I use a sqlite3 database for a node.js express. If I return the request as in the tutorial in router.js it works and I get all the items. Now I have created a service to get the sql from the route (controller). But unfortunately I don't get anything back. I had already tried it with async await in the service. That didn't help either.
my code:
// router.js
const dbService = require("../services/dbService/");
router.get("/users", (req, res, next) => {
try {
res.status(200).send({
data: dbService.getAllUsers();
})
return;
} catch(err) {
next(err);
}
});
// dbService.js
const db = require("../db/database.js");
module.exports = {
getAllUsers() {
const sql = "select * from users";
db.all(sql,[], (err, rows) => {
return {"data": rows};
});
}
}
For simple reasons, I have not included error handling in the code. Why can't I get database values from the service? What do I have to do?
Thanks in advance! Mike
CodePudding user response:
You're running afoul of asynchronous JS. db.all
returns results to the callback.
A refactor to use callbacks would look something like:
// router.js
const dbService = require("../services/dbService/");
router.get("/users", (req, res, next) => {
dbService.getAllUsers((err, result) => {
if (err) next(err);
res.json({
data: result;
});
});
});
// dbService.js
const db = require("../db/database.js");
module.exports = {
getAllUsers(cb) {
const sql = "select * from users";
db.all(sql,[], (err, rows) => {
cb(err, rows);
});
}
}
And promises woudl look like:
// router.js
const dbService = require("../services/dbService/");
router.get("/users", async (req, res, next) => {
try {
const result = await dbService.getAllUsers();
res.json({
data: result;
});
} catch (err) {
next(err);
}
});
// dbService.js
const db = require("../db/database.js");
module.exports = {
getAllUsers(cb) {
const sql = "select * from users";
return new Promise((resolve, reject) =>
db.all(sql,[], (err, rows) => {
if (err) reject(err);
resolve(rows);
})
);
}
}