Merged in feature/from-pantheon (pull request #16)

code from pantheon

* code from pantheon

wp/wp-content/plugins/imagify/classes/Webp/RewriteRules/Nginx.php

@@ -0,0 +1,52 @@
+<?php
+namespace Imagify\Webp\RewriteRules;
+
+defined( 'ABSPATH' ) || die( 'Cheatin’ uh?' );
+
+/**
+ * Add and remove rewrite rules to the imagify.conf file to display WebP images on the site.
+ *
+ * @since  1.9
+ * @author Grégory Viguier
+ */
+class Nginx extends \Imagify\WriteFile\AbstractNginxDirConfFile {
+
+	/**
+	 * Name of the tag used as block delemiter.
+	 *
+	 * @var    string
+	 * @since  1.9
+	 * @author Grégory Viguier
+	 */
+	const TAG_NAME = 'Imagify: rewrite rules for webp';
+
+	/**
+	 * Get unfiltered new contents to write into the file.
+	 *
+	 * @since  1.9
+	 * @access protected
+	 * @author Grégory Viguier
+	 *
+	 * @return string
+	 */
+	protected function get_raw_new_contents() {
+		$extensions = $this->get_extensions_pattern();
+		$home_root  = wp_parse_url( home_url( '/' ) );
+		$home_root  = $home_root['path'];
+
+		return trim( '
+location ~* ^(' . $home_root . '.+)\.(' . $extensions . ')$ {
+	add_header Vary Accept;
+
+	if ($http_accept ~* "webp"){
+		set $imwebp A;
+	}
+	if (-f $request_filename.webp) {
+		set $imwebp  "${imwebp}B";
+	}
+	if ($imwebp = AB) {
+		rewrite ^(.*) $1.webp;
+	}
+}' );
+	}
+}