001/* 002 * Copyright 2002-2017 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.web.socket.sockjs.client; 018 019import java.net.URI; 020 021import org.springframework.http.HttpHeaders; 022import org.springframework.lang.Nullable; 023 024/** 025 * A component that can execute the SockJS "Info" request that needs to be 026 * performed before the SockJS session starts in order to check server endpoint 027 * capabilities such as whether the endpoint permits use of WebSocket. 028 * 029 * <p>Typically {@link XhrTransport} implementations are also implementations 030 * of this contract. 031 * 032 * @author Rossen Stoyanchev 033 * @since 4.1 034 * @see AbstractXhrTransport 035 */ 036public interface InfoReceiver { 037 038 /** 039 * Perform an HTTP request to the SockJS "Info" URL. 040 * and return the resulting JSON response content, or raise an exception. 041 * <p>Note that as of 4.2 this method accepts a {@code headers} parameter. 042 * @param infoUrl the URL to obtain SockJS server information from 043 * @param headers the headers to use for the request 044 * @return the body of the response 045 */ 046 String executeInfoRequest(URI infoUrl, @Nullable HttpHeaders headers); 047 048}