Workarounded MIME::Base64 for 'Content-MD5' header.
[MyWeb.git] / Web.pm
diff --git a/Web.pm b/Web.pm
index 6a4d6ab..07db01c 100644 (file)
--- a/Web.pm
+++ b/Web.pm
@@ -1,6 +1,6 @@
 # $Id$
 # Common functions for HTML/XHTML output generation
-# Copyright (C) 2003 Jan Kratochvil <project-www.jankratochvil.net@jankratochvil.net>
+# Copyright (C) 2003-2005 Jan Kratochvil <project-www.jankratochvil.net@jankratochvil.net>
 # 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -24,14 +24,28 @@ use strict;
 use warnings;
 
 use Exporter;
-sub Wrequire ($);
-sub Wuse ($@);
+sub Wrequire($);
+sub Wuse($@);
 our $W;
-our @EXPORT=qw(&Wrequire &Wuse &a_href &a_href_cz &vskip &img &centerimg &rightimg $W &top_dir &top_dir_disk &Wprint &input_hidden_persistents);
-our @ISA=qw(Exporter Tie::Handle);
+our @EXPORT=qw(
+               &Wrequire &Wuse
+               &path_web &path_abs_disk
+               &uri_escaped
+               &a_href &a_href_cc
+               &vskip
+               &img &centerimg &rightimg
+               $W
+               &input_hidden_persistents
+               &escapeHTML
+               );
+our @ISA=qw(Tie::Handle Exporter);
+
+my %packages_used_hash;        # $packages_used_hash{$W->{"__PACKAGE__"}}{"_done"}=1;
+my %packages_used_array;
 
 BEGIN
 {
+       use Carp qw(cluck confess);
        $W->{"__My::Web_init"}=1;
 
        sub Wrequire ($)
@@ -44,14 +58,20 @@ BEGIN
                my $class=$file;
                $file=~s#::#/#g;
                $file.=".pm";
-               my $who=$W->{"__PACKAGE__"};
-               $who||="__My::Web" if $W->{"__My::Web_init"};
-               if ($who) {
-                       my $aref=($W->{"packages_used"}{$who}||=[]);
-                       push @$aref,$class
-                                       if !{ map(($_=>1),@$aref) }->{$class};  # Prevent duplicated entries.
+               my %callers;
+               for (my $depth=0;defined caller($depth);$depth++) {
+                       $callers{caller($depth)}=1;
                        }
-               CORE::require $file;
+               my $selfpkg=__PACKAGE__;
+               $callers{$selfpkg}=1;
+               for my $target ($class,__PACKAGE__) {
+                       for my $caller (keys(%callers)) {
+                               next if $caller eq $target;
+                               next if $packages_used_hash{$caller}{$target}++;
+                               push @{$packages_used_array{$caller}},$target;
+                               }
+                       }
+               eval { CORE::require "$file"; } or confess $@;
                1;      # Otherwise 'require' would already file above.
        }
 
@@ -65,38 +85,69 @@ BEGIN
                $file->import(@list);
                1;
        }
+
+       sub import
+       {
+       my($class,@rest)=@_;
+
+               local $Exporter::ExportLevel=$Exporter::ExportLevel+1;
+               Wrequire("$class");
+               return $class->SUPER::import(@rest);
+       }
 }
 
-BEGIN { Wuse 'WebConfig'; }    # for %WebConfig
-require CGI;   # for &escapeHTML
+use WebConfig; # see also below: Wuse 'WebConfig';
+require CGI;
 require Image::Size;   # for &imgsize
 use File::Basename;    # &basename
 use Carp qw(cluck confess);
 use URI::Escape;
 require HTTP::BrowserDetect;
 require HTTP::Negotiate;
-my $have_Geo_IP; BEGIN { $have_Geo_IP=eval { require Geo::IP; 1; }; }
+our $have_Geo_IP; BEGIN { $have_Geo_IP=eval { require Geo::IP; 1; }; }
 # Do not: use ModPerl::Util qw(exit);
 # to prevent in mod_perl2: "exit" is not exported by the ModPerl::Util module
 # I do not know why.
 use POSIX qw(strftime);
 use Tie::Handle;
-use Apache2::Const qw(HTTP_MOVED_TEMPORARILY);
+use Apache2::Const qw(HTTP_MOVED_TEMPORARILY OK HTTP_OK);
 use URI;
 use URI::QueryParam;
+use Cwd;
+require HTTP::Date;
+require Storable;
+require Digest::MD5;
+require Data::Compare;
+use Data::Dumper;
+require Encode;
+use Apache2::Filter;
+use Apache2::Connection;
+require MIME::Base64;
 
 
 #our $W;
-               # $W->{"title"}
-               # $W->{"head"}
-               # $W->{"force_charset"}
-               # $W->{"heading_done"}
-               # $W->{"footer_passed"}
-               # %{$W->{"headers"}}
-               # %{$W->{"headers_lc"}} # maps lc($headers_key)=>$headers_key
-               # @{$W->{"packages_used"}{$W->{"__PACKAGE__"}}}
-               # @{$W->{"packages_used"}{"__My::Web"}}
-               # %{$W->{"args"}}
+
+sub cleanup($)
+{
+my($apache_request)=@_;
+
+       $packages_used_hash{$W->{"__PACKAGE__"}}{"_done"}=1;
+       cache_finish();
+       # Sanity protection.
+       $W=undef();
+       return OK;
+}
+
+sub request_check(;$)
+{
+my($self)=@_;
+
+       # Use &eval to prevent: Global $r object is not available. Set:\n\tPerlOptions +GlobalRequest\nin ...
+       # CGI requires valid "r": check it beforehand here.
+       confess "Calling sensitive dynamic code from a static code" if !eval { Apache2::RequestUtil->request(); };
+       # Do not: confess "Calling sensitive dynamic code without My::Web::init" if !$W->{"__PACKAGE__"};
+       # as it is valid at least while preparing arguments to call: &project::Lib::init
+}
 
 sub init ($%)
 {
@@ -104,30 +155,40 @@ my($class,%args)=@_;
 
        print STDERR "$class->init ".Apache2::RequestUtil->request()->unparsed_uri()."\n";
 
-       my $packages_used_save=$W->{"packages_used"};
-       $W={ %WebConfig,%args };        # override %WebConfig settings
-       $W->{"packages_used"}=$packages_used_save;
+       # We need to track package dependencies, so we need to call it from &init.
+       # We cannot do it in BEGIN { } block
+       # as it would not be tracked for each of the toplevel users later.
+       Wuse 'WebConfig';
+       Wrequire 'My::Hash';
+
+       $W=My::Hash->new({
+               "__PACKAGE__"=>scalar(caller()),
+               %WebConfig,
+               %args,  # override %WebConfig settings
+               },"My::Hash::Sub","My::Hash::Push");
 
        # {"__PACKAGE__"} is mandatory for mod_perl-2.0;
        # $Apache2::Registry::curstash is no longer supported.
        do { cluck "No $_" if !$W->{$_}; } for "__PACKAGE__";
 
