From mboxrd@z Thu Jan  1 00:00:00 1970
From: Leo-Andres Hofmann <hofmann@leo-andres.de>
To: development@lists.ipfire.org
Subject: [PATCH 5/7] pakfire.cgi: Implement Post/Redirect/Get pattern
Date: Sun, 08 May 2022 14:09:50 +0200
Message-ID: <20220508120952.52-5-hofmann@leo-andres.de>
In-Reply-To: <20220508120952.52-1-hofmann@leo-andres.de>
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Refreshing the Pakfire page may cause a command to be
executed multiple times and induce odd errors.

This patch implements a HTTP 303 redirect after form processing,
which causes the browser to discard the POST form data.
Navigating backward or reloading the page now does not trigger
multiple executions anymore.

Fixes: #12781

Signed-off-by: Leo-Andres Hofmann <hofmann(a)leo-andres.de>
---
 html/cgi-bin/pakfire.cgi | 56 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 50 insertions(+), 6 deletions(-)

diff --git a/html/cgi-bin/pakfire.cgi b/html/cgi-bin/pakfire.cgi
index ec3ee2cc6..6fade81bd 100644
--- a/html/cgi-bin/pakfire.cgi
+++ b/html/cgi-bin/pakfire.cgi
@@ -21,6 +21,7 @@
=20
 use strict;
 use List::Util qw(any);
+use URI;
=20
 # enable only the following on debugging purpose
 #use warnings;
@@ -37,12 +38,17 @@ my %color =3D ();
 my %pakfiresettings =3D ();
 my %mainsettings =3D ();
=20
+# The page mode is used to explictly switch between user interface functions:
+my $PM_DEFAULT =3D 'default'; # Default user interface with command processi=
ng
+my $PM_LOGREAD =3D 'logread'; # Log messages viewer (ignores all commands)
+my $pagemode =3D $PM_DEFAULT;
+
 # Load general settings
 &General::readhash("${General::swroot}/main/settings", \%mainsettings);
 &General::readhash("${General::swroot}/pakfire/settings", \%pakfiresettings);
 &General::readhash("/srv/web/ipfire/html/themes/ipfire/include/colors.txt", =
\%color);
=20
-# Get CGI request data
+# Get CGI POST request data
 $cgiparams{'ACTION'} =3D '';
 $cgiparams{'FORCE'} =3D '';
=20
@@ -51,6 +57,17 @@ $cgiparams{'DELPAKS'} =3D '';
=20
 &Header::getcgihash(\%cgiparams);
=20
+# Get CGI GET request data (if available)
+if($ENV{'QUERY_STRING'}) {
+	my $uri =3D URI->new($ENV{'REQUEST_URI'});
+	my %query =3D $uri->query_form;
+
+	my $mode =3D lc($query{'mode'} // '');
+	if(($mode eq $PM_DEFAULT) || ($mode eq $PM_LOGREAD)) {
+		$pagemode =3D $mode; # Limit to existing modes
+	}
+}
+
 ### Process AJAX/JSON request ###
 if($cgiparams{'ACTION'} eq 'json-getstatus') {
 	# Send HTTP headers
@@ -96,19 +113,24 @@ if($cgiparams{'ACTION'} eq 'json-getstatus') {
 }
=20
 ### Process Pakfire install/update commands ###
-if($cgiparams{'ACTION'} ne '') {
+if(($cgiparams{'ACTION'} ne '') && ($pagemode eq $PM_DEFAULT)) {
 	if(&_is_pakfire_busy()) {
 		$errormessage =3D $Lang::tr{'pakfire already busy'};
+		$pagemode =3D $PM_LOGREAD; # Running Pakfire instance found, switch to log=
 viewer mode
 	} elsif(($cgiparams{'ACTION'} eq 'install') && ($cgiparams{'FORCE'} eq 'on'=
)) {
 		my @pkgs =3D split(/\|/, $cgiparams{'INSPAKS'});
 		&General::system_background("/usr/local/bin/pakfire", "install", "--non-in=
teractive", "--no-colors", @pkgs);
