Merge pull request #17510 from dirkdeyne

* pr/17510:
  Polish "Add support for configuring Tomcat's relaxed path and query chars"
  Add support for configuring Tomcat's relaxed path and query chars

Closes gh-17510

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java

@@ -61,6 +61,7 @@ import org.springframework.util.unit.DataSize;
  * @author Artsiom Yudovin
  * @author Andrew McGhie
  * @author Rafiullah Hamedy
+ * @author Dirk Deyne
  * @since 1.0.0
  */
 @ConfigurationProperties(prefix = "server", ignoreUnknownFields = true)
@@ -395,6 +396,18 @@ public class ServerProperties {
 		 */
 		private List<String> additionalTldSkipPatterns = new ArrayList<>();
 
+		/**
+		 * Comma-separated list of additional unencoded characters that should be allowed
+		 * in URI paths. Only "< > [ \ ] ^ ` { | }" are allowed.
+		 */
+		private List<Character> relaxedPathChars = new ArrayList<>();
+
+		/**
+		 * Comma-separated list of additional unencoded characters that should be allowed
+		 * in URI query strings. Only "< > [ \ ] ^ ` { | }" are allowed.
+		 */
+		private List<Character> relaxedQueryChars = new ArrayList<>();
+
 		/**
 		 * Static resource configuration.
 		 */
@@ -553,6 +566,22 @@ public class ServerProperties {
 			this.additionalTldSkipPatterns = additionalTldSkipPatterns;
 		}
 
+		public List<Character> getRelaxedPathChars() {
+			return this.relaxedPathChars;
+		}
+
+		public void setRelaxedPathChars(List<Character> relaxedPathChars) {
+			this.relaxedPathChars = relaxedPathChars;
+		}
+
+		public List<Character> getRelaxedQueryChars() {
+			return this.relaxedQueryChars;
+		}
+
+		public void setRelaxedQueryChars(List<Character> relaxedQueryChars) {
+			this.relaxedQueryChars = relaxedQueryChars;
+		}
+
 		public Resource getResource() {
 			return this.resource;
 		}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/embedded/TomcatWebServerFactoryCustomizer.java

@@ -17,6 +17,8 @@
 package org.springframework.boot.autoconfigure.web.embedded;
 
 import java.time.Duration;
+import java.util.List;
+import java.util.stream.Collectors;
 
 import org.apache.catalina.Lifecycle;
 import org.apache.catalina.valves.AccessLogValve;
@@ -51,6 +53,7 @@ import org.springframework.util.unit.DataSize;
  * @author Artsiom Yudovin
  * @author Chentao Qu
  * @author Andrew McGhie
+ * @author Dirk Deyne
  * @since 2.0.0
  */
 public class TomcatWebServerFactoryCustomizer
@@ -102,6 +105,10 @@ public class TomcatWebServerFactoryCustomizer
 				.to((acceptCount) -> customizeAcceptCount(factory, acceptCount));
 		propertyMapper.from(tomcatProperties::getProcessorCache)
 				.to((processorCache) -> customizeProcessorCache(factory, processorCache));
+		propertyMapper.from(tomcatProperties::getRelaxedPathChars).as(this::joinCharacters).whenHasText()
+				.to((relaxedChars) -> customizeRelaxedPathChars(factory, relaxedChars));
+		propertyMapper.from(tomcatProperties::getRelaxedQueryChars).as(this::joinCharacters).whenHasText()
+				.to((relaxedChars) -> customizeRelaxedQueryChars(factory, relaxedChars));
 		customizeStaticResources(factory);
 		customizeErrorReportValve(properties.getError(), factory);
 	}
@@ -149,6 +156,18 @@ public class TomcatWebServerFactoryCustomizer
 		});
 	}
 
