apigateway-template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Description: 'Cloudformation stack for the article "Using Amazon API Gateway 
    as proxy for DynamoDB" by Stefano Buliani on 26-02-2016'
Parameters:
    DynamoDBRoleARN:
        Type: String
Resources:
    CommentsApi:
        Type: AWS::ApiGateway::RestApi
        Properties:
            Name: CommentsApi
    CommentsResource:
        Type: AWS::ApiGateway::Resource
        Properties:
            RestApiId: !Ref CommentsApi
            ParentId: !GetAtt CommentsApi.RootResourceId
            PathPart: comments
    PostComments:
        Type: AWS::ApiGateway::Method
        Properties:
            ApiKeyRequired: false
            AuthorizationType: NONE
            HttpMethod: POST
            RequestModels: 
                application/json: 'CommentModel'
            MethodResponses:
            - ResponseModels: { "application/json": "Empty" }
              StatusCode: 200
            Integration:
                Type: AWS
                Credentials: !Ref DynamoDBRoleARN
                Uri: arn:aws:apigateway:eu-west-2:dynamodb:action/PutItem
                IntegrationHttpMethod: POST
                RequestTemplates: 
                    application/json: "{\"TableName\": \"dev-apigateway-proxy-dynamo-CommentsTable-C8UVLP5VJUPE\", \"Item\": { \"commentId\": { \"S\": \"$context.requestId\" }, \"pageId\": { \"S\": \"$input.path('$.pageId')\" }, \"userName\": { \"S\": \"$input.path('$.userName')\" }, \"message\": { \"S\": \"$input.path('$.message')\" }}}"
                IntegrationResponses:
                    - StatusCode: 200
            OperationName: 'CreateComment'
            ResourceId: !Ref CommentsResource
            RestApiId: !Ref CommentsApi
            RequestValidatorId: !Ref PostCommentValidator
    PostCommentValidator:
        Type: AWS::ApiGateway::RequestValidator
        Properties: 
            Name: PostCommentValidator
            RestApiId: !Ref CommentsApi
            ValidateRequestBody: true
            ValidateRequestParameters: false
    GetCommentsByPageIdResource:
        Type: AWS::ApiGateway::Resource
        Properties:
            RestApiId: !Ref CommentsApi
            ParentId: !Ref CommentsResource
            PathPart: "{pageId}"
    GetCommentsByPageIdMethod:
        Type: AWS::ApiGateway::Method
        Properties:
            ApiKeyRequired: false
            AuthorizationType: NONE
            HttpMethod: GET
            MethodResponses:
                - StatusCode: 200  
            Integration:
                Type: AWS
                Credentials: !Ref DynamoDBRoleARN
                Uri: arn:aws:apigateway:eu-west-2:dynamodb:action/Query
                IntegrationHttpMethod: POST
                RequestTemplates: 
                    application/json: "{\"TableName\": \"dev-apigateway-proxy-dynamo-CommentsTable-C8UVLP5VJUPE\", \"IndexName\": \"pageId-index\", \"KeyConditionExpression\": \"pageId = :v1\", \"ExpressionAttributeValues\": { \":v1\": { \"S\": \"$input.params('pageId')\" } } }"
                IntegrationResponses:
                    - StatusCode: 200
                      ResponseTemplates: 
                        application/json: "#set($inputRoot = $input.path('$')) { \"comments\": [ #foreach($elem in $inputRoot.Items) { \"commentId\": \"$elem.commentId.S\", \"userName\": \"$elem.userName.S\", \"message\": \"$elem.message.S\" } #if($foreach.hasNext),#end #end ]}"
            OperationName: 'GetCommentsByPageId'
            ResourceId: !Ref GetCommentsByPageIdResource
            RestApiId: !Ref CommentsApi
    CommentModel:
        Type: AWS::ApiGateway::Model
        Properties:
            ContentType: 'application/json'
            RestApiId: !Ref CommentsApi
            Name: 'CommentModel'
            Schema:
                $schema: 'http://json-schema.org/draft-04/schema#'
                title: Comment
                type: object
                properties: 
                    commentId: 
                        type: string
                    message: 
                        type: string
                    pageId: 
                        type: string
                    userName: 
                        type: string
                required: ['pageId', 'message', 'userName']