Rewrite AbstractAuthenticationTargetUrlRequestHandler#determineTargetUrl logic for clarity

web/src/main/java/org/springframework/security/web/authentication/AbstractAuthenticationTargetUrlRequestHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -107,31 +107,36 @@ protected String determineTargetUrl(HttpServletRequest request, HttpServletRespo
 		if (isAlwaysUseDefaultTargetUrl()) {
 			return this.defaultTargetUrl;
 		}
-		// Check for the parameter and use that if available
-		String targetUrl = null;
-		if (this.targetUrlParameter != null) {
-			targetUrl = request.getParameter(this.targetUrlParameter);
-			if (StringUtils.hasText(targetUrl)) {
-				if (this.logger.isTraceEnabled()) {
-					this.logger.trace(LogMessage.format("Using url %s from request parameter %s", targetUrl,
-							this.targetUrlParameter));
-				}
-				return targetUrl;
-			}
+		String targetUrlParameterValue = getTargetUrlParameterValue(request);
+		if (StringUtils.hasText(targetUrlParameterValue)) {
+			trace("Using url %s from request parameter %s", targetUrlParameterValue, this.targetUrlParameter);
+			return targetUrlParameterValue;
 		}
-		if (this.useReferer && !StringUtils.hasLength(targetUrl)) {
-			targetUrl = request.getHeader("Referer");
-			if (this.logger.isTraceEnabled()) {
-				this.logger.trace(LogMessage.format("Using url %s from Referer header", targetUrl));
-			}
+		if (this.useReferer) {
+			trace("Using url %s from Referer header", request.getHeader("Referer"));
+			return request.getHeader("Referer");
 		}
-		if (!StringUtils.hasText(targetUrl)) {
-			targetUrl = this.defaultTargetUrl;
-			if (this.logger.isTraceEnabled()) {
-				this.logger.trace(LogMessage.format("Using default url %s", targetUrl));
-			}
+		return this.defaultTargetUrl;
+	}
+
+	private String getTargetUrlParameterValue(HttpServletRequest request) {
+		if (this.targetUrlParameter == null) {
+			return null;
+		}
+		String value = request.getParameter(this.targetUrlParameter);
+		if (value == null) {
+			return null;
+		}
+		if (StringUtils.hasText(value)) {
+			return value;
+		}
+		return this.defaultTargetUrl;
+	}
+
+	private void trace(String msg, String... msgParts) {
+		if (this.logger.isTraceEnabled()) {
+			this.logger.trace(LogMessage.format(msg, msgParts));
 		}
-		return targetUrl;
 	}
 
 	/**

web/src/test/java/org/springframework/security/web/authentication/AbstractAuthenticationTargetUrlRequestHandlerTests.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2002-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.springframework.security.web.authentication;
+
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Dayan Kodippily
+ */
+public class AbstractAuthenticationTargetUrlRequestHandlerTests {
+
+	public static final String REQUEST_URI = "https://example.org";
+
+	public static final String DEFAULT_TARGET_URL = "/defaultTarget";
+
+	public static final String REFERER_URL = "https://www.springsource.com/";
+
+	public static final String TARGET_URL = "https://example.org/target";
+
+	private MockHttpServletRequest request;
+
+	private MockHttpServletResponse response;
+
+	private AbstractAuthenticationTargetUrlRequestHandler handler;
+
+	@BeforeEach
+	void setUp() {
+		this.request = new MockHttpServletRequest();
+		this.response = new MockHttpServletResponse();
+		this.handler = new AbstractAuthenticationTargetUrlRequestHandler() {
+			@Override
+			protected String determineTargetUrl(HttpServletRequest request, HttpServletResponse response) {
+				return super.determineTargetUrl(request, response);
+			}
+		};
+		this.handler.setDefaultTargetUrl(DEFAULT_TARGET_URL);
+		this.request.setRequestURI(REQUEST_URI);
+	}
+
+	@Test
+	void returnDefaultTargetUrlIfUseDefaultTargetUrlTrue() {
+		this.handler.setAlwaysUseDefaultTargetUrl(true);
+		assertThat(this.handler.determineTargetUrl(this.request, this.response)).isEqualTo(DEFAULT_TARGET_URL);
+	}
+
+	@Test
+	void returnTargetUrlParamValueIfParamHasValue() {
+		this.handler.setTargetUrlParameter("param");
+		this.request.setParameter("param", TARGET_URL);
+		assertThat(this.handler.determineTargetUrl(this.request, this.response)).isEqualTo(TARGET_URL);
+	}
+
+	@Test
+	void targetUrlParamValueTakePrecedenceOverRefererIfParamHasValue() {
+		this.handler.setUseReferer(true);
+		this.handler.setTargetUrlParameter("param");
+		this.request.setParameter("param", TARGET_URL);
+		assertThat(this.handler.determineTargetUrl(this.request, this.response)).isEqualTo(TARGET_URL);
+	}
+
+	@Test
+	void returnDefaultTargetUrlIfTargetUrlParamHasNoValue() {
+		this.handler.setTargetUrlParameter("param");
+		this.request.setParameter("param", "");
+		assertThat(this.handler.determineTargetUrl(this.request, this.response)).isEqualTo(DEFAULT_TARGET_URL);
+	}
+
+	@Test
+	void returnDefaultTargetUrlIfTargetUrlParamHasNoValueContainsOnlyWhiteSpaces() {
+		this.handler.setTargetUrlParameter("param");
+		this.request.setParameter("param", "   ");
+		assertThat(this.handler.determineTargetUrl(this.request, this.response)).isEqualTo(DEFAULT_TARGET_URL);
+	}
+
+	@Test
+	void returnRefererUrlIfUseRefererIsTrue() {
+		this.handler.setUseReferer(true);
+		this.request.addHeader("Referer", REFERER_URL);
+		assertThat(this.handler.determineTargetUrl(this.request, this.response)).isEqualTo(REFERER_URL);
+	}
+
+	@Test
+	void returnDefaultTargetUrlIfUseRefererIsFalse() {
+		this.handler.setUseReferer(false);
+		this.request.addHeader("Referer", REFERER_URL);
+		assertThat(this.handler.determineTargetUrl(this.request, this.response)).isEqualTo(DEFAULT_TARGET_URL);
+	}
+
+}