@lambdaless/comment

An AWS CDK construct of Lambdaless comment service.

Why?

Just for fun 🥳

How?

Just use AWS Service integration with API Gateway built-ins (Request Validation, Request Template...)

Getting Started

Install @lambdaless/comment construct package from NPM:

$ npm i @lambdaless/comment --save

Add service construct to your AWS CDK based Stack:

import * as cdk from "@aws-cdk/core";

import * as apigw from "@aws-cdk/aws-apigateway";
import { CommentService } from "@lambdaless/comment";

export class MyStack extends cdk.Stack {
  public constructor(scope: cdk.App, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    // Create or reference pre-existing API Gateway RestAPI
    const api = new apigw.RestApi(this, "API", {
      restApiName: "my-awesome-apigw",
      endpointTypes: [apigw.EndpointType.EDGE],
      deployOptions: {
        loggingLevel: apigw.MethodLoggingLevel.INFO,
      },
    });

    // Create Email Subscription Service and Attach API to given API Gateway RestAPI target
    const emailSubscriptionService = new EmailSubscriptionService(this, "EmailSubscriptionService", {
      api,
      resource: api.root.addResource("subscriptions"),
      tableName: "lambdaless-email-subscriptions",
    });
  }
}

and then, Deploy your CDK App. Done! 🎉

API

Current implementation has two APIs - createComment and listComments.

createComment

POST /base_path/comments

Create a new comment.

Request Parameters

N/A

Request Body

Content-Type: application/json

{
  "title": "createCommentRequestBody",
  "type": "object",
  "required": ["parent_id", "name", "content"],
  "properties": {
    "parent_id": {
        "type": "string",
        "minLength": 1,
        "maxLength": 256
    },
    "name": {
        "type": "string",
        "minLength": 1,
        "maxLength": 64
    },
    "content": {
        "type": "string",
        "minLength": 1,
        "maxLength": 2048
    }
  }
}

For example:

{
  "parent_id": "/posts/12345",
  "name": "mooyoul",
  "content": "Hello there!"
}

Responses

Status	Description
200	Successfully created comment. Empty response body will be provided.
400	Validation Error. Specified query parameter does not exists, or request body does not match to schema.
422	Failed to create comment due to DynamoDB Error.
500	API Gateway Internal Error.

listComments

GET /base_path/comments

List comments

Request Parameters

location	name	type	required	description
query	parent_id	string	yes	Parent Identifier of given comment. THis is a kind of topic, or category. You can use this field to separate comments.
query	sort_by	oldest / latest	no	The option to sort results. If oldest is used, Ascending order of comments will be returned. If latest is used, descending order of comments will be returned. Otherwise oldest will be used as default value.
query	count	integer	no	Pagination size
query	after	string	no	Pagination key (cursor)

Responses

Status	Description
200	Successfully fetched comment.
400	Validation Error. Specified query parameter does not exists, or request body does not match to schema.
422	Failed to create comment due to DynamoDB Error.
500	API Gateway Internal Error.

Response Schema

{
  "title": "listCommentsResponseBody",
  "type": "object",
  "required": ["parent_id", "name", "content"],
  "properties": {
    "data": {
      "type": "object",
      "required": ["id", "content", "created_at"],
      "properties": {
        "id": {
          "type": "string"
        },
        "content": {
          "type": "string"
        },
        "created_at": {
          "type": "number"
        }
      }
    },
    "paging": {
      "type": "object",
      "properties": {
        "after": {
          "type": "string"
        }
      }
    }
  }
}

Testing

Since there are no any business logic, Testing is not necessary.

Debugging

Use API Gateway built-in API Tester. You can inspect full request/response and execution logs.

See: https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-test-method.html