-       $W->{"top_dir"}||=eval '$'.$W->{"__PACKAGE__"}.'::top_dir';
-
-       do { $W->{$_}=0  if !defined $W->{$_}; } for ("detect_ent");
-       do { $W->{$_}=0  if !defined $W->{$_}; } for ("detect_js");
-       do { $W->{$_}=1  if !defined $W->{$_}; } for ("have_css");      # AFAIK it does not hurt anyone.
-       do { $W->{$_}=1  if !defined $W->{$_}; } for ("footer");
-       do { $W->{$_}=1  if !defined $W->{$_}; } for ("footer_delimit");
-       do { $W->{$_}=1  if !defined $W->{$_}; } for ("footer_mailme");
-       do { $W->{$_}=1  if !defined $W->{$_}; } for ("footer_ids");
-       do { $W->{$_}=1  if !defined $W->{$_}; } for ("indexme");
-       do { $W->{$_}="" if !defined $W->{$_}; } for ("head");
-       do { $W->{$_}="" if !defined $W->{$_}; } for ("body_attr");
-       do { $W->{$_}="en-US" if !defined $W->{$_}; } for ("language");
+       # See: &escapeHTML
+       do { cluck "charset==$_, expecting ISO-8859-1" if $_ ne "ISO-8859-1"; } for CGI::charset();
+       CGI::charset("utf-8");
+
+       do { $W->{$_}=0  if !defined $W->{$_}; } for "detect_ent";
+       do { $W->{$_}=0  if !defined $W->{$_}; } for "detect_js";
+       do { $W->{$_}=1  if !defined $W->{$_}; } for "have_css";        # AFAIK it does not hurt anyone.
+       do { $W->{$_}=0  if !defined $W->{$_}; } for "css_inherit";
+       do { $W->{$_}=1  if !defined $W->{$_}; } for "footer";
+       do { $W->{$_}=1  if !defined $W->{$_}; } for "footer_delimit";
+       do { $W->{$_}=1  if !defined $W->{$_}; } for "footer_ids";
+       do { $W->{$_}=1  if !defined $W->{$_}; } for "indexme";
+       do { $W->{$_}="" if !defined $W->{$_}; } for "head";
+       do { $W->{$_}="" if !defined $W->{$_}; } for "body_attr";
+       do { $W->{$_}="en-US" if !defined $W->{$_}; } for "language";
 
        my $footer_any=0;
-       for (qw(footer_mailme footer_ids)) {
+       for (qw(footer_ids)) {
                $W->{$_}=0 if !$W->{"footer"};
                $footer_any=1 if $W->{$_};
                }
@@ -136,6 +197,14 @@ my($class,%args)=@_;
 
        $W->{"r"}=Apache2::RequestUtil->request();
 
+       $W->{"r"}->push_handlers("PerlCleanupHandler"=>\&cleanup);
+
+       $W->{"web_hostname"}||=$W->{"r"}->hostname();
+
+       tie *STDOUT,$W->{"r"};
+       select *STDOUT;
+       $|=1;
+
        $W->{"QUERY_STRING"}=$W->{"r"}->args() || "";
        if ($W->{"detect_ent"}) {
                         if ($W->{"QUERY_STRING"}=~/[&]amp;have_ent/)
@@ -146,7 +215,7 @@ my($class,%args)=@_;
                        { delete $W->{"have_ent"}; }
                if (!defined $W->{"have_ent"} && $W->{"r"}->method() eq "GET") {
                        $W->{"head"}.='<meta http-equiv="Refresh" content="0; URL='
-                                       .CGI::escapeHTML("http://".&{$W->{"web_hostname_sub"}}()."/".($W->{"r"}->uri()=~m#^/*(.*)$#)[0]
+                                       .escapeHTML("http://".$W->{"web_hostname"}."/".($W->{"r"}->uri()=~m#^/*(.*)$#)[0]
                                                        ."?".($W->{"QUERY_STRING"} || "detect_ent_glue=1").'&have_ent=detect')
                                        .'" />'."\n";
                        }
@@ -157,17 +226,48 @@ my($class,%args)=@_;
        do { $W->{"r"}->args(""); delete $ENV{"QUERY_STRING"}; } if $W->{"r"}->method() eq "POST";
        # Do not: $W->{"r"}->args()
        # as it parses only QUERY_STRING (not POST data).
-       $W->{"args"}={ CGI->new($W->{"r"})->Vars() };
+       $W->{"args_orig_array"}=[ CGI->new($W->{"r"})->Vars() ];
+       $W->{"args"}={ @{$W->{"args_orig_array"}} };
        for my $name (keys(%{$W->{"args"}})) {
                my @vals=split /\x00/,$W->{"args"}{$name};
                next if @vals<=1;
                $W->{"args"}{$name}=[@vals];
                }
 
-       do { $W->{$_}=$W->{"r"}->headers_in()->{"Accept"}     if !defined $W->{$_}; } for ("accept");
-       do { $W->{$_}=$W->{"r"}->headers_in()->{"User-Agent"} if !defined $W->{$_}; } for ("user_agent");
+       $W->{"headers_in"}=$W->{"r"}->headers_in();
+       Wrequire 'My::Hash::Merge';
+       $W->{"headers_in"}=My::Hash::Merge->new(
+                       $W->{"headers_in"},
+                       My::Hash::Sub->new({
+                               "_remote_ip"=>sub { return $W->{"r"}->connection()->remote_ip(); },
+                               }),
+                       );
+       Wrequire 'My::Hash::Readonly';
+       $W->{"headers_in"}=My::Hash::Readonly->new($W->{"headers_in"});
+       
+       if ($W->{"r"}->method() eq "GET" || $W->{"r"}->method() eq "HEAD") {
+               for (\$W->{"http_safe"}) {
+                       # Do not: # Extend the current ETag system instead if you would need it:
+                       #         cluck "Explicitely NOT HTTP-Safe for method \"".$W->{"r"}->method()."\"?!?"
+                       #                       if defined($$_) && !$$_;
+                       # as sometimes it just does not make sense to cache it.
+                       $$_=1 if !defined $$_;
+                       }
+               }
+       else {
+               for (\$W->{"http_safe"}) {
+                       cluck "Undefined HTTP-Safe-ty for method \"".$W->{"r"}->method()."\"!"
+                                       if !defined($$_);
+                       $$_=0 if !defined $$_;
+                       }
+               }
+       if ($W->{"http_safe"}) {
+               Wrequire 'My::Hash::RecordKeys';
+               $W->{"headers_in_RecordKeys"}=My::Hash::RecordKeys->new($W->{"headers_in"});
+               $W->{"headers_in"}=$W->{"headers_in_RecordKeys"};
+               }
 
-       $W->{"browser"}=HTTP::BrowserDetect->new($W->{"user_agent"});
+       $W->{"browser"}=HTTP::BrowserDetect->new($W->{"headers_in"}{"User-Agent"});
 
        if (!defined $W->{"have_style"}) {
                $W->{"have_style"}=(!$W->{"browser"}->netscape() || ($W->{"browser"}->major() && $W->{"browser"}->major()>4) ? 1 : 0);
@@ -175,98 +275,156 @@ my($class,%args)=@_;
 
        $W->{"have_js"}=($W->{"args"}{"have_js"} ? 1 : 0);
        if ($W->{"detect_js"} && !$W->{"have_js"}) {
-               $W->{"head"}.='<script type="text/javascript" src="'.top_dir('/have_js.js.pl').'"></script>'."\n";
+               $W->{"head"}.='<script type="text/javascript" src="'.uri_escaped(path_web('/My/HaveJS.pm')).'"></script>'."\n";
                }
 
