21. What is a method in Amazon API Gateway?
Each resource within a REST API can support one or more of the standard HTTP methods. You define which verbs should be supported for each resource (GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS) and their implementation.
22. What are stage variables in Amazon API Gateway?
Stage variables let you define key/value pairs of configuration values associated with a stage. These values, similarly to environment variables, can be used in your API configuration. For example, you could define the HTTP endpoint for your method integration as a stage variable, and use the variable in your API configuration instead of hardcoding the endpoint – this allows you to use a different endpoint for each stage
23. What is a Resource Policy in Amazon API Gateway ?
A Resource Policy is a JSON policy document that you attach to an API to control whether a specified principal (typically an IAM user or role) can invoke the API. You can use a Resource Policy to enable users from a different AWS account to securely access your API or to allow the API to be invoked only from specified source IP address ranges or CIDR blocks. Resource Policies can be used with REST APIs in Amazon API Gateway.
24. Can I restrict access to private APIs to a specific Amazon VPC or VPC endpoint ?
Yes, you can apply a Resource Policy to an API to restrict access to a specific Amazon VPC or VPC endpoint. You can also give an Amazon VPC or VPC endpoint from a different account access to the Private API using a Resource Policy.
25. What is a Lambda authorizer in Amazon API Gateway?
Lambda authorizers are AWS Lambda functions. With custom request authorizers, you will be able to authorize access to APIs using a bearer token auth strategy such as OAuth. When an API is called, API Gateway checks if a Lambda authorizer is configured, API Gateway then calls the Lambda function with the incoming authorization token.