@@ -0,0 +1,18 @@
+{
+  "Projects": [
+    {
+      "Name": "Amazon.Lambda.AspNetCoreServer",
+      "Type": "Patch",
+      "ChangelogMessages": [
+        "Null-safe marshalling for Path, HttpMethod, path parameters, and headers to avoid NullReferenceException with incomplete API Gateway events"
+      ]
+    },
+    {
+      "Name": "Amazon.Lambda.TestTool",
+      "Type": "Patch",
+      "ChangelogMessages": [
+        "Populate RequestContext (and Path/HttpMethod defaults) when the API Gateway emulator builds REST APIGatewayProxyRequest events"
+      ]
+    }
+  ]
+}
@@ -157,6 +157,18 @@ protected override Amazon.Lambda.Core.ResponseStreaming.HttpResponseStreamPrelud
         /// <param name="lambdaContext"></param>
         protected override void MarshallRequest(InvokeFeatures features, APIGatewayProxyRequest apiGatewayRequest, ILambdaContext lambdaContext)
         {
+            if (apiGatewayRequest == null)
+            {
+                _logger.LogError("MarshallRequest: apiGatewayRequest is null");
+                throw new ArgumentNullException(nameof(apiGatewayRequest));
+            }
+
+            _logger.LogDebug("MarshallRequest: Path={Path}, HttpMethod={HttpMethod}, Resource={Resource}, RequestContext={HasContext}",
+                apiGatewayRequest.Path ?? "(null)",
+                apiGatewayRequest.HttpMethod ?? "(null)",
+                apiGatewayRequest.Resource ?? "(null)",
+                apiGatewayRequest.RequestContext != null);
+
             {
                 var authFeatures = (IHttpAuthenticationFeature)features;
 
@@ -201,7 +213,8 @@ protected override void MarshallRequest(InvokeFeatures features, APIGatewayProxy
                 var rawQueryString = Utilities.CreateQueryStringParameters(
                     apiGatewayRequest.QueryStringParameters, apiGatewayRequest.MultiValueQueryStringParameters, true);
 
-                requestFeatures.RawTarget = apiGatewayRequest.Path + rawQueryString;
+                var pathForTarget = apiGatewayRequest.Path ?? "/";
+                requestFeatures.RawTarget = pathForTarget + rawQueryString;
                 requestFeatures.QueryString = rawQueryString;
                 requestFeatures.Path = path;
 
@@ -365,24 +378,24 @@ protected virtual string ParseHttpPath(APIGatewayProxyRequest apiGatewayRequest)
             if (apiGatewayRequest.PathParameters != null && apiGatewayRequest.PathParameters.TryGetValue("proxy", out var proxy) &&
                 !string.IsNullOrEmpty(apiGatewayRequest.Resource))
             {
-                var proxyPath = proxy;
+                var proxyPath = proxy ?? "";
                 path = apiGatewayRequest.Resource.Replace("{proxy+}", proxyPath);
 
                 // Adds all the rest of non greedy parameters in apiGateway.Resource to the path
                 foreach (var pathParameter in apiGatewayRequest.PathParameters.Where(pp => pp.Key != "proxy"))
                 {
-                    path = path.Replace($"{{{pathParameter.Key}}}", pathParameter.Value);
+                    path = path.Replace($"{{{pathParameter.Key}}}", pathParameter.Value ?? "");
                 }
             }
 
             if (string.IsNullOrEmpty(path))
             {
-                path = apiGatewayRequest.Path;
+                path = apiGatewayRequest.Path ?? "/";
             }
 
-            if (!path.StartsWith("/"))
+            if (string.IsNullOrEmpty(path) || !path.StartsWith("/"))
             {
-                path = "/" + path;
+                path = "/" + (path ?? "");
             }
             return path;
         }
@@ -394,7 +407,7 @@ protected virtual string ParseHttpPath(APIGatewayProxyRequest apiGatewayRequest)
         /// </summary>
         protected virtual string ParseHttpMethod(APIGatewayProxyRequest apiGatewayRequest)
         {
-            return apiGatewayRequest.HttpMethod;
+            return apiGatewayRequest.HttpMethod ?? "GET";
         }
 
