Stopping point with initial POC

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/main/java/org/springframework/cloud/function/adapter/aws/web/FunctionClassUtils.java

@@ -0,0 +1,153 @@
+/*
+ * Copyright 2019-2021 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.cloud.function.adapter.aws.web;
+
+import java.io.InputStream;
+import java.net.URL;
+import java.util.Collections;
+import java.util.List;
+import java.util.jar.JarFile;
+import java.util.jar.Manifest;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+//import org.springframework.boot.SpringBootConfiguration;
+//import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.core.KotlinDetector;
+import org.springframework.core.io.Resource;
+import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
+import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
+import org.springframework.util.StringUtils;
+
+/**
+ * General utility class which aggregates various class-level utility functions
+ * used by the framework.
+ *
+ * @author Oleg Zhurakousky
+ * @since 3.0.1
+ */
+public final class FunctionClassUtils {
+
+	private static Log logger = LogFactory.getLog(FunctionClassUtils.class);
+
+	private FunctionClassUtils() {
+
+	}
+
+	/**
+	 * Discovers the start class in the currently running application.
+	 * The discover search order is 'MAIN_CLASS' environment property,
+	 * 'MAIN_CLASS' system property, META-INF/MANIFEST.MF:'Start-Class' attribute,
+	 * meta-inf/manifest.mf:'Start-Class' attribute.
+	 *
+	 * @return instance of Class which represent the start class of the application.
+	 */
+	public static Class<?> getStartClass() {
+		ClassLoader classLoader = FunctionClassUtils.class.getClassLoader();
+		return getStartClass(classLoader);
+	}
+
+	static Class<?> getStartClass(ClassLoader classLoader) {
+		Class<?> mainClass = null;
+		if (System.getenv("MAIN_CLASS") != null) {
+			mainClass = ClassUtils.resolveClassName(System.getenv("MAIN_CLASS"), classLoader);
+		}
+		else if (System.getProperty("MAIN_CLASS") != null) {
+			mainClass = ClassUtils.resolveClassName(System.getProperty("MAIN_CLASS"), classLoader);
+		}
+		else {
+			try {
+				Class<?> result = getStartClass(
+						Collections.list(classLoader.getResources(JarFile.MANIFEST_NAME)), classLoader);
+				if (result == null) {
+					result = getStartClass(Collections
+							.list(classLoader.getResources("meta-inf/manifest.mf")), classLoader);
+				}
+				Assert.notNull(result, "Failed to locate main class");
+				mainClass = result;
+			}
+			catch (Exception ex) {
+				throw new IllegalStateException("Failed to discover main class. An attempt was made to discover "
+						+ "main class as 'MAIN_CLASS' environment variable, system property as well as "
+						+ "entry in META-INF/MANIFEST.MF (in that order).", ex);
+			}
+		}
+		logger.info("Main class: " + mainClass);
+		return mainClass;
+	}
+
+	private static Class<?> getStartClass(List<URL> list, ClassLoader classLoader) {
+		if (logger.isTraceEnabled()) {
+			logger.trace("Searching manifests: " + list);
+		}
+		for (URL url : list) {
+			try {
+				InputStream inputStream = null;
+				Manifest manifest = new Manifest(url.openStream());
+				logger.info("Searching for start class in manifest: " + url);
+				if (logger.isDebugEnabled()) {
+					manifest.write(System.out);
+				}
+				try {
+					String startClassName = manifest.getMainAttributes().getValue("Start-Class");
+					if (!StringUtils.hasText(startClassName)) {
+						startClassName = manifest.getMainAttributes().getValue("Main-Class");
+					}
+
+					if (StringUtils.hasText(startClassName)) {
+						Class<?> startClass = ClassUtils.forName(startClassName, classLoader);
+
+						if (KotlinDetector.isKotlinType(startClass)) {
+							PathMatchingResourcePatternResolver r = new PathMatchingResourcePatternResolver(classLoader);
+							String packageName = startClass.getPackage().getName();
+							Resource[] resources = r.getResources("classpath:" + packageName.replace(".", "/") + "/*.class");
+							for (int i = 0; i < resources.length; i++) {
+								Resource resource = resources[i];
+								String className = packageName + "." + (resource.getFilename().replace("/", ".")).replace(".class", "");
+								startClass = ClassUtils.forName(className, classLoader);
+//								if (isSpringBootApplication(startClass)) {
+//									logger.info("Loaded Main Kotlin Class: " + startClass);
+//									return startClass;
+//								}
+							}
+						}
+//						else if (isSpringBootApplication(startClass)) {
+//							logger.info("Loaded Start Class: " + startClass);
+//							return startClass;
+//						}
+					}
+				}
+				finally {
+					if (inputStream != null) {
+						inputStream.close();
+					}
+				}
+			}
+			catch (Exception ex) {
+				logger.debug("Failed to determine Start-Class in manifest file of " + url, ex);
+			}
+		}
+		return null;
+	}
+
+//	private static boolean isSpringBootApplication(Class<?> startClass) {
+//		return startClass.getDeclaredAnnotation(SpringBootApplication.class) != null
+//				|| startClass.getDeclaredAnnotation(SpringBootConfiguration.class) != null;
+//	}
+}

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/main/java/org/springframework/cloud/function/adapter/aws/web/README.md

@@ -0,0 +1,5 @@
+Classes in this package would remain specific to AWS (in this case). There would be something similar in Azure and others.
+
+And these classes would depend on what is currently in `org.springframework.web.client` package of this module. 
+However, ideally the contents of the `org.springframework.web.client` package should reside in spring-web somewhere as a light weight 
+HTTP proxy as we technically already have it in a form of MockMVC.

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/main/java/org/springframework/cloud/function/adapter/aws/web/WebProxyInvoker.java

