So basically I wrote a simple API where you can perform http POST and http GET on a nedb.
My problem however is, that after posting an entry (customer), the entry appears in the nedb file but when I use the GET method it isn't returned.
However after restarting the API it works as expected and the expected data is returned. But why does it have to restart in order to "refresh" the data?
Get-Function:
const db = new Datastore({filename: __dirname + '/db.dat', autoload:true});
export function getAll(req: Request, res:Response, next: Next):void{
db.find({}, (err, customers) => {
res.send(customers);
});
next();
}
In situations where you get weird errors or something strange is not working with nedb and you cannot figure out what's wrong, try to delete the .dat file and try again.
Often you accidentally modify the nedb file (e.g. with autosave of your editor) and you corrupt it.
Related
I am new to programming, and I heard that some guys on this website are quite angry, but please don't be. I am creating one web app, that has a web page and also makes som ecalculations and works with database (NeDB). I have an index.js
const selects = document.getElementsByClassName("sel");
const arr = ["Yura", "Nairi", "Mher", "Hayko"];
for (let el in selects) {
for (let key in arr) {
selects[el].innerHTML += `<option>${arr[key]}</option>`;
}
}
I have a function which fills the select elements with data from an array.
In other file named: getData.js:
var Datastore = require("nedb");
var users = new Datastore({ filename: "players" });
users.loadDatabase();
const names = [];
users.find({}, function (err, doc) {
for (let key in doc) {
names.push(doc[key].name);
}
});
I have some code that gets data from db and puts it in array. And I need that data to use in the index.js mentioned above, but the problem is that I don't know how to tranfer the data from getData.js to index.js. I have tried module.exports but it is not working, the browser console says that it can't recognize require keyword, I also can't get data directly in index.js because the browse can't recognize the code related to database.
You need to provide a server, which is connected to the Database.
Browser -> Server -> DB
Browser -> Server: Server provides endpoints where the Browser(Client) can fetch data from. https://expressjs.com/en/starter/hello-world.html
Server -> DB: gets the Data out of the Database and can do whatever it want with it. In your case the Data should get provided to the Client.
TODOs
Step 1: set up a server. For example with express.js (google it)
Step 2: learn how to fetch Data from the Browser(Client) AJAX GET are the keywords to google.
Step 3: setup a Database connection from you Server and get your data
Step 4: Do whatever you want with your data.
At first I thought it is a simple method, but them I researched a little bit and realized that I didn't have enough information about how it really works. Now I solved the problem, using promises and templete engine ejs. Thank you all for your time. I appreciate your help)
I haven't figured out how to get a response from restler in sails.js script. The goal is to import some data each day from a REST API to my database. So I chose to use sails.js script to be able to crontab the call.
When I search what I could use to contact the API. I saw a topic about restler which seem pretty easy to use.
Sadly when I try it I cannot catch the response from the API, I use this basic example
module.exports = {
friendlyName: 'test',
description: 'this is a test',
fn: async function () {
sails.log('Running custom shell script... (`sails run test`)');
var rest = require('restler');
rest.get('http://google.com').on('complete', function(result) {
sails.log("In callback")
if (result instanceof Error) {
sails.log('Error:', result.message);
this.retry(5000); // try again after 5 sec
} else {
sails.log(result);
}
});
sails.log('finished');
}
};
When I run the script this is what I get
info: Initializing hook... (`api/hooks/custom`)
info: Initializing `apianalytics` hook... (requests to monitored routes will be logged!)
info: ·• Auto-migrating... (alter)
info: Hold tight, this could take a moment.
info: ✓ Auto-migration complete.
debug: Running custom shell script... (`sails run test`)
debug: finished
I try other method and other URL too, but apparently I never get in the callback.
So I assume that the script doesn't "wait" the .on('complete') before continuing his execution.
I know, and use, on the database call .then to avoiding that, I think this is called a 'promise'. So from what I understand the problem is around that but sadly after searching, I don't find any answer to solve my issue.