-       do { args_check(%$_) if $_; } for ($W->{"args_check"});
-
-       $ENV{"HOSTNAME"}||=&{$W->{"web_hostname_sub"}}();
+       do { _args_check(%$_) if $_; } for ($W->{"args_check"});
 
        return bless $W,$class;
 }
 
-sub Wprint($)
+# Be aware other parts of code (non-My::Web) will NOT use this function!
+# Do not: Wprint $W->{"heading"},"undef"=>1;
+# as we would need to undef() it to turn it off and it would get defaulted in such case.
+# Do not: exists $W->{"heading"}
+# as we use a lot of 'for $W->{"heading"}' which instantiates it with the value: undef()
+sub Wprint($%)
 {
-my($text)=@_;
-
+my($text,%args)=@_;
+
+       cluck "undef Wprint" if !defined $text && !$args{"undef"};
+       delete $args{"undef"};
+       cluck join(" ","Invalid arguments:",keys(%args)) if keys(%args);
+       return if !defined $text;
+       # Do not: cluck "utf-8 untested" if Encode::is_utf8($text);
+       # as it is valid here.
        $W->{"r"}->puts($text);
 }
 
-# local *FH;
-# tie *FH,ref($W),$W;
-sub TIEHANDLE($)
+sub escapeHTML($)
 {
-my($class,$W)=@_;
+my($text)=@_;
+
+       # Prevent &CGI::escapeHTML breaking utf-8 strings like: \xC4\x9B eq \x{11B}
+       # Prevent case if we run under mod_perl but still just initializing:
+       request_check() if $ENV{"MOD_PERL"};
+       # Generally we are initialized from &init but we may be used without it without mod_perl
+       # and in such case check the change on all non-first invocations.
+       our $init;
+       if (!$ENV{"MOD_PERL"} && $init++) {
+               do { cluck "charset==$_" if $_ ne "utf-8"; } for CGI::charset();
+               }
+       CGI::charset("utf-8");
 
-       my $self={};
-       $self->{"W"}=$W or confess "Missing W";
-       return bless $self,$class;
+       return CGI::escapeHTML($text);
 }
 
-sub WRITE
+# /home/user/www/webdir
+sub dir_top_abs_disk()
 {
-my($self,$scalar,$length,$offset)=@_;
+       our $dir_top_abs_disk;
+       if (!$dir_top_abs_disk) {
+               my $selfpkg_relpath=__PACKAGE__;
+               $selfpkg_relpath=~s{::}{/}g;
+               $selfpkg_relpath.=".pm";
+               my $selfpkg_abspath=$INC{$selfpkg_relpath} or do {
+                       cluck "Unable to find self package $selfpkg_relpath";
+                       return;
+                       };
+               $selfpkg_abspath=~s{/*\Q$selfpkg_relpath\E$}{} or do {
+                       cluck "Unable to strip myself \"$selfpkg_relpath\" from the abspath: $selfpkg_abspath";
+                       return;
+                       };
+               cluck "INC{myself} is relative?: $selfpkg_abspath" if $selfpkg_abspath!~m{^/};
+               $dir_top_abs_disk=$selfpkg_abspath;
+               }
+       return $dir_top_abs_disk;
+}
 
-       Wprint substr($scalar,0,$length);
+sub unparsed_uri()
+{
+       request_check();
+       if (!$W->{"unparsed_uri"}) {
+               # Do not: $W->{"r"}
+               # as we may be called before &init from: &My::Project::init
+               my $r=Apache2::RequestUtil->request();
+               cluck "Calling ".'&unparsed_uri'." from a static code, going to fail" if !$r;
+               my $uri_string=$r->unparsed_uri() or cluck "Valid 'r' missing unparsed_uri()?";
+               my $uri=URI->new_abs($uri_string,"http://".$W->{"web_hostname"}."/");
+               $W->{"unparsed_uri"}=$uri;
+               }
+       return $W->{"unparsed_uri"};
 }
 
-sub top_dir_disk ()
+sub in_to_uri_abs($)
 {
-       do { return $_ if $_; } for ($W->{"top_dir"});
-       return $INC[0]; # fallback
+my($in)=@_;
+
+       # Otherwise we may have been already processed and thus legally relativized.
+       # FIXME data: Currently disabled, all the data are too violating such rule.
+       if (0 && !ref $in) {
+               my $uri_check=URI->new($in);
+               $uri_check->scheme() || $in=~m{^\Q./\E} || $in=~m{^/}
+                               or cluck "Use './' or '/' prefix for all the local references: $in";
+               }
+       my $uri=URI->new_abs($in,unparsed_uri());
+       $uri=$uri->canonical();
+       return $uri;
 }
 
-# $args{"abs"}
-sub top_dir (;$%)
+# $args{"uri_as_in"}=1 to permit passing URI objects as: $in
+# $args{"abs"}=1;
+sub path_web($%)
 {
 my($in,%args)=@_;
 
-       if (my $uri=$W->{"r"}->unparsed_uri()) {
-               if ($W->{"args"}{"Wabs"} || $args{"abs"}) {
-                       # FIXME: $in may not be defined here!
-                       # to prevent: Use of uninitialized value in ...
-                       if ($in=~m#^/#) {
-                               $in=~s#^/*##;
-                               }
-                       else {
-                               $in=$uri."/".$in;
-                               $in=~tr#/#/#s;
-                               1 while $in=~s#/(?:[^/]+)/\Q..\E/#/#g
-                               }
-                       return "http://".&{$W->{"web_hostname_sub"}}()."/".(defined $in ? $in : "");
-                       }
-               $uri.="Index" if $uri=~m#/$#;
-               if (defined $in) {
-                       my($inpath,$inquery)=split /[?]/,$in,2;
-                       $inpath=~tr///cs;
-                       $uri=~tr///cs;
-                       for (;;) {
-                               my($in1 ,$in2 )=($in =~m#^(/[^/]+)(/.*)$#);
-                               my($uri1,$uri2)=($uri=~m#^(/[^/]+)(/.*)$#);
-                               last if !defined $in1 || !defined $uri1 || $in1 ne $uri1;
-                               $in=$in2;
-                               $uri=$uri2;
-                               }
-                       }
-               $uri=~s#^/*##;
-               $uri=~s#[^/]+#..#g;
-               $uri=File::Basename::dirname($uri);
-               my $r=$uri.(defined $in ? $in : "");
-#              1 while $r=~s#^[.]/##;
-#              $r="./$r" if $r=~m#^(?:?.*)$#;  # empty pathname?
-               return $r;
+       cluck if !$args{"uri_as_in"} && ref $in;
+       my $uri=in_to_uri_abs($in);
+       if (uri_is_local($uri)) {
+               # Prefer the $uri values over "args_persistent" values.
+               $uri->query_form_hash({
+                               map({
+                                       my $key=$_;
+                                       my $val=$W->{"args"}{$key};
+                                       (!defined $val ? () : ($key=>$val));
+                                       } keys(%{$W->{"args_persistent"}})),
+                               %{$uri->query_form_hash()},
+                               });
                }
-       return top_dir_disk().$in;
+       return $uri->abs(unparsed_uri()) if $W->{"args"}{"Wabs"} || $args{"abs"};
+       return $uri->rel(unparsed_uri());
+}
+
+sub path_abs_disk_register($)
+{
+my($path_abs_disk)=@_;
+
+       $W->{"path_abs_disk_register"}{$path_abs_disk}=1;
+}
+
+# $args{"uri_as_in"}=1 to permit passing URI objects as: $in
+sub path_abs_disk($%)
+{
+my($in,%args)=@_;
+
+       cluck if !$args{"uri_as_in"} && ref $in;
+       my $uri=in_to_uri_abs($in);
+       cluck if !uri_is_local($uri);
+       my $path=$uri->path();
+       cluck "URI compatibility: ->path() not w/leading slash of URI \"$uri\"; path: $path" if $path!~m{^/};
+       my $r=dir_top_abs_disk().$path;
+       path_abs_disk_register $r if !defined $args{"register"} || $args{"register"};
+       return $r;
 }
 
 sub fatal (;$);
 
