chore(docs): add documentation for Lambda Functoin URLs

Author: rubenfonseca

docs/core/event_handler/api_gateway.md

@@ -3,11 +3,11 @@ title: REST API
 description: Core utility
 ---
 
-Event handler for Amazon API Gateway REST and HTTP APIs, and Application Loader Balancer (ALB).
+Event handler for Amazon API Gateway REST and HTTP APIs, Application Loader Balancer (ALB), and Lambda Function URLs.
 
 ## Key Features
 
-* Lightweight routing to reduce boilerplate for API Gateway REST/HTTP API and ALB
+* Lightweight routing to reduce boilerplate for API Gateway REST/HTTP API, ALB and Lambda Function URLs.
 * Support for CORS, binary and Gzip compression, Decimals JSON encoding and bring your own JSON serializer
 * Built-in integration with [Event Source Data Classes utilities](../../utilities/data_classes.md){target="_blank"} for self-documented event schema
 
@@ -18,23 +18,31 @@ Event handler for Amazon API Gateway REST and HTTP APIs, and Application Loader
 
 ### Required resources
 
-You must have an existing [API Gateway Proxy integration](https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html){target="_blank"} or [ALB](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/lambda-functions.html){target="_blank"} configured to invoke your Lambda function.
+If you're using any API Gateway integration, you must have an existing [API Gateway Proxy integration](https://docs.aws.amazon.com/apigateway/latest/developerguide/set-up-lambda-proxy-integrations.html){target="_blank"} or [ALB](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/lambda-functions.html){target="_blank"} configured to invoke your Lambda function.
 
-This is the sample infrastructure for API Gateway we are using for the examples in this documentation.
+This is the sample infrastructure for API Gateway and Lambda Function URLs we are using for the examples in this documentation.
 
 ???+ info "There is no additional permissions or dependencies required to use this utility."
 
-```yaml title="AWS Serverless Application Model (SAM) example"
---8<-- "examples/event_handler_rest/sam/template.yaml"
-```
+=== "API Gateway SAM Template"
+
+    ```yaml title="AWS Serverless Application Model (SAM) example"
+    --8<-- "examples/event_handler_rest/sam/template.yaml"
+    ```
+
+=== "Lambda Function URL SAM Template"
+
+    ```yaml title="AWS Serverless Application Model (SAM) example"
+    --8<-- "examples/event_handler_lambda_function_url/sam/template.yaml"
+    ```
 
 ### Event Resolvers
 
 Before you decorate your functions to handle a given path and HTTP method(s), you need to initialize a resolver.
 
 A resolver will handle request resolution, including [one or more routers](#split-routes-with-router), and give you access to the current event via typed properties.
 
-For resolvers, we provide: `APIGatewayRestResolver`, `APIGatewayHttpResolver`, and `ALBResolver`.
+For resolvers, we provide: `APIGatewayRestResolver`, `APIGatewayHttpResolver`, `ALBResolver`, and `LambdaFunctionUrlResolver` .
 
 ???+ info
     We will use `APIGatewayRestResolver` as the default across examples.
@@ -87,6 +95,22 @@ When using Amazon Application Load Balancer (ALB) to front your Lambda functions
 --8<-- "examples/event_handler_rest/src/getting_started_alb_api_resolver.py"
 ```
 
+#### Lambda Function URL
+
+When using an [AWS Lambda Function URL](https://docs.aws.amazon.com/lambda/latest/dg/urls-configuration.html), you can use `LambdaFunctionUrlResolver`.
+
+=== "getting_started_lambda_function_url_resolver.py"
+
+    ```python hl_lines="5 11" title="Using Lambda Function URL resolver"
+    --8<-- "examples/event_handler_lambda_function_url/src/getting_started_lambda_function_url_resolver.py"
+    ```
+
+=== "getting_started_lambda_function_url_resolver.json"
+
+    ```json hl_lines="4-5" title="Example payload delivered to the handler"
+    --8<-- "examples/event_handler_lambda_function_url/src/getting_started_lambda_function_url_resolver.json"
+    ```
+
 ### Dynamic routes
 
 You can use `/todos/<todo_id>` to configure dynamic URL paths, where `<todo_id>` will be resolved at runtime.
@@ -270,7 +294,7 @@ This will ensure that CORS headers are always returned as part of the response w
 
 #### Pre-flight
 
-Pre-flight (OPTIONS) calls are typically handled at the API Gateway level as per [our sample infrastructure](#required-resources), no Lambda integration necessary. However, ALB expects you to handle pre-flight requests.
+Pre-flight (OPTIONS) calls are typically handled at the API Gateway or Lambda Function URL level as per [our sample infrastructure](#required-resources), no Lambda integration necessary. However, ALB expects you to handle pre-flight requests.
 
 For convenience, we automatically handle that for you as long as you [setup CORS in the constructor level](#cors).
 
@@ -338,6 +362,7 @@ Like `compress` feature, the client must send the `Accept` header with the corre
 
 ???+ warning
     This feature requires API Gateway to configure binary media types, see [our sample infrastructure](#required-resources) for reference.
+    For Lambda Function URLs, no additional configuration is necessary.
 
 === "binary_responses.py"
 
@@ -380,7 +405,7 @@ This will enable full tracebacks errors in the response, print request and respo
 
 ### Custom serializer
 
-You can instruct API Gateway handler to use a custom serializer to best suit your needs, for example take into account Enums when serializing.
+You can instruct an event handler to use a custom serializer to best suit your needs, for example take into account Enums when serializing.
 
 ```python hl_lines="35 40" title="Using a custom JSON serializer for responses"
 --8<-- "examples/event_handler_rest/src/custom_serializer.py"
@@ -501,7 +526,7 @@ A micro function means that your final code artifact will be different to each f
 
 **Downsides**
 
-* **Upfront investment**. You need custom build tooling to bundle assets, including [C bindings for runtime compatibility](https://docs.aws.amazon.com/lambda/latest/dg/lambda-runtimes.html){target="_blank"}. `Operations become more elaborate — you need to standardize tracing labels/annotations, structured logging, and metrics to pinpoint root causes.
+* **Upfront investment**. You need custom build tooling to bundle assets, including [C bindings for runtime compatibility](https://docs.aws.amazon.com/lambda/latest/dg/lambda-runtimes.html){target="_blank"}. Operations become more elaborate — you need to standardize tracing labels/annotations, structured logging, and metrics to pinpoint root causes.
     * Engineering discipline is necessary for both approaches. Micro-function approach however requires further attention in consistency as the number of functions grow, just like any distributed system.
 * **Harder to share code**. Shared code must be carefully evaluated to avoid unnecessary deployments when that changes. Equally, if shared code isn't a library,
 your development, building, deployment tooling need to accommodate the distinct layout.