@@ -0,0 +1,178 @@
+/*
+ * Copyright 2023-2023 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.cloud.function.adapter.aws.web;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import javax.servlet.Filter;
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+
+import org.springframework.util.StreamUtils;
+import org.springframework.util.StringUtils;
+import org.springframework.web.client.ProxyHttpServletRequest;
+import org.springframework.web.client.ProxyHttpServletResponse;
+import org.springframework.web.client.ProxyMvc;
+import org.springframework.web.client.ProxyServletContext;
+import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
+import org.springframework.web.servlet.DispatcherServlet;
+
+/**
+ *
+ * AWS Lambda specific handler that will proxy API Gateway request to Spring Web-app
+ * This class represents AWS Lambda fronted by API Gateway  and is identified as 'handler' during the deployment.
+ *
+ * @author Oleg Zhurakousky
+ *
+ */
+public class WebProxyInvoker {
+
+	private static Log logger = LogFactory.getLog(WebProxyInvoker.class);
+
+	private final ProxyMvc mvc;
+
+	private final ServletContext servletContext;
+
+	ObjectMapper mapper = new ObjectMapper();
+
+	public WebProxyInvoker() throws ServletException {
+		Class<?> startClass = FunctionClassUtils.getStartClass();
+		AnnotationConfigWebApplicationContext applpicationContext = new AnnotationConfigWebApplicationContext();
+		applpicationContext.register(startClass);
+
+		this.servletContext = new ProxyServletContext();
+		ServletConfig servletConfig = new ProxyServletConfig(this.servletContext);
+
+		DispatcherServlet servlet = new DispatcherServlet(applpicationContext);
+		servlet.init(servletConfig);
+		this.mvc = new ProxyMvc(servlet, applpicationContext.getBeansOfType(Filter.class).values().toArray(new Filter[0]));
+	}
+
+	/*
+	 * TODO
+	 * - Security context propagation from AWS API Gateway (easy)
+	 * - Error handling
+	 */
+	@SuppressWarnings("unchecked")
+	private HttpServletRequest prepareRequest(InputStream input) throws IOException {
+
+		Map<String, Object> request = mapper.readValue(input, Map.class);
+		if (logger.isDebugEnabled()) {
+			logger.debug("Request: " + request);
+		}
+		String httpMethod = (String) request.get("httpMethod");
+		String path = (String) request.get("path");
+		if (logger.isDebugEnabled()) {
+			logger.debug("httpMethod: " + httpMethod);
+			logger.debug("path: " + path);
+		}
+		ProxyHttpServletRequest httpRequest = new ProxyHttpServletRequest(servletContext, httpMethod, path);
+		if (StringUtils.hasText((String) request.get("body"))) {
+			httpRequest.setContent(((String) request.get("body")).getBytes());
+		}
+		if (request.get("queryStringParameters") != null) {
+			httpRequest.setParameters((Map<String, ?>) request.get("queryStringParameters"));
+		}
+
+		Map<String, Object> headers = (Map<String, Object>) request.get("headers");
+		headers.putAll((Map<String, Object>) request.get("multiValueHeaders"));
+		for (Entry<String, Object> entry : headers.entrySet()) {
+			httpRequest.addHeader(entry.getKey(), entry.getValue());
+		}
+		return httpRequest;
+	}
+
+
+	public void handleRequest(InputStream input, OutputStream output) throws IOException {
+		HttpServletRequest httpRequest = this.prepareRequest(input);
+
+		ProxyHttpServletResponse httpResponse = new ProxyHttpServletResponse();
+		try {
+			this.mvc.perform(httpRequest, httpResponse);
+		}
+		catch (Exception e) {
+			e.printStackTrace();
+			throw new IllegalStateException(e);
+		}
+
+		String responseString = httpResponse.getContentAsString();
+		if (StringUtils.hasText(responseString)) {
+			if (logger.isDebugEnabled()) {
+				logger.debug("Response: " + responseString);
+			}
+			Map<String, Object> apiGatewayResponseStructure = new HashMap<String, Object>();
+			apiGatewayResponseStructure.put("isBase64Encoded", false);
+			apiGatewayResponseStructure.put("statusCode", 200);
+			apiGatewayResponseStructure.put("body", responseString);
+
+			Map<String, List<String>> multiValueHeaders = new HashMap<>();
+			for (String headerName : httpResponse.getHeaderNames()) {
+				multiValueHeaders.put(headerName, httpResponse.getHeaders(headerName));
+			}
+			// TODO investigate why AWS doesn't like List as value
+//			apiGatewayResponseStructure.put("headers", multiValueHeaders);
+
+			byte[] apiGatewayResponseBytes = mapper.writeValueAsBytes(apiGatewayResponseStructure);
+			StreamUtils.copy(apiGatewayResponseBytes, output);
+		}
+	}
+
+	private static class ProxyServletConfig implements ServletConfig {
+
+		private final ServletContext servletContext;
+
+		ProxyServletConfig(ServletContext servletContext) {
+			this.servletContext = servletContext;
+		}
+
+		@Override
+		public String getServletName() {
+			return "serverless-proxy";
+		}
+
+		@Override
+		public ServletContext getServletContext() {
+			return this.servletContext;
+		}
+
+		@Override
+		public Enumeration<String> getInitParameterNames() {
+			return Collections.enumeration(new ArrayList<String>());
+		}
+
+		@Override
+		public String getInitParameter(String name) {
+			return null;
+		}
+	}
+}

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/main/java/org/springframework/web/client/HeaderValueHolder.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2023-2023 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.web.client;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.springframework.lang.Nullable;
+import org.springframework.util.CollectionUtils;
+
+class HeaderValueHolder {
+
+	private final List<Object> values = new LinkedList<>();
+
+	void setValue(@Nullable Object value) {
+		this.values.clear();
+		if (value != null) {
+			this.values.add(value);
+		}
+	}
+
+	void addValue(Object value) {
+		this.values.add(value);
+	}
+
+	void addValues(Collection<?> values) {
+		this.values.addAll(values);
+	}
+
+	void addValueArray(Object values) {
+		CollectionUtils.mergeArrayIntoCollection(values, this.values);
+	}
+
+	List<Object> getValues() {
+		return Collections.unmodifiableList(this.values);
+	}
+
+	List<String> getStringValues() {
+		List<String> stringList = new ArrayList<>(this.values.size());
+		for (Object value : this.values) {
+			stringList.add(value.toString());
+		}
+		return Collections.unmodifiableList(stringList);
+	}
+
+	@Nullable
+	Object getValue() {
+		return (!this.values.isEmpty() ? this.values.get(0) : null);
+	}
+
+	@Nullable
+	String getStringValue() {
+		return (!this.values.isEmpty() ? String.valueOf(this.values.get(0)) : null);
+	}
+
+	@Override
+	public String toString() {
+		return this.values.toString();
+	}
+
+}

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/main/java/org/springframework/web/client/ProxyHttpServletResponse.java