-sub args_check (%)
+sub _args_check (%)
 {
 my(%tmpl)=@_;
 
        while (my($name,$regex)=each(%tmpl)) {
-               my $name_html="Parameter <span class=\"quote\">".CGI::escapeHTML($name)."</span>";
+               my $name_html="Parameter <span class=\"quote\">".escapeHTML($name)."</span>";
                $W->{"args"}{$name}="" if !defined $W->{"args"}{$name};
                $W->{"args"}{$name}=[ $W->{"args"}{$name} ] if !ref $W->{"args"}{$name} && ref $regex;
                fatal "$name_html passed as multivar although singlevar expected"
@@ -274,8 +432,8 @@ my(%tmpl)=@_;
                $regex=$regex->[0] if ref $regex;
                for my $val (!ref $W->{"args"}{$name} ? $W->{"args"}{$name} : @{$W->{"args"}{$name}}) {
                        $val="" if !defined $val;
-                       fatal "$name_html <span class=\"quote\">".CGI::escapeHTML($val)."</span>"
-                                                       ." does not match the required regex <span class=\"quote\">".CGI::escapeHTML($regex)."</span> "
+                       fatal "$name_html <span class=\"quote\">".escapeHTML($val)."</span>"
+                                                       ." does not match the required regex <span class=\"quote\">".escapeHTML($regex)."</span> "
                                        if $regex ne "" && $val!~/$regex/;
                        }
                }
@@ -317,33 +475,12 @@ sub footer (;$)
 
        Wprint vskip if $W->{"footer_delimit"};
 
-       do { &{$_}() if $_; } for ($W->{"footing_delimit"});
+       do { Wprint $_ if $_; } for $W->{"footing_delimit"};
 
        Wprint "<hr />\n" if $W->{"footer"};
 
-       if ($W->{"footer_mailme"}) {
-               Wprint '<form action="'.top_dir('/SendMsg.pl').'" method="post" onsubmit="'
-                               ."this.elements['msgscript'].value=this.elements['msghtml'].value;"
-                               ."this.elements['msghtml'].value='';"
-                               ."this.submit();"
-                               .'">'."\n";
-                       Wprint input_hidden_persistents()."\n";
-                       Wprint '<p align="right">'."\n";
-                               Wprint '<input name="msgscript" type="hidden" />'."\n";
-                               Wprint '<input name="msghtml" type="text" size="32" alt="Message" />'."\n";
-                               Wprint '<input name="submit" type="submit" value="Quick Note" />'."\n";
-                       Wprint '</p>'."\n";
-               Wprint '</form>'."\n";
-               }
-
-       my @packages_used=(
-                       $W->{"__PACKAGE__"},
-                       __PACKAGE__,
-                       @{$W->{"packages_used"}{"__My::Web"}},
-                       map((!$_ ? () : @$_),$W->{"packages_used"}{$W->{"__PACKAGE__"}}),
-                       );
-       my %packages_used;
-       @packages_used=grep((!$packages_used{$_}++),@packages_used);
+       my $packages_used=$packages_used_array{$W->{"__PACKAGE__"}};
+
        if ($W->{"footer_ids"}) {
                Wprint '<p class="cvs-id">';
                Wprint join("<br />\n",map({ my $package=$_;
@@ -361,11 +498,11 @@ sub footer (;$)
                                        $file=~s#::#/#g;
                                        my $ext;
                                        my @tried;
-                                       for (qw(.html.pl .pl .pm),"") {
+                                       for (qw(.pm)) {
                                                $ext=$_;
-                                               my $pathname=top_dir_disk()."/$file$ext";
-                                               push @tried,$pathname;
-                                               last if -r $pathname;
+                                               my $path_abs_disk=path_abs_disk("/$file$ext");
+                                               push @tried,$path_abs_disk;
+                                               last if -r $path_abs_disk;
                                                cluck "Class file $file not found; tried: ".join(" ",@tried) if !$ext;
                                                }
                                        $file.=$ext;
@@ -374,38 +511,35 @@ sub footer (;$)
                                                                        $cvs_id_split[2]);
                                        $cvs_id_split[1]=a_href($W->{"viewcvs"}.$file,
                                                        ($package!~/^Apache2::/ ? $package : $cvs_id_split[1]));
-                                       $cvs_id_split[5]=&{$W->{"cvs_id_author"}}($cvs_id_split[5]);
+                                       $cvs_id_split[5]=&{$W->{"cvs_id_author_sub"}}($cvs_id_split[5]);
                                        }
                                join " ",@cvs_id_split;
                                }
-                       } @packages_used));
+                       } @$packages_used));
                Wprint "</p>\n";
                }
 
-       for my $package (@packages_used) {
+       for my $package (@$packages_used) {
                my $cvs_id=(eval('$'.$package."::CVS_ID")
 #                              || $package     # debug
                                );
                Wprint '<!-- '.$package.' - $'.$cvs_id.'$ -->'."\n" if $cvs_id;
                }
 
-       do { &{$_}() if $_; } for ($W->{"footing"});
+       do { Wprint $_ if $_; } for $W->{"footing"};
 
        Wprint "</body></html>\n";
-       exit(0);
+       exit 0;
 }
 
-sub header (%)
+# Existing entries are overwritten.
+sub header(%)
 {
 my(%pairs)=@_;
 
        while (my($key,$val)=each(%pairs)) {
                do { cluck "Headers already sent"; next; } if $W->{"heading_done"};
-               for ($W->{"headers_lc"}{lc $key} || ()) {
-                       delete $W->{"headers"}{$_};
-                       }
-               $W->{"headers_lc"}{lc $key}=$key;
-               $W->{"headers"}{$key}=$val;
+               $W->{"r"}->headers_out()->set($key,$val);
                }
 }
 
@@ -423,84 +557,82 @@ my($size)=@_;
        return $size;
 }
 
-sub url_is_local ($)
+sub uri_is_local($)
 {
-my($url)=@_;
-
-       return $url!~m#^[a-z]+://#;
+my($in)=@_;
+
+       my $uri_rel=in_to_uri_abs($in)->rel(unparsed_uri());
+       # Do not: defined $uri_rel->("userinfo"|"host"|"port")();
+       # as they fail to be called for schemes not supporting them.
+       return 0 if $uri_rel->scheme();
+       return 0 if $uri_rel->authority();
+       return 1;
 }
 
-sub url_out($%)
+# &path_web still may be required for &uri_escaped !
+sub uri_escaped($)
 {
-my($url,%args)=@_;
-
-       return $url if !url_is_local $url;
-       $url=top_dir($url,%args) if $url=~m#^/# || $args{"abs"};
-
-       my $uri=URI->new($url);
-       # Prefer the $uri values over "args_persistent" values.
-       $uri->query_form_hash({
-                       map({
-                               my $key=$_;
-                               my $val=$W->{"args"}{$key};
-                               (!defined $val ? () : ($key=>$val));
-                               } keys(%{$W->{"args_persistent"}})),
-                       %{$uri->query_form_hash()},
-                       });
-       $url="".$uri;
-
-       return $url;
+my($uri)=@_;
+
+       cluck if !ref $uri;
+       my $urient=escapeHTML($uri);
+       return $uri    if $uri eq $urient;
+       request_check();
+       return $urient if uri_is_local $uri;
+       return $uri    if defined $W->{"have_ent"} && !$W->{"have_ent"};        # non-ent client
+       return $urient if $W->{"have_ent"};     # ent client
+       # Unknown client, &escapeHTML should not be needed here:
+       return escapeHTML(path_web('/My/Redirect.pm?location='.uri_escape($uri->abs(unparsed_uri()))));
 }
 
