Add handling for api delays in case of rate limit

Author: aq-ikhwa-tech

server/api-service/lowcoder-server/src/main/java/org/lowcoder/api/framework/filter/APIDelayFilter.java

@@ -0,0 +1,38 @@
+package org.lowcoder.api.framework.filter;
+
+import org.lowcoder.infra.config.repository.ServerConfigRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.Ordered;
+import org.springframework.stereotype.Component;
+import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.server.WebFilter;
+import org.springframework.web.server.WebFilterChain;
+import reactor.core.publisher.Mono;
+
+import java.time.Duration;
+
+import static org.lowcoder.api.framework.filter.FilterOrder.API_DELAY_FILTER;
+
+@Component
+public class APIDelayFilter implements WebFilter, Ordered {
+
+    @Autowired
+    private ServerConfigRepository serverConfigRepository;
+
+    @Override
+    public int getOrder() {
+        return API_DELAY_FILTER.getOrder();
+    }
+
+    @Override
+    public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
+        return serverConfigRepository.findByKey("isRateLimited")
+                .map(serverConfig -> {
+                    if(serverConfig.getValue() != null && Boolean.parseBoolean(serverConfig.getValue().toString())) {
+                        return Mono.delay(Duration.ofSeconds(5)).block();
+                    } else {
+                        return Mono.empty();
+                    }
+                }).then(chain.filter(exchange));
+    }
+}

server/api-service/lowcoder-server/src/main/java/org/lowcoder/api/framework/filter/FilterOrder.java

@@ -10,6 +10,8 @@ public enum FilterOrder {
     REQUEST_COST(BEFORE_PROXY_CHAIN),
     THROTTLING(BEFORE_PROXY_CHAIN),
 
+    API_DELAY_FILTER(BEFORE_PROXY_CHAIN),
+
     // WEB_FILTER_CHAIN_PROXY here
 
     USER_BAN(AFTER_PROXY_CHAIN),

server/api-service/lowcoder-server/src/main/java/org/lowcoder/api/framework/plugin/SharedPluginServices.java

@@ -5,9 +5,11 @@
 import java.util.function.Consumer;
 
 import org.lowcoder.api.framework.plugin.endpoint.PluginEndpointHandler;
+import org.lowcoder.infra.config.repository.ServerConfigRepository;
 import org.lowcoder.plugin.api.LowcoderServices;
 import org.lowcoder.plugin.api.PluginEndpoint;
 import org.lowcoder.plugin.api.event.LowcoderEvent;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.event.EventListener;
 import org.springframework.stereotype.Component;
 
@@ -18,6 +20,9 @@
 public class SharedPluginServices implements LowcoderServices
 {
 	private final PluginEndpointHandler pluginEndpointHandler;
+
+	@Autowired
+	private ServerConfigRepository serverConfigRepository;
 
 	private List<Consumer<LowcoderEvent>> eventListeners = new LinkedList<>();
 
@@ -41,4 +46,14 @@ public void registerEndpoints(String urlPrefix, List<PluginEndpoint> endpoints)
 	{
 		pluginEndpointHandler.registerEndpoints(urlPrefix, endpoints);
 	}
+
+	@Override
+	public void setConfig(String key, Object value) {
+		serverConfigRepository.upsert(key, value).block();
+	}
+
+	@Override
+	public Object getConfig(String key) {
+		return serverConfigRepository.findByKey(key).block();
+	}
 }