#220 Fix case-sensitivity of HTTP headers in models

aws-lambda-java-events/pom.xml

@@ -83,6 +83,13 @@
       <version>${lombok.version}</version>
       <scope>provided</scope>
     </dependency>
+
+    <dependency>
+      <groupId>org.assertj</groupId>
+      <artifactId>assertj-core</artifactId>
+      <version>3.18.1</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <profiles>

aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/ApplicationLoadBalancerRequestEvent.java

@@ -59,8 +59,8 @@ public static class RequestContext implements Serializable {
     private String path;
     private Map<String, String> queryStringParameters;
     private Map<String, List<String>> multiValueQueryStringParameters;
-    private Map<String, String> headers;
-    private Map<String, List<String>> multiValueHeaders;
+    private HttpHeaders<String> headers;
+    private HttpHeaders<List<String>> multiValueHeaders;
     private String body;
     private boolean isBase64Encoded;
 }

aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/ApplicationLoadBalancerResponseEvent.java

@@ -39,7 +39,7 @@ public class ApplicationLoadBalancerResponseEvent implements Serializable {
     private int statusCode;
     private String statusDescription;
     private boolean isBase64Encoded;
-    private Map<String, String> headers;
-    private Map<String, List<String>> multiValueHeaders;
+    private HttpHeaders<String> headers;
+    private HttpHeaders<List<String>> multiValueHeaders;
     private String body;
 }

aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/HttpHeaders.java

@@ -0,0 +1,89 @@
+package com.amazonaws.services.lambda.runtime.events;
+
+import java.util.Collection;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+
+/**
+ * Class that represents Http Headers.
+ * <br>
+ * Http Headers are case-insensitive.
+ * Thus, requesting a header "host" will yield the same result as "Host" or "HOST"
+ */
+public class HttpHeaders<T> implements Map<String, T> {
+
+    // Headers are case insensitive (https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2)
+    private final Map<String, T> map = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
+
+    @Override
+    public int size() {
+        return map.size();
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return map.isEmpty();
+    }
+
+    @Override
+    public boolean containsKey(Object key) {
+        return map.containsKey(key);
+    }
+
+    @Override
+    public boolean containsValue(Object value) {
+        return map.containsValue(value);
+    }
+
+    @Override
+    public T get(Object key) {
+        return map.get(key);
+    }
+
+    @Override
+    public T put(String key, T value) {
+        return map.put(key, value);
+    }
+
+    @Override
+    public T remove(Object key) {
+        return map.remove(key);
+    }
+
+    @Override
+    public void putAll(Map<? extends String, ? extends T> m) {
+        map.putAll(m);
+    }
+
+    @Override
+    public void clear() {
+        map.clear();
+    }
+
+    @Override
+    public Set<String> keySet() {
+        return map.keySet();
+    }
+
+    @Override
+    public Collection<T> values() {
+        return map.values();
+    }
+
+    @Override
+    public Set<Entry<String, T>> entrySet() {
+        return map.entrySet();
+    }
+
+    public static <T> HttpHeaders<T> mergeOrReplace(Map<String, T> from) {
+        if (from == null) return null;
+        if (from instanceof HttpHeaders) return (HttpHeaders<T>) from;
+
+        HttpHeaders<T> out = new HttpHeaders<>();
+        if (from.isEmpty()) return out;
+
+        out.putAll(from);
+        return out;
+    }
+}

aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/apigateway/APIGatewayCustomAuthorizerEvent.java

@@ -13,6 +13,7 @@
 
 package com.amazonaws.services.lambda.runtime.events.apigateway;
 
+import com.amazonaws.services.lambda.runtime.events.HttpHeaders;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
@@ -39,7 +40,7 @@ public class APIGatewayCustomAuthorizerEvent {
     private String resource;
     private String path;
     private String httpMethod;
-    private Map<String, String> headers;
+    private HttpHeaders<String> headers;
     private Map<String, String> queryStringParameters;
     private Map<String, String> pathParameters;
     private Map<String, String> stageVariables;

aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/apigateway/APIGatewayProxyRequestEvent.java

@@ -13,6 +13,7 @@
 
 package com.amazonaws.services.lambda.runtime.events.apigateway;
 
+import com.amazonaws.services.lambda.runtime.events.HttpHeaders;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
@@ -37,8 +38,8 @@ public class APIGatewayProxyRequestEvent implements Serializable {
     private String resource;
     private String path;
     private String httpMethod;
-    private Map<String, String> headers;
-    private Map<String, List<String>> multiValueHeaders;
+    private HttpHeaders<String> headers;
+    private HttpHeaders<List<String>> multiValueHeaders;
     private Map<String, String> queryStringParameters;
     private Map<String, List<String>> multiValueQueryStringParameters;
     private Map<String, String> pathParameters;

aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/apigateway/APIGatewayProxyResponseEvent.java

