Create Habit Controller

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>> Scott Moss: So what we want to do is go to our Controllers folder here, make a new controller, we'll say habit. Controller.ts and we'll get to work on this, so we'll say import type Response from Express, so we get that and we're gonna use our authenticated. Request from our middleware instead of Express's request. You need to get our database in here cause we're gonna be doing database things, that's the whole point of a server or a whole point of the API I should say.

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You need to get our database in here cause we're gonna be doing database things, that's the whole point of a server or a whole point of the API I should say. Then we're going to import. The habits table. And because of relations, we might have.

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And because of relations, we might have. The entries table because you can create entries for a habit. You might also have habit tags if someone wants to create tag or associate a habit with a tag, and we're allowing them to do that through the habit resource, we might also allow them to do that through the tag resource because it's a many to many, so it's denormalized. You can do either on either side.

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You can do either on either side. You can say I'm gonna create a tag and assign it to these habits, but maybe I also wanna create a habit and assign it these tags, so either way. And then, yeah, tags for that. And then just some helper methods from Drizzle to help us with our querying.

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And then just some helper methods from Drizzle to help us with our querying. Not Drizzle Kit Drizzle ORM. We're gonna get the one that we used before equals, we'll get a and, we'll get a descending order for sorting, we'll get an array for checking. In an array.

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In an array. OK, so the first one we want to do is the C part of CRUD, which is create. So we'll export a function here called it create habit. And it's going to.

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And it's going to. Take a request, but it's gonna be an authenticated request. We're gonna take a response. It's gonna be the response from Express.

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It's gonna be the response from Express. And we're gonna do a try catch. Like this. And then we're just gonna destructure the payload, the body, so we can say req.body And we're gonna get the name, we're gonna get the description.

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And then we're just gonna destructure the payload, the body, so we can say req.body And we're gonna get the name, we're gonna get the description. We're gonna get the frequency, we're gonna get the target count. Target count. And any tag IDs.

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And any tag IDs. If you have some tag IDs, you can send them up and we'll associate this new habit with these tags so you can pass those up if you want. And then we'll get the User ID. Well, I'll just use req.user.

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Well, I'll just use req.user. ID so I'll have to make a new variable. And it's something new that if you've never worked with databases, you're gonna see something new here is we're gonna make a transaction on the database. So what is a transaction?

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So what is a transaction? So what if you have to write to the database more than once for this function, right? And what if the first right operation worked, but then the second operation failed? Now your database is left in a broken state because you needed both of those things to succeed in order to do your job.

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Now your database is left in a broken state because you needed both of those things to succeed in order to do your job. Like imagine transferring money from a bank account and then like there was 3 database operations, 2 of them succeeded, like the part where it took your money out of your account succeeded, but the part where it sent it to the other account failed. Now what? Where's that money?

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Where's that money? It's not in your account and it's not in the other account because it failed. OK, a transaction is there for that reason. A transaction will basically group a bunch of database right operations into one call to the database and if one of them fail, it'll roll back all the other ones.

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A transaction will basically group a bunch of database right operations into one call to the database and if one of them fail, it'll roll back all the other ones. So pretty much they all have to pass or none of them pass. It's essentially a git commit. It's the best way I can describe it is you're doing it git commit.

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It's the best way I can describe it is you're doing it git commit. But instead of to get, you're doing it to the database, so you're like, here's all the changes I wanna do, commit them all at once. That's what a transaction is. Any asset compliant database has transactions.

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Any asset compliant database has transactions. So we're gonna start a transaction here. The way this works is you just call transaction and you get this object right here. I'm just gonna call it TX for transaction, and it does the exact same thing as the DB up here does the exact same thing You just treat it like DB.

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I'm just gonna call it TX for transaction, and it does the exact same thing as the DB up here does the exact same thing You just treat it like DB. That's it. So will create a new. Have it I actually just call it new habit, so I don't get confused.

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Have it I actually just call it new habit, so I don't get confused. Equals await instead of using DB we use DB here, it will not be on this transaction. We have to use TX. TX.insert.

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TX.insert. On habits. But this value. In this case, Oh yeah, I'm sorry.

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In this case, Oh yeah, I'm sorry. In this case we want to just pass in. The User ID will be req.user. The name is name We already destructured that, the description is description, the frequency is frequency, and the target count is target count So we already destructured all those things, and then we're gonna say returning.

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The name is name We already destructured that, the description is description, the frequency is frequency, and the target count is target count So we already destructured all those things, and then we're gonna say returning. Give me all the things. Cool. Once we have that new habit, we're gonna be like, did you pass up some tag IDs?

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Once we have that new habit, we're gonna be like, did you pass up some tag IDs? So if you passed up some tag IDs. These are IDs of tags that you already created and you have the IDs for. Then, so if you did pass the tag IDs and.

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Then, so if you did pass the tag IDs and. Which is just check and see if you have an array. But Does that array have a length? So are there some tag IDs actually in it?

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So are there some tag IDs actually in it? And this is something we could also do on the. Input Validation middleware it's like let's check if there is if there are tag IDs it must have at least one in it and we can like write a Zod thing for that so we don't have to write this if statement here that way we can get rid of all the if statements inside of this thing, which is what I'm always shooting for but for now let's just do this. So we can say habit tag.

