From 25443d3a7f2554c813c6110748fbc8625529bc47 Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov@git.wordpress.org>
Date: Sun, 13 Aug 2023 10:29:04 +0000
Subject: [PATCH] Coding Standards: Bring more consistency to `Last-Modified`
 and `ETag` checks.

This updates two fragments for sending a `304 Not Modified` header to better align with each other by using consistent variable names and formatting.

Follow-up to [1036], [1037], [1043], [2534], [2584], [2627], [12603], [12936], [56362].

See #58831.

git-svn-id: https://develop.svn.wordpress.org/trunk@56395 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/class-wp.php | 19 ++++++++++++-------
 src/wp-includes/ms-files.php | 32 +++++++++++++++++++-------------
 2 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/src/wp-includes/class-wp.php b/src/wp-includes/class-wp.php
index 8f66d98929c64..ce88c102cfade 100644
--- a/src/wp-includes/class-wp.php
+++ b/src/wp-includes/class-wp.php
@@ -505,8 +505,8 @@ public function send_headers() {
 			}
 
 			$wp_last_modified .= ' GMT';
+			$wp_etag           = '"' . md5( $wp_last_modified ) . '"';
 
-			$wp_etag                  = '"' . md5( $wp_last_modified ) . '"';
 			$headers['Last-Modified'] = $wp_last_modified;
 			$headers['ETag']          = $wp_etag;
 
@@ -514,19 +514,24 @@ public function send_headers() {
 			if ( isset( $_SERVER['HTTP_IF_NONE_MATCH'] ) ) {
 				$client_etag = wp_unslash( $_SERVER['HTTP_IF_NONE_MATCH'] );
 			} else {
-				$client_etag = false;
+				$client_etag = '';
+			}
+
+			if ( isset( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
+				$client_last_modified = trim( $_SERVER['HTTP_IF_MODIFIED_SINCE'] );
+			} else {
+				$client_last_modified = '';
 			}
 
-			$client_last_modified = empty( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ? '' : trim( $_SERVER['HTTP_IF_MODIFIED_SINCE'] );
 			// If string is empty, return 0. If not, attempt to parse into a timestamp.
 			$client_modified_timestamp = $client_last_modified ? strtotime( $client_last_modified ) : 0;
 
-			// Make a timestamp for our most recent modification..
+			// Make a timestamp for our most recent modification.
 			$wp_modified_timestamp = strtotime( $wp_last_modified );
 
-			if ( ( $client_last_modified && $client_etag ) ?
-					( ( $client_modified_timestamp >= $wp_modified_timestamp ) && ( $client_etag === $wp_etag ) ) :
-					( ( $client_modified_timestamp >= $wp_modified_timestamp ) || ( $client_etag === $wp_etag ) )
+			if ( ( $client_last_modified && $client_etag )
+				? ( ( $client_modified_timestamp >= $wp_modified_timestamp ) && ( $client_etag === $wp_etag ) )
+				: ( ( $client_modified_timestamp >= $wp_modified_timestamp ) || ( $client_etag === $wp_etag ) )
 			) {
 				$status        = 304;
 				$exit_required = true;
diff --git a/src/wp-includes/ms-files.php b/src/wp-includes/ms-files.php
index 6026a71db6f38..c909a32407d64 100644
--- a/src/wp-includes/ms-files.php
+++ b/src/wp-includes/ms-files.php
@@ -54,30 +54,36 @@
 	exit;
 }
 
-$last_modified = gmdate( 'D, d M Y H:i:s', filemtime( $file ) );
-$etag          = '"' . md5( $last_modified ) . '"';
-header( "Last-Modified: $last_modified GMT" );
-header( 'ETag: ' . $etag );
+$wp_last_modified = gmdate( 'D, d M Y H:i:s', filemtime( $file ) );
+$wp_etag          = '"' . md5( $wp_last_modified ) . '"';
+
+header( "Last-Modified: $wp_last_modified GMT" );
+header( 'ETag: ' . $wp_etag );
 header( 'Expires: ' . gmdate( 'D, d M Y H:i:s', time() + 100000000 ) . ' GMT' );
 
 // Support for conditional GET - use stripslashes() to avoid formatting.php dependency.
-$client_etag = isset( $_SERVER['HTTP_IF_NONE_MATCH'] ) ? stripslashes( $_SERVER['HTTP_IF_NONE_MATCH'] ) : false;
+if ( isset( $_SERVER['HTTP_IF_NONE_MATCH'] ) ) {
+	$client_etag = stripslashes( $_SERVER['HTTP_IF_NONE_MATCH'] );
+} else {
+	$client_etag = '';
+}
 
-if ( ! isset( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
-	$_SERVER['HTTP_IF_MODIFIED_SINCE'] = false;
+if ( isset( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) ) {
+	$client_last_modified = trim( $_SERVER['HTTP_IF_MODIFIED_SINCE'] );
+} else {
+	$client_last_modified = '';
 }
 
-$client_last_modified = trim( $_SERVER['HTTP_IF_MODIFIED_SINCE'] );
 // If string is empty, return 0. If not, attempt to parse into a timestamp.
 $client_modified_timestamp = $client_last_modified ? strtotime( $client_last_modified ) : 0;
 
-// Make a timestamp for our most recent modification...
-$modified_timestamp = strtotime( $last_modified );
+// Make a timestamp for our most recent modification.
+$wp_modified_timestamp = strtotime( $wp_last_modified );
 
 if ( ( $client_last_modified && $client_etag )
-	? ( ( $client_modified_timestamp >= $modified_timestamp ) && ( $client_etag == $etag ) )
-	: ( ( $client_modified_timestamp >= $modified_timestamp ) || ( $client_etag == $etag ) )
-	) {
+	? ( ( $client_modified_timestamp >= $wp_modified_timestamp ) && ( $client_etag === $wp_etag ) )
+	: ( ( $client_modified_timestamp >= $wp_modified_timestamp ) || ( $client_etag === $wp_etag ) )
+) {
 	status_header( 304 );
 	exit;
 }