@@ -0,0 +1,601 @@
+/*
+ * Copyright 2023-2023 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.web.client;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.UnsupportedEncodingException;
+import java.nio.charset.Charset;
+import java.text.DateFormat;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Date;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.TimeZone;
+
+import javax.servlet.ServletOutputStream;
+import javax.servlet.WriteListener;
+import javax.servlet.http.Cookie;
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+import org.springframework.util.LinkedCaseInsensitiveMap;
+import org.springframework.web.util.WebUtils;
+
+public class ProxyHttpServletResponse implements HttpServletResponse {
+
+	private static final String CHARSET_PREFIX = "charset=";
+
+	private static final String DATE_FORMAT = "EEE, dd MMM yyyy HH:mm:ss zzz";
+
+	private static final TimeZone GMT = TimeZone.getTimeZone("GMT");
+
+	// ---------------------------------------------------------------------
+	// ServletResponse properties
+	// ---------------------------------------------------------------------
+
+	private boolean outputStreamAccessAllowed = true;
+
+	private String defaultCharacterEncoding = WebUtils.DEFAULT_CHARACTER_ENCODING;
+
+	private String characterEncoding = this.defaultCharacterEncoding;
+
+	/**
+	 * {@code true} if the character encoding has been explicitly set through
+	 * {@link HttpServletResponse} methods or through a {@code charset} parameter on
+	 * the {@code Content-Type}.
+	 */
+	private boolean characterEncodingSet = false;
+
+	private final ByteArrayOutputStream content = new ByteArrayOutputStream(1024);
+
+	private final ServletOutputStream outputStream = new ResponseServletOutputStream();
+
+	private long contentLength = 0;
+
+	private String contentType;
+
+	private int bufferSize = 4096;
+
+	private boolean committed;
+
+	private Locale locale = Locale.getDefault();
+
+	// ---------------------------------------------------------------------
+	// HttpServletResponse properties
+	// ---------------------------------------------------------------------
+
+	private final List<Cookie> cookies = new ArrayList<>();
+
+	private final Map<String, HeaderValueHolder> headers = new LinkedCaseInsensitiveMap<>();
+
+	private int status = HttpServletResponse.SC_OK;
+
+	@Nullable
+	private String errorMessage;
+
+	// ---------------------------------------------------------------------
+	// ServletResponse interface
+	// ---------------------------------------------------------------------
+
+	@Override
+	public void setCharacterEncoding(String characterEncoding) {
+		setExplicitCharacterEncoding(characterEncoding);
+		updateContentTypePropertyAndHeader();
+	}
+
+	private void setExplicitCharacterEncoding(String characterEncoding) {
+		Assert.notNull(characterEncoding, "'characterEncoding' must not be null");
+		this.characterEncoding = characterEncoding;
+		this.characterEncodingSet = true;
+	}
+
+	private void updateContentTypePropertyAndHeader() {
+		if (this.contentType != null) {
+			String value = this.contentType;
+			if (this.characterEncodingSet && !value.toLowerCase().contains(CHARSET_PREFIX)) {
+				value += ';' + CHARSET_PREFIX + getCharacterEncoding();
+				this.contentType = value;
+			}
+			doAddHeaderValue(HttpHeaders.CONTENT_TYPE, value, true);
+		}
+	}
+
+	@Override
+	public String getCharacterEncoding() {
+		return this.characterEncoding;
+	}
+
+	@Override
+	public ServletOutputStream getOutputStream() {
+		Assert.state(this.outputStreamAccessAllowed, "OutputStream access not allowed");
+		return this.outputStream;
+	}
+
+	@Override
+	public PrintWriter getWriter() throws UnsupportedEncodingException {
+		throw new UnsupportedOperationException();
+	}
+
+	public byte[] getContentAsByteArray() {
+		return this.content.toByteArray();
+	}
+
+	/**
+	 * Get the content of the response body as a {@code String}, using the charset
+	 * specified for the response by the application, either through
+	 * {@link HttpServletResponse} methods or through a charset parameter on the
+	 * {@code Content-Type}. If no charset has been explicitly defined, the
+	 * {@linkplain #setDefaultCharacterEncoding(String) default character encoding}
+	 * will be used.
+	 *
+	 * @return the content as a {@code String}
+	 * @throws UnsupportedEncodingException if the character encoding is not
+	 *                                      supported
+	 * @see #getContentAsString(Charset)
+	 * @see #setCharacterEncoding(String)
+	 * @see #setContentType(String)
+	 */
+	public String getContentAsString() throws UnsupportedEncodingException {
+		return this.content.toString(getCharacterEncoding());
+	}
+
+	/**
+	 * Get the content of the response body as a {@code String}, using the provided
+	 * {@code fallbackCharset} if no charset has been explicitly defined and
+	 * otherwise using the charset specified for the response by the application,
+	 * either through {@link HttpServletResponse} methods or through a charset
+	 * parameter on the {@code Content-Type}.
+	 *
+	 * @return the content as a {@code String}
+	 * @throws UnsupportedEncodingException if the character encoding is not
+	 *                                      supported
+	 * @since 5.2
+	 * @see #getContentAsString()
+	 * @see #setCharacterEncoding(String)
+	 * @see #setContentType(String)
+	 */
+	public String getContentAsString(Charset fallbackCharset) throws UnsupportedEncodingException {
+		String charsetName = (this.characterEncodingSet ? getCharacterEncoding() : fallbackCharset.name());
+		return this.content.toString(charsetName);
+	}
+
+	@Override
+	public void setContentLength(int contentLength) {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public void setContentLengthLong(long len) {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public void setContentType(@Nullable String contentType) {
+		this.contentType = contentType;
+	}
+
+	@Override
+	@Nullable
+	public String getContentType() {
+		return this.contentType;
+	}
+
+	@Override
+	public void setBufferSize(int bufferSize) {
+		this.bufferSize = bufferSize;
+	}
+
+	@Override
+	public int getBufferSize() {
+		return this.bufferSize;
+	}
+
+	@Override
+	public void flushBuffer() {
+
+	}
+
+	@Override
+	public void resetBuffer() {
+		Assert.state(!isCommitted(), "Cannot reset buffer - response is already committed");
+		this.content.reset();
+	}
+
+	public void setCommitted(boolean committed) {
+		this.committed = committed;
+	}
+
+	@Override
+	public boolean isCommitted() {
+		return this.committed;
+	}
+
+	@Override
+	public void reset() {
+		resetBuffer();
+		this.characterEncoding = this.defaultCharacterEncoding;
+		this.characterEncodingSet = false;
+		this.contentLength = 0;
+		this.contentType = null;
+		this.locale = Locale.getDefault();
+		this.cookies.clear();
+		this.headers.clear();
+		this.status = HttpServletResponse.SC_OK;
+		this.errorMessage = null;
+	}
+
+	@Override
+	public void setLocale(@Nullable Locale locale) {
+		// Although the Javadoc for javax.servlet.ServletResponse.setLocale(Locale) does
+		// not
+		// state how a null value for the supplied Locale should be handled, both Tomcat
+		// and
+		// Jetty simply ignore a null value. So we do the same here.
+		if (locale == null) {
+			return;
+		}
+		this.locale = locale;
+		doAddHeaderValue(HttpHeaders.CONTENT_LANGUAGE, locale.toLanguageTag(), true);
+	}
+
+	@Override
+	public Locale getLocale() {
+		return this.locale;
+	}
+
+	// ---------------------------------------------------------------------
+	// HttpServletResponse interface
+	// ---------------------------------------------------------------------
+
+	@Override
+	public void addCookie(Cookie cookie) {
+		throw new UnsupportedOperationException();
+	}
+
+	@Nullable
+	public Cookie getCookie(String name) {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public boolean containsHeader(String name) {
+		return this.headers.containsKey(name);
+	}
+
+	/**
+	 * Return the names of all specified headers as a Set of Strings.
+	 * <p>
+	 * As of Servlet 3.0, this method is also defined in
