NAME CGI::Header - Handle CGI.pm-compatible HTTP header properties SYNOPSIS 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 VERSION This document refers to CGI::Header version 0.46. DEPENDENCIES This module is compatible with CGI.pm 3.51 or higher. DESCRIPTION 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 "header()" method, but complements CGI.pm. This module can be used in the following situation: 1. $header is a hash reference which represents CGI response headers For example, CGI::Application implements "header_add()" method which can be used to add CGI.pm-compatible HTTP header properties. Instances of CGI.pm-based applications often hold those properties. my $header = { type => 'text/plain' }; 2. Manipulates $header using CGI::Header 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', # } 3. Passes $header to CGI::header() to stringify the variable 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 response header array references. See CGI::Header::PSGI. ATTRIBUTES $query = $header->query Returns your current query object. This attribute defaults to the Singleton instance of CGI.pm ($CGI::Q) which is shared by functions exported by the module. $self = $header->handler('redirect') 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 $hashref = $header->header 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 ); METHODS $self = $header->rehash 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: 1. lowercased 'Content-Length' -> 'content-length' 2. use dashes instead of underscores in property name '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" $value = $header->get( $field ) $value = $header->set( $field => $value ) Get or set the value of the header field. The header field name ($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 $bool = $header->exists( $field ) Returns a Boolean value telling whether the specified field exists. if ( $header->exists('ETag') ) { ... } $value = $header->delete( $field ) Deletes the specified field form CGI response headers. Returns the value of the deleted field. my $value = $header->delete('Content-Disposition'); # => 'inline' $self = $header->clear This will remove all header properties. $header->as_string If "$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 ); PROPERTIES 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. $self = $header->attachment( $filename ) $filename = $header->attachment 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" $self = $header->charset( $character_set ) $character_set = $header->charset Get or set the "charset" property. Represents the character set sent to the browser. $self = $header->cookie( $cookie ) $cookie = $header->cookie Get or set the "cookie" property. $header->push_cookie({ name => $name, value => $value, ... }) The given argument will be passed to "$header->query->cookie" method to create CGI::Cookie object. The object will be added to the "cookie" property. $header->push_cookie( riddle_name => "The Sphynx's Question" ); $self = $header->expires $header->expires( $format ) 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' ); $self = $header->location( $url ) $url = $header->location Get or set the Location header. $header->location('http://somewhere.else/in/movie/land'); $self = $header->nph( $bool ) $bool = $header->nph 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); $tags = $header->p3p $self = $header->p3p( $tags ) Get or set the "p3p" property. The parameter can be an arrayref or a space-delimited string. $header->p3p([qw/CAO DSP LAW CURa/]); # or $header->p3p('CAO DSP LAW CURa'); In this case, the outgoing header will be formatted as: P3P: policyref="/w3c/p3p.xml", CP="CAO DSP LAW CURa" $self = $header->status( $status ) $status = $header->status Get or set the Status header. $header->status('304 Not Modified'); $self = $header->target( $window_target ) $window_target = $header->target Get or set the Window-Target header. $header->target('ResultsWindow'); $self = $header->type( $media_type ) $media_type = $header->type Get or set the "type" property. Represents the media type of the message content. $header->type('text/html'); EXAMPLES WRITING Blosxom PLUGINS The following plugin just adds the Content-Length header to CGI response headers sent by blosxom.cgi: package content_length; use CGI::Header; sub start { !$blosxom::static_entries; } sub last { my $h = CGI::Header->new( header => $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 $query to "new()" in this case. LIMITATIONS Since the following strings conflict with property names, you can't use them as field names ($field): "Attachment" "Charset" "Cookie" "Cookies" "NPH" "Target" "Type" Content-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{}); Date 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 ) { $header->set( 'Date' => 'Thu, 25 Apr 1999 00:40:33 GMT' ); # wrong $header->delete('Date'); # wrong } P3P 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()". Pragma 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 ) { $header->set( 'Pragma' => 'no-cache' ); # wrong $header->delete('Pragma'); # wrong } Server 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 ) { $header->set( 'Server' => 'Apache/1.3.27 (Unix)' ); # wrong $header->delete('Server'); # wrong } SEE ALSO CGI, HTTP::Headers BUGS There are no known bugs in this module. Please report problems to ANAZAWA (anazawa@cpan.org). Patches are welcome. AUTHOR Ryo Anazawa (anazawa@cpan.org) LICENSE This module is free software; you can redistibute it and/or modify it under the same terms as Perl itself. See perlartistic.