP="CAO DSP LAW CURa"
Get or set the Status header.
$header->status('304 Not Modified');
Get or set the Window-Target header.
$header->target('ResultsWindow');
Get or set the type property. Represents the media type of the message content.
$header->type('text/html');
The following plugin just adds the Content-Length header to CGI response headers sent by blosxom.cgi:
package content_length;
use CGI::Header;
sub start {
!$blosxom::static_entries;
}
sub last {
my $h = CGI::Header->new( $blosxom::header )->rehash;
$h->set( 'Content-Length' => length $blosxom::output );
}
1;
Since Blosxom depends on the procedural interface of CGI.pm, you don't have to pass $query to new() in this case.
use CGI::Header; use HTTP::Headers; my @header_props = ( type => 'text/plain', ... ); my $h = HTTP::Headers->new( CGI::Header->new(@header_props)->flatten ); $h->header( 'Content-Type' ); # => "text/plain"
Since the following strings conflict with property names, you can't use them as field names ($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{} );
Set type property to an empty string:
$header->type(q{});
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->cookie or $header->expires ) {
my $date = $header->as_hashref->{'Date'}; # => HTTP-Date (current time)
$header->set( 'Date' => 'Thu, 25 Apr 1999 00:40:33 GMT' ); # wrong
$header->delete('Date'); # wrong
}
You shouldn't assign to the Expires header directly because the following behavior will surprise us:
# confusing
$header->set( 'Expires' => '+3d' );
my $value = $header->get('Expires');
# => "+3d" (not "Thu, 25 Apr 1999 00:40:33 GMT")
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().
If the following condition is met, the Pragma header will be set automatically, and also the header field will become read-only:
if ( $header->query->cache ) {
my $pragma = $header->as_hashref->{'Pragma'}; # => 'no-cache'
$header->set( 'Pragma' => 'no-cache' ); # wrong
$header->delete('Pragma'); # wrong
}
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->as_hashref->{'Server'};
# => $header->query->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.