-sub a_href ($;$%)
+our $a_href_inhibited;
+sub a_href($;$%)
 {
-my($url,$contents,%args)=@_;
+my($in,$contents,%args)=@_;
 
+       request_check();
        do { $$_=1 if !defined $$_; } for (\$args{"size"});
        if (!defined $contents) {
-               $contents=$url;
+               $contents=$in;
                $contents=File::Basename::basename($contents) if $args{"basename"};
-               $contents=CGI::escapeHTML($contents);
+               $contents=escapeHTML($contents);
                }
        $contents=~s#<a\b[^>]*>##gi;
        $contents=~s#</a>##gi;
+       return $contents if $a_href_inhibited;
 
-       $url=url_out($url,%args);
-
-       my $r='<a href="';
-       my $urlent=CGI::escapeHTML($url);
-          if ($url eq $urlent)
-               { $r.=$url; }
-       elsif (url_is_local $url)
-               { $r.=$urlent; }
-       elsif (defined $W->{"have_ent"} && !$W->{"have_ent"})   # non-ent client
-               { $r.=$url; }
-       elsif ($W->{"have_ent"})        # ent client
-               { $r.=$urlent; }
-       else    # unknown client, &CGI::escapeHTML should not be needed here
-               { $r.=CGI::escapeHTML(top_dir('/Redirect.pl?location='.uri_escape($url))); }
+       my $path_web=path_web $in,%args;
+       my $r="";
+       $r.='<a href="';
+       $r.=uri_escaped $path_web;
        $r.='"';
        do { $r.=" $_" if $_; } for ($args{"attr"});
        $r.='>'.$contents.'</a>';
-       if ($args{"size"} && url_is_local($url) && ($args{"size"}>=2 || $url=~/[.](?:gz|Z|rpm|zip|deb|lha)/)) { # Downloadable?
-               $url=top_dir_disk().$url if $url=~m#^/#;
-               if (!-r $url)
-                       { cluck "File not readable: $url"; }
-               else {
-                       $r.='&nbsp;('.size_display((stat($url))[7]).')';
-                       }
+       if ($args{"size"} && uri_is_local($in) && ($args{"size"}>=2 || $in=~/[.](?:gz|Z|rpm|zip|deb|lha)/)) {   # Downloadable?
+               my $path_abs_disk=path_abs_disk $in,%args;
+               cluck "File not readable: $path_abs_disk" if !-r $path_abs_disk;
+               $r.='&nbsp;('.size_display((stat($path_abs_disk))[7]).')';
                }
        return $r;
 }
 
+sub a_href_inhibit($$;@)
+{
+my($self,$sub,@sub_args)=@_;
+
+       local $a_href_inhibited=1;
+       return &{$sub}(@sub_args);
+}
+
 sub input_hidden_persistents()
 {
+       request_check();
        return join("",map({
                my $key=$_;
                my $val=$W->{"args"}{$key};
                (!defined $val ? () : '<input type="hidden"'
-                               .' name="'.CGI::escapeHTML($key).'"'
-                               .' value="'.CGI::escapeHTML($val).'"'
+                               .' name="'.escapeHTML($key).'"'
+                               .' value="'.escapeHTML($val).'"'
                                .' />'."\n");
                } (keys(%{$W->{"args_persistent"}}))));
 }
@@ -509,7 +641,7 @@ sub http_moved($$;$)
 {
 my($self,$url,$status)=@_;
 
-       $url=url_out($url,"abs"=>1);
+       $url=path_web($url,"abs"=>1);
        $status||=HTTP_MOVED_TEMPORARILY;
        $W->{"r"}->status($status);
        $W->{"r"}->headers_out()->{"Location"}=$url;
@@ -526,22 +658,29 @@ sub remote_ip ()
        # As 'Apache2::ForwardedFor' takes the first of $ENV{"HTTP_X_FORWARDED_FOR"}
        # while the contents is '127.0.0.1, 213.220.195.171' if client has its own proxy.
        # We must take the last item ourselves.
-       my $r=$W->{"r"}->headers_in()->{"X-Forwarded-For"} || $W->{"r"}->get_remote_host();
-       $r=~s/^.*,\s*//;
+       # Be VERY sure you always retrieve all the headers unconditionally to hit: My::Hash::RecordKeys
+       my $x_forwarded_for=$W->{"headers_in"}{"X-Forwarded-For"};
+       $x_forwarded_for=~s/^.*,\s*// if $x_forwarded_for;
+       my $remote_ip=$W->{"headers_in"}{"_remote_ip"};
+       my $r;
+       $r||=$x_forwarded_for;
+       $r||=$remote_ip;
        return $r;
 }
 
-sub is_cz ()
-{
-       return 0 if !$have_Geo_IP;
-       return "CZ" eq Geo::IP->new()->country_code_by_addr(remote_ip());
-}
-
-sub a_href_cz ($$;%)
+# $url={"JP"=>"http://specific",...};
+# $url={""=>"http://default",...};
+sub a_href_cc($$;%)
 {
 my($url,$contents,%args)=@_;
 
-       return a_href $url,$contents,%args if is_cz();
+       # A bit ineffective but we must process all the possibilities to get stable 'headers_in' hits!
+       my %map=map(($_=>a_href($url->{$_},$contents,%args)),keys(%$url));
+       my $cc;
+       $cc||=Geo::IP->new()->country_code_by_addr(remote_ip()) if $have_Geo_IP;
+       $cc||="";
+       my $r=$map{$cc};
+       return $r if $r;
        return $contents;
 }
 
@@ -549,13 +688,30 @@ sub make ($)
 {
 my($cmd)=@_;
 
-       system {'flock'} 'flock','-x',top_dir_disk(),$cmd.' >&2';
+       # FIXME: &alarm, --timeout is now infinite.
+       # FIXME: Try to remove bash(1).
+       # FIXME: Use: @PATH_FLOCK@
+       my @argv=('flock',dir_top_abs_disk(),'bash','-c',$cmd.' >&2');
+       print STDERR join(" ","SPAWN:",@argv)."\n";
+       system @argv;
+}
+
+sub make_file($$)
+{
+my($self,$file)=@_;
+
+       cluck "Pathname not absolute: $file" if $file!~m{^/};
+       return if -f $file;
+       # TODO: Somehow quickly check dependencies?
+       return make('make -s --no-print-directory'
+                                       .' -C '."'".File::Basename::dirname($file)."' '".File::Basename::basename($file)."'");
 }
 
 sub img_size ($$)
 {
 my($width,$height)=@_;
 
+       cluck if !defined $width || !defined $height;
        return ($W->{"have_style"} ? "style=\"border:0;width:${width}px;height:${height}px\"" : "border=\"0\"")
                        ." width=\"$width\" height=\"$height\"";
 }
@@ -575,6 +731,13 @@ sub Negotiate_choose($$)
 {
 my($self,$variants)=@_;
 
