I was following a tutorial, and I've have some methods in a controller to get data from database in SQL Server. Typical CRUD methods, and in each method I've wrote
let pool = await sql.connect(config);
I want to optimise the code and call this only once and not everytime in every method, so the connection will be established from the first time I run the code.
Thank you in advance.
Apparently you have to create .js file and add two methods one to get the connection and the other one to close the pool.
Then you import the .js file and use the functions.
Here is an example from David Neal.
Related
I have two Django projects with DRF and have some Rest API's
I want to use db connection of one Django project to another so i need to pass db connection/credentials over api network. I know we can get connection object using following
from django.db import connections
db_conn = connections['default']
and what am thinking is
1- to pass above db_conn in an api call as parameter to second project api but when am getting on other side its showing as string not as db connection object.
2- Another option is to pass credentials and create connection using sql alchemy in second project.
So what is the best approach in above two scenarios?. Also it would be great if you can answer how to pass db connection object in api params as object not string
I dont think you can put the object as parameter in the api request. A string is the best result you will get. Besides i would not be very happy with that info in the api!
Option 2 is the better aproach i would think.
Creating new project with auto-testing feature.
It uses basic express.
The question is how to orginize the code in order to be able to test it properly. (with mocha)
Almost every controller needs to have access to the database in order to fetch some data to proceed. But while testing - reaching the actual database is unwanted.
There are two ways as I see:
Stubbing a function, which intends to read/write from/to database.
Building two separate controller builders, one of each will be used to reach it from the endpoints, another one from tests.
just like that:
let myController = new TargetController(AuthService, DatabaseService...);
myController.targetMethod()
let myTestController = new TargetController(FakeAuthService, FakeDatabaseService...);
myTestController.targetMethod() // This method will use fake services which doesnt have any remote connection functionality
Every property passed will be set to a private variable inside the constructor of the controller. And by aiming to this private variable we could not care about what type of call it is. Test or Production one.
Is that a good approach of should it be remade?
Alright, It's considered to be a good practice as it is actually a dependency injection pattern
It's been a while since I used node and express and I was sure that this was possible, but i'm having an issue of figuring it out now.
I have a simple postgres database with sequelize. I am building a back end and don't have a populated database yet. I want to be able to provide fake data to use to build the front end and to test with. Is there a way to populate a database when the node server is started? Maybe by reading a json file into the database?
I know that I could point to this fake data using a setting in the environment file, but I don't see how to read in the data on startup. Is there a way to create a local database, read in the data, and point to that?
You can use fake factory package, I think it can solve your problem.
https://www.npmjs.com/package/faker-factory
FakerJs provides that solution.
import { faker } from '#faker-js/faker';
const randomName = faker.name.findName();
const randomEmail = faker.internet.email();
with the above, you can run a loop for loop to be specific to create
the desired data you may need for your project.
Also, check on the free web-API that provides fake or real data to workon
The project I'm working on uses the feathers JS framework server side. Many of the services have hooks (or middleware) that make other calls and attach data before sending back to the client. If I have a new feature that needs to query a database but for a only few specific things I'm thinking I don't want to use the already built out "find" method for this database query as that "find" method has many other unneeded hooks and calls to other databases to get data I do not need for this new query on my feature.
My two solutions so far:
I could use the standard "find" query and just write if statements in all hooks that check for a specific string parameter that can be passed in on client side so these hooks are deactivated on this specific call but that seems tedious especially if I find this need for several other different services that have already been built out.
I initialize a second service below my main service so if my main service is:
app.use('/comments', new JHService(options));
right underneath I write:
app.use('/comments/allParticipants', new JHService(options));
And then attach a whole new set of hooks for that service. Basically it's a whole new service with the only relation to the origin in that the first part of it's name is 'comments' Since I'm new to feathers I'm not sure if that is a performant or optimal solution.
Is there a better solution then those options? or is option 1 or option 2 the most correct way to solve my current issue?
You can always wrap the population hooks into a conditional hook:
const hooks = require('feathers-hooks-common');
app.service('myservice').after({
create: hooks.iff(hook => hook.params.populate !== false, populateEntries)
});
Now population will only run if params.populate is not false.
I have a few PHP scripts which I am in the process of migrating to Node.js. I am using Sails.js for this and I would like to know how I can change databases for each request based on a request parameter.
Currently I have 3-4 identical PostgreSQL databases. Let's just say that each database corresponds to a different client.
Below is a segment of the current PHP script where the database connection is established:
$database = $_GET['db'];
$conn_details = "host=localhost port=5432 dbname=$database user=****** password=******";
$dbconn = pg_connect($conn_details);
Here you can see that the database name is coming from the request parameter "db".
I would like to have a similar functionality in my sails.js controller. I know that i can declare multiple databases in the connections.js and that I can have models use different databases but what i am after is for the models to stay the same and only the database to change based on each request.
I have found 2 similar questions but they have both stayed unanswered for quite some time now. (Here and here)
I think you are looking for something like sub apps
sails-hook-subapps
but it's experimental module. So i wouldn't recommend using it on production. Other option also not good is multiplying your Models like that:
One main model with all methods, attributes and "stuff"
Many models with connections config
In 'parent' model you will select to which model you want to send send action. For example write method:
getModel: function(dbName){
return models[dbName];
}
in models Object you will store all Models with different connections. Not sure how validators will works in this scenario. You need to test if it will not be required do do something like this in child Models
attributes: parentModel.attributes