Make an Ajax call to fork the process.

This should be more reliable then close_connection because
close_connection might not be supported in all browsers/servers.

Author: octalmage

src/wpephpcompat.php

@@ -174,9 +174,6 @@ public function start_test() {
 		}
 
 		if ( ! $this->is_command_line() ) {
-			// Close the connection to the browser.
-			$this->close_connection("started");
-
 			/**
 			 * Kill cron after a configurable timeout.
 			 * Subtract 5 from the timeout if we can to avoid race conditions.
@@ -466,29 +463,4 @@ private function is_command_line()
 	{
 		return defined( 'WP_CLI' ) || defined( 'PHPUNIT_TEST' );
 	}
-
-	/**
-	* Close the connection to the browser but continue processing the operation.
-	* @since  1.0.0
-	* @param  string $body The message to send to the client.
-	* @return null
-	*/
-	private function close_connection( $body ) {
-		ignore_user_abort( true );
-		if (ob_get_length()) ob_end_clean();
-		// Start buffering.
-		ob_start();
-		// Echo our response.
-		echo $body;
-		// Get the length of the buffer.
-		$size = ob_get_length();
-		// Close the connection.
-		header( 'Connection: close\r\n' );
-		header( 'Content-Encoding: none\r\n' );
-		header( 'Content-Length: $size' );
-		// Flush and close the buffer.
-		ob_end_flush();
-		// Flush the system output buffer.
-		flush();
-	}
 }

wpengine-phpcompat.php

@@ -78,16 +78,27 @@ function start_test() {
 
 			$wpephpc = new \WPEPHPCompat( __DIR__ );
 
+			foreach ( array( 'test_version', 'only_active' ) as $key ) {
+				if ( isset( $_POST[ $key ] ) ) {
+					$$key = sanitize_text_field( $_POST[ $key ] );
+				}
+			}
+
+			// New scan!
 			if ( isset( $_POST['startScan'] ) ) {
-				$test_version = sanitize_text_field( $_POST['test_version'] );
-				$only_active = sanitize_text_field( $_POST['only_active'] );
+				// Make sure we clean up after the last test.
+				$wpephpc->clean_after_scan();
 
+				// Fork so we can close the connection.
+				$this->fork_scan( $test_version, $only_active );
+			}
+			else {
 				$wpephpc->test_version = $test_version;
 				$wpephpc->only_active = $only_active;
-				$wpephpc->clean_after_scan();
+
+				$wpephpc->start_test();
 			}
 
-			$wpephpc->start_test();
 			wp_die();
 		}
 	}
@@ -147,6 +158,41 @@ function check_status() {
 			wp_die();
 		}
 	}
+	
+	/**
+	 * Make an Ajax call to start the scan in the background.
+	 *
+	 * @since 1.1.2
+	 * @param  string $test_version Version of PHP to test.
+	 * @param  string $only_active  Scan only active plugins or all?
+	 * @return null
+	 */
+	function fork_scan( $test_version, $only_active ) {
+		$query = array(
+			'action' => 'wpephpcompat_start_test',
+		);
+		
+		// Keep track of these variables.
+		$body = array(
+			'test_version'=> $test_version,
+			'only_active'=> $only_active,
+		);
+		
+		// Instantly return!
+		$args = array(
+			'timeout'   => 0.01,
+			'blocking'  => false,
+			'body'      => $body,
+			'cookies'   => $_COOKIE,
+			'sslverify' => apply_filters( 'https_local_ssl_verify', false ),
+		);
+
+		// Build our URL.
+		$url = add_query_arg( $query, admin_url( 'admin-ajax.php' ) );
+		
+		// POST.
+		wp_remote_post( esc_url_raw( $url ), $args );
+	}
 
 	/**
 	 * Create custom post type to store the directories we need to process.