[英]Enable CORS in Java Play Framework 2.2.x
我在Java Play 2.2.x中启用跨域时遇到问题
在Java Play 2.1.3中,此代码通过将其放在Global.java中来工作
public class Global extends GlobalSettings {
private class ActionWrapper extends Action.Simple {
public ActionWrapper(Action action) {
this.delegate = action;
}
@Override
public Result call(Http.Context ctx) throws java.lang.Throwable {
Result result = this.delegate.call(ctx);
Http.Response response = ctx.response();
response.setHeader("Access-Control-Allow-Origin", "*");
return result;
}
}
@Override
public Action onRequest(Http.Request request, java.lang.reflect.Method actionMethod) {
return new ActionWrapper(super.onRequest(request, actionMethod));
}
}
但是当我尝试在java play 2.2.x上编译时,它不再编译了。
编译错误消息:
Global.ActionWrapper不是抽象的,并且不会覆盖Action中的抽象方法调用(Context)...
java play 2.2.x有没有相同的代码?
谢谢。
它看起来像这样:
import play.GlobalSettings;
import play.libs.F.Promise;
import play.mvc.Action;
import play.mvc.Http;
import play.mvc.SimpleResult;
public class Global extends GlobalSettings {
private class ActionWrapper extends Action.Simple {
public ActionWrapper(Action<?> action) {
this.delegate = action;
}
@Override
public Promise<SimpleResult> call(Http.Context ctx) throws java.lang.Throwable {
Promise<SimpleResult> result = this.delegate.call(ctx);
Http.Response response = ctx.response();
response.setHeader("Access-Control-Allow-Origin", "*");
return result;
}
}
@Override
public Action<?> onRequest(Http.Request request, java.lang.reflect.Method actionMethod) {
return new ActionWrapper(super.onRequest(request, actionMethod));
}
}
对于使用2.3.1+(撰写本文时)Play的人来说,它现在是Promise<Result>
而不是Promise<SimpleResult>
import play.GlobalSettings;
import play.libs.F.Promise;
import play.mvc.Action;
import play.mvc.Http;
import play.mvc.Result;
public class Global extends GlobalSettings {
private class ActionWrapper extends Action.Simple {
public ActionWrapper(Action<?> action) {
this.delegate = action;
}
@Override
public Promise<Result> call(Http.Context ctx) throws java.lang.Throwable {
Promise<Result> result = this.delegate.call(ctx);
Http.Response response = ctx.response();
response.setHeader("Access-Control-Allow-Origin", "*");
return result;
}
}
@Override
public Action<?> onRequest(Http.Request request, java.lang.reflect.Method actionMethod) {
return new ActionWrapper(super.onRequest(request, actionMethod));
}
}
@alexhanschke提出的解决方案在请求抛出异常(内部服务器错误)时不起作用,因为当发生异常时不应用过滤器(请参阅https://github.com/playframework/playframework/issues/2429 )。 要解决这个问题,你必须包装一个scala类并返回结果,如下所示。 请注意,这仍然需要指定的选项路由和控制器来处理选项请求。
在这里查看整个内容https://gist.github.com/tinusn/38c4c110f7cd1e1ec63f 。
import static play.core.j.JavaResults.BadRequest;
import static play.core.j.JavaResults.InternalServerError;
import static play.core.j.JavaResults.NotFound;
import java.util.ArrayList;
import java.util.List;
import play.GlobalSettings;
import play.api.mvc.Results.Status;
import play.libs.F.Promise;
import play.libs.Scala;
import play.mvc.Action;
import play.mvc.Http;
import play.mvc.Result;
import scala.Tuple2;
import scala.collection.Seq;
public class Global extends GlobalSettings {
private class ActionWrapper extends Action.Simple {
public ActionWrapper(Action<?> action) {
this.delegate = action;
}
@Override
public Promise<Result> call(Http.Context ctx) throws java.lang.Throwable {
Promise<Result> result = this.delegate.call(ctx);
Http.Response response = ctx.response();
response.setHeader("Access-Control-Allow-Origin", "*");
return result;
}
}
/*
* Adds the required CORS header "Access-Control-Allow-Origin" to successfull requests
*/
@Override
public Action<?> onRequest(Http.Request request, java.lang.reflect.Method actionMethod) {
return new ActionWrapper(super.onRequest(request, actionMethod));
}
private static class CORSResult implements Result {
final private play.api.mvc.Result wrappedResult;
public CORSResult(Status status) {
List<Tuple2<String, String>> list = new ArrayList<Tuple2<String, String>>();
Tuple2<String, String> t = new Tuple2<String, String>("Access-Control-Allow-Origin","*");
list.add(t);
Seq<Tuple2<String, String>> seq = Scala.toSeq(list);
wrappedResult = status.withHeaders(seq);
}
public play.api.mvc.Result toScala() {
return this.wrappedResult;
}
}
/*
* Adds the required CORS header "Access-Control-Allow-Origin" to bad requests
*/
@Override
public Promise<Result> onBadRequest(Http.RequestHeader request, String error) {
return Promise.<Result>pure(new CORSResult(BadRequest()));
}
/*
* Adds the required CORS header "Access-Control-Allow-Origin" to requests that causes an exception
*/
@Override
public Promise<Result> onError(Http.RequestHeader request, Throwable t) {
return Promise.<Result>pure(new CORSResult(InternalServerError()));
}
/*
* Adds the required CORS header "Access-Control-Allow-Origin" when a route was not found
*/
@Override
public Promise<Result> onHandlerNotFound(Http.RequestHeader request) {
return Promise.<Result>pure(new CORSResult(NotFound()));
}
}
另一种选择可能是使用过滤器 。 目前只有Scala过滤器可用。 但是,正如本文中为了简单地修改响应头而指出的,您可以复制并粘贴以下内容以启用CORS。
package filters
import play.api.mvc._
import play.mvc.Http.HeaderNames
import scala.concurrent.Future
import scala.concurrent.ExecutionContext.Implicits.global
class EnableCORS extends Filter {
def apply(f: (RequestHeader) => Future[Result])(rh: RequestHeader): Future[Result] = {
val result = f(rh)
result.map(_.withHeaders(HeaderNames.ACCESS_CONTROL_ALLOW_ORIGIN -> "*"))
}
}
然后在Global.java
添加过滤器:
@Override
public <T extends EssentialFilter> Class<T>[] filters() {
return new Class[] {EnableCORS.class};
}
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