MongoDB and Mongoose databases not connecting across directories - node.js

I have a web server running, that uses mongoDB to store posts created on the website.
I would like to use a separate script to manage some things on the site, however for some reason I can't seem to get the code working across directories.
The website is running in /home/username/program/
I want my utility script to reside in /home/myname/utils/
This is currently the script I have:
#!/usr/bin/nodejs
var mongoose = require('mongoose');
var db = mongoose.connect('mongodb://localhost/db_name',{useNewUrlParser:true});
var chat = require('/home/username/project/lib/models/chat');
chat.findOne(function(err,doc) {
console.log(err,doc);
});
This code works, and gets data, but only if the file it's written it resides in /home/username/project/lib/.
If the file is in /home/mynameutil/ then it doesn't get any data at all. Why is this?

It is appropriate, because you don't start your project on /home/username so your program shared same instance, If you want to create something across the folder considers using workspaces.
Some tools make it easy to create workspaces like yarn and pnpm with this your code can be run in the same instance and share same node_modules. So you can use it across folder

Related

docker httpd/Apache - adding new node,js modules

I'm new to the web developing stuff and currently watching on udemy a 70h course.
I like to practice new learned stuff in real world applications. Therefore I've setted up an httpd container (https://hub.docker.com/_/httpd) with a bootstrap template in it (https://startbootstrap.com/theme/sb-admin-2)
My question: how do I add new node.js modules to this template? I want to add a module to connect the website to my postgres database.
The volume I made for the httpd container is as follows: /usr/local/apache2/sb/src/:/usr/local/apache2/htdocs/
In this directory I have installed the postgres module via npm and wrote a simple javascript code in index.js. If I call index.js via node index.js from the terminal it works fine. If I try to call it from the website it doesnt work. I know I missed something important to get this module work but I can't figure it out.
Edit
It was a really simple example of using extern modules in node.js shown in udemy. I've tried to use this example in my website.
index.js
var superhero = require('superheroes');
var hero = superhero.random();
function testCall(){
// alert("just a test!");
alert(hero);
}
In index.html I call the "testCall" function as follows
<body id="page-top" onload="testCall()">
This part works well, If I put a simple string as alert, for instance "alert("just a test!");"
I want to build a dashboard to display some values stored in postgres

Moving specific collections from mongodb atlas to archive db

I did my homework before posting this question
So the case is that I want to create a utility in my nodejs application that will move specific collections from my main database to an archive database and vice versa. I am using mongo db atlas for my application. I have been doing my research and I found two possible ways one is to create a mongodump and store and other is to create a backup file myself using my node application and upload it to archive db. Using the later approach will cause to loose my collection indexes.
I am planning to use mongodump for the purpose but can't find a resource that shows how to achieve that. Any help would be appreciated. Also if any one has any experience with similar situation I am open to suggestions as well.
I recently created a mongodump & mongorestore wrapper for nodejs: node-mongotools
What does it mean?
you have to install mongo binary on your host by following official mongo documentation(example) and then, you could use node-mongotools to call them from nodeJS.
Here is an example but tool doc contains more details:
var mt = new MongoTools();
const dumpResult = await mt.mongodump({ uri, path })
.catch(console.log);

Exporting sqlite3 db file from inside electron app. Is this possible?

I've got an app I've put together in Electron which saves data using sqlite3. Everything works as expected. I'd like to be able to export/save the actual database file so I can share it with others, treating it sort of like a save file.
I assume that if this is possible then I need to be using fs as well, which is fine.
Even better, can I just create the database file outside the compiled app from the start? And if so what's the best way to accomplish that?
Otherwise I can switch over to kripken/sql.js or something like that, but I'd rather not put the time in to make those changes if there's an easy way to just have the existing sqlite database file get saved to the user's computer outside the app.
I'm an idiot.
Instead of storing the file internally in the packaged app like this…
const dbPath = path.resolve(__dirname, 'data.db')
…I'm just storing it in the filesystem like this…
const {app} = require('electron').remote;
const dbPath = path.resolve(app.getPath('userData'), 'data.db');
…so that it's accessible from the start.
I'm leaving this question up because I'd be interested if there is a way to have a save file dialogue for an extant file in the packaged app, but in the mean time this is my answer.

