Consolidate matrix vars parsing in HttpRequestPathHelper

Restore matrix variable parsing code not resorting to the use of
WebUtils which brings Servlet API dependencies with it.

Instead the parsing logic is now exposed through HttpRequestPathHelper
which already contained the decoding logic and also the knowledge of
whether to decode the parsed variables or not.

Issue: SPR-15397

spring-web/src/main/java/org/springframework/web/server/support/HttpRequestPathHelper.java

@@ -19,6 +19,7 @@ package org.springframework.web.server.support;
 import java.io.UnsupportedEncodingException;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import java.util.StringTokenizer;
 
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.util.LinkedMultiValueMap;
@@ -108,6 +109,43 @@ public class HttpRequestPathHelper {
 		return decodedVars;
 	}
 
+	/**
+	 * Parse the given string with matrix variables. An example string would look
+	 * like this {@code "q1=a;q1=b;q2=a,b,c"}. The resulting map would contain
+	 * keys {@code "q1"} and {@code "q2"} with values {@code ["a","b"]} and
+	 * {@code ["a","b","c"]} respectively.
+	 * <p>The returned values are decoded unless {@link #setUrlDecode(boolean)}
+	 * is set to {@code true} in which case it is assumed the URL path from
+	 * which the variables were extracted is already decoded through a call to
+	 * {@link #getLookupPathForRequest(ServerWebExchange)}.
+	 * @param semicolonContent path parameter content to parse
+	 * @return a map with matrix variable names and values (never {@code null})
+	 */
+	public MultiValueMap<String, String> parseMatrixVariables(ServerWebExchange exchange,
+			String semicolonContent) {
+
+		MultiValueMap<String, String> result = new LinkedMultiValueMap<>();
+		if (!StringUtils.hasText(semicolonContent)) {
+			return result;
+		}
+		StringTokenizer pairs = new StringTokenizer(semicolonContent, ";");
+		while (pairs.hasMoreTokens()) {
+			String pair = pairs.nextToken();
+			int index = pair.indexOf('=');
+			if (index != -1) {
+				String name = pair.substring(0, index);
+				String rawValue = pair.substring(index + 1);
+				for (String value : StringUtils.commaDelimitedListToStringArray(rawValue)) {
+					result.add(name, value);
+				}
+			}
+			else {
+				result.add(pair, "");
+			}
+		}
+		return decodeMatrixVariables(exchange, result);
+	}
+
 	/**
 	 * Decode the given matrix variables unless {@link #setUrlDecode(boolean)}
 	 * is set to {@code true} in which case it is assumed the URL path from
@@ -117,7 +155,7 @@ public class HttpRequestPathHelper {
 	 * @param vars URI variables extracted from the URL path
 	 * @return the same Map or a new Map instance
 	 */
-	public MultiValueMap<String, String> decodeMatrixVariables(ServerWebExchange exchange,
+	private MultiValueMap<String, String> decodeMatrixVariables(ServerWebExchange exchange,
 			MultiValueMap<String, String> vars) {
 