+	 * {@link HttpServletResponse}.
+	 *
+	 * @return the {@code Set} of header name {@code Strings}, or an empty
+	 *         {@code Set} if none
+	 */
+	@Override
+	public Collection<String> getHeaderNames() {
+		return this.headers.keySet();
+	}
+
+	/**
+	 * Return the primary value for the given header as a String, if any. Will
+	 * return the first value in case of multiple values.
+	 * <p>
+	 * As of Servlet 3.0, this method is also defined in
+	 * {@link HttpServletResponse}. As of Spring 3.1, it returns a stringified value
+	 * for Servlet 3.0 compatibility. Consider using {@link #getHeaderValue(String)}
+	 * for raw Object access.
+	 *
+	 * @param name the name of the header
+	 * @return the associated header value, or {@code null} if none
+	 */
+	@Override
+	@Nullable
+	public String getHeader(String name) {
+		HeaderValueHolder header = this.headers.get(name);
+		return (header != null ? header.getStringValue() : null);
+	}
+
+	/**
+	 * Return all values for the given header as a List of Strings.
+	 * <p>
+	 * As of Servlet 3.0, this method is also defined in
+	 * {@link HttpServletResponse}. As of Spring 3.1, it returns a List of
+	 * stringified values for Servlet 3.0 compatibility. Consider using
+	 * {@link #getHeaderValues(String)} for raw Object access.
+	 *
+	 * @param name the name of the header
+	 * @return the associated header values, or an empty List if none
+	 */
+	@Override
+	public List<String> getHeaders(String name) {
+		HeaderValueHolder header = this.headers.get(name);
+		if (header != null) {
+			return header.getStringValues();
+		}
+		else {
+			return Collections.emptyList();
+		}
+	}
+
+	/**
+	 * Return the primary value for the given header, if any.
+	 * <p>
+	 * Will return the first value in case of multiple values.
+	 *
+	 * @param name the name of the header
+	 * @return the associated header value, or {@code null} if none
+	 */
+	@Nullable
+	public Object getHeaderValue(String name) {
+		HeaderValueHolder header = this.headers.get(name);
+		return (header != null ? header.getValue() : null);
+	}
+
+	/**
+	 * Return all values for the given header as a List of value objects.
+	 *
+	 * @param name the name of the header
+	 * @return the associated header values, or an empty List if none
+	 */
+	public List<Object> getHeaderValues(String name) {
+		HeaderValueHolder header = this.headers.get(name);
+		if (header != null) {
+			return header.getValues();
+		}
+		else {
+			return Collections.emptyList();
+		}
+	}
+
+	/**
+	 * The default implementation returns the given URL String as-is.
+	 * <p>
+	 * Can be overridden in subclasses, appending a session id or the like.
+	 */
+	@Override
+	public String encodeURL(String url) {
+		return url;
+	}
+
+	/**
+	 * The default implementation delegates to {@link #encodeURL}, returning the
+	 * given URL String as-is.
+	 * <p>
+	 * Can be overridden in subclasses, appending a session id or the like in a
+	 * redirect-specific fashion. For general URL encoding rules, override the
+	 * common {@link #encodeURL} method instead, applying to redirect URLs as well
+	 * as to general URLs.
+	 */
+	@Override
+	public String encodeRedirectURL(String url) {
+		return encodeURL(url);
+	}
+
+	@Override
+	@Deprecated
+	public String encodeUrl(String url) {
+		return encodeURL(url);
+	}
+
+	@Override
+	@Deprecated
+	public String encodeRedirectUrl(String url) {
+		return encodeRedirectURL(url);
+	}
+
+	@Override
+	public void sendError(int status, String errorMessage) throws IOException {
+		Assert.state(!isCommitted(), "Cannot set error status - response is already committed");
+		this.status = status;
+		this.errorMessage = errorMessage;
+		setCommitted(true);
+	}
+
+	@Override
+	public void sendError(int status) throws IOException {
+		Assert.state(!isCommitted(), "Cannot set error status - response is already committed");
+		this.status = status;
+		setCommitted(true);
+	}
+
+	@Override
+	public void sendRedirect(String url) throws IOException {
+		Assert.state(!isCommitted(), "Cannot send redirect - response is already committed");
+		Assert.notNull(url, "Redirect URL must not be null");
+		setHeader(HttpHeaders.LOCATION, url);
+		setStatus(HttpServletResponse.SC_MOVED_TEMPORARILY);
+		setCommitted(true);
+	}
+
+	@Nullable
+	public String getRedirectedUrl() {
+		return getHeader(HttpHeaders.LOCATION);
+	}
+
+	@Override
+	public void setDateHeader(String name, long value) {
+		setHeaderValue(name, formatDate(value));
+	}
+
+	@Override
+	public void addDateHeader(String name, long value) {
+		addHeaderValue(name, formatDate(value));
+	}
+
+	public long getDateHeader(String name) {
+		String headerValue = getHeader(name);
+		if (headerValue == null) {
+			return -1;
+		}
+		try {
+			return newDateFormat().parse(getHeader(name)).getTime();
+		}
+		catch (ParseException ex) {
+			throw new IllegalArgumentException("Value for header '" + name + "' is not a valid Date: " + headerValue);
+		}
+	}
+
+	private String formatDate(long date) {
+		return newDateFormat().format(new Date(date));
+	}
+
+	private DateFormat newDateFormat() {
+		SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMAT, Locale.US);
+		dateFormat.setTimeZone(GMT);
+		return dateFormat;
+	}
+
+	@Override
+	public void setHeader(String name, @Nullable String value) {
+		setHeaderValue(name, value);
+	}
+
+	@Override
+	public void addHeader(String name, @Nullable String value) {
+		addHeaderValue(name, value);
+	}
+
+	@Override
+	public void setIntHeader(String name, int value) {
+		setHeaderValue(name, value);
+	}
+
+	@Override
+	public void addIntHeader(String name, int value) {
+		addHeaderValue(name, value);
+	}
+
+	private void setHeaderValue(String name, @Nullable Object value) {
+		if (value == null) {
+			return;
+		}
+		boolean replaceHeader = true;
+		doAddHeaderValue(name, value, replaceHeader);
+	}
+
+	private void addHeaderValue(String name, @Nullable Object value) {
+		if (value == null) {
+			return;
+		}
+		boolean replaceHeader = false;
+		doAddHeaderValue(name, value, replaceHeader);
+	}
+
+	private void doAddHeaderValue(String name, Object value, boolean replace) {
+		Assert.notNull(value, "Header value must not be null");
+		HeaderValueHolder header = this.headers.computeIfAbsent(name, key -> new HeaderValueHolder());
+		if (replace) {
+			header.setValue(value);
+		}
+		else {
+			header.addValue(value);
+		}
+	}
+
+	@Override
+	public void setStatus(int status) {
+		if (!this.isCommitted()) {
+			this.status = status;
+		}
+	}
+
+	@Override
+	@Deprecated
+	public void setStatus(int status, String errorMessage) {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public int getStatus() {
+		return this.status;
+	}
+
+	@Nullable
+	public String getErrorMessage() {
+		return this.errorMessage;
+	}
+
+	// ---------------------------------------------------------------------
+	// Methods for MockRequestDispatcher
+	// ---------------------------------------------------------------------
+
+	@Nullable
+	public String getForwardedUrl() {
+		throw new UnsupportedOperationException();
+	}
+
+	@Nullable
+	public String getIncludedUrl() {
+		throw new UnsupportedOperationException();
+	}
+
+	/**
+	 * Inner class that adapts the ServletOutputStream to mark the response as
+	 * committed once the buffer size is exceeded.
+	 */
+	private class ResponseServletOutputStream extends ServletOutputStream {
+
+		private WriteListener listener;
+
+		@Override
+		public boolean isReady() {
+			return true;
+		}
+
+		@Override
+		public void setWriteListener(WriteListener writeListener) {
+			if (writeListener != null) {
+				try {
+					writeListener.onWritePossible();
+				}
+				catch (IOException e) {
+					// log.error("Output stream is not writable", e);
+				}
+
+				listener = writeListener;
+			}
+		}
+
+		@Override
+		public void write(int b) throws IOException {
+			try {
+				content.write(b);
+			}
+			catch (Exception e) {
+				if (listener != null) {
+					listener.onError(e);
+				}
+			}
+		}
+
+		@Override
+		public void close() throws IOException {
+			super.close();
+			flushBuffer();
+		}
+	}
+
+}