         /// <summary>
 
@@ -190,14 +190,21 @@ internal static void SetHeadersCollection(IHeaderDictionary headers, IDictionary
             {
                 foreach (var kvp in multiValues)
                 {
-                    headers[kvp.Key] = new StringValues(kvp.Value.ToArray());
+                    var values = kvp.Value?.Where(v => v != null).ToArray() ?? Array.Empty<string>();
+                    if (values.Length > 0)
+                    {
+                        headers[kvp.Key] = new StringValues(values);
+                    }
                 }
             }
             else if (singleValues?.Count > 0)
             {
                 foreach (var kvp in singleValues)
                 {
-                    headers[kvp.Key] = new StringValues(kvp.Value);
+                    if (kvp.Value != null)
+                    {
+                        headers[kvp.Key] = new StringValues(kvp.Value);
+                    }
                 }
             }
         }
 
@@ -177,13 +177,34 @@ public static async Task<APIGatewayProxyRequest> ToApiGatewayRequest(
             pathParameters = encodedPathParameters;
         }
 
+        var pathValue = path ?? "/";
+        var resourceValue = apiGatewayRouteConfig.Path ?? "";
+        var httpMethodValue = request.Method ?? "GET";
+        var userAgent = request.Headers.UserAgent.ToString();
+
         var proxyRequest = new APIGatewayProxyRequest
         {
-            Resource = apiGatewayRouteConfig.Path,
-            Path = path,
-            HttpMethod = request.Method,
+            Resource = resourceValue,
+            Path = pathValue,
+            HttpMethod = httpMethodValue,
             Body = body,
-            IsBase64Encoded = false
+            IsBase64Encoded = false,
+            RequestContext = new APIGatewayProxyRequest.ProxyRequestContext
+            {
+                Path = pathValue,
+                AccountId = "123456789012",
+                ResourceId = "test-invoke-resource-id",
+                Stage = "test-invoke-stage",
+                RequestId = HttpRequestUtility.GenerateRequestId(),
+                Identity = new APIGatewayProxyRequest.RequestIdentity
+                {
+                    SourceIp = "127.0.0.1",
+                    UserAgent = userAgent
+                },
+                ResourcePath = resourceValue,
+                HttpMethod = httpMethodValue,
+                ApiId = "test-invoke-api-id"
+            }
         };
 
