Java Play Framework 2.6不返回`Access Control Allow Origin`CORS头

Question

Play不遵守我的application.conf配置以返回Access-Control-Allow-Origin标头。当我从Ajax发送请求时，响应总是：

Failed to load http://localhost:9000/: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access.

这就是我的application.conf的样子：

# disable the built in filters
play.http.filters = play.api.http.NoHttpFilters
play.filters.enabled += "play.filters.cors.CORSFilter"
play.filters {
cors {
# The allowed origins. If null, all origins are allowed.
allowedOrigins = null
}
}

我成功获得Ajax请求的唯一方法是在控制器中添加行response().setHeader("Access-Control-Allow-Origin", "*");。但我想通过application.conf来完成，所以我不必在所有控制器中添加这个setHeader()代码。

public class HomeController extends Controller {
public Result index() {
// this is the only hack that works
//response().setHeader("Access-Control-Allow-Origin", "*");
return ok(
Json.toJson("A long time ago in a galaxy far, far away....")
);
}
}

我的Ajax请求如下：

$.ajax({
url: "http://localhost:9000",
type: "GET",
dataType: 'json',
success: function(_out) {
alert(_out);
},
fail: function() {
alert("error");
}
});

为什么Play不尊重我的CORSapplication.conf配置？

Answer 1

我已经确定了这个问题。在我的application.conf:中

play.http.filters = play.api.http.NoHttpFilters
play.filters.enabled += "play.filters.cors.CORSFilter"

这两行不是相加的。换句话说，第一行禁用所有过滤器，第二行启用过滤器，但最终结果仍然是所有过滤器都被禁用(即使启用是在DIsabling之后(。