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/main/java/org/springframework/web/client/ProxyMvc.java

@@ -0,0 +1,214 @@
+/*
+ * Copyright 2023-2023 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.web.client;
+
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.List;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.Servlet;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
+import org.springframework.web.servlet.DispatcherServlet;
+
+public class ProxyMvc {
+
+	static final String MVC_RESULT_ATTRIBUTE = ProxyMvc.class.getName().concat(".MVC_RESULT_ATTRIBUTE");
+
+	private final DispatcherServlet servlet;
+
+	private final Filter[] filters;
+
+	@Nullable
+	private Charset defaultResponseCharacterEncoding;
+
+	/**
+	 * Private constructor, not for direct instantiation.
+	 *
+	 * @see org.springframework.test.web.servlet.setup.MockMvcBuilders
+	 */
+	public ProxyMvc(DispatcherServlet servlet, Filter... filters) {
+		Assert.notNull(servlet, "DispatcherServlet is required");
+		Assert.notNull(filters, "Filters cannot be null");
+		Assert.noNullElements(filters, "Filters cannot contain null values");
+
+		this.servlet = servlet;
+		this.filters = filters;
+	}
+
+	/**
+	 * The default character encoding to be applied to every response.
+	 *
+	 * @see org.springframework.test.web.servlet.setup.ConfigurableMockMvcBuilder#defaultResponseCharacterEncoding(Charset)
+	 */
+	void setDefaultResponseCharacterEncoding(@Nullable Charset defaultResponseCharacterEncoding) {
+		this.defaultResponseCharacterEncoding = defaultResponseCharacterEncoding;
+	}
+
+	/**
+	 * Return the underlying {@link DispatcherServlet} instance that this
+	 * {@code MockMvc} was initialized with.
+	 * <p>
+	 * This is intended for use in custom request processing scenario where a
+	 * request handling component happens to delegate to the
+	 * {@code DispatcherServlet} at runtime and therefore needs to be injected with
+	 * it.
+	 * <p>
+	 * For most processing scenarios, simply use {@link MockMvc#perform}, or if you
+	 * need to configure the {@code DispatcherServlet}, provide a
+	 * {@link DispatcherServletCustomizer} to the {@code MockMvcBuilder}.
+	 *
+	 * @since 5.1
+	 */
+	public DispatcherServlet getDispatcherServlet() {
+		return this.servlet;
+	}
+
+	/**
+	 * Perform a request and return a type that allows chaining further actions,
+	 * such as asserting expectations, on the result.
+	 *
+	 * @param requestBuilder used to prepare the request to execute; see static
+	 *                       factory methods in
+	 *                       {@link org.springframework.test.web.servlet.request.MockMvcRequestBuilders}
+	 * @return an instance of {@link ResultActions} (never {@code null})
+	 * @see org.springframework.test.web.servlet.request.MockMvcRequestBuilders
+	 * @see org.springframework.test.web.servlet.result.MockMvcResultMatchers
+	 */
+	public void perform(HttpServletRequest request, HttpServletResponse response) throws Exception {
+		ProxyFilterChain filterChain = new ProxyFilterChain(this.servlet, this.filters);
+		filterChain.doFilter(request, response);
+	}
+
+	private static class ProxyFilterChain implements FilterChain {
+
+		@Nullable
+		private ServletRequest request;
+
+		@Nullable
+		private ServletResponse response;
+
+		private final List<Filter> filters;
+
+		@Nullable
+		private Iterator<Filter> iterator;
+
+
+		/**
+		 * Create a {@code FilterChain} with Filter's and a Servlet.
+		 *
+		 * @param servlet the {@link Servlet} to invoke in this {@link FilterChain}
+		 * @param filters the {@link Filter}'s to invoke in this {@link FilterChain}
+		 * @since 3.2
+		 */
+		ProxyFilterChain(Servlet servlet, Filter... filters) {
+			Assert.notNull(filters, "filters cannot be null");
+			Assert.noNullElements(filters, "filters cannot contain null values");
+			this.filters = initFilterList(servlet, filters);
+		}
+
+		private static List<Filter> initFilterList(Servlet servlet, Filter... filters) {
+			Filter[] allFilters = ObjectUtils.addObjectToArray(filters, new ServletFilterProxy(servlet));
+			return Arrays.asList(allFilters);
+		}
+
+		/**
+		 * Return the request that {@link #doFilter} has been called with.
+		 */
+		@Nullable
+		public ServletRequest getRequest() {
+			return this.request;
+		}
+
+		/**
+		 * Return the response that {@link #doFilter} has been called with.
+		 */
+		@Nullable
+		public ServletResponse getResponse() {
+			return this.response;
+		}
+
+		/**
+		 * Invoke registered {@link Filter Filters} and/or {@link Servlet} also saving
+		 * the request and response.
+		 */
+		@Override
+		public void doFilter(ServletRequest request, ServletResponse response) throws IOException, ServletException {
+			Assert.notNull(request, "Request must not be null");
+			Assert.notNull(response, "Response must not be null");
+			Assert.state(this.request == null, "This FilterChain has already been called!");
+
+			if (this.iterator == null) {
+				this.iterator = this.filters.iterator();
+			}
+
+			if (this.iterator.hasNext()) {
+				Filter nextFilter = this.iterator.next();
+				nextFilter.doFilter(request, response, this);
+			}
+
+			this.request = request;
+			this.response = response;
+		}
+
+		/**
+		 * A filter that simply delegates to a Servlet.
+		 */
+		private static final class ServletFilterProxy implements Filter {
+
+			private final Servlet delegateServlet;
+
+			private ServletFilterProxy(Servlet servlet) {
+				Assert.notNull(servlet, "servlet cannot be null");
+				this.delegateServlet = servlet;
+			}
+
+			@Override
+			public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
+					throws IOException, ServletException {
+
+				this.delegateServlet.service(request, response);
+			}
+
+			@Override
+			public void init(FilterConfig filterConfig) throws ServletException {
+			}
+
+			@Override
+			public void destroy() {
+			}
+
+			@Override
+			public String toString() {
+				return this.delegateServlet.toString();
+			}
+		}
+
+	}
+}