+		&_http_pagemode_redirect($PM_LOGREAD, 1);
 	} elsif(($cgiparams{'ACTION'} eq 'remove') && ($cgiparams{'FORCE'} eq 'on')=
) {
 		my @pkgs =3D split(/\|/, $cgiparams{'DELPAKS'});
 		&General::system_background("/usr/local/bin/pakfire", "remove", "--non-int=
eractive", "--no-colors", @pkgs);
+		&_http_pagemode_redirect($PM_LOGREAD, 1);
 	} elsif($cgiparams{'ACTION'} eq 'update') {
 		&General::system_background("/usr/local/bin/pakfire", "update", "--force",=
 "--no-colors");
+		&_http_pagemode_redirect($PM_LOGREAD, 1);
 	} elsif($cgiparams{'ACTION'} eq 'upgrade') {
 		&General::system_background("/usr/local/bin/pakfire", "upgrade", "-y", "--=
no-colors");
+		&_http_pagemode_redirect($PM_LOGREAD, 1);
 	} elsif($cgiparams{'ACTION'} eq $Lang::tr{'save'}) {
 		$pakfiresettings{"TREE"} =3D $cgiparams{"TREE"};
=20
@@ -122,6 +144,7 @@ if($cgiparams{'ACTION'} ne '') {
=20
 			# Update lists
 			&General::system_background("/usr/local/bin/pakfire", "update", "--force"=
, "--no-colors");
+			&_http_pagemode_redirect($PM_LOGREAD, 1);
 		}
 	}
 }
@@ -221,8 +244,8 @@ if ($errormessage) {
 	&Header::closebox();
 }
=20
-# Show log output while Pakfire is running
-if(&_is_pakfire_busy()) {
+# Show only log output while Pakfire is running and stop afterwards
+if(($pagemode eq $PM_LOGREAD) || (&_is_pakfire_busy())) {
 	&Header::openbox("100%", "center", "Pakfire");
=20
 	print <<END
@@ -253,7 +276,8 @@ END
 }
=20
 # Show Pakfire install/remove dependencies and confirm form
-if (($cgiparams{'ACTION'} eq 'install') && (! &_is_pakfire_busy())) {
+# (_is_pakfire_busy status was checked before and can be omitted)
+if (($cgiparams{'ACTION'} eq 'install') && ($pagemode eq $PM_DEFAULT)) {
 	&Header::openbox("100%", "center", $Lang::tr{'request'});
=20
 	my @pkgs =3D split(/\|/, $cgiparams{'INSPAKS'});
@@ -291,7 +315,7 @@ END
 	&Header::closepage();
 	exit;
=20
-} elsif (($cgiparams{'ACTION'} eq 'remove') && (! &_is_pakfire_busy())) {
+} elsif (($cgiparams{'ACTION'} eq 'remove') && ($pagemode eq $PM_DEFAULT)) {
 	&Header::openbox("100%", "center", $Lang::tr{'request'});
=20
 	my @pkgs =3D split(/\|/, $cgiparams{'DELPAKS'});
@@ -476,3 +500,23 @@ sub _start_json_output {
 	print "Content-Type: application/json\n";
 	print "\n"; # End of HTTP headers
 }
+
+# Send HTTP 303 redirect headers to change page mode
+# GET is always used to display the redirected page, which will remove alrea=
dy processed POST form data.
+# Note: Custom headers must be sent before the HTML output is started by &He=
ader::showhttpheaders().
+# If switch_mode is set to true, the global page mode variable ("$pagemode")=
 is also updated immediately.
+sub _http_pagemode_redirect {
+	my ($mode, $switch_mode) =3D @_;
+	$mode //=3D $PM_DEFAULT;
+	$switch_mode //=3D 0;
+
+	# Send HTTP redirect with GET parameter
+	my $location =3D "https://$ENV{'SERVER_NAME'}:$ENV{'SERVER_PORT'}$ENV{'SCRI=
PT_NAME'}?mode=3D${mode}";
+	print "Status: 303 See Other\n";
+	print "Location: $location\n";
+
+	# Change global page mode
+	if($switch_mode) {
+		$pagemode =3D $mode;
+	}
+}
--=20
2.27.0.windows.1


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