Added Header interceptor and test

core/src/main/java/com/predic8/membrane/core/interceptor/rewrite/HeaderInterceptor.java

@@ -0,0 +1,95 @@
+/* Copyright 2023 predic8 GmbH, www.predic8.com
+
+   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 com.predic8.membrane.core.interceptor.rewrite;
+
+import com.predic8.membrane.annot.MCAttribute;
+import com.predic8.membrane.annot.MCElement;
+import com.predic8.membrane.annot.Required;
+import com.predic8.membrane.core.exchange.Exchange;
+import com.predic8.membrane.core.http.*;
+import com.predic8.membrane.core.interceptor.AbstractInterceptor;
+import com.predic8.membrane.core.interceptor.Outcome;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.xml.sax.SAXException;
+
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.xpath.XPathExpressionException;
+import java.awt.font.TextHitInfo;
+import java.io.IOException;
+
+import static com.predic8.membrane.core.interceptor.Interceptor.Flow.Set.REQUEST_RESPONSE;
+import static com.predic8.membrane.core.interceptor.Outcome.CONTINUE;
+
+/**
+ * @description <p>
+ *              Adds or overwrites headers in requests and responses using a value or expression.
+ *              </p>
+ * @topic 4. Interceptors/Features
+ */
+@MCElement(name="header")
+public class HeaderInterceptor extends AbstractInterceptor {
+    private static final Logger log = LoggerFactory.getLogger(HeaderInterceptor.class.getName());
+    private String identifier;
+    private String value;
+
+    public HeaderInterceptor() {
+        name = "Header Modifier";
+        setFlow(REQUEST_RESPONSE);
+    }
+
+    private Outcome handleInternal(Message msg) {
+        Header h = msg.getHeader();
+
+        if (h.contains(identifier))
+            h.remove(
+                    new HeaderField(
+                            identifier,
+                            h.getFirstValue(identifier)
+                    )
+            );
+
+        h.add(identifier, value);
+        return CONTINUE;
+    }
+
+    @Override
+    public Outcome handleRequest(Exchange exc) throws Exception {
+        return handleInternal(exc.getRequest());
+    }
+
+    @Override
+    public Outcome handleResponse(Exchange exc) throws Exception {
+        return handleInternal(exc.getResponse());
+    }
+
+    /**
+     * @description The name of the header.
+     */
+    @Required
+    @MCAttribute(attributeName="name")
+    public void setHeaderIdentifier(String identifier) {
+        this.identifier = identifier;
+    }
+
+    /**
+     * @description The value of the header.
+     */
+    @Required
+    @MCAttribute(attributeName="value")
+    public void setHeaderValue(String value) {
+        this.value = value;
+    }
+}

core/src/test/java/com/predic8/membrane/core/interceptor/rewrite/HeaderInterceptorTest.java

@@ -0,0 +1,38 @@
+package com.predic8.membrane.core.interceptor.rewrite;
+
+import com.predic8.membrane.core.exchange.Exchange;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class HeaderInterceptorTest {
+    Exchange exc;
+    HeaderInterceptor hicpt1 = new HeaderInterceptor() {{
+        setHeaderIdentifier("New");
+        setHeaderValue("Header");
+    }};
+    HeaderInterceptor hicpt2 = new HeaderInterceptor() {{
+        setHeaderIdentifier("Demo");
+        setHeaderValue("New Value");
+    }};
+
+    @BeforeEach
+    void initialize() throws Exception {
+        exc = new Exchange(null);
+        exc.getRequest().getHeader().add("Demo", "Test");
+    }
+
+    @Test
+    void addHeader() throws Exception {
+        hicpt1.handleRequest(exc);
+        assertTrue(exc.getRequest().getHeader().contains("New"));
+    }
+
+    @Test
+    void overwriteHeader() throws Exception {
+        hicpt2.handleRequest(exc);
+        assertEquals("New Value", exc.getRequest().getHeader().getFirstValue("Demo"));
+    }
+}