Merge pull request #1827 from ag2s20150909/master

添加java.head方法

app/src/main/java/io/legado/app/help/JsExtensions.kt

@@ -218,6 +218,19 @@ interface JsExtensions {
             .execute()
     }
 
+    /**
+     * js实现重定向拦截,网络访问head,不返回Response Body更省流量
+     */
+    fun head(urlStr: String, headers: Map<String, String>): Connection.Response {
+        return Jsoup.connect(urlStr)
+            .sslSocketFactory(SSLHelper.unsafeSSLSocketFactory)
+            .ignoreContentType(true)
+            .followRedirects(false)
+            .headers(headers)
+            .method(Connection.Method.HEAD)
+            .execute()
+    }
+
     /**
      * 网络访问post
      */