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
Related
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
As per the title, can a Node.js package require a database connection?
For example, I have written a specific piece of middlware functionality that I plan to publish via NPM, however, it requires a connection to a NoSQL database. The functionality in its current state uses Mongoose to save data in a specific format and returns a boolean value.
Is this considered bad practice?
It is not a bad practice as long as you require the DB needed and also explicitly state it clearly in your Readme.md file, it's only a bad practice when you go ahead and work without provide a comment in your codes or a readme.md file that will guide any other person going through your codes.
Example:
//require your NoSQL database eg MongoDB
const mongoose = require('mongoose');
// to connect to the database. **boy** is the database name
mongoose.connect('mongodb://localhost/boy', function(err) {
if (err) {
console.log(err);
} else {
console.log("Success");
}
});
You generally have two choices when your module needs a database and wants to remain as independently useful as possible:
You can load a preferred database in your code and use it.
You can provide the developer using your module a means of passing in a database that meets your specification to be used by your module. The usual way of passing in the database would be for the developer using your module to pass your module the data in a module constructor function.
In the first case, you may need to allow the developer to specify a disk store path to be used. In the second case, you have to be very specific in your documentation about what kind of database interface is required.
There's also a hybrid option where you offer the developer the option of configuring and passing you a database, but if not provided, then you load your own.
The functionality in its current state uses Mongoose to save data in a specific format and returns a boolean value. Is this considered bad practice?
No, it's not a bad practice. This would be an implementation of option number 1 above. As long as your customers (the developers using your module) don't mind you loading and using Mongoose, then this is perfectly fine.
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.
Good Afternoon,
I am new with node.js and I try to develope an only command app.
For this app I need an ORM and I wish to use WATERLINE as standalone but not in express framework.
I looked at the example and I succeed to see my different collections.
// Our collections (i.e. models):
ontology.collections;
console.log(ontology.collections);
// Our connections (i.e. databases):
ontology.connections;
I am stucked after this. I can't find a way to return my models and make queries.
If someone could help me taht would be great.
Thanks
If you initialized Waterline in the ontology variable and got the collections successfully loaded as you say, now you can access each collection loaded (with loadCollection()) like this:
ontology.collection.mycollection
Where mycollection is the identity defined in your model.
Then you can make queries:
ontology.collection.mycollection.find(...)
Can anyone guide me on how to setup relational schema & performs joins in sails.js?
Associations are officially Supported in Waterline
Overview
From the docs:
With Sails and Waterline, you can associate models across multiple data stores. This means that even if your users live in PostgreSQL and their photos live in MongoDB, you can interact with the data as if they lived together in the same database. You can also have associations that span different connections (i.e. datastores/databases) using the same adapter. This comes in handy if, for example, your app needs to access/update legacy recipe data stored in a MySQL database in your company's data center, but also store/retrieve ingredient data from a brand new MySQL database in the cloud.
Supported Association Types
One to Many
Many to Many
Cross-adapter Dominance
One to One
One Way
Planned Association Types
Through Associations
Original Post
I'm the author of Waterline, the ORM used in Sails. Waterline is brand
new and we are adding features all the time. Currently we don't have
support for associations but it's next on the roadmap. We worked out
an API for associations that I think most people will really like. You
can view the work in progress and the proposed API at: [Proposed Sails
Associations API][1].
We are going to tackle Associations and Transactions next and hope to
have them ready in the next month or so.
In the mean time if you are using the MySQL or PostgreSQL adapters
they both expose a raw .query() method that allows you to pass in a
hand built sql query and have it executed. I totally realize this
isn't ideal but should allow you to continue building your app while
we get support for associations and joins.
The function signature for the query method is:
Model.query(<sql query>, <optional data>, callback);
The example from particle banana works but should actually use "new" like "var instance = new User._model(values)". I'm using the following code and it works.
Accounts.query(query, function(err, accounts) {
if (err)
return fn(err);
accounts = _.map(accounts, function(account) {
return new Accounts._model(account);
});
fn(null, accounts);
});