Skip sending Content-Type header if headers already sent

westonruter · westonruter · commit 1faaf3271c85 · 2020-02-15T17:06:14.000-08:00
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
@@ -2054,7 +2054,9 @@ public static function prepare_response( $response, $args = [] ) {
 		}
 
 		// Enforce UTF-8 encoding as it is a requirement for AMP.
-		header( 'Content-Type: text/html; charset=utf-8' );
+		if ( ! headers_sent() ) {
+			header( 'Content-Type: text/html; charset=utf-8' );
+		}
 
 		/**
 		 * Filters whether response (post-processor) caching is enabled.

Original file line number	Diff line number	Diff line change
`@@ -2054,7 +2054,9 @@ public static function prepare_response( $response, $args = [] ) {`
`2054`	`2054`	`}`
`2055`	`2055`
`2056`	`2056`	`// Enforce UTF-8 encoding as it is a requirement for AMP.`
`2057`		`- header( 'Content-Type: text/html; charset=utf-8' );`
	`2057`	`+ if ( ! headers_sent() ) {`
	`2058`	`+ header( 'Content-Type: text/html; charset=utf-8' );`
	`2059`	`+ }`
`2058`	`2060`
`2059`	`2061`	`/**`
`2060`	`2062`	`* Filters whether response (post-processor) caching is enabled.`