[入門]API Gatewayを利用してS3バケットのオブジェクトを一覧表示させてみた

AWSTemplateFormatVersion: "2010-09-09"

Parameters:
  AppName: 
    Description: Application Name.
    Type: String
    Default: api-gateway-s3-list

Resources:
# ==========
# S3
# ==========
  S3Bucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketEncryption: 
        ServerSideEncryptionConfiguration:
          - ServerSideEncryptionByDefault:
              SSEAlgorithm: AES256
      BucketName: !Sub "api-gateway-s3-${AWS::AccountId}"
      OwnershipControls: 
        Rules:
          - ObjectOwnership: BucketOwnerEnforced
      PublicAccessBlockConfiguration: 
        BlockPublicAcls: true
        BlockPublicPolicy: true
        IgnorePublicAcls: true
        RestrictPublicBuckets: true
# ==========
# API Gateway
# ==========
  ApiGatewayRestApi:
    Type: AWS::ApiGateway::RestApi
    Properties:
      BinaryMediaTypes: 
        - 'image/*'
      EndpointConfiguration: 
        Types:
          - REGIONAL
      Name: !Ref AppName
  ApiGatewayMethodRootList:
    Type: AWS::ApiGateway::Method
    Properties:
      AuthorizationType: AWS_IAM
      HttpMethod: GET
      Integration:
        Type: AWS
        IntegrationHttpMethod: GET
        Uri: !Sub "arn:aws:apigateway:${AWS::Region}:s3:path/${S3Bucket}/"
        IntegrationResponses:
          - StatusCode: 200
            ResponseParameters:
              method.response.header.Content-Length : integration.response.header.Content-Length
              method.response.header.Content-Type : integration.response.header.Content-Type
              method.response.header.Timestamp : integration.response.header.Date
          - StatusCode: 400
            SelectionPattern: '4\d{2}'
            ResponseTemplates:
              application/json: '{"error": "Client error"}'
          - StatusCode: 500
            SelectionPattern: '5\d{2}'
            ResponseTemplates:
              application/json: '{"error": "Server error"}'
        Credentials: !GetAtt ApiGatewayS3RoleRootList.Arn
      MethodResponses:
        - StatusCode: 200
          ResponseParameters:
            method.response.header.Content-Type: true
            method.response.header.Content-Length: true
            method.response.header.Timestamp: true
        - StatusCode: 400
        - StatusCode: 500
      ResourceId: !GetAtt ApiGatewayRestApi.RootResourceId
      RestApiId: !Ref ApiGatewayRestApi
  ApiGatewayS3RoleRootList:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service: apigateway.amazonaws.com
            Action: 'sts:AssumeRole'
      Policies:
        - PolicyName: APIGatewayS3ProxyPolicy-ListPolicy
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action:
                  - s3:ListBucket
                Resource: 
                  - !Sub "arn:aws:s3:::${S3Bucket}"
      Path: /
      RoleName: APIGatewayS3ProxyPolicy-List