Add headers to data binding values

Closes gh-32676

framework-docs/modules/ROOT/pages/web/webflux/controller/ann-methods/modelattrib-method-args.adoc

@@ -3,8 +3,8 @@
 
 [.small]#xref:web/webmvc/mvc-controller/ann-methods/modelattrib-method-args.adoc[See equivalent in the Servlet stack]#
 
-The `@ModelAttribute` method parameter annotation binds request parameters onto a model
-object. For example:
+The `@ModelAttribute` method parameter annotation binds form data, query parameters,
+URI path variables, and request headers onto a model object. For example:
 
 [tabs]
 ======
@@ -27,6 +27,10 @@ Kotlin::
 <1> Bind to an instance of `Pet`.
 ======
 
+Form data and query parameters take precedence over URI variables and headers, which are
+included only if they don't override request parameters with the same name. Dashes are
+stripped from header names.
+
 The `Pet` instance may be:
 
 * Accessed from the model where it could have been added by a

framework-docs/modules/ROOT/pages/web/webmvc/mvc-controller/ann-methods/modelattrib-method-args.adoc

@@ -3,8 +3,8 @@
 
 [.small]#xref:web/webflux/controller/ann-methods/modelattrib-method-args.adoc[See equivalent in the Reactive stack]#
 
-The `@ModelAttribute` method parameter annotation binds request parameters onto a model
-object. For example:
+The `@ModelAttribute` method parameter annotation binds request parameters, URI path variables,
+and request headers onto a model object. For example:
 
 [tabs]
 ======
@@ -31,7 +31,11 @@ fun processSubmit(@ModelAttribute pet: Pet): String { // <1>
 <1> Bind to an instance of `Pet`.
 ======
 
-The `Pet` instance may be:
+Request parameters are a Servlet API concept that includes form data from the request body,
+and query parameters. URI variables and headers are also included, but only if they don't
+override request parameters with the same name. Dashes are stripped from header names.
+
+The `Pet` instance above may be:
 
 * Accessed from the model where it could have been added by a
   xref:web/webmvc/mvc-controller/ann-modelattrib-methods.adoc[@ModelAttribute method].

spring-webflux/src/main/java/org/springframework/web/reactive/BindingContext.java

@@ -18,6 +18,7 @@ package org.springframework.web.reactive;
 
 import java.lang.annotation.Annotation;
 import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 
 import reactor.core.publisher.Mono;
@@ -26,6 +27,7 @@ import org.springframework.beans.BeanUtils;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.ReactiveAdapterRegistry;
 import org.springframework.core.ResolvableType;
+import org.springframework.http.HttpHeaders;
 import org.springframework.lang.Nullable;
 import org.springframework.ui.Model;
 import org.springframework.util.CollectionUtils;
@@ -214,6 +216,14 @@ public class BindingContext {
 				if (!CollectionUtils.isEmpty(vars)) {
 					vars.forEach((key, value) -> addValueIfNotPresent(map, "URI variable", key, value));
 				}
+				HttpHeaders headers = exchange.getRequest().getHeaders();
+				for (Map.Entry<String, List<String>> entry : headers.entrySet()) {
+					List<String> values = entry.getValue();
+					if (!CollectionUtils.isEmpty(values)) {
+						String name = entry.getKey().replace("-", "");
+						addValueIfNotPresent(map, "Header", name, (values.size() == 1 ? values.get(0) : values));
+					}
+				}
 			});
 		}
 

spring-webflux/src/test/java/org/springframework/web/reactive/BindingContextTests.java

@@ -69,24 +69,50 @@ class BindingContextTests {
 	}
 
 	@Test
-	void uriVariablesAddedConditionally() {
+	void bindUriVariablesAndHeaders() {
+
+		MockServerHttpRequest request = MockServerHttpRequest.get("/path")
+				.header("Some-Int-Array", "1")
+				.header("Some-Int-Array", "2")
+				.build();
+
+		MockServerWebExchange exchange = MockServerWebExchange.from(request);
+		exchange.getAttributes().put(
+				HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE,
+				Map.of("name", "John", "age", "25"));
+
+		TestBean target = new TestBean();
+
+		BindingContext bindingContext = new BindingContext(null);
+		WebExchangeDataBinder binder = bindingContext.createDataBinder(exchange, target, "testBean", null);
+
+		binder.bind(exchange).block();
+
+		assertThat(target.getName()).isEqualTo("John");
+		assertThat(target.getAge()).isEqualTo(25);
+		assertThat(target.getSomeIntArray()).containsExactly(1, 2);
+	}
+
+	@Test
+	void bindUriVarsAndHeadersAddedConditionally() {
 
 		MockServerHttpRequest request = MockServerHttpRequest.post("/path")
+				.header("name", "Johnny")
 				.contentType(MediaType.APPLICATION_FORM_URLENCODED)
 				.body("name=John&age=25");
 
 		MockServerWebExchange exchange = MockServerWebExchange.from(request);
 		exchange.getAttributes().put(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE, Map.of("age", "26"));
 
-		TestBean testBean = new TestBean();
+		TestBean target = new TestBean();
 
 		BindingContext bindingContext = new BindingContext(null);
-		WebExchangeDataBinder binder = bindingContext.createDataBinder(exchange, testBean, "testBean", null);
+		WebExchangeDataBinder binder = bindingContext.createDataBinder(exchange, target, "testBean", null);
 
 		binder.bind(exchange).block();
 