@@ -13,6 +13,7 @@
 
 package com.amazonaws.services.lambda.runtime.events.apigateway;
 
+import com.amazonaws.services.lambda.runtime.events.HttpHeaders;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
@@ -34,7 +35,7 @@ public class APIGatewayProxyResponseEvent implements Serializable {
     private static final long serialVersionUID = 2263167344670024172L;
 
     private Integer statusCode;
-    private Map<String, String> headers;
+    private HttpHeaders<String> headers;
     private String body;
     private Boolean isBase64Encoded;
 }

aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/apigateway/APIGatewayV2CustomAuthorizerEvent.java

@@ -13,6 +13,7 @@
 
 package com.amazonaws.services.lambda.runtime.events.apigateway;
 
+import com.amazonaws.services.lambda.runtime.events.HttpHeaders;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
@@ -43,7 +44,7 @@ public class APIGatewayV2CustomAuthorizerEvent {
     private String rawPath;
     private String rawQueryString;
     private List<String> cookies;
-    private Map<String, String> headers;
+    private HttpHeaders<String> headers;
     private Map<String, String> queryStringParameters;
     private RequestContext requestContext;
     private Map<String, String> pathParameters;

aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/apigateway/APIGatewayV2HTTPEvent.java

@@ -13,6 +13,7 @@
 
 package com.amazonaws.services.lambda.runtime.events.apigateway;
 
+import com.amazonaws.services.lambda.runtime.events.HttpHeaders;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
@@ -37,14 +38,18 @@ public class APIGatewayV2HTTPEvent {
     private String rawPath;
     private String rawQueryString;
     private List<String> cookies;
-    private Map<String, String> headers;
+    private HttpHeaders<String> headers;
     private Map<String, String> queryStringParameters;
     private Map<String, String> pathParameters;
     private Map<String, String> stageVariables;
     private String body;
     private boolean isBase64Encoded;
     private RequestContext requestContext;
 
+    public void setHeaders(Map<String, String> headers) {
+        this.headers = HttpHeaders.mergeOrReplace(headers);
+    }
+
     @AllArgsConstructor
     @Builder(setterPrefix = "with")
     @Data

aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/apigateway/APIGatewayV2HTTPResponse.java

@@ -13,6 +13,7 @@
 
 package com.amazonaws.services.lambda.runtime.events.apigateway;
 
+import com.amazonaws.services.lambda.runtime.events.HttpHeaders;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Data;
@@ -28,9 +29,28 @@
 public class APIGatewayV2HTTPResponse {
 
     private int statusCode;
-    private Map<String, String> headers;
-    private Map<String, List<String>> multiValueHeaders;
+    private HttpHeaders<String> headers;
+    private HttpHeaders<List<String>> multiValueHeaders;
     private List<String> cookies;
     private String body;
     private boolean isBase64Encoded;
+
+    public static APIGatewayV2HTTPResponseBuilder builder() {
+        return new APIGatewayV2HTTPResponseBuilder();
+    }
+
+    public static class APIGatewayV2HTTPResponseBuilder {
+        private HttpHeaders<String> headers;
+        private HttpHeaders<List<String>> multiValueHeaders;
+
+        public APIGatewayV2HTTPResponseBuilder withHeaders(Map<String, String> headers) {
+            this.headers = HttpHeaders.mergeOrReplace(headers);
+            return this;
+        }
+
+        public APIGatewayV2HTTPResponseBuilder withMultiValueHeaders(Map<String, List<String>> multiValueHeaders) {
+            this.multiValueHeaders = HttpHeaders.mergeOrReplace(multiValueHeaders);
+            return this;
+        }
+    }
 }

aws-lambda-java-events/src/main/java/com/amazonaws/services/lambda/runtime/events/apigateway/APIGatewayV2WebSocketEvent.java

@@ -13,6 +13,7 @@
 
 package com.amazonaws.services.lambda.runtime.events.apigateway;
 
+import com.amazonaws.services.lambda.runtime.events.HttpHeaders;
 import lombok.Data;
 import lombok.Builder;
 import lombok.NoArgsConstructor;
@@ -91,8 +92,8 @@ public static class RequestContext implements Serializable {
     private String resource;
     private String path;
     private String httpMethod;
-    private Map<String, String> headers;
-    private Map<String, List<String>> multiValueHeaders;
+    private HttpHeaders<String> headers;
+    private HttpHeaders<List<String>> multiValueHeaders;
     private Map<String, String> queryStringParameters;
     private Map<String, List<String>> multiValueQueryStringParameters;
     private Map<String, String> pathParameters;