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/main/java/org/springframework/web/client/ProxyServletContext.java

@@ -0,0 +1,397 @@
+/*
+ * Copyright 2023-2023 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.web.client;
+
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Enumeration;
+import java.util.EventListener;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterRegistration;
+import javax.servlet.RequestDispatcher;
+import javax.servlet.Servlet;
+import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRegistration;
+import javax.servlet.ServletRegistration.Dynamic;
+import javax.servlet.SessionCookieConfig;
+import javax.servlet.SessionTrackingMode;
+import javax.servlet.descriptor.JspConfigDescriptor;
+
+public class ProxyServletContext implements ServletContext {
+
+	@Override
+	public Enumeration<String> getInitParameterNames() {
+		List<String> arrlist = new ArrayList<String>();
+		return Collections.enumeration(arrlist);
+	}
+
+	@Override
+	public Enumeration<String> getAttributeNames() {
+		List<String> arrlist = new ArrayList<String>();
+		return Collections.enumeration(arrlist);
+	}
+
+	@Override
+	public String getContextPath() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public ServletContext getContext(String uripath) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public int getMajorVersion() {
+		// TODO Auto-generated method stub
+		return 0;
+	}
+
+	@Override
+	public int getMinorVersion() {
+		// TODO Auto-generated method stub
+		return 0;
+	}
+
+	@Override
+	public int getEffectiveMajorVersion() {
+		// TODO Auto-generated method stub
+		return 0;
+	}
+
+	@Override
+	public int getEffectiveMinorVersion() {
+		// TODO Auto-generated method stub
+		return 0;
+	}
+
+	@Override
+	public String getMimeType(String file) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Set<String> getResourcePaths(String path) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public URL getResource(String path) throws MalformedURLException {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public InputStream getResourceAsStream(String path) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public RequestDispatcher getRequestDispatcher(String path) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public RequestDispatcher getNamedDispatcher(String name) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Servlet getServlet(String name) throws ServletException {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Enumeration<Servlet> getServlets() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Enumeration<String> getServletNames() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public void log(String msg) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public void log(Exception exception, String msg) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public void log(String message, Throwable throwable) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public String getRealPath(String path) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public String getServerInfo() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public String getInitParameter(String name) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public boolean setInitParameter(String name, String value) {
+		// TODO Auto-generated method stub
+		return false;
+	}
+
+	@Override
+	public Object getAttribute(String name) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public void setAttribute(String name, Object object) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public void removeAttribute(String name) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public String getServletContextName() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Dynamic addServlet(String servletName, String className) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Dynamic addServlet(String servletName, Servlet servlet) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Dynamic addServlet(String servletName, Class<? extends Servlet> servletClass) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Dynamic addJspFile(String jspName, String jspFile) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public <T extends Servlet> T createServlet(Class<T> c) throws ServletException {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public ServletRegistration getServletRegistration(String servletName) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Map<String, ? extends ServletRegistration> getServletRegistrations() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public javax.servlet.FilterRegistration.Dynamic addFilter(String filterName, String className) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public javax.servlet.FilterRegistration.Dynamic addFilter(String filterName, Filter filter) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public javax.servlet.FilterRegistration.Dynamic addFilter(String filterName, Class<? extends Filter> filterClass) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public <T extends Filter> T createFilter(Class<T> c) throws ServletException {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public FilterRegistration getFilterRegistration(String filterName) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Map<String, ? extends FilterRegistration> getFilterRegistrations() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public SessionCookieConfig getSessionCookieConfig() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public void setSessionTrackingModes(Set<SessionTrackingMode> sessionTrackingModes) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public Set<javax.servlet.SessionTrackingMode> getDefaultSessionTrackingModes() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public Set<javax.servlet.SessionTrackingMode> getEffectiveSessionTrackingModes() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public void addListener(String className) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public <T extends EventListener> void addListener(T t) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public void addListener(Class<? extends EventListener> listenerClass) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public <T extends EventListener> T createListener(Class<T> c) throws ServletException {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public JspConfigDescriptor getJspConfigDescriptor() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public ClassLoader getClassLoader() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public void declareRoles(String... roleNames) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public String getVirtualServerName() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public int getSessionTimeout() {
+		// TODO Auto-generated method stub
+		return 0;
+	}
+
+	@Override
+	public void setSessionTimeout(int sessionTimeout) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public String getRequestCharacterEncoding() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public void setRequestCharacterEncoding(String encoding) {
+		// TODO Auto-generated method stub
+
+	}
+
+	@Override
+	public String getResponseCharacterEncoding() {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	@Override
+	public void setResponseCharacterEncoding(String encoding) {
+		// TODO Auto-generated method stub
+
+	}
+}

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/main/java/org/springframework/web/client/README.md

@@ -0,0 +1,3 @@
+Classes in this package should ideally reside in spring-web somewhere as a light weight HTTP proxy, since they are independent of the 
+context of the execution (i.e., AWS or Azure or whatever).
+In fact classes in these package is a slimed-down copy of similar classes in MockMVC.

