Amazon CloudFormation template of a sample API with basic request validation - Amazon API Gateway
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Amazon CloudFormation template of a sample API with basic request validation

The following Amazon CloudFormation example template definition defines a sample API with request validation enabled. The API is a subset of the PetStore API. It exposes a POST method to add a pet to the pets collection and a GET method to query pets by a specified type.

There are two request validators declared:

GETValidator

This validator is enabled on the GET method. It allows API Gateway to verify that the required query parameter (q1) is included and not blank in the incoming request.

POSTValidator

This validator is enabled on the POST method. It allows API Gateway to verify that payload request format adheres to the specified RequestBodyModel when the content type is application/json if no matching content type is found, request validation is not performed. To use the same model regardless of the content type, specify $default. RequestBodyModel contains an additional model, RequestBodyModelId, to define the pet ID.

AWSTemplateFormatVersion: 2010-09-09
Parameters:
  StageName:
    Type: String
    Default: v1
    Description: Name of API stage.
Resources:
  Api:
    Type: 'AWS::ApiGateway::RestApi'
    Properties:
      Name: ReqValidatorsSample
  RequestBodyModelId:
    Type: 'AWS::ApiGateway::Model'
    Properties:
      RestApiId: !Ref Api
      ContentType: application/json
      Description: Request body model for Pet ID.
      Schema:
        $schema: 'http://json-schema.org/draft-04/schema#'
        title: RequestBodyModelId
        properties:
            id:
              type: integer
  RequestBodyModel: 
    Type: 'AWS::ApiGateway::Model'
    Properties:
      RestApiId: !Ref Api
      ContentType: application/json
      Description: Request body model for Pet type, name, price, and ID.
      Schema:
        $schema: 'http://json-schema.org/draft-04/schema#'
        title: RequestBodyModel
        required:
          - price
          - name
          - type
        type: object
        properties:
            id:
              "$ref": !Sub 
                - 'https://apigateway.amazonaws.com/restapis/${Api}/models/${RequestBodyModelId}'
                - Api: !Ref Api
                  RequestBodyModelId: !Ref RequestBodyModelId
            price: 
              type: number
              minimum: 25
              maximum: 500
            name:
              type: string
            type:
              type: string
              enum:
                - "dog"
                - "cat"
                - "fish"
  GETValidator:
    Type: AWS::ApiGateway::RequestValidator
    Properties:
      Name: params-only
      RestApiId: !Ref Api
      ValidateRequestBody: False
      ValidateRequestParameters: True 
  POSTValidator:
    Type: AWS::ApiGateway::RequestValidator
    Properties:
      Name: body-only
      RestApiId: !Ref Api
      ValidateRequestBody: True
      ValidateRequestParameters: False
  ValidationResource:
    Type: 'AWS::ApiGateway::Resource'
    Properties:
      RestApiId: !Ref Api
      ParentId: !GetAtt Api.RootResourceId
      PathPart: 'validation'
  ValidationMethodGet:
    Type: 'AWS::ApiGateway::Method'
    Properties:
      RestApiId: !Ref Api
      ResourceId: !Ref ValidationResource
      HttpMethod: GET
      AuthorizationType: NONE
      RequestValidatorId: !Ref GETValidator
      RequestParameters:
        method.request.querystring.q1: true
      Integration:
        Type: HTTP_PROXY
        IntegrationHttpMethod: GET
        Uri: http://petstore-demo-endpoint.execute-api.com/petstore/pets/
  ValidationMethodPost:
    Type: 'AWS::ApiGateway::Method'
    Properties:
      RestApiId: !Ref Api
      ResourceId: !Ref ValidationResource
      HttpMethod: POST
      AuthorizationType: NONE
      RequestValidatorId: !Ref POSTValidator
      RequestModels:
        application/json : !Ref RequestBodyModel 
      Integration:
        Type: HTTP_PROXY
        IntegrationHttpMethod: POST
        Uri: http://petstore-demo-endpoint.execute-api.com/petstore/pets/
  ApiDeployment:
    Type: 'AWS::ApiGateway::Deployment'
    DependsOn:
      - ValidationMethodGet
      - RequestBodyModel 
    Properties:
      RestApiId: !Ref Api
      StageName: !Sub '${StageName}'
Outputs:
  ApiRootUrl:
    Description: Root Url of the API
    Value: !Sub 'https://${Api}.execute-api.${AWS::Region}.amazonaws.com/${StageName}'