I am not married to restler, and if another and better solution exists don't hesitate, the goal is again to get the content from a REST API from sails.js script.
Thank you for the time you take to answer my question.
I use lowDB dependency to control the JSON Data with Express and actually it works. But there is a bug and I cannot find how to solve it.
I create /create page to add information in JSON file and it contains 4 form and submit button.
And In express I code like this. each forms data will save it in variable and push with lowdb module.
router.post('/post', function (req, res) {
let pjName = req.body.projectName;
let pjURL = req.body.projectURL;
let pjtExplanation = req.body.projectExplanation;
let pjImgURL = req.body.projectImgURL;
console.log(pjName);
db.get('project').push({
name: pjName,
url: pjURL,
explanation: pjtExplanation,
imgurl: pjImgURL
}).write();
console.log(db.get('project'));
console.log(db.get('project').value());
res.redirect('/');
})
And it works well. But when I modify the JSON file myself (ex. reset the JSON file) and execute again. It shows the data that I reset before. I think in this app somewhere saves the all data and show save it in array again.
And When I shutdown the app in CMD and execute again, the Array is initialized.
As you may already know the lowdb persist the data into your secondary memory (hdd), and may return a promise depending on your environment when you call write method.As mentioned in the doc
Persists database using adapter.write (depending on the adapter, may return a promise).
So the data may be still getting write when you read them, so the old data is queried. Try this,
db.get('project').push({
name: pjName,
url: pjURL,
explanation: pjtExplanation,
imgurl: pjImgURL
}).write().then(() => {
console.log(db.get('project'));
console.log(db.get('project').value());
});
I am working with NodeJs with expressjs and I would like to use a middleware that will read a variable from dynamic configuration file before each request (some js file that holds an object that I can change manually while the server is running).
I would like to store a flag that will close down all requests (i.e send response without proceeding to next routes) until I change the variable value to true and then the middleware will call next() so all routes will work.
I prefer to avoid shutting down the server for that, and I also don't want to store this variable in a database...
Is there something similar to what I need?
Thanks
You will read config.json file each time, if you just put it inside function. If you will use require('config.json), then you will read this file only once on start.
var fs = require("fs");
function (req,res,next) {
var config = fs.readFileSync('./config.json');
config = JSON.parse(config.toString());
if (config.registrationStatus === "open") {
next();
} else {
res.send("registration closed");
}
}
Check supervisor: https://github.com/petruisfan/node-supervisor
It will watch for file changes and crashes and will restart your application each time.
You will get much better performance.
The title might sound strange, but I have a website that will query some data in a Mongo collection. However, there is no user system (no logins, etc). Everyone is an anonymouse user.
The issue is that I need to query some data on the Mongo collection based on the input text boxes the user gives. Hence I cannot use this.userId to insert a row of specifications, and the server end reads this specifications, and sends the data to the client.
Hence:
// Code ran at the server
if (Meteor.isServer)
{
Meteor.publish("comments", function ()
{
return comments.find();
});
}
// Code ran at the client
if (Meteor.isClient)
{
Template.body.helpers
(
{
comments: function ()
{
return comments.find()
// Add code to try to parse out the data that we don't want here
}
}
);
}
It seems possible that at the user end I filter some data based on some user input. However, it seems that if I use return comments.find() the server will be sending a lot of data to the client, then the client would take the job of cleaning the data.
By a lot of data, there shouldn't be much (10,000 rows), but let's assume that there are a million rows, what should I do?
I'm very new to MeteorJS, just completed the tutorial, any advice is appreciated!
My advice is to read the docs, in particular the section on Publish and Subscribe.
By changing the signature of your publish function above to one that takes an argument, you can filter the collection on the server, and limiting the data transferred to what is required.
Meteor.publish("comments", function (postId)
{
return comments.find({post_id: postId});
});
Then on the client you will need a subscribe call that passes a value for the argument.
Meteor.subscribe("comments", postId)
Ensure you have removed the autopublish package, or it will ignore this filtering.