Do each parent directories need to have their own node_modules folder?

I am working on an app powered by node which has a few (three) different folders. It looks like this:
Client-
Server-
-node_modules
-mongoose
Database-
-index.js
Config-
-credentials.js
I have made an exports object with all of my passwords and put it in the database folder (this way I can easily ignore it from being checked in to any version control).
I am wondering if there is a way to have ALL of the node_modules used by my server and database directories in the server directory so that the package.json file in my server directory would contain all of the needed packages for the "backend" of my project.
However, when I do this, and try to require(mongoose) from the Database/index.js file, I get "cannot find module" errors. I tried the following combinations and still get the error in every case:
require(mongoose) require(../server/mongoose) require(../server/node_modules/mongoose)
Installing the mongoose module directly in the Database directory fixes this problem but this means that I have to have a node_modules (and thus package.json) file in each directory. Is that the right way to fix this issue or is there a more simple solution?
Thanks
Maybe you find interesting having a look at the following article: "Where does Node.js and require() look for modules?", in order to understand why the different ways you are trying to "require" mongoose are not actually working - and that is because the way you are organizing your code (your node_modules directory is inside your Server and your Database directory is under the / - root directory).
So, in your case, you will have to specify your /Database/index.js the relative file path to mongoose in order to find your module:
require('../server/node_modules/mongoose');
Another solution (I personally organize my code like this) would be moving your database code within the server code; after all, it's all backend code.
I aware this not elegant way but i have an advice for your case.
You can try like below;.
var mongoose = require('../server/node_modules/mongoose/index');
I was simulated your case in my local and this worked.

Temporary File Download

Is there a service that creates basically a one-time download of a file, preferably something I can use from NodeJS?
I've done some research on FilePicker, and haven't found anything about regenerating the link it gives you for a file. There may be a way to do this with NodeJS, but I'm using Meteor at the same time so many Node things probably will conflict.
You could build it with meteor. Using meteor-router with meteorite & use server side routing to deliver the files.
You need a collection to keep track of downloaded files:
Server JS
var downloads = new Meteor.Collection("downloads");
//create a link
downloads.insert({url:"/mydownload.zip",downloaded:false})
Meteor.Router.add('/file/:id', 'GET', function(id) {
download = downloads.findOne(id);
if( download) {
if(dowload.downloaded) {
this.response.send("You've already downloaded me")
}
else
{
//I guess you could just redirect or stream the file for an extra layer of surety
this.response.redirect(download.url);
}
}
});
On the client you can use /files/{{_id}} with _id of the file from downloads the person has as the link
My recommendation would also be to add custom server-side logic to count # of uploads (or just flag a file as downloaded/not downloaded) and respond accordingly. The closest you could do with Filepicker.io would be using the security policies to restrict downloading the file to a specific time interval.
in addition to using the router package
in Meteor.startup you can add
var require = __meteor_bootstrap__.require;
fs = require( 'fs' );
the fs variable should be declared on the server only. the fs package is used by Meteor and does not need to be added separately.
once you have done this, you can create files with Meteor.uuid() as their name which makes them unique and very difficult to guess. It is also possible to delete the file after a certain amount of time by using Meteor.setTimeout
the question is: where do the files to be downloaded come from?
Solution using Heroku Cloud and NodeJS Meteor Hooks
Heroku in particular is actually great for temporary file download links: they offer a "temporary scratchpad" filesystem that is reset every time the program restarts, and each running Node server cannot see the files other instances have created.
Each dyno gets its own ephemeral filesystem, with a fresh copy of the
most recently deployed code. During the dyno’s lifetime its running
processes can use the filesystem as a temporary scratchpad, but no
files that are written are visible to processes in any other dyno and
any files written will be discarded the moment the dyno is stopped or
restarted.
Taken from the Heroku documentation: https://devcenter.heroku.com/articles/dynos#ephemeral-filesystem
Thus, any files written to the "filesystem" will be temporary.
This allows for a very easy solution to this problem: you can simply use NodeJS filesystem manipulation to create temporary files on the server, serve them once (or for a limited time), and then remove them so they cannot be downloaded again.
This in combination with something like $.download() will make a seamless experience which in turn prevents unauthorized downloads.

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