fix: multi value header handling

function-aws-api-proxy-test/src/main/java/io/micronaut/function/aws/proxy/test/DefaultServletToAwsProxyResponseAdapter.java

@@ -19,7 +19,6 @@
 import io.micronaut.core.annotation.NonNull;
 import io.micronaut.core.annotation.Nullable;
 import io.micronaut.core.convert.ConversionService;
-import io.micronaut.function.aws.proxy.MutableMapListOfStringAndMapStringConvertibleMultiValue;
 import io.micronaut.http.HttpMethod;
 
 import jakarta.inject.Singleton;
@@ -32,7 +31,6 @@
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.util.Base64;
-import java.util.List;
 import java.util.Map;
 
 /**
@@ -47,7 +45,7 @@ public void handle(@NonNull ConversionService conversionService,
                        @NonNull HttpServletRequest request,
                        @NonNull APIGatewayV2HTTPResponse awsProxyResponse,
                        @NonNull HttpServletResponse response) throws IOException {
-        populateHeaders(conversionService, awsProxyResponse, response);
+        populateHeaders(awsProxyResponse, response);
         response.setStatus(awsProxyResponse.getStatusCode());
         HttpMethod httpMethod = HttpMethod.parse(request.getMethod());
         if (httpMethod != HttpMethod.HEAD && httpMethod != HttpMethod.OPTIONS) {
@@ -65,15 +63,10 @@ public void handle(@NonNull ConversionService conversionService,
         }
     }
 
-    private void populateHeaders(@NonNull ConversionService conversionService,
-                                 @NonNull APIGatewayV2HTTPResponse apiGatewayV2HTTPResponse,
+    private void populateHeaders(@NonNull APIGatewayV2HTTPResponse apiGatewayV2HTTPResponse,
                                  @NonNull HttpServletResponse response) {
-        Map<String, String> singleHeaders = apiGatewayV2HTTPResponse.getHeaders();
-        Map<String, List<String>> multiValueHeaders = apiGatewayV2HTTPResponse.getMultiValueHeaders();
-        MutableMapListOfStringAndMapStringConvertibleMultiValue entries = new MutableMapListOfStringAndMapStringConvertibleMultiValue(conversionService, multiValueHeaders, singleHeaders);
-
-        for (String name: entries.names()) {
-            response.addHeader(name, String.join(",", entries.getAll(name)));
+        for (Map.Entry<String, String> entry : apiGatewayV2HTTPResponse.getHeaders().entrySet()) {
+            response.addHeader(entry.getKey(), entry.getValue());
         }
     }
 

function-aws-api-proxy/src/main/java/io/micronaut/function/aws/proxy/MapCollapseUtils.java

@@ -16,9 +16,13 @@
 package io.micronaut.function.aws.proxy;
 
 import io.micronaut.core.annotation.Internal;
+import io.micronaut.core.annotation.NonNull;
+import io.micronaut.core.annotation.Nullable;
 import io.micronaut.core.util.CollectionUtils;
+import io.micronaut.http.HttpHeaders;
 import io.micronaut.http.MutableHttpHeaders;
 
+import java.util.Arrays;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -31,6 +35,8 @@
 @Internal
 public final class MapCollapseUtils {
 
+    private static final List<String> HEADERS_ALLOWING_COMMAS = Arrays.asList(HttpHeaders.DATE, HttpHeaders.USER_AGENT);
+
     private MapCollapseUtils() {
     }
 
@@ -81,9 +87,20 @@ public static Map<String, List<String>> collapse(Map<String, List<String>> multi
         }
         if (CollectionUtils.isNotEmpty(single)) {
             for (var entry: single.entrySet()) {
-                List<String> strings = values.computeIfAbsent(entry.getKey(), s -> new ArrayList<>());
-                if (!strings.contains(entry.getValue())) {
-                    strings.add(entry.getValue());
+                String headerName = entry.getKey();
+                List<String> strings = values.computeIfAbsent(headerName, s -> new ArrayList<>());
+                String value = entry.getValue();
+                if (HEADERS_ALLOWING_COMMAS.contains(headerName)) {
+                    if (!strings.contains(value)) {
+                        strings.add(value);
+                    }
+                } else {
+                    for (String v : splitCommaSeparatedValue(value)) {
+                        v = v.trim();
+                        if (!strings.contains(v)) {
+                            strings.add(v);
+                        }
+                    }
                 }
             }
         }
@@ -103,4 +120,12 @@ public static Map<String, String> collapse(Map<String, List<String>> input) {
         }
         return result;
     }
+
+    @NonNull
+    private static List<String> splitCommaSeparatedValue(@Nullable String value) {
+        if (value == null) {
+            return Collections.emptyList();
+        }
+        return Arrays.asList(value.split(","));
+    }
 }

function-aws-api-proxy/src/test/groovy/io/micronaut/function/aws/proxy/MapCollapseUtilsSpec.groovy