         if (headers.Any())
Original file line number	Diff line number	Diff line change
`@@ -157,6 +157,18 @@ protected override Amazon.Lambda.Core.ResponseStreaming.HttpResponseStreamPrelud`
`157`	`157`	`/// <param name="lambdaContext"></param>`
`158`	`158`	`protected override void MarshallRequest(InvokeFeatures features, APIGatewayProxyRequest apiGatewayRequest, ILambdaContext lambdaContext)`
`159`	`159`	`{`
	`160`	`+ if (apiGatewayRequest == null)`
	`161`	`+ {`
	`162`	`+ _logger.LogError("MarshallRequest: apiGatewayRequest is null");`
	`163`	`+ throw new ArgumentNullException(nameof(apiGatewayRequest));`
	`164`	`+ }`
	`165`	`+`
	`166`	`+ _logger.LogDebug("MarshallRequest: Path={Path}, HttpMethod={HttpMethod}, Resource={Resource}, RequestContext={HasContext}",`
	`167`	`+ apiGatewayRequest.Path ?? "(null)",`
	`168`	`+ apiGatewayRequest.HttpMethod ?? "(null)",`
	`169`	`+ apiGatewayRequest.Resource ?? "(null)",`
	`170`	`+ apiGatewayRequest.RequestContext != null);`
	`171`	`+`
`160`	`172`	`{`
`161`	`173`	`var authFeatures = (IHttpAuthenticationFeature)features;`
`162`	`174`
`@@ -201,7 +213,8 @@ protected override void MarshallRequest(InvokeFeatures features, APIGatewayProxy`
`201`	`213`	`var rawQueryString = Utilities.CreateQueryStringParameters(`
`202`	`214`	`apiGatewayRequest.QueryStringParameters, apiGatewayRequest.MultiValueQueryStringParameters, true);`
`203`	`215`
`204`		`- requestFeatures.RawTarget = apiGatewayRequest.Path + rawQueryString;`
	`216`	`+ var pathForTarget = apiGatewayRequest.Path ?? "/";`
	`217`	`+ requestFeatures.RawTarget = pathForTarget + rawQueryString;`
`205`	`218`	`requestFeatures.QueryString = rawQueryString;`
`206`	`219`	`requestFeatures.Path = path;`
`207`	`220`
`@@ -365,24 +378,24 @@ protected virtual string ParseHttpPath(APIGatewayProxyRequest apiGatewayRequest)`
`365`	`378`	`if (apiGatewayRequest.PathParameters != null && apiGatewayRequest.PathParameters.TryGetValue("proxy", out var proxy) &&`
`366`	`379`	`!string.IsNullOrEmpty(apiGatewayRequest.Resource))`
`367`	`380`	`{`
`368`		`- var proxyPath = proxy;`
	`381`	`+ var proxyPath = proxy ?? "";`
`369`	`382`	`path = apiGatewayRequest.Resource.Replace("{proxy+}", proxyPath);`
`370`	`383`
`371`	`384`	`// Adds all the rest of non greedy parameters in apiGateway.Resource to the path`
`372`	`385`	`foreach (var pathParameter in apiGatewayRequest.PathParameters.Where(pp => pp.Key != "proxy"))`
`373`	`386`	`{`
`374`		`- path = path.Replace($"{{{pathParameter.Key}}}", pathParameter.Value);`
	`387`	`+ path = path.Replace($"{{{pathParameter.Key}}}", pathParameter.Value ?? "");`
`375`	`388`	`}`
`376`	`389`	`}`
`377`	`390`
`378`	`391`	`if (string.IsNullOrEmpty(path))`
`379`	`392`	`{`
`380`		`- path = apiGatewayRequest.Path;`
	`393`	`+ path = apiGatewayRequest.Path ?? "/";`
`381`	`394`	`}`
`382`	`395`
`383`		`- if (!path.StartsWith("/"))`
	`396`	`+ if (string.IsNullOrEmpty(path) \|\| !path.StartsWith("/"))`
`384`	`397`	`{`
`385`		`- path = "/" + path;`
	`398`	`+ path = "/" + (path ?? "");`
`386`	`399`	`}`
`387`	`400`	`return path;`
`388`	`401`	`}`
`@@ -394,7 +407,7 @@ protected virtual string ParseHttpPath(APIGatewayProxyRequest apiGatewayRequest)`
`394`	`407`	`/// </summary>`
`395`	`408`	`protected virtual string ParseHttpMethod(APIGatewayProxyRequest apiGatewayRequest)`
`396`	`409`	`{`
`397`		`- return apiGatewayRequest.HttpMethod;`
	`410`	`+ return apiGatewayRequest.HttpMethod ?? "GET";`
`398`	`411`	`}`
`399`	`412`
`400`	`413`	`/// <summary>`
Original file line number	Diff line number	Diff line change
`@@ -190,14 +190,21 @@ internal static void SetHeadersCollection(IHeaderDictionary headers, IDictionary`
`190`	`190`	`{`
`191`	`191`	`foreach (var kvp in multiValues)`
`192`	`192`	`{`
`193`		`- headers[kvp.Key] = new StringValues(kvp.Value.ToArray());`
	`193`	`+ var values = kvp.Value?.Where(v => v != null).ToArray() ?? Array.Empty<string>();`
	`194`	`+ if (values.Length > 0)`
	`195`	`+ {`
	`196`	`+ headers[kvp.Key] = new StringValues(values);`
	`197`	`+ }`
`194`	`198`	`}`
`195`	`199`	`}`
`196`	`200`	`else if (singleValues?.Count > 0)`
`197`	`201`	`{`
`198`	`202`	`foreach (var kvp in singleValues)`
`199`	`203`	`{`
`200`		`- headers[kvp.Key] = new StringValues(kvp.Value);`
	`204`	`+ if (kvp.Value != null)`
	`205`	`+ {`
	`206`	`+ headers[kvp.Key] = new StringValues(kvp.Value);`
	`207`	`+ }`
`201`	`208`	`}`
`202`	`209`	`}`
`203`	`210`	`}`