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So we can say habit tag. Habits, tag values is gonna be. Tag IDs. Map.

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Map. So now we got a map over each one of these tag IDs. And we need to essentially create a on our many to many table our habit tag, it's a tag ID and a habit ID so for each tag ID we gotta create one of those and insert into the database, right? So the habit ID.

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So the habit ID. Habits ID. It's gonna be that new habit that we just created, right? And then we wanna associate this habit ID to any.

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And then we wanna associate this habit ID to any. Tag ID that we're currently on, so. These will be an array of objects that we can then. can insert into the habit tag.

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can insert into the habit tag. Table. Like this. Cool, so we'll insert all those that'll create any associations with this new habit that we created with all the tag IDs that you sent up.

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Cool, so we'll insert all those that'll create any associations with this new habit that we created with all the tag IDs that you sent up. And then lastly, still inside the transaction, we want to return, new habit. So the way the transaction works is whatever you return at the end, that's what you get up here. So this is the new habit.

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So this is the new habit. Now if any of this breaks, This will all be rolled back, this transaction with their own error. I try catch what catch that error, and we'll get down there. Cool, so if we get here, we can assume that everything is good.

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Cool, so if we get here, we can assume that everything is good. We'll say REST our status is 201. That was a successful post. We can say cool.

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We can say cool. Here's a message. Habits Created And then here's your habit. Or yeah.

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Or yeah. There you go. Otherwise, If anything failed here. It's because of us.

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It's because of us. It's definitely something on our side. It's a database issue, it's something because the inputs were validated, the user was authenticated and identified. Yeah, if so if something fails here, it's our fault, it's our system, so we have to just say this is a 500.

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Yeah, if so if something fails here, it's our fault, it's our system, so we have to just say this is a 500. So, great Have it E And then REST status. 500 JSON E That to create habit. Cool.

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Cool. So we have create habit here. And before we make new ones, we can just Go ahead and add this to our habit route. So let's go to where that is.

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So let's go to where that is. That would be this one right here. The post to slash inside the habit route is where you would create a habit. So I will get rid of this controller right here.

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So I will get rid of this controller right here. I would say, create. Habit, we already have this Validate body with this create habit schema. I forgot what, is this the one I made in oops.

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I forgot what, is this the one I made in oops. It's the one I made in the DB. Let's see. Oh no, it's just like some fake one that I made.

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Oh no, it's just like some fake one that I made. So here's our create habit schema, it's like a fake one that I made as an example. I'm not gonna use that one instead. If I go to our database Schema.

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If I go to our database Schema. And go down to the bottom. I'll just export one from the Database Schema, so I'll say insert. Well, actually, no, I can't do this because I'm adding something special to our ability to create habits, which is an array of tag IDs and the habits in the database.

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Well, actually, no, I can't do this because I'm adding something special to our ability to create habits, which is an array of tag IDs and the habits in the database. Don't take an array of IDs. Of tag ID so I couldn't use that one. I gotta make my own essentially.

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I gotta make my own essentially. I could extend it, but I've never done that and I don't know if it's gonna break, so. I guess I'll add that one back, but I'll just actually change it to what it's supposed to do. Which I can just go look at the controller that we just made.

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Which I can just go look at the controller that we just made. And it's expecting these, not that one, it's expecting these things. And if I look at the database, I know for sure name is required. And what else is required?

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And what else is required? So name is for sure required, frequency is required. Everything else is either. Not required or default, so really only need to check for frequency.

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Not required or default, so really only need to check for frequency. And name as far as like being required, all the other ones are just like. You know, doesn't really matter so. I'll go back to the.

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I'll go back to the. Habit routes I'll say name, this is a Z. String. I'll say description.

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I'll say description. This is also a Z string. Frequency This is a Z dot. Number Is that right?

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Number Is that right? No, this is also a string. Oh yes, I don't know why I thought it was no. This is a string, not no target count, that's what it was, it was a number, we don't need that.

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This is a string, not no target count, that's what it was, it was a number, we don't need that. Cool, so I'll go back to. This is a string. Target Counts a Z.

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Target Counts a Z. String. And then we have tag IDs. Which is a Z string or I'm sorry, Z.

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Which is a Z string or I'm sorry, Z. Array. Which includes a bunch of strings. But some of these are optional, right?

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But some of these are optional, right? So tags is optional, so I'll mark that as optional, Description is optional. Frequency. It's not optional, so we gotta have that.

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It's not optional, so we gotta have that. The name is not optional, so I think we're good on those. Yeah, I think that's it, and then now we can take this. And oh yeah, it's already there, so that's good, so we posted that one's good to go.

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And oh yeah, it's already there, so that's good, so we posted that one's good to go. We can try it, or actually let's just keep moving and we'll try them all at the end just in case so we don't get through them all, so. That's our schema for that. That's how I would go about making that schema.

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That's how I would go about making that schema. Ideally I would just keep it in sync with the database, but, yeah, sometimes like I said, what you expect from the user and what the Database expects could be two different things, yeah, it's a type of frequency. Oh yeah, thank you. Frequency.

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Frequency. There we go. Oh, frequency.