@@ -0,0 +1,77 @@
+package io.micronaut.function.aws.proxy
+
+import com.amazonaws.services.lambda.runtime.events.APIGatewayProxyRequestEvent
+import com.amazonaws.services.lambda.runtime.events.APIGatewayV2HTTPEvent
+import io.micronaut.core.convert.ConversionService
+import io.micronaut.http.CaseInsensitiveMutableHttpHeaders
+import io.micronaut.http.HttpHeaders
+import io.micronaut.http.MutableHttpHeaders
+import io.micronaut.test.extensions.spock.annotation.MicronautTest
+import jakarta.inject.Inject
+import spock.lang.Specification
+
+@MicronautTest
+class MapCollapseUtilsSpec extends Specification {
+
+    @Inject
+    ConversionService conversionService
+
+    /**
+     *
+     * GET /prod/ HTTP/1.1
+     * Key: value1,value2,value3
+     * Foo: Bar
+     */
+    void "payload v2 example"() {
+        given:
+        APIGatewayV2HTTPEvent event = new APIGatewayV2HTTPEvent()
+        Map<String, String> headers = new HashMap<>();
+        headers.put(HttpHeaders.DATE, "Wed, 21 Oct 2015 07:28:00 GMT")
+        headers.put("foo", "Bar")
+        headers.put("key", "value1,value2,value3")
+        headers.put(HttpHeaders.USER_AGENT, "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko)")
+        event.setHeaders(headers)
+
+        when:
+        MutableHttpHeaders httpHeaders = new CaseInsensitiveMutableHttpHeaders(MapCollapseUtils.collapse(Collections.emptyMap(), event.getHeaders()), conversionService);
+
+        then:
+        noExceptionThrown()
+
+        and:
+        "Bar" == httpHeaders.get("Foo")
+        ["value1", "value2", "value3"] == httpHeaders.getAll("Key")
+        "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko)" == httpHeaders.get(HttpHeaders.USER_AGENT)
+        "Wed, 21 Oct 2015 07:28:00 GMT" == httpHeaders.get(HttpHeaders.DATE)
+    }
+
+    /**
+     *
+     * GET /prod/ HTTP/1.1
+     * Key: value1,value2,value3
+     * Foo: Bar
+     */
+    void "payload v1 example"() {
+        given:
+        APIGatewayProxyRequestEvent request = new APIGatewayProxyRequestEvent()
+        Map<String, String> headers = new HashMap<>()
+        headers.put("Foo", "Bar")
+        headers.put("Key", "value1,value2,value3")
+        request.setHeaders(headers)
+        Map<String, List<String>> multiValueHeaders = new HashMap<>()
+        multiValueHeaders.put("Key", Arrays.asList("value1", "value2", "value3"))
+        multiValueHeaders.put("Foo", Collections.singletonList("Bar"))
+        request.setMultiValueHeaders(multiValueHeaders)
+
+        when:
+        MutableHttpHeaders httpHeaders = new CaseInsensitiveMutableHttpHeaders(MapCollapseUtils.collapse(request.getMultiValueHeaders(), request.getHeaders()), conversionService);
+
+        then:
+        noExceptionThrown()
+
+        and:
+        "Bar" == httpHeaders.get("Foo")
+        ["value1", "value2", "value3"] == httpHeaders.getAll("Key")
+
+    }
+}

test-suite-http-server-tck-function-aws-api-gateway-proxy-payloadv2/src/test/java/io/micronaut/http/server/tck/lambda/APIGatewayV2HTTPEventFactory.java

@@ -33,6 +33,7 @@
  */
 @Internal
 public final class APIGatewayV2HTTPEventFactory {
+    private final static String COMMA = ",";
 
     private APIGatewayV2HTTPEventFactory() {
     }
@@ -44,7 +45,7 @@ public static APIGatewayV2HTTPEvent create(HttpRequest<?> request, JsonMapper js
             public Map<String, String> getHeaders() {
                 Map<String, String> result = new HashMap<>();
                 for (String headerName : request.getHeaders().names()) {
-                    result.put(headerName, request.getHeaders().get(headerName));
+                    result.put(headerName, String.join(COMMA, request.getHeaders().getAll(headerName)));
                 }
                 return result;
             }

test-suite-http-server-tck-function-aws-api-gateway-proxy-payloadv2/src/test/java/io/micronaut/http/server/tck/lambda/tests/FunctionAwsApiGatewayProxyV2HttpServerTestSuite.java

@@ -11,7 +11,6 @@
     "io.micronaut.http.server.tck.lambda.tests"
 })
 @ExcludeClassNamePatterns({
-    "io.micronaut.http.server.tck.tests.HeadersTest", // https://github.com/micronaut-projects/micronaut-aws/issues/1861
     "io.micronaut.http.server.tck.tests.FilterProxyTest" // Immmutable request
 })
 @SuiteDisplayName("HTTP Server TCK for Function AWS API Gateway Proxy v2 Event model")

test-suite-http-server-tck-function-aws-api-proxy-test/src/test/java/io/micronaut/http/server/tck/lambda/tests/MicronautLambdaHandlerHttpServerTestSuite.java

@@ -11,7 +11,6 @@
     "io.micronaut.http.server.tck.lambda.tests"
 })
 @ExcludeClassNamePatterns({
-    "io.micronaut.http.server.tck.tests.HeadersTest", // https://github.com/micronaut-projects/micronaut-aws/issues/1861
     "io.micronaut.http.server.tck.tests.LocalErrorReadingBodyTest", // Binding body different type (e.g. a String in error handler)
     "io.micronaut.http.server.tck.tests.FilterProxyTest" // Immmutable request