+       # Limit these entries to generate proper 'Vary' header.
+       my %hash=(map(($_=>$W->{"headers_in"}{$_}),qw(
+                       Accept
+                       Accept-Charset
+                       Accept-Encoding
+                       Accept-Language
+                       )));
        my $best=HTTP::Negotiate::choose($variants,
                        # Do not: $W->{"r"}
                        # to prevent: Can't locate object method "scan" via package "Apache2::RequestRec" at HTTP/Negotiate.pm line 84.
@@ -582,8 +745,8 @@ my($self,$variants)=@_;
                        # to prevent: Can't locate object method "scan" via package "APR::Table" at HTTP/Negotiate.pm line 84.
                        # Do not: HTTP::Headers->new($W->{"r"}->headers_in());
                        # to prevent empty result or even: Odd number of elements in anonymous hash
-                       HTTP::Headers->new(%{$W->{"r"}->headers_in()}));
-       $best||=$variants->[0]{"id"};   # &HTTP::Negotiate::choose failed?
+                       HTTP::Headers->new(%hash));
+       $best||=$variants->[0][0];      # $variants->[0]{"id"}; &HTTP::Negotiate::choose failed?
        return $best;
 }
 
@@ -593,67 +756,55 @@ my @img_variants=(
                );
 my $img_variants_re='[.](?:'.join('|',"jpeg",map(($_->{"id"}),@img_variants)).')$';
 
-sub img_src ($)
+# Returns: ($path_web,$path_abs_disk)
+# URI path segments support ignored here. Where it is used? (';' path segment options)
+sub _img_src($%)
 {
-my($file_base)=@_;
+my($in,%args)=@_;
 
-       if (!url_is_local($file_base)) {
-               return $file_base if !wantarray();
-               return ($file_base,$file_base);
-               }
-       # Known image extension?
-       if ($file_base=~m#$img_variants_re#o) {
-               return $file_base if !wantarray();
-               return ($file_base,$file_base) if $file_base!~m#^/#;
-               return (top_dir($file_base),top_dir_disk().$file_base);
-               }
+       cluck if !uri_is_local $in;
+       my $uri=in_to_uri_abs $in;
+       my $path_abs_disk=path_abs_disk $uri,%args,"uri_as_in"=>1,"register"=>0;
 
-       my $file_base_disk;
-       my $file_base_uri;
-       if ($file_base!~m#^/#) {
-               $file_base_disk=$file_base_uri=$file_base;
-               }
-       else {
-               $file_base_disk=top_dir_disk().$file_base;
-               $file_base_uri=top_dir($file_base);
-               }
+       # Known image extension?
+       return path_web($uri,%args,"uri_as_in"=>1),$path_abs_disk if $uri->path()=~m#$img_variants_re#o;
 
        my @nego_variants;
        for my $var (@img_variants) {
-               my $file=$file_base_disk.".".$var->{"id"};
-               # TODO: Somehow quickly check dependencies?
-               make('make -s --no-print-directory'
-                                               .' -C '."'".File::Basename::dirname($file)."' '".File::Basename::basename($file)."'")
-                               if !-f $file;
+               my $path_abs_disk_variant=$path_abs_disk.".".$var->{"id"};
+               path_abs_disk_register($path_abs_disk_variant);
+               __PACKAGE__->make_file($path_abs_disk_variant);
                push @nego_variants,negotiate_variant(
                                %$var,
-                               "size"=>(stat $file)[7],
+                               "size"=>(stat $path_abs_disk_variant)[7],
                                );
                }
        my $ext=__PACKAGE__->Negotiate_choose(\@nego_variants);
 
-       return $file_base_uri.".".$ext if !wantarray();
-       return ($file_base_uri.".".$ext,$file_base_disk.".".$ext);
+       $uri->path($uri->path().".$ext");
+       return path_web($uri,%args,"uri_as_in"=>1),path_abs_disk($uri,%args,"uri_as_in"=>1);
 }
 
-sub img ($$;%)
+# $args{"attr"}
+sub img ($$%)
 {
-my($file_base,$alt,%attr)=@_;
+my($in,$alt,%args)=@_;
 
-       my($file_uri,$file_disk)=img_src $file_base;
-       my($width,$height)=Image::Size::imgsize($file_disk);
+       request_check();
+       my($path_web,$path_abs_disk)=_img_src($in,%args);
+       my($width,$height)=Image::Size::imgsize($path_abs_disk);
        $alt=~s/<[^>]*>//g;
-       $alt=CGI::escapeHTML($alt);
-       my $content="<img src=\"$file_uri\" alt=\"$alt\" title=\"$alt\" ".img_size($width,$height)
-                       .(!$attr{"attr"} ? "" : " ".$attr{"attr"})." />";
-       return a_href img_src($attr{"a_href_img"}),$content if $attr{"a_href_img"};
-       return a_href $attr{"a_href"},$content if $attr{"a_href"};
+       $alt=escapeHTML($alt);
+       my $content="<img src=\"".uri_escaped($path_web)."\" alt=\"$alt\" title=\"$alt\" ".img_size($width,$height)
+                       .(!$args{"attr"} ? "" : " ".$args{"attr"})." />";
+       do { return a_href((_img_src($_))[0],$content,"uri_as_in"=>1) if $_; } for $args{"a_href_img"};
+       do { return a_href $_,$content if $_; } for $args{"a_href"};
        return $content;
 }
 
 sub centerimg
 {
-       my $r.="";
+       my $r="";
        $r.='<table border="0" width="100%"><tr>'."\n";
        @_=( [@_] ) if !ref $_[0];
        for (@_) {
@@ -667,11 +818,12 @@ sub rightimg
 {
 my($text,@args_img)=@_;
 
-       # Workaround bug of 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)':
+       # FIXME: Workaround bug of 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)':
+       #        <col width="@{[ (!$W->{"browser"}->ie() ? "1*" : "90%" ) ]}" />
+       #        <col width="@{[ (!$W->{"browser"}->ie() ? "0*" : "10%" ) ]}" />
+       # causes whole invisible projects in: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.10) Gecko/20050719 Galeon/1.3.21
        return <<"HERE";
 <table border="0" width="100%">
-       <col width="@{[ (!$W->{"browser"}->ie() ? "1*" : "90%" ) ]}" />
-       <col width="@{[ (!$W->{"browser"}->ie() ? "0*" : "10%" ) ]}" />
        <tr>
                <td align="left">
                        @{[ $text ]}
@@ -684,66 +836,223 @@ my($text,@args_img)=@_;
 HERE
 }
 
-sub readfile ($$)
+sub readfile($$)
 {
 my($class,$filename)=@_;
 
        local *F;
-       open F,$filename or die "Cannot open \"$filename\": $!";
-       local $/=undef();
-       my $data=<F>;
-       close F;
-       return $data;
+       open F,$filename or cluck "Cannot open \"$filename\": $!";
+       my $F=do { local $/=undef(); <F>; };
+       close F or cluck "Cannot close \"$filename\": $!";
+       return $F;
 }
 
-sub arr_keys (@)
+sub _no_cache($)
 {
-my(@arr)=@_;
+my($self)=@_;
+
+       header("Expires"=>HTTP::Date::time2str(1000000000));    # date in the past
+       header("Last-Modified"=>HTTP::Date::time2str());        # always modified
+       header("Cache-Control"=>join(", ",
+                       "no-cache",
+                       "no-store",
+                       "must-revalidate",
+                       "max-age=0",
+                       "pre-check=0",  # MSIE
+                       "post-check=0", # MSIE
+                       ));     # HTTP/1.1
+       header("Pragma"=>"no-cache");   # HTTP/1.0
+       header("Vary"=>"*");    # content may ba based on unpredictable sources
+}
 
