Quack Service & Controller
We will create our Quack service and controller
Having created the model we can now begin implementing the CRUD functionalities.
We want to list, create, read, update, and delete the Quacks.
Quack Service#
We start with the service, so let's go over them one by one. We can start with the imports:
import { httpErrors } from "oak";
import { AppRouterContext } from "../../main.ts";
import { getClient } from "../utils.ts";
import { Quack, QuackKeys } from "./model.ts";
List Quacks#
export async function listQuack(ctx: AppRouterContext): Promise<Array<Quack>> {
const client = await getClient(ctx);
const result = await client.queryObject<Quack>(
`SELECT * FROM ${QuackKeys.TableName}`,
);
client.release();
return result.rows;
}
The list method is straightforward. With larger applications you would want to
have some filtering, sorting and pagination, but that is a bit outside of the
scope of this course, and is usually handled by ORMs
Create Quack#
export async function createQuack(
ctx: AppRouterContext,
data: Partial<Quack>,
): Promise<Quack> {
if (!data.text || !data.createdBy) {
throw new httpErrors.BadRequest("Missing data");
}
const client = await getClient(ctx);
const result = await client.queryObject<Quack>({
text:`INSERT INTO ${QuackKeys.TableName} (${QuackKeys.ColText}, ${QuackKeys.ColCreatedBy}) VALUES ($1, $2) RETURNING *`,
args: [data.text,
data.createdBy,
],
});
client.release();
return result.rows[0];
}
With a failsafe for missing data, this method creates a Quack with created_by
and text while using default values for the rest.
Read Quack#
export async function readQuack(
ctx: AppRouterContext,
id: Quack["id"],
): Promise<Quack | null> {
const client = await getClient(ctx);
const result = await client.queryObject<Quack>({
text:`SELECT * FROM ${QuackKeys.TableName} WHERE ${QuackKeys.ColId} = $1 LIMIT 1`,
args: [id],
});
client.release();
if (result.rows?.[0]?.id !== id) {
return null;
}
return result.rows[0];
}
Here we simply pass in the id and return either the Quack or null
Update Quack#
export async function updateQuack(
ctx: AppRouterContext,
id: Quack["id"],
data: Partial<Quack>,
): Promise<Quack> {
if (!data.text) {
throw new httpErrors.BadRequest("Missing data");
}
const client = await getClient(ctx);
const result = await client.queryObject<Quack>({
text:`UPDATE ${QuackKeys.TableName} SET ${QuackKeys.ColText} = $1 WHERE ${QuackKeys.ColId} = $2 RETURNING *`,
args: [data.text,
id,],
});
client.release();
return result.rows[0];
}
As only the creator can edit a Quack, we don't need to update anything else than the text.
Delete Quack#
export async function deleteQuack(
ctx: AppRouterContext,
id: Quack["id"],
): Promise<void> {
const client = await getClient(ctx);
await client.queryObject({
text: `DELETE FROM ${QuackKeys.TableName} WHERE ${QuackKeys.ColId} = $1`,
args: [id],
});
client.release();
}
Simply deleting the Quack based on the ID, we don't need to return anything and just assume that something was deleted if no error was thrown.
Quack controller#
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