Add new rewrite rule to return response status code based on matching headers

jetty-core/jetty-rewrite/src/main/java/org/eclipse/jetty/rewrite/handler/ResponseStatusHeaderRegexRule.java

@@ -0,0 +1,139 @@
+//
+// ========================================================================
+// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+// which is available at https://www.apache.org/licenses/LICENSE-2.0.
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.rewrite.handler;
+
+import java.io.IOException;
+import java.lang.IllegalArgumentException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.eclipse.jetty.http.HttpStatus;
+import org.eclipse.jetty.server.Response;
+import org.eclipse.jetty.util.Callback;
+import org.eclipse.jetty.util.StringUtil;
+
+/**
+ * Sends a response with the configured status code whenever the value of the configured request header matches a regular expression.
+ */
+public class ResponseStatusHeaderRegexRule extends Rule
+{
+    private String _headerName;
+    private Pattern _headerRegex;
+    private int _code;
+    private String _message;
+
+    public ResponseStatusHeaderRegexRule()
+    {
+    }
+
+    @Override
+    public boolean isTerminating()
+    {
+        return true;
+    }
+
+    public String getHeaderName()
+    {
+        return _headerName;
+    }
+
+    /**
+     * Set the http header to match on
+     * @param headerName the http header to match on
+     */
+    public void setHeaderName(String headerName)
+    {
+        _headerName = headerName;
+    }
+
+    public String getHeaderRegex()
+    {
+        return _headerRegex == null ? null : _headerRegex.pattern();
+    }
+
+    /**
+     * Set the regex to match against the header value, null to match on any value
+     * @param headerRegex regex to match against the header value
+     */
+    public void setHeaderRegex(String headerRegex)
+    {
+        _headerRegex = headerRegex == null ? null : Pattern.compile(headerRegex);
+    }
+
+    public int getCode()
+    {
+        return _code;
+    }
+
+    /**
+     * Set the http status code returned on a match.
+     * @param code the http status code
+     */
+    public void setCode(int code)
+    {
+        if (code < HttpStatus.CONTINUE_100)
+            throw new IllegalArgumentException("invalid http status code");
+
+        _code = code;
+    }
+
+    public String getMessage()
+    {
+        return _message;
+    }
+
+    /**
+     * <p>Sets the message for the response body.</p>
+     *
+     * @param message the response body message
+     */
+    public void setMessage(String message)
+    {
+        _message = message;
+    }
+
+    @Override
+    public Handler matchAndApply(Handler input) throws IOException
+    {
+        String value = input.getHeaders().get(getHeaderName());
+        if (value == null)
+            return null;
+        if (_headerRegex == null)
+            return apply(input, value);
+        Matcher matcher = _headerRegex.matcher(value);
+        if (matcher.matches())
+            return apply(input, value);
+        return null;
+    }
+
+    public Handler apply(Handler input, String value) throws IOException
+    {
+        return new Handler(input)
+        {
+            @Override
+            protected boolean handle(Response response, Callback callback)
+            {
+                Response.writeError(this, response, callback, _code, _message);
+
+                return true;
+            }
+        };
+    }
+
+    @Override
+    public String toString()
+    {
+        return "%s[header:%s=%s][response:%d>%s]".formatted(super.toString(), getHeaderName(), getHeaderRegex(), getCode(), getMessage());
+    }
+}

jetty-core/jetty-rewrite/src/test/java/org/eclipse/jetty/rewrite/handler/ResponseStatusHeaderRegexRuleTest.java

@@ -0,0 +1,140 @@
+//
+// ========================================================================
+// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+// which is available at https://www.apache.org/licenses/LICENSE-2.0.
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.rewrite.handler;
+
+import org.eclipse.jetty.http.HttpStatus;
+import org.eclipse.jetty.http.HttpTester;
+import org.eclipse.jetty.server.Handler;
+import org.eclipse.jetty.server.Request;
+import org.eclipse.jetty.server.Response;
+import org.eclipse.jetty.util.Callback;
+import org.junit.jupiter.api.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class ResponseStatusHeaderRegexRuleTest extends AbstractRuleTest
+{
+    private void start(ResponseStatusHeaderRegexRule rule) throws Exception
+    {
+        _rewriteHandler.addRule(rule);
+        start(new Handler.Abstract()
+        {
+            @Override
+            public boolean handle(Request request, Response response, Callback callback)
+            {
+                callback.succeeded();
+                return true;
+            }
+        });
+    }
+
+    @Test
+    public void testNoMatch() throws Exception
+    {
+        ResponseStatusHeaderRegexRule rule = new ResponseStatusHeaderRegexRule();
+        rule.setHeaderName("Regex-Test");
+        start(rule);
+
+        String request = """
+            GET /test HTTP/1.1
+            Host: localhost
+
+            """;
+
+        HttpTester.Response response = HttpTester.parseResponse(_connector.getResponse(request));
+        assertEquals(200, response.getStatus());
+    }
+
+    @Test
+    public void testMatchNoRegex() throws Exception
+    {
+        ResponseStatusHeaderRegexRule rule = new ResponseStatusHeaderRegexRule();
+        rule.setHeaderName("Regex-Test");
+        rule.setCode(403);
+        start(rule);
+
+        String request = """
+            GET /test HTTP/1.1
+            Host: localhost
+            Regex-Test: random stuff
+
+            """;
+
+        HttpTester.Response response = HttpTester.parseResponse(_connector.getResponse(request));
+        assertEquals(403, response.getStatus());
+    }
+
+    @Test
+    public void testMatchStaticRegexNoMessage() throws Exception
+    {
+        ResponseStatusHeaderRegexRule rule = new ResponseStatusHeaderRegexRule();
+        rule.setHeaderName("Regex-Test");
+        rule.setHeaderRegex("value");
+        rule.setCode(403);
+        start(rule);
+
+        String request = """
+            GET /test HTTP/1.1
+            Host: localhost
+            Regex-Test: value
+
+            """;
+
+        HttpTester.Response response = HttpTester.parseResponse(_connector.getResponse(request));
+        assertEquals(403, response.getStatus());
+    }
+
+    @Test
+    public void testMatchRegexNoMessage() throws Exception
+    {
+        ResponseStatusHeaderRegexRule rule = new ResponseStatusHeaderRegexRule();
+        rule.setHeaderName("Regex-Test");
+        rule.setHeaderRegex(".*value.*");
+        rule.setCode(403);
+        start(rule);
+
+        String request = """
+            GET /test HTTP/1.1
+            Host: localhost
+            Regex-Test: this is the value found
+
+            """;
+
+        HttpTester.Response response = HttpTester.parseResponse(_connector.getResponse(request));
+        assertEquals(403, response.getStatus());
+    }
+
+    @Test
+    public void testMatchRegexMessage() throws Exception
+    {
+        ResponseStatusHeaderRegexRule rule = new ResponseStatusHeaderRegexRule();
+        rule.setHeaderName("Regex-Test");
+        rule.setCode(403);
+        rule.setMessage("Matched");
+        start(rule);
+
+        String request = """
+            GET /test HTTP/1.1
+            Host: localhost
+            Regex-Test: random stuff
+
+            """;
+
+        HttpTester.Response response = HttpTester.parseResponse(_connector.getResponse(request));
+        assertEquals(403, response.getStatus());
+        assertThat(response.getContent(), containsString(rule.getMessage()));
+    }
+}