-       my @r=();
-       while (@arr) {
-               push @r,shift @arr;     # key
-               shift @arr;     # val
+sub headers_in_filtered(@)
+{
+my(@keys)=@_;
+
+       return map(($_=>$W->{"headers_in"}{$_}),@keys);
+}
+
+our %uri_args_frozen_to_headers_in_keys;
+our %uri_args_headers_in_frozen_to_headers_out;
+
+sub uri_args_headers_in_frozen_get($)
+{
+my($headers_in_keys_arrayref)=@_;
+
+       my %uri_args_headers_in_hash=(
+               "uri_args_frozen"=>$W->{"uri_args_frozen"},
+               "headers_in"=>{ headers_in_filtered(@$headers_in_keys_arrayref) },
+               );
+       return do { local $Storable::canonical=1; Storable::freeze(\%uri_args_headers_in_hash); };
+}
+
+sub cache_output_filter($)
+{
+my($f)=@_;
+
+       while ($f->read(my $text,0x400)) {
+               cluck "utf-8 untested" if Encode::is_utf8($text);       # Possible here at all?
+               $f->print($text);
+               $W->{"digest-md5"}->add($text);
                }
-       return @r;
+       return OK;
 }
 
-sub no_cache($)
+sub cache_start()
 {
-my($self)=@_;
+       if (!$W->{"http_safe"}) {
+               __PACKAGE__->_no_cache();
+               return;
+               }
 
-       header("Expires"=>"Mon, 26 Jul 1997 05:00:00 GMT");     # date in the past
-       header("Last-Modified"=>strftime("%a, %d %b %Y %H:%M:%S GMT",gmtime()));        # always modified
-       header("Cache-Control"=>"no-cache, must-revalidate");   # HTTP/1.1
-       header("Pragma"=>"no-cache");   # HTTP/1.0
+       {
+               # &Wrequire it here even if it will not be later used; to be stable!
+               Wrequire 'My::Hash::RestrictTo';
+               my %uri_args_hash=(
+                       "uri"=>"http://".$W->{"web_hostname"}."/".$W->{"r"}->uri(),
+                       "args"=>$W->{"args_orig_array"},
+                       );
+               $W->{"uri_args_frozen"}=do { local $Storable::canonical=1; Storable::freeze(\%uri_args_hash); };
+               last if !(my $headers_in_keys_arrayref=$uri_args_frozen_to_headers_in_keys{$W->{"uri_args_frozen"}});
+
+               # Protection to be sure we are stable:
+               $W->{"headers_in"}=My::Hash::RestrictTo->new($W->{"headers_in"},@$headers_in_keys_arrayref);
+
+               $W->{"uri_args_headers_in_frozen"}=uri_args_headers_in_frozen_get($headers_in_keys_arrayref);
+               last if !(my $headers_out_hashref=$uri_args_headers_in_frozen_to_headers_out{$W->{"uri_args_headers_in_frozen"}});
+               header(%$headers_out_hashref);
+               my $status;
+               {
+                       # &meets_conditions will always deny the attempt if !2xx status().
+                       # At least ap_read_request() sets: r->status=HTTP_REQUEST_TIME_OUT;     /* Until we get a request */
+                       my $status_old=$W->{"r"}->status();
+                       $W->{"r"}->status(HTTP_OK);
+                       # Update httpd's 'r->mtime' as the header "Last-Modified" is just not enough for ap_meets_conditions():
+                       # &update_mtime() argument is really in _secs_, not in _msecs_ as the docs claim.
+                       # Be aware '*1000000' would overflow Perl integer anyway.
+                       # &set_last_modified would also override the "Last-Modified" headers_out!
+                       # &mtime may exist but somehow does not work.
+                       $W->{"r"}->update_mtime(HTTP::Date::str2time($headers_out_hashref->{"Last-Modified"}));
+                       $status=$W->{"r"}->meets_conditions();
+                       $W->{"r"}->status($status_old);
+                       }
+               last if OK==$status;
+               $W->{"r"}->status($status);
+               exit 0;
+               die "NOTREACHED";
+               }
+
+       $W->{"digest-md5"}=Digest::MD5->new();
+       $W->{"cache_active"}=1;
+       $W->{"r"}->add_output_filter(\&cache_output_filter);
+}
+
+sub cache_finish_last_modified()
+{
+       cluck "Not yet done now? W __PACKAGE__: ".$W->{"__PACKAGE__"}
+                       if !$packages_used_hash{$W->{"__PACKAGE__"}}{"_done"};
+       for my $package_orig (@{$packages_used_array{$W->{"__PACKAGE__"}}}) {
+               local $_=$package_orig.".pm";
+               s{::}{/}g;
+               path_abs_disk "/$_","register"=>1;
+               }
+       my $mtime_newest;
+       for my $path_abs_disk (keys(%{$W->{"path_abs_disk_register"}})) {
+               my $mtime=(stat $path_abs_disk)[9];
+               do { cluck "No mtime for: $path_abs_disk"; next; } if !$mtime;
+               $mtime_newest=$mtime if !$mtime_newest || $mtime_newest<$mtime;
+               }
+       cluck "No mtime_newest found for the current W __PACKAGE__: ".$W->{"__PACKAGE__"}
+                       if !$mtime_newest;
+       return HTTP::Date::time2str($mtime_newest);
+}
+
+
+sub cache_finish()
+{
+       # Do not: return if !$W->{"uri_args_frozen"};
+       # as we may have just gave 304 and 'exit 0;' without starting the caching.
+       return if !$W->{"cache_active"};
+
+       # Fill-in/check: %uri_args_frozen_to_headers_in_keys
+       my $headers_in_keys_stored_arrayref_ref=\$uri_args_frozen_to_headers_in_keys{$W->{"uri_args_frozen"}};
+       my @headers_in_keys=tied(%{$W->{"headers_in_RecordKeys"}})->accessed();
+       if (!$$headers_in_keys_stored_arrayref_ref
+                       || !Data::Compare::Compare(\@headers_in_keys,$$headers_in_keys_stored_arrayref_ref)) {
+               cluck "Non-matching generated 'headers_in_keys' per 'uri_args_frozen' key:\n"
+                                               .Dumper(\@headers_in_keys,$$headers_in_keys_stored_arrayref_ref)
+                               if $$headers_in_keys_stored_arrayref_ref;
+               # Build or possibly prevent such further warn dupes:
+               $$headers_in_keys_stored_arrayref_ref=\@headers_in_keys;
+               # Build or regenerate as obsoleted now:
+               $W->{"uri_args_headers_in_frozen"}=uri_args_headers_in_frozen_get(\@headers_in_keys);
+               }
+
+       # Prepare 'headers_out' for the future reusal:
+       my %headers_out;
+       # Do not: $W->{"digest-md5"}->b64digest();
+       # as it will not provide the trailing filling '='s.
+       # RFC 1864 is not clear but the same provides them.
+       # FIXME: Should we somehow provide "\r\n" newlines for the text data? Which content is "text"?
+       # ',""' to avoid breaking the headers by its default "\n".
+       $headers_out{"Content-MD5"}=MIME::Base64::encode_base64($W->{"digest-md5"}->digest(),"");
+       # In fact we could also use MD5 for ETag as if we know ETag we also know MD5.
+       # But this way we do not need to calculate MD5 and we still can provide such ETag. So.
+       # $W->{"r"}->set_etag() ?
+       $headers_out{"ETag"}='"'.Digest::MD5::md5_base64($W->{"uri_args_headers_in_frozen"}).'"';
+       # $W->{"r"}->set_content_length() ?
+       $headers_out{"Content-Length"}=$W->{"r"}->bytes_sent();
+       my %Vary=map(($_=>1),(@headers_in_keys));
+       for (keys(%Vary)) {
+               next if !/^_/;
+               $Vary{"*"}=1;
+               delete $Vary{$_};
+               }
+       %Vary=("*"=>1) if $Vary{"*"};
+       $headers_out{"Vary"}=join(", ",sort keys(%Vary));
+       # $W->{"r"}->set_last_modified() ?
+       $headers_out{"Last-Modified"}=cache_finish_last_modified();
+
+       # Fill-in/check: %uri_args_headers_in_frozen_to_headers_out
+       my $headers_out_stored_hashref_ref=\$uri_args_headers_in_frozen_to_headers_out{$W->{"uri_args_headers_in_frozen"}};
+       if (!$$headers_out_stored_hashref_ref
+                       || !Data::Compare::Compare(\%headers_out,$$headers_out_stored_hashref_ref)) {
+               cluck "Non-matching generated 'headers_out' per 'uri_args_headers_in_frozen' key:\n"
+                                               .Dumper(\%headers_out,$$headers_out_stored_hashref_ref)
+                               if $$headers_out_stored_hashref_ref;
+               # Build or possibly prevent such further warn dupes:
+               $$headers_out_stored_hashref_ref=\%headers_out;
+               }
+
+###print STDERR Dumper(\%uri_args_frozen_to_headers_in_keys,\%uri_args_headers_in_frozen_to_headers_out);
 }
 
