我是spring websocket的新手。我想将产品更改发送给客户。为此,我想按如下方式执行:客户端创建套接字连接并订阅目标:
var socket = new SockJS('/websocket');
var stompClient = Stomp.over(socket);
stompClient.connect({}, function (frame) {
stompClient.subscribe('/product/changes', function (scoredata) {
// We received product changes
});
});
//Send Ajax request and say server I want to know product with id=5 changes.
sendAjaxRequest(5);
我已将弹簧应用程序配置如下:
@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {
@Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("/websocket").withSockJS();
}
@Override
public void configureMessageBroker(MessageBrokerRegistry registry) {
registry.enableSimpleBroker("/product/");
registry.setApplicationDestinationPrefixes("/app");
}
}
现在我需要以下方法:
@RestController
public class ProductController {
@GetMapping("product-{id}")
public void startSubscribe(@PathVariable("id") Long id) {
// register current websocket session with product id and
// then with convertAndSendToUser send changes to current user.
}
}
我该如何实现它?
首先我的问题是,当你成功地将webockets与stomp一起集成时,为什么要尝试向其他控制器发送http请求?如果我正确理解您的用例,我应该考虑三种解决方案。
您可以通过开放的websocket连接将您的请求直接从您的客户端发送到服务器。然后,Spring可以确定哪个Websocket会话进行了调用,您可以实现业务逻辑。您需要激活另一个名为“/ queue”的代理,并指定订阅不适用于广播时所需的用户目标的前缀。在客户端,您还必须更改订阅路径。最后,您必须创建一个使用@Controller注释的类,该类包含您的消息映射以从连接的客户端接收消息。
@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {
@Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("/websocket").withSockJS();
}
@Override
public void configureMessageBroker(MessageBrokerRegistry registry) {
registry.enableSimpleBroker("/queue", "/product"); // <- added "/queue"
registry.setApplicationDestinationPrefixes("/app");
registry.setUserDestinationPrefix("/user");
}
}
@Controller
public class WebSocketContoller{
@Autowired
private SimpMessagingTemplate simpMessagingTemplate;
@MessageMapping("/product/register")
public void register(@Payload Long productId, @Header("simpSessionId") String sessionId) {
// register current websocket session with product id and
// then with convertAndSendToUser send changes to current user.
// Example of how to send a message to the user using the sessionId
String response = "This could also be one of your product objects of type Product";
SimpMessageHeaderAccessor headerAccessor = SimpMessageHeaderAccessor.create(SimpMessageType.MESSAGE);
headerAccessor.setSessionId(sessionId);
headerAccessor.setLeaveMutable(true);
messagingTemplate.convertAndSendToUser(sessionId,"/queue/product/changes", response, headerAccessor.getMessageHeaders());
}
}
stompClient.subscribe('/user/queue/product/changes', function (scoredata) {
// We received product changes
});
有关详细信息,您还可以查看以下答案:https://stackoverflow.com/a/26288475/11133168
但是,如果您真的想考虑使用其他控制器来开始注册您的流程,或者它只是不符合您的要求,您应该查看下面的链接。 Spring还可以通过公开的SimpUserRegistry bean跟踪活动的websocket会话及其用户。但是,您需要为客户端输入通道配置自定义ChannelInterceptor适配器,具体取决于应用程序的安全性,以确定用户。请查看此答案以获取详细信息和代码示例:https://stackoverflow.com/a/45359294/11133168
您还可以订阅特定的产品ID主题,这样您甚至不需要知道哪个用户希望收到有关特定产品更改的通知。
//e.g if you want to be notified about changes for products with id 5
stompClient.subscribe('/product/changes/5', function (scoredata) {
// We received product changes
});
@Service
public class WebSocketProductService{
@Autowired
private SimpMessagingTemplate simpMessagingTemplate;
// This would be the method which should inform your clients about specific product
// changes, instead of the String parameters a Product object should be used instead,
// you have to call this method yourself on product changes or schedule it or sth.
public void sendProductChange(String product, String productId) {
this.simpMessagingTemplate.convertAndSend("/product/changes/"+productId, product);
}
}
如果要管理产品ID订阅列表,则需要。就像在解决方案1中解释的那样,你需要一个用@Controller注释的类,它包含一个用@SubscribeMapping注释的方法。如果客户端尝试订阅指定的路径,则会调用此方法。
@Controller
public class WebSocketContoller{
@SubscribeMapping("/product/changes/{productId}")
public void productIdSubscription(@DestinationVariable Long productId) {
//Manage your product id subscription list e.g.
}
}
如果只想在用户请求时向用户发送产品更新,则可以使用普通的HTTP请求。但我知道您希望根据用户特定的业务逻辑推送通知。您还必须实施Spring Security
来验证您的用户。
解
我建议使用user_product_updates( user_id, product_id)
表在后端添加此业务逻辑 - 每行对应product_id
,user_id
用户想要订阅更新:
@GetMapping("product-{id}")
public void startSubscribe(@PathVariable("id") Long id) {
// Save this custom setting into your models
}
现在,您可以运行计划的后端作业(可以是基于推送通知的业务逻辑的cron作业)来向用户发送更新:
@Autowired
org.springframework.messaging.simp.SimpMessagingTemplate simpMessagingTemplate;
@Scheduled(cron = "0 0 1 * * ?") // based on your business logic (say daily at 12:01 am)
public void scheduleTaskUsingCronExpression() {
// loop through user_product_updates table and construct "data"
// username is from your spring security username (principal.getName())
simpMessagingTemplate.convertAndSendToUser(username, "/queue/products", data);
}
展望未来,您可能需要添加一些缓存以优化它们(尤其是从product_id
获取产品信息)以便事情顺利进行。
您的Web套接字配置:
@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {
@Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("/websocket").withSockJS();
}
@Override
public void configureMessageBroker(MessageBrokerRegistry registry) {
config.setApplicationDestinationPrefixes("/app")
.setUserDestinationPrefix("/user")
.enableSimpleBroker("/topic", "/queue", "/product");
}
}
前端应用程序中的侦听器可能如下所示:
that.stompClient.subscribe("/user/queue/products", (message) => {
if (message.body) {
// We received product changes
}
});
用户将注册产品更新:
@GetMapping("product-{id}")
public void startSubscribe(@PathVariable("id") Long id) {
// Save to your persistence module
// (that the particular user wants updates from such-and-such products)
}
后端调度程序作业将在可用时发送更新:
@Scheduled(cron = "0 0 1 * * ?") // based on your business logic
public void scheduleTaskUsingCronExpression() {
// loop through user_product_updates table and construct "data"
// username is from your spring security username (principal.getName())
template.convertAndSendToUser(username, "/queue/products", data);
}
Spring documentation是学习Web套接字概念的一个很好的起点。要发送给客户,您可以使用SimpMessageSendingOperations。
@Autowired
private SimpMessageSendingOperations messageSendingOperations;
从控制器方法,消息可以通过以下内容发送:
messageSendingOperations.convertAndSendToUser(websocketUserId, "/product/changes", messageObject);