From 5a732a26c85785a9b801583f2fff0ce47314aa03 Mon Sep 17 00:00:00 2001
From: Anton Tananaev <anton@traccar.org>
Date: Sat, 25 Jun 2022 07:54:39 -0700
Subject: Add throttling filter

---
 build.gradle                                       |  1 +
 src/main/java/org/traccar/config/Keys.java         |  7 +++
 .../java/org/traccar/web/ThrottlingFilter.java     | 53 ++++++++++++++++++++++
 src/main/java/org/traccar/web/WebModule.java       |  1 +
 4 files changed, 62 insertions(+)
 create mode 100644 src/main/java/org/traccar/web/ThrottlingFilter.java

diff --git a/build.gradle b/build.gradle
index 8c196043a..8ce916432 100644
--- a/build.gradle
+++ b/build.gradle
@@ -54,6 +54,7 @@ dependencies {
     implementation "org.glassfish:javax.json:1.1.4"
     implementation "org.eclipse.jetty:jetty-server:$jettyVersion"
     implementation "org.eclipse.jetty:jetty-servlet:$jettyVersion"
+    implementation "org.eclipse.jetty:jetty-servlets:$jettyVersion"
     implementation "org.eclipse.jetty:jetty-webapp:$jettyVersion"
     implementation "org.eclipse.jetty:jetty-jndi:$jettyVersion"
     implementation "org.eclipse.jetty:jetty-proxy:$jettyVersion"
diff --git a/src/main/java/org/traccar/config/Keys.java b/src/main/java/org/traccar/config/Keys.java
index 3f52fbd96..8e11b4013 100644
--- a/src/main/java/org/traccar/config/Keys.java
+++ b/src/main/java/org/traccar/config/Keys.java
@@ -628,6 +628,13 @@ public final class Keys {
             "web.port",
             List.of(KeyType.CONFIG));
 
+    /**
+     * Maximum API requests per second. Above this limit requests and delayed and throttled.
+     */
+    public static final ConfigKey<Integer> WEB_MAX_REQUESTS_PER_SECOND = new IntegerConfigKey(
+            "web.maxRequestsPerSec",
+            List.of(KeyType.CONFIG));
+
     /**
      * Sanitize all strings returned via API. This is needed to fix XSS issues in the old web interface. New React-based
      * interface doesn't require this.
diff --git a/src/main/java/org/traccar/web/ThrottlingFilter.java b/src/main/java/org/traccar/web/ThrottlingFilter.java
new file mode 100644
index 000000000..054af652f
--- /dev/null
+++ b/src/main/java/org/traccar/web/ThrottlingFilter.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright 2022 Anton Tananaev (anton@traccar.org)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.traccar.web;
+
+import org.eclipse.jetty.servlets.DoSFilter;
+import org.traccar.config.Config;
+import org.traccar.config.Keys;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpSession;
+
+@Singleton
+public class ThrottlingFilter extends DoSFilter {
+
+    @Inject
+    private Config config;
+
+    @Override
+    public void init(FilterConfig filterConfig) throws ServletException {
+        super.init(filterConfig);
+        if (config.hasKey(Keys.WEB_MAX_REQUESTS_PER_SECOND)) {
+            setMaxRequestsPerSec(config.getInteger(Keys.WEB_MAX_REQUESTS_PER_SECOND));
+        }
+    }
+
+    @Override
+    protected String extractUserId(ServletRequest request) {
+        HttpSession session = ((HttpServletRequest) request).getSession(false);
+        if (session != null) {
+            var userId = session.getAttribute("userId");
+            return userId != null ? userId.toString() : null;
+        }
+        return null;
+    }
+}
diff --git a/src/main/java/org/traccar/web/WebModule.java b/src/main/java/org/traccar/web/WebModule.java
index 6c133ff74..0722c5d1e 100644
--- a/src/main/java/org/traccar/web/WebModule.java
+++ b/src/main/java/org/traccar/web/WebModule.java
@@ -23,6 +23,7 @@ public class WebModule extends ServletModule {
 
     @Override
     protected void configureServlets() {
+        filter("/api/*").through(ThrottlingFilter.class);
         filter("/api/media/*").through(MediaFilter.class);
         serve("/api/socket").with(AsyncSocketServlet.class);
     }
-- 
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