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/test/java/org/springframework/cloud/function/adapter/aws/web/Pet.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2023-2023 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.cloud.function.adapter.aws.web;
+
+import java.util.Date;
+
+public class Pet {
+	private String id;
+	private String breed;
+	private String name;
+	private Date dateOfBirth;
+
+	public String getId() {
+		return id;
+	}
+
+	public void setId(String id) {
+		this.id = id;
+	}
+
+	public String getBreed() {
+		return breed;
+	}
+
+	public void setBreed(String breed) {
+		this.breed = breed;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public Date getDateOfBirth() {
+		return dateOfBirth;
+	}
+
+	public void setDateOfBirth(Date dateOfBirth) {
+		this.dateOfBirth = dateOfBirth;
+	}
+}

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/test/java/org/springframework/cloud/function/adapter/aws/web/PetData.java

@@ -0,0 +1,118 @@
+/*
+ * Copyright 2023-2023 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.cloud.function.adapter.aws.web;
+
+
+import java.util.ArrayList;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.GregorianCalendar;
+import java.util.List;
+import java.util.concurrent.ThreadLocalRandom;
+
+public class PetData {
+	private static List<String> breeds = new ArrayList<>();
+	static {
+		breeds.add("Afghan Hound");
+		breeds.add("Beagle");
+		breeds.add("Bernese Mountain Dog");
+		breeds.add("Bloodhound");
+		breeds.add("Dalmatian");
+		breeds.add("Jack Russell Terrier");
+		breeds.add("Norwegian Elkhound");
+	}
+
+	private static List<String> names = new ArrayList<>();
+	static {
+		names.add("Bailey");
+		names.add("Bella");
+		names.add("Max");
+		names.add("Lucy");
+		names.add("Charlie");
+		names.add("Molly");
+		names.add("Buddy");
+		names.add("Daisy");
+		names.add("Rocky");
+		names.add("Maggie");
+		names.add("Jake");
+		names.add("Sophie");
+		names.add("Jack");
+		names.add("Sadie");
+		names.add("Toby");
+		names.add("Chloe");
+		names.add("Cody");
+		names.add("Bailey");
+		names.add("Buster");
+		names.add("Lola");
+		names.add("Duke");
+		names.add("Zoe");
+		names.add("Cooper");
+		names.add("Abby");
+		names.add("Riley");
+		names.add("Ginger");
+		names.add("Harley");
+		names.add("Roxy");
+		names.add("Bear");
+		names.add("Gracie");
+		names.add("Tucker");
+		names.add("Coco");
+		names.add("Murphy");
+		names.add("Sasha");
+		names.add("Lucky");
+		names.add("Lily");
+		names.add("Oliver");
+		names.add("Angel");
+		names.add("Sam");
+		names.add("Princess");
+		names.add("Oscar");
+		names.add("Emma");
+		names.add("Teddy");
+		names.add("Annie");
+		names.add("Winston");
+		names.add("Rosie");
+	}
+
+	public static List<String> getBreeds() {
+		return breeds;
+	}
+
+	public static List<String> getNames() {
+		return names;
+	}
+
+	public static String getRandomBreed() {
+		return breeds.get(ThreadLocalRandom.current().nextInt(0, breeds.size() - 1));
+	}
+
+	public static String getRandomName() {
+		return names.get(ThreadLocalRandom.current().nextInt(0, names.size() - 1));
+	}
+
+	public static Date getRandomDoB() {
+		GregorianCalendar gc = new GregorianCalendar();
+
+		int year = ThreadLocalRandom.current().nextInt(Calendar.getInstance().get(Calendar.YEAR) - 15,
+				Calendar.getInstance().get(Calendar.YEAR));
+
+		gc.set(Calendar.YEAR, year);
+
+		int dayOfYear = ThreadLocalRandom.current().nextInt(1, gc.getActualMaximum(Calendar.DAY_OF_YEAR));
+
+		gc.set(Calendar.DAY_OF_YEAR, dayOfYear);
+		return gc.getTime();
+	}
+}

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/test/java/org/springframework/cloud/function/adapter/aws/web/PetStoreSpringAppConfig.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2023-2023 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.cloud.function.adapter.aws.web;
+
+import java.io.IOException;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.web.servlet.HandlerAdapter;
+import org.springframework.web.servlet.HandlerMapping;
+import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
+import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
+
+//@SpringBootApplication
+@Configuration
+@Import({ PetsController.class })
+public class PetStoreSpringAppConfig {
+	/*
+	 * Create required HandlerMapping, to avoid several default HandlerMapping
+	 * instances being created
+	 */
+	@Bean
+	public HandlerMapping handlerMapping() {
+		return new RequestMappingHandlerMapping();
+	}
+
+	/*
+	 * Create required HandlerAdapter, to avoid several default HandlerAdapter
+	 * instances being created
+	 */
+	@Bean
+	public HandlerAdapter handlerAdapter() {
+		return new RequestMappingHandlerAdapter();
+	}
+
+	@Bean
+	public Filter filter() {
+		return new Filter() {
+			@Override
+			public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
+					throws IOException, ServletException {
+				System.out.println("FILTER ===> Hello from: " + request.getLocalAddr());
+				chain.doFilter(request, response);
+			}
+		};
+	}
+
+}

