amp-wp-encoding-failure.diff

diff --git a/amp.php b/amp.php
index 449a814..731e4c6 100644
--- a/amp.php
+++ b/amp.php
@@ -283,6 +283,7 @@ function amp_render_post( $post ) {
 	}
 	$post_id = $post->ID;
 
+
 	/*
 	 * If amp_render_post is called directly outside of the standard endpoint, is_amp_endpoint() will return false,
 	 * which is not ideal for any code that expects to run in an AMP context.
@@ -292,6 +293,12 @@ function amp_render_post( $post ) {
 	if ( ! $was_set ) {
 		$wp_query->query_vars[ AMP_QUERY_VAR ] = true;
 	}
+//
+//	$is_utf8 = 'utf-8' === strtolower( get_bloginfo( 'charset' ) );
+//	if ( ! $is_utf8 ) {
+//		header( 'Content-Type: text/html; charset=utf-8' );
+//		ob_start();
+//	}
 
 	/**
 	 * Fires before rendering a post in AMP.
@@ -304,8 +311,22 @@ function amp_render_post( $post ) {
 
 	amp_add_post_template_actions();
 	$template = new AMP_Post_Template( $post );
+	header( 'content-type: text/html; charset=' . get_bloginfo( 'charset' ) );
+	print_r( $template );
+	exit;
+
+//	header( 'content-type: text/html; charset=' . get_bloginfo( 'charset' ) );
+//	print_r( $template );exit;
 	$template->load();
 
+
+	// AMP requires UTF-8.
+	if ( ! $is_utf8 ) {
+		$buffer = ob_get_clean();
+		$buffer = mb_convert_encoding( $buffer, 'utf-8', get_bloginfo( 'charset' ) );
+		echo $buffer; // WPCS: xss ok.
+	}
+
 	if ( ! $was_set ) {
 		unset( $wp_query->query_vars[ AMP_QUERY_VAR ] );
 	}
diff --git a/includes/templates/class-amp-content-sanitizer.php b/includes/templates/class-amp-content-sanitizer.php
index ddf5330..1b3508d 100644
--- a/includes/templates/class-amp-content-sanitizer.php
+++ b/includes/templates/class-amp-content-sanitizer.php
@@ -20,14 +20,17 @@ class AMP_Content_Sanitizer {
 	 * @param string   $content HTML content string or DOM document.
 	 * @param string[] $sanitizer_classes Sanitizer classes.
 	 * @param array    $global_args       Global args.
-	 * @return array Tuple containing sanitized HTML, scripts array, and styles array.
+	 * @return array Tuple containing sanitized HTML (in site's character encoding), scripts array, and styles array.
 	 */
 	public static function sanitize( $content, array $sanitizer_classes, $global_args = array() ) {
 		$dom = AMP_DOM_Utils::get_dom_from_content( $content );
 
 		$results = self::sanitize_document( $dom, $sanitizer_classes, $global_args );
+
+		$html = AMP_DOM_Utils::get_content_from_dom( $dom );
+
 		return array(
-			AMP_DOM_Utils::get_content_from_dom( $dom ),
+			$html,
 			$results['scripts'],
 			$results['styles'],
 		);
diff --git a/includes/templates/class-amp-post-template.php b/includes/templates/class-amp-post-template.php
index 313fe1f..3effdae 100644
--- a/includes/templates/class-amp-post-template.php
+++ b/includes/templates/class-amp-post-template.php
@@ -363,6 +363,10 @@ class AMP_Post_Template {
 			)
 		);
 
+		# GOOD
+//		header( 'content-type: text/html; charset=' . get_bloginfo( 'charset' ) );
+//		print_r( $amp_content );exit;
+
 		$this->add_data_by_key( 'post_amp_content', $amp_content->get_amp_content() );
 		$this->merge_data_for_key( 'amp_component_scripts', $amp_content->get_amp_scripts() );
 		$this->merge_data_for_key( 'post_amp_styles', $amp_content->get_amp_styles() );
diff --git a/includes/utils/class-amp-dom-utils.php b/includes/utils/class-amp-dom-utils.php
index 9492dd4..db07e81 100644
--- a/includes/utils/class-amp-dom-utils.php
+++ b/includes/utils/class-amp-dom-utils.php
@@ -54,14 +54,9 @@ class AMP_DOM_Utils {
 	public static function get_dom( $document ) {
 		$libxml_previous_state = libxml_use_internal_errors( true );
 
-		$dom = new DOMDocument();
+		$dom = new DOMDocument( '1.0', get_bloginfo( 'charset' ) );
+//		$dom->substituteEntities = false;
 
-		/*
-		 * Wrap in dummy tags, since XML needs one parent node.
-		 * It also makes it easier to loop through nodes.
-		 * We can later use this to extract our nodes.
-		 * Add charset so loadHTML does not have problems parsing it.
-		 */
 		$result = $dom->loadHTML( $document );
 
 		libxml_clear_errors();
@@ -86,6 +81,12 @@ class AMP_DOM_Utils {
 	 * @return DOMDocument|false Returns DOMDocument, or false if conversion failed.
 	 */
 	public static function get_dom_from_content( $content ) {
+
+		// Make sure content is converted to UTF-8 first.
+		if ( function_exists( 'mb_convert_encoding' ) && 'utf-8' !== strtolower( get_bloginfo( 'charset' ) ) ) {
+			$content = mb_convert_encoding( $content, 'utf-8', get_bloginfo( 'charset' ) );
+		}
+
 		/*
 		 * Wrap in dummy tags, since XML needs one parent node.
 		 * It also makes it easier to loop through nodes.
@@ -94,8 +95,7 @@ class AMP_DOM_Utils {
 		 * See: http://php.net/manual/en/domdocument.loadhtml.php#78243
 		 */
 		$document = sprintf(
-			'<html><head><meta http-equiv="content-type" content="text/html; charset=%s"></head><body>%s</body></html>',
-			get_bloginfo( 'charset' ),
+			'<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body>%s</body></html>',
 			$content
 		);
 
@@ -112,7 +112,7 @@ class AMP_DOM_Utils {
 	 *
 	 * @param DOMDocument $dom Represents an HTML document from which to extract HTML content.
 	 *
-	 * @return string Returns the HTML content represented in the DOMDocument
+	 * @return string Returns the HTML content represented in the DOMDocument in UTF-8.
 	 */
 	public static function get_content_from_dom( $dom ) {
 
@@ -136,6 +136,25 @@ class AMP_DOM_Utils {
 			$out .= self::get_content_from_dom_node( $dom, $child_node );
 		}
 
+		/*
+		 * Since AMP_DOM_Utils::get_content_from_dom() always returns markup as UTF-8 HTML,
+		 * we must convert the content back to to the blog's encoding prior to finally
+		 * convert everything back to UTF-8 in the end, since AMP mandates UTF-8.
+		 */
+		if ( function_exists( 'mb_convert_encoding' ) && 'utf-8' !== strtolower( get_bloginfo( 'charset' ) ) ) {
+//			header( 'content-type: text/html; charset=utf-8' );
+//			echo $html;exit;
+
+//			header( 'content-type: text/html; charset=UTF-8' );
+			header( 'content-type: text/html; charset=' . get_bloginfo( 'charset' ) );
+			$out = mb_convert_encoding( $out, get_bloginfo( 'charset' ), 'UTF-8' );
+			echo $out;exit;
+
+			// GOOD: Converted to blog charset properly.
+//			header( 'content-type: text/html; charset=' . get_bloginfo( 'charset' ) );
+//			echo $html;exit;
+		}
+
 		return $out;
 	}