-sub heading ()
+sub heading()
 {
 my($class)=@_;
 
+       if (!$W->{"header_only"}) {
+               header("Content-Style-Type"=>"text/css");
+               header("Content-Script-Type"=>"text/javascript");
+               # $W->{"r"}->content_languages() ?
+               do { header("Content-Language"=>$_) if $_; } for $W->{"language"};
+               }
+       # TODO: Support also: private
+       header("Cache-Control"=>"public");      # HTTP/1.1
+
        # $ENV{"CLIENT_CHARSET"} ignored (mod_czech support dropped!)
        my $client_charset=$W->{"force_charset"} || "us-ascii";
-       header("Content-Style-Type"=>"text/css");
-       header("Content-Script-Type"=>"text/javascript");
-       do { header("Content-Language"=>$_) if $_; } for $W->{"language"};
-       $class->no_cache() if $W->{"no_cache"};
 
-       while (my($key,$val)=each(%{$W->{"headers"}})) {
-               $W->{"r"}->headers_out()->{$key}=$val;
-               }
-       exit if $W->{"r"}->header_only();
-       return if $W->{"header_only"};
-       # We still can append headers before we put out some text.
-       # FIXME: It is not clean to still append them without overwriting.
-       return if $W->{"heading_done"}++;
-
-       my $lang=($W->{"language"}||"en-US");
        # Workaround bug
        #   https://bugzilla.mozilla.org/show_bug.cgi?id=120556
        # of at least
        #   Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8b) Gecko/20050217
-       my $mime=$class->Negotiate_choose([
+       my $mime;
+       # http://validator.w3.org/ does not send ANY "Accept" headers!
+       $mime||="application/xhtml+xml" if 1
+                       && !$W->{"headers_in"}{"Accept"}
+                       && ($W->{"headers_in"}{"User-Agent"}||"")=~m{^W3C_Validator/}i;
+       $mime||=$class->Negotiate_choose([
                        # Put the fallback variant as the first one.
                        # Rate both variants the same to prefer "text/html" for undecided clients.
                        # At least
@@ -755,38 +1064,57 @@ my($class)=@_;
                                        "content-type"=>"text/html",
                                        "qs"=>0.6,
                                        "charset"=>$client_charset,
-                                       "lang"=>$lang,
+                                       "lang"=>$W->{"language"},
                                        ),
                        negotiate_variant(
                                        "id"=>"application/xhtml+xml",
                                        "content-type"=>"application/xhtml+xml",
                                        "qs"=>0.6,
                                        "charset"=>$client_charset,
-                                       "lang"=>$lang,
+                                       "lang"=>$W->{"language"},
                                        ),
                        # application/xml ?
                        # text/xml ?
                        ]);
+       # mod_perl doc: If you set this header via the headers_out table directly, it
+       #               will be ignored by Apache. So do not do that.
        $W->{"r"}->content_type("$mime; charset=$client_charset");
-       if (1) { # || !$msie_major || $msie_major>=4) # TODO:dyn
-               Wprint '<?xml version="1.0" encoding="'.$client_charset.'"?>'."\n";
-               }
+
+       cache_start();
+       return if $W->{"header_only"};
+       # We still can append headers before we put out some text.
+       # FIXME: It is not clean to still append them without overwriting.
+       return if $W->{"heading_done"}++;
+
+       Wprint '<?xml version="1.0" encoding="'.$client_charset.'"?>'."\n" if $mime=~m{^application/\w+[+]xml$};
+       return if $W->{"xml_header_only"};
        Wprint '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">'."\n";
-       Wprint '<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="'.$lang.'">'."\n";
+       Wprint '<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="'.$W->{"language"}.'">'."\n";
        my $title=$W->{"title_prefix"}.join("",map({ ': '.$_; } ($W->{"title"} || ())));
+       # Do not: cluck if $title=~/[<>]/;
+       # as it is not solved just by: &a_href_inhibit
+       # as sometimes titles use also: <i>...</i>
        $title=~s#<[^>]*>##g;
        Wprint "<head>";
        Wprint "<title>$title</title>\n";
        if ($W->{"have_css"}) {
                # Everything can get overriden later.
-               Wprint <<"HERE";
-<link rel="stylesheet" type="text/css" href="@{[ url_out("/My/Web.css") ]}" />
+               for my $css ("/My/Web.css",map((!$_ ? () : ("ARRAY" ne ref($_) ? $_ : @$_)),$W->{"css_push"})) {
+                       Wprint <<"HERE";
+<link rel="stylesheet" type="text/css" href="@{[ uri_escaped(path_web $css) ]}" />
+HERE
+                       }
+               if ($W->{"css_inherit"}) {
+                       Wprint <<"HERE";
+<script type="text/javascript" src="@{[ uri_escaped(path_web('/My/css_inherit.js')) ]}" />
 HERE
+                       }
                }
        Wprint '<meta name="robots" content="'.($W->{"indexme"} ? "" : "no" ).'index,follow" />'."\n";
        Wprint $W->{"head"};
        for my $type (qw(prev next index contents start up)) {
-               do { Wprint '<link rel="'.$type.'" href="'.$_.'" />'."\n" if $_; } for ($W->{"rel_$type"});
+               do { Wprint '<link rel="'.$type.'" href="'.uri_escaped(path_web $_).'" />'."\n" if $_; }
+                               for ($W->{"rel_$type"});
                }
        Wprint "</head><body";
 #      Wprint ' bgcolor="black" text="white" link="aqua" vlink="teal"'
@@ -794,7 +1122,7 @@ HERE
        Wprint $W->{"body_attr"};
        Wprint ">\n";
 
-       do { &{$_}() if $_; } for ($W->{"heading"});
+       do { Wprint $_ if $_; } for $W->{"heading"};
 }
 
 BEGIN {