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/test/java/org/springframework/cloud/function/adapter/aws/web/PetsController.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2023-2023 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.cloud.function.adapter.aws.web;
+
+import java.security.Principal;
+import java.util.Optional;
+import java.util.UUID;
+
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+
+@RestController
+@EnableWebMvc
+public class PetsController {
+	@RequestMapping(path = "/pets", method = RequestMethod.POST)
+	public Pet createPet(@RequestBody Pet newPet) {
+		if (newPet.getName() == null || newPet.getBreed() == null) {
+			return null;
+		}
+
+		Pet dbPet = newPet;
+		dbPet.setId(UUID.randomUUID().toString());
+		return dbPet;
+	}
+
+	@RequestMapping(path = "/pets", method = RequestMethod.GET)
+	public Pet[] listPets(@RequestParam("limit") Optional<Integer> limit, Principal principal) {
+		System.out.println("=====> EXECUTING");
+		int queryLimit = 10;
+		if (limit.isPresent()) {
+			queryLimit = limit.get();
+		}
+
+		Pet[] outputPets = new Pet[queryLimit];
+
+		for (int i = 0; i < queryLimit; i++) {
+			Pet newPet = new Pet();
+			newPet.setId(UUID.randomUUID().toString());
+			newPet.setName(PetData.getRandomName());
+			newPet.setBreed(PetData.getRandomBreed());
+			newPet.setDateOfBirth(PetData.getRandomDoB());
+			outputPets[i] = newPet;
+		}
+
+		return outputPets;
+	}
+
+	@RequestMapping(path = "/pets/{petId}", method = RequestMethod.GET)
+	public Pet listPets() {
+		System.out.println("=====> Getting pet by id");
+		Pet newPet = new Pet();
+		newPet.setId(UUID.randomUUID().toString());
+		newPet.setBreed(PetData.getRandomBreed());
+		newPet.setDateOfBirth(PetData.getRandomDoB());
+		newPet.setName(PetData.getRandomName());
+		return newPet;
+	}
+}

spring-cloud-function-adapters/spring-cloud-function-adapter-aws-web/src/test/java/org/springframework/cloud/function/adapter/aws/web/WebProxyInvokerTests.java

@@ -0,0 +1,124 @@
+/*
+ * Copyright 2023-2023 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.cloud.function.adapter.aws.web;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.InputStream;
+import java.util.Map;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.Test;
+
+
+
+
+public class WebProxyInvokerTests {
+
+	static String apiGatewayEvent = "{\n" +
+			"    \"resource\": \"/pets\",\n" +
+			"    \"path\": \"/pets/64f56d94-a059-4111-9eeb-ee0c994b1ba8?foo=bar\",\n" +
+			"    \"httpMethod\": \"GET\",\n" +
+			"    \"headers\": {\n" +
+			"        \"accept\": \"*/*\",\n" +
+			"        \"content-type\": \"application/json\",\n" +
+			"        \"Host\": \"fhul32ccy2.execute-api.eu-west-3.amazonaws.com\",\n" +
+			"        \"User-Agent\": \"curl/7.54.0\",\n" +
+			"        \"X-Amzn-Trace-Id\": \"Root=1-5ece339e-e0595766066d703ec70f1522\",\n" +
+			"        \"X-Forwarded-For\": \"90.37.8.133\",\n" +
+			"        \"X-Forwarded-Port\": \"443\",\n" +
+			"        \"X-Forwarded-Proto\": \"https\"\n" +
+			"    },\n" +
+			"    \"multiValueHeaders\": {\n" +
+			"        \"accept\": [\n" +
+			"            \"*/*\"\n" +
+			"        ],\n" +
+			"        \"content-type\": [\n" +
+			"            \"application/json\"\n" +
+			"        ],\n" +
+			"        \"Host\": [\n" +
+			"            \"fhul32ccy2.execute-api.eu-west-3.amazonaws.com\"\n" +
+			"        ],\n" +
+			"        \"User-Agent\": [\n" +
+			"            \"curl/7.54.0\"\n" +
+			"        ],\n" +
+			"        \"X-Amzn-Trace-Id\": [\n" +
+			"            \"Root=1-5ece339e-e0595766066d703ec70f1522\"\n" +
+			"        ],\n" +
+			"        \"X-Forwarded-For\": [\n" +
+			"            \"90.37.8.133\"\n" +
+			"        ],\n" +
+			"        \"X-Forwarded-Port\": [\n" +
+			"            \"443\"\n" +
+			"        ],\n" +
+			"        \"X-Forwarded-Proto\": [\n" +
+			"            \"https\"\n" +
+			"        ]\n" +
+			"    },\n" +
+			"    \"queryStringParameters\": null,\n" +
+			"    \"multiValueQueryStringParameters\": null,\n" +
+			"    \"pathParameters\": null,\n" +
+			"    \"stageVariables\": null,\n" +
+			"    \"requestContext\": {\n" +
+			"        \"resourceId\": \"qf0io6\",\n" +
+			"        \"resourcePath\": \"/pets\",\n" +
+			"        \"httpMethod\": \"GET\",\n" +
+			"        \"extendedRequestId\": \"NL0A1EokCGYFZOA=\",\n" +
+			"        \"requestTime\": \"27/May/2020:09:32:14 +0000\",\n" +
+			"        \"path\": \"/test/uppercase2\",\n" +
+			"        \"accountId\": \"123456789098\",\n" +
+			"        \"protocol\": \"HTTP/1.1\",\n" +
+			"        \"stage\": \"test\",\n" +
+			"        \"domainPrefix\": \"fhul32ccy2\",\n" +
+			"        \"requestTimeEpoch\": 1590571934872,\n" +
+			"        \"requestId\": \"b96500aa-f92a-43c3-9360-868ba4053a00\",\n" +
+			"        \"identity\": {\n" +
+			"            \"cognitoIdentityPoolId\": null,\n" +
+			"            \"accountId\": null,\n" +
+			"            \"cognitoIdentityId\": null,\n" +
+			"            \"caller\": null,\n" +
+			"            \"sourceIp\": \"90.37.8.133\",\n" +
+			"            \"principalOrgId\": null,\n" +
+			"            \"accessKey\": null,\n" +
+			"            \"cognitoAuthenticationType\": null,\n" +
+			"            \"cognitoAuthenticationProvider\": null,\n" +
+			"            \"userArn\": null,\n" +
+			"            \"userAgent\": \"curl/7.54.0\",\n" +
+			"            \"user\": null\n" +
+			"        },\n" +
+			"        \"domainName\": \"fhul32ccy2.execute-api.eu-west-3.amazonaws.com\",\n" +
+			"        \"apiId\": \"fhul32ccy2\"\n" +
+			"    },\n" +
+			"    \"body\":\"\",\n" +
+			"    \"isBase64Encoded\": false\n" +
+			"}";
+
+	@Test
+	public void testApiGatewayProxy() throws Exception {
+		System.setProperty("MAIN_CLASS", PetStoreSpringAppConfig.class.getName());
+		WebProxyInvoker invoker = new WebProxyInvoker();
+
+		InputStream targetStream = new ByteArrayInputStream(this.apiGatewayEvent.getBytes());
+		ByteArrayOutputStream output = new ByteArrayOutputStream();
+		invoker.handleRequest(targetStream, output);
+
+		ObjectMapper mapper = new ObjectMapper();
+		System.out.println("RESULT: =======> " + new String(output.toByteArray()));
+		Map result = mapper.readValue(output.toByteArray(), Map.class);
+		System.out.println(result);
+	}
+}