-		assertThat(testBean.getName()).isEqualTo("John");
-		assertThat(testBean.getAge()).isEqualTo(25);
+		assertThat(target.getName()).isEqualTo("John");
+		assertThat(target.getAge()).isEqualTo(25);
 	}
 
 

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ExtendedServletRequestDataBinder.java

@@ -16,10 +16,14 @@
 
 package org.springframework.web.servlet.mvc.method.annotation;
 
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
 import jakarta.servlet.ServletRequest;
+import jakarta.servlet.http.HttpServletRequest;
 
 import org.springframework.beans.MutablePropertyValues;
 import org.springframework.lang.Nullable;
@@ -83,6 +87,17 @@ public class ExtendedServletRequestDataBinder extends ServletRequestDataBinder {
 		if (uriVars != null) {
 			uriVars.forEach((name, value) -> addValueIfNotPresent(mpvs, "URI variable", name, value));
 		}
+		if (request instanceof HttpServletRequest httpRequest) {
+			Enumeration<String> names = httpRequest.getHeaderNames();
+			while (names.hasMoreElements()) {
+				String name = names.nextElement();
+				Object value = getHeaderValue(httpRequest, name);
+				if (value != null) {
+					name = name.replace("-", "");
+					addValueIfNotPresent(mpvs, "Header", name, value);
+				}
+			}
+		}
 	}
 
 	@SuppressWarnings("unchecked")
@@ -91,19 +106,35 @@ public class ExtendedServletRequestDataBinder extends ServletRequestDataBinder {
 		return (Map<String, String>) request.getAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE);
 	}
 
-	private static void addValueIfNotPresent(
-			MutablePropertyValues mpvs, String label, String name, @Nullable Object value) {
-
-		if (value != null) {
-			if (mpvs.contains(name)) {
-				if (logger.isDebugEnabled()) {
-					logger.debug(label + " '" + name + "' overridden by request bind value.");
-				}
-			}
-			else {
-				mpvs.addPropertyValue(name, value);
+	private static void addValueIfNotPresent(MutablePropertyValues mpvs, String label, String name, Object value) {
+		if (mpvs.contains(name)) {
+			if (logger.isDebugEnabled()) {
+				logger.debug(label + " '" + name + "' overridden by request bind value.");
 			}
 		}
+		else {
+			mpvs.addPropertyValue(name, value);
+		}
+	}
+
+	@Nullable
+	private static Object getHeaderValue(HttpServletRequest request, String name) {
+		Enumeration<String> valuesEnum = request.getHeaders(name);
+		if (!valuesEnum.hasMoreElements()) {
+			return null;
+		}
+
+		String value = valuesEnum.nextElement();
+		if (!valuesEnum.hasMoreElements()) {
+			return value;
+		}
+
+		List<Object> values = new ArrayList<>();
+		values.add(value);
+		while (valuesEnum.hasMoreElements()) {
+			values.add(valuesEnum.nextElement());
+		}
+		return values;
 	}
 
 

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/ExtendedServletRequestDataBinderTests.java

@@ -16,7 +16,6 @@
 
 package org.springframework.web.servlet.mvc.method.annotation;
 
-import java.util.HashMap;
 import java.util.Map;
 
 import org.junit.jupiter.api.BeforeEach;
@@ -38,41 +37,45 @@ class ExtendedServletRequestDataBinderTests {
 
 	private MockHttpServletRequest request;
 
+
 	@BeforeEach
 	void setup() {
 		this.request = new MockHttpServletRequest();
 	}
 
+
 	@Test
 	void createBinder() {
-
-		this.request.setAttribute(
+		request.setAttribute(
 				HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE,
-				Map.of("name", "nameValue", "age", "25"));
+				Map.of("name", "John", "age", "25"));
+
+		request.addHeader("Some-Int-Array", "1");
+		request.addHeader("Some-Int-Array", "2");
 
 		TestBean target = new TestBean();
 		ServletRequestDataBinder binder = new ExtendedServletRequestDataBinder(target, "");
 		binder.bind(request);
 
-		assertThat(target.getName()).isEqualTo("nameValue");
+		assertThat(target.getName()).isEqualTo("John");
 		assertThat(target.getAge()).isEqualTo(25);
+		assertThat(target.getSomeIntArray()).containsExactly(1, 2);
 	}
 
 	@Test
-	void uriTemplateVarAndRequestParam() {
-		request.addParameter("age", "35");
+	void uriVarsAndHeadersAddedConditionally() {
+		request.addParameter("name", "John");
+		request.addParameter("age", "25");
 
-		Map<String, String> uriTemplateVars = new HashMap<>();
-		uriTemplateVars.put("name", "nameValue");
-		uriTemplateVars.put("age", "25");
-		request.setAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE, uriTemplateVars);
+		request.addHeader("name", "Johnny");
+		request.setAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE, Map.of("age", "26"));
 
 		TestBean target = new TestBean();
 		ServletRequestDataBinder binder = new ExtendedServletRequestDataBinder(target, "");
 		binder.bind(request);
 
-		assertThat(target.getName()).isEqualTo("nameValue");
-		assertThat(target.getAge()).isEqualTo(35);
+		assertThat(target.getName()).isEqualTo("John");
+		assertThat(target.getAge()).isEqualTo(25);
 	}
 
 	@Test