+	private void customizeRelaxedPathChars(ConfigurableTomcatWebServerFactory factory, String relaxedChars) {
+		factory.addConnectorCustomizers((connector) -> connector.setAttribute("relaxedPathChars", relaxedChars));
+	}
+
+	private void customizeRelaxedQueryChars(ConfigurableTomcatWebServerFactory factory, String relaxedChars) {
+		factory.addConnectorCustomizers((connector) -> connector.setAttribute("relaxedQueryChars", relaxedChars));
+	}
+
+	private String joinCharacters(List<Character> content) {
+		return content.stream().map(String::valueOf).collect(Collectors.joining());
+	}
+
 	private void customizeRemoteIpValve(ConfigurableTomcatWebServerFactory factory) {
 		Tomcat tomcatProperties = this.serverProperties.getTomcat();
 		String protocolHeader = tomcatProperties.getProtocolHeader();

spring-boot-project/spring-boot-autoconfigure/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -2089,6 +2089,76 @@
     }
   ],
   "hints": [
+    {
+      "name": "server.tomcat.relaxed-query-chars",
+      "values": [
+        {
+          "value": "<"
+        },
+        {
+          "value": ">"
+        },
+        {
+          "value": "["
+        },
+        {
+          "value": "\\"
+        },
+        {
+          "value": "]"
+        },
+        {
+          "value": "^"
+        },
+        {
+          "value": "`"
+        },
+        {
+          "value": "{"
+        },
+        {
+          "value": "|"
+        },
+        {
+          "value": "}"
+        }
+      ]
+    },
+    {
+      "name": "server.tomcat.relaxed-path-chars",
+      "values": [
+        {
+          "value": "<"
+        },
+        {
+          "value": ">"
+        },
+        {
+          "value": "["
+        },
+        {
+          "value": "\\"
+        },
+        {
+          "value": "]"
+        },
+        {
+          "value": "^"
+        },
+        {
+          "value": "`"
+        },
+        {
+          "value": "{"
+        },
+        {
+          "value": "|"
+        },
+        {
+          "value": "}"
+        }
+      ]
+    },
     {
       "name": "spring.liquibase.change-log",
       "providers": [

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/ServerPropertiesTests.java

@@ -127,6 +127,8 @@ class ServerPropertiesTests {
 		map.put("server.tomcat.remote-ip-header", "Remote-Ip");
 		map.put("server.tomcat.internal-proxies", "10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}");
 		map.put("server.tomcat.background-processor-delay", "10");
+		map.put("server.tomcat.relaxed-path-chars", "|,<");
+		map.put("server.tomcat.relaxed-query-chars", "^  ,  | ");
 		bind(map);
 		ServerProperties.Tomcat tomcat = this.properties.getTomcat();
 		Accesslog accesslog = tomcat.getAccesslog();
@@ -146,6 +148,8 @@ class ServerPropertiesTests {
 		assertThat(tomcat.getProtocolHeader()).isEqualTo("X-Forwarded-Protocol");
 		assertThat(tomcat.getInternalProxies()).isEqualTo("10\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}");
 		assertThat(tomcat.getBackgroundProcessorDelay()).isEqualTo(Duration.ofSeconds(10));
+		assertThat(tomcat.getRelaxedPathChars()).containsExactly('|', '<');
+		assertThat(tomcat.getRelaxedQueryChars()).containsExactly('^', '|');
 	}
 
 	@Test

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/embedded/TomcatWebServerFactoryCustomizerTests.java

@@ -198,6 +198,22 @@ class TomcatWebServerFactoryCustomizerTests {
 		});
 	}
 
+	@Test
+	void customRelaxedPathChars() {
+		bind("server.tomcat.relaxed-path-chars=|,^");
+		customizeAndRunServer((server) -> assertThat(
+				((AbstractHttp11Protocol<?>) server.getTomcat().getConnector().getProtocolHandler())
+						.getRelaxedPathChars()).isEqualTo("|^"));
+	}
+
+	@Test
+	void customRelaxedQueryChars() {
+		bind("server.tomcat.relaxed-query-chars=^  ,  | ");
+		customizeAndRunServer((server) -> assertThat(
+				((AbstractHttp11Protocol<?>) server.getTomcat().getConnector().getProtocolHandler())
+						.getRelaxedQueryChars()).isEqualTo("^|"));
+	}
+
 	@Test
 	void deduceUseForwardHeaders() {
 		this.environment.setProperty("DYNO", "-");