 		if (this.urlDecode) {

spring-web/src/test/java/org/springframework/web/server/support/HttpRequestPathHelperTests.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2002-2017 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
+ *
+ *      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.springframework.web.server.support;
+
+import java.util.Arrays;
+
+import org.junit.Test;
+
+import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
+import org.springframework.util.MultiValueMap;
+import org.springframework.web.server.ServerWebExchange;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Unit tests for {@link HttpRequestPathHelper}.
+ * @author Rossen Stoyanchev
+ */
+public class HttpRequestPathHelperTests {
+
+
+	@Test
+	public void parseMatrixVariables() {
+
+		HttpRequestPathHelper pathHelper = new HttpRequestPathHelper();
+		ServerWebExchange exchange = MockServerHttpRequest.get("").toExchange();
+		MultiValueMap<String, String> variables;
+
+		variables = pathHelper.parseMatrixVariables(exchange, null);
+		assertEquals(0, variables.size());
+
+		variables = pathHelper.parseMatrixVariables(exchange, "year");
+		assertEquals(1, variables.size());
+		assertEquals("", variables.getFirst("year"));
+
+		variables = pathHelper.parseMatrixVariables(exchange, "year=2012");
+		assertEquals(1, variables.size());
+		assertEquals("2012", variables.getFirst("year"));
+
+		variables = pathHelper.parseMatrixVariables(exchange, "year=2012;colors=red,blue,green");
+		assertEquals(2, variables.size());
+		assertEquals(Arrays.asList("red", "blue", "green"), variables.get("colors"));
+		assertEquals("2012", variables.getFirst("year"));
+
+		variables = pathHelper.parseMatrixVariables(exchange, ";year=2012;colors=red,blue,green;");
+		assertEquals(2, variables.size());
+		assertEquals(Arrays.asList("red", "blue", "green"), variables.get("colors"));
+		assertEquals("2012", variables.getFirst("year"));
+
+		variables = pathHelper.parseMatrixVariables(exchange, "colors=red;colors=blue;colors=green");
+		assertEquals(1, variables.size());
+		assertEquals(Arrays.asList("red", "blue", "green"), variables.get("colors"));
+	}
+
+	@Test
+	public void parseMatrixVariablesAndDecode() {
+
+		HttpRequestPathHelper pathHelper = new HttpRequestPathHelper();
+		pathHelper.setUrlDecode(false);
+
+		ServerWebExchange exchange = MockServerHttpRequest.get("").toExchange();
+		MultiValueMap<String, String> variables;
+
+		variables = pathHelper.parseMatrixVariables(exchange, "mvar=a%2fb");
+		assertEquals(1, variables.size());
+		assertEquals("a/b", variables.getFirst("mvar"));
+	}
+
+}

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/RequestMappingInfoHandlerMapping.java

@@ -27,6 +27,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.StringTokenizer;
 import java.util.stream.Collectors;
 
 import org.springframework.http.HttpHeaders;
@@ -34,7 +35,9 @@ import org.springframework.http.HttpMethod;
 import org.springframework.http.InvalidMediaTypeException;
 import org.springframework.http.MediaType;
 import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
+import org.springframework.util.StringUtils;
 import org.springframework.web.method.HandlerMethod;
 import org.springframework.web.reactive.HandlerMapping;
 import org.springframework.web.reactive.result.condition.NameValueExpression;
@@ -44,7 +47,7 @@ import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.ServerWebInputException;
 import org.springframework.web.server.UnsupportedMediaTypeStatusException;
 import org.springframework.web.server.support.LookupPath;
-import org.springframework.web.util.WebUtils;
+
 
 /**
  * Abstract base class for classes for which {@link RequestMappingInfo} defines
@@ -145,19 +148,16 @@ public abstract class RequestMappingInfoHandlerMapping extends AbstractHandlerMe
 				continue;
 			}
 
-			String matrixVariables;
-
+			String semicolonContent;
 			int semicolonIndex = uriVarValue.indexOf(';');
 			if ((semicolonIndex == -1) || (semicolonIndex == 0) || (equalsIndex < semicolonIndex)) {
-				matrixVariables = uriVarValue;
+				semicolonContent = uriVarValue;
 			}
 			else {
-				matrixVariables = uriVarValue.substring(semicolonIndex + 1);
+				semicolonContent = uriVarValue.substring(semicolonIndex + 1);
 				uriVariables.put(uriVar.getKey(), uriVarValue.substring(0, semicolonIndex));
 			}
-
-			MultiValueMap<String, String> vars = WebUtils.parseMatrixVariables(matrixVariables);
-			result.put(uriVar.getKey(), getPathHelper().decodeMatrixVariables(exchange, vars));
+			result.put(uriVar.getKey(), getPathHelper().parseMatrixVariables(exchange, semicolonContent));
 		}
 		return result;
 	}