The reply functionality is even easier that the like one. We don’t even have to create an entity because, technically, a reply is a tweet, so we can use the Tweet entity as an actual tweet and also as a reply to a tweet.
We will have to add a self referencing relationship to our Tweet entity:
Typetron Beta
📁 Entities/Tweet.ts
import { ID, BelongsTo, Column, CreatedAt, Entity, HasMany, Options, PrimaryColumn, Relation } from '@Typetron/Database'
import { User } from './User'
import { Like } from './Like'
@Options({
table: 'tweets'
})
export class Tweet extends Entity {
@PrimaryColumn()
id: ID
@Column()
content: string
@Relation(() => User, 'tweets')
user: BelongsTo<User>
@Relation(() => Like, 'tweet')
likes: HasMany<Like>
@Relation(() => Tweet, 'replies')
replyParent: BelongsTo<Tweet>
@Relation(() => Tweet, 'replyParent')
replies: HasMany<Tweet>
@CreatedAt()
createdAt: Date
}
This might be a bit confusing but let’s explain what is happening. We added the replyParent column which is actually the id of the parent tweet. The replies relationship is the inverse of the replyParent. It will give us all the replies of a tweet.
The only thing we need to do is to create an endpoint in the TweetsController that will create a reply for a tweet:
📁 Controllers/Http/TweetsController.ts
import { Controller, Middleware, Post } from '@Typetron/Router'
import { Tweet } from 'App/Entities/Tweet'
import { Like } from 'App/Entities/Like'
import { TweetForm } from 'App/Forms/TweetForm'
import { Tweet as TweetModel } from 'App/Models/Tweet'
import { User } from 'App/Entities/User'
import { AuthMiddleware } from '@Typetron/Framework/Middleware'
import { AuthUser } from '@Typetron/Framework/Auth'
@Controller('tweets')
@Middleware(AuthMiddleware)
export class TweetsController {
@AuthUser()
user: User
@Post()
tweet(form: TweetForm) {
return TweetModel.from(
Tweet.create({
content: form.content,
user: this.user
})
)
}
@Post(':Tweet/reply')
reply(parent: Tweet, form: TweetForm) {
return TweetModel.from(
Tweet.create({
content: form.content,
replyParent: parent,
user: this.user
})
)
}
@Post(':Tweet/like')
async like(tweet: Tweet) {
const like = await Like.firstOrNew({tweet, user: this.user})
if (like.exists) {
await like.delete()
} else {
await like.save()
}
return TweetModel.from(tweet)
}
}
Let’s make a request to add a reply to a tweet:
🌐 [POST] /tweets/1/reply
{
"content": "my tweet content"
}
Let’s clean this controller a bit because there is some duplicated code in the tweet and reply methods:
📁 Controllers/Http/TweetsController.ts
import { Controller, Middleware, Post } from '@Typetron/Router'
import { Tweet } from 'App/Entities/Tweet'
import { Like } from 'App/Entities/Like'
import { TweetForm } from 'App/Forms/TweetForm'
import { Tweet as TweetModel } from 'App/Models/Tweet'
import { User } from 'App/Entities/User'
import { AuthMiddleware } from '@Typetron/Framework/Middleware'
import { AuthUser } from '@Typetron/Framework/Auth'
import { EntityObject } from '@Typetron/Database'
@Controller('tweets')
@Middleware(AuthMiddleware)
export class TweetsController {
@AuthUser()
user: User
@Post()
tweet(form: TweetForm) {
return TweetModel.from(this.createTweet(form))
}
@Post(':Tweet/reply')
reply(parent: Tweet, form: TweetForm) {
return TweetModel.from(this.createTweet(form, {replyParent: parent}))
}
private async createTweet(form: TweetForm, additional: Partial<EntityObject<Tweet>> = {}) {
return Tweet.create({
content: form.content,
user: this.user,
...additional
})
}
@Post(':Tweet/like')
async like(tweet: Tweet) {
const like = await Like.firstOrNew({tweet, user: this.user})
if (like.exists) {
await like.delete()
} else {
await like.save()
}
return TweetModel.from(tweet)
}
}
The argument additional is used to pass additional properties to the tweet entity like the replyParent. It has the type EntityObject<Tweet> because it should contain only properties and values accepted by the Tweet entity. Also, it has the Partial type because those additional properties should be optional.
The last thing we need to do, is to update the endpoint that returns all the tweets, to show the replies count of a tweet:
📁 Controllers/Http/HomeController.ts
import { Controller, Get, Middleware } from '@Typetron/Router'
import { Tweet } from 'App/Entities/Tweet'
import { User } from 'App/Entities/User'
import { Tweet as TweetModel } from 'App/Models/Tweet'
import { AuthMiddleware } from '@Typetron/Framework/Middleware'
import { AuthUser } from '@Typetron/Framework/Auth'
@Controller()
@Middleware(AuthMiddleware)
export class HomeController {
@AuthUser()
user: User
@Get()
async tweets() {
const tweets = await Tweet
.with('user', ['likes', query => query.where('userId', this.user.id)])
.withCount('likes', 'replies')
.orderBy('createdAt', 'DESC')
.get()
return TweetModel.from(tweets)
}
}
Before we wrap up this step, let’s also add one more thing. If you used Twitter before, you would know that you can see a reply’s parent with its content and user. Let’s add this functionality in our HomeController that :
📁 Controllers/Http/HomeController.ts
import { Controller, Get, Middleware, Query } from '@Typetron/Router'
import { Tweet } from 'App/Entities/Tweet'
import { Tweet as TweetModel } from 'App/Models/Tweet'
import { AuthMiddleware } from '@Typetron/Framework/Middleware'
import { User } from 'App/Entities/User'
import { AuthUser } from '@Typetron/Framework/Auth'
@Controller()
@Middleware(AuthMiddleware)
export class HomeController {
@AuthUser()
user: User
@Get()
async tweets() {
const tweets = await Tweet
.with(
'user',
'replyParent.user',
['likes', query => query.where('userId', this.user.id)]
)
.withCount('likes', 'replies')
.orderBy('createdAt', 'DESC')
.get()
return TweetModel.from(tweets)
}
}
Here we deeply eager-load relationships. This will return the parent of replies and its user as well. Let’s also update the Tweet model:
📁 Models/Tweet.ts
import { Field, FieldMany, Model } from '@Typetron/Models'
import { User } from './User'
import { Like } from './Like'
export class Tweet extends Model {
@Field()
id: number
@Field()
content: string
@Field()
user: User
@Field()
likesCount = 0
@FieldMany(Like)
likes: Like[] = []
@Field()
replyParent?: Tweet
@Field()
repliesCount = 0
@Field()
createdAt: Date
}
