Sail.js has ORM, I can make queries to databases.
I want to make a frontend that uses AJAX to communicate with the backend. But I want the backend to query different databases based on an id/name given with the ajax query. And it would be good to be able to add/remove those same databases during runtime.
Is this possible with Sails.js? I can only find ways to have a static amount of DBs (declared in conf files).
Related
I am attempting to write an Azure CosmosDB integration (Core SQL Api) that integrates with an external service to provide some of the query data. As an example, I need a query made on Cosmos DB to convert some of the data returned (e.g. ID's) by the query into real data by calling an external service via a REST API. This should only happen when querying certain columns.
I initially investigated using a JS stored procedure and/or a UDF to make this external call, but the JS environment seems to be extremely limited and doesn't provide any way to make external calls. I then tried using this https://github.com/Oblarg/cosmosdb-storedprocs-ts repository, which uses webpack to bundle all of node.js into the stored procedure, allowing node modules to be used in stored procedures. Whilst this does allow some node modules to be used, whenever I try and use "https", "fetch", or "axios" modules to make an HTTP GET request I get errors (the same code works fine in a normal node environment, but I'm not a JS expert and can't seem to work past these errors). After a day of attempts it seems like the stored procedure approach is not possible.
Is this the case or is there some way of making HTTP GET requests from a JS stored procedure? If not possible with stored procedures, are there any other techniques to achieve the requirement of reading data from a remote API when querying cosmos DB?
Thanks
There is no way to achieve this from CosmosDB directly, for queries you also cannot use the change feed as the document dont change, so really your only option is to use a function or some preprocessor app to handle it, as you say its not ideal but there is no other solution here. If it was an insert or an update then change feed would allow you to do this but for plain queries its not possible.
If one Nodejs app connects to a Mongo instance, and that app has defined a User schema with pre-save hooks, validation, etc.
And then another Nodejs app connects to the same database, and tries to register a User schema with different properties.
And then the second app saves a User
What happens?
I'm confused with how two Nodejs apps may communicate to the same database.
For example, it's very easy to see how one might want to have V2 of an api on a separate nodejs app developed by a separate team. But they will plug it into the same database and use the same Schema (or will they?), and I'm confused with how things are shared between the two apps.
Any help clarifying this in best-practices would be appreciated
I believe I've found the answer in the Documentation.
This connection object is then used to create and retrieve models. Models are always scoped to a single connection. docs
And
Models are fancy constructors compiled from our Schema definitions. docs
Which explains that a DB Connection 1's Schema Definitions (pre-save, etc), do not affect DB Connection 2's writes/etc.
Essentially, they are completely independent of validation and everything else. They only need to be OK in their own context.
I am trying out React-Starter-Kit for the first time and loving all the cutting edge features baked in (apollo/graphql-client in particular). A crucial part of any app for me is the database, and for that my understanding is the same author provides nodejs-api-starter which sets up a REST interface for accessing Postgres at localhost:5000 and has a graphql webui at localhost:5000/graphl.
That is about as far as I have been able to understand of the setup so far. I have changed the frontend code a little bit so a new Component "Counter" is loaded on the home page. I need to be able to make a new counter, fetch the latest counter, and increment decrement the counter. Write now the component just outputs the 'value' retrieved from the server at 5000.
I do not think I am accessing the 5000 server correctly, do I put the port in this url line somehow?
You can pull the repo down from : https://github.com/Falieson/react-starter-kit-crud-counter-demo
This is my first time setting up a nodejs api server, I am used to using MeteorJS which has pub/sub to MongoDB baked in. I am looking forward to the separation the RSK strategy (which seems more industry standard?) provides.
I've just done setting up the full site with Database from React-Stater-Kit, I'm also a newbie so I understand your frustration.
About this question, you don't need the NodeJS-API-Starter, it has enhanced function ( such as Redis cache ) and it's not suited for newbies. You should look deeper into the RSK, it already has the DB. If you ran the boilerplate and played around, change is you'll see file database.sqlite in your folder, it's the database. Here are the things you should learn:
Use SequelizeJS to connect the NodeJS server with database. Your database can be MySQL/MariaDB, PostgreSQL or SQLite. The connection is easy and there's tool to auto-generate Models from your database
How to create GraphQL's Types and Queries. If your queries need to search through the database, import Sequelize's models and use its functions.
Test your API via GraphQLi
Note: if you want to use MongoDB or other NoSQL, try Mongoose instead of Sequelize.
I am developing a Nodejs application and my database is Postgres and I am using Sequelize as my ORM because of its excellent support for migrations.
I am on the lookout for a good REST API generator based on the schema I have defined. There are two main hurdles I am facing and they are that the generators don't do a good job of creating association API routes and lack of ACL support.
On the associations front, my schema has multiple levels of association i.e. for example..
Student.hasMany(Courses);
Courses.hasMany(Subjects);
So ideally the generated REST API should be something like
/student/:student_id/course/:course_id/subject/:subjectId
I found a few projects that are doing this, but are incomplete.
https://github.com/sequelize/sequelize-restful - is good but does not have ACL support
https://www.npmjs.org/package/restizr - is in alpha stage and does not generate API routes for associations.
Is there any module that supports this?
What you were doing here is writing a webservice without a domain model. https://en.wikipedia.org/wiki/Anemic_domain_model Ofc. you have every right to do it, but I wonder if you really understood what a webservice means. https://stackoverflow.com/a/1530607/607033 It is not a database with CRUD HTTP interface normally, though nowadays it is popular doing something this way and call it REST. A response to a REST HTTP request is a viewmodel https://softwareengineering.stackexchange.com/a/425001/65755 and it contains not just data, but a lot of metadata and hyperlinks. A REST API is a special type of webservice with many constraints. https://www.ics.uci.edu/~fielding/pubs/dissertation/fielding_dissertation.pdf http://www.markus-lanthaler.com/research/hydra-a-vocabulary-for-hypermedia-driven-web-apis.pdf Your ORM is used 2 layers deeper in the data layer and it has nothing to do with the presentation layer where your REST API should be. I really wonder why people are making applications, which are doing nothing except serving data directly from the database and use the most inconvenient technology to do it. I guess there are databases nowadays with ACL and REST API support, so all you need is just using them. https://learn.microsoft.com/en-us/rest/api/sql/ Or there was something for PgSQL and Nodejs too around the time you asked this. https://github.com/QBisConsult/psql-api
I'm trying to dynamically generate databases/collections on application startup, in case they do not exist yet. This works fine when working with the _system database. The thing is that it seems not to be allowed when trying to switch to other databases. From the docs:
db._useDatabase(name)
Changes the current database to the database specified by name. Note
that the database specified by name must already exist.
Changing the database might be disallowed in some contexts, for
example server-side actions (including Foxx).
Does this mean that Foxx applications can only create collections within the _system database? My manifest file sets the isSystem property to false. What is the meaning of such limitation?
A Foxx is included in one database context and has access to the collections there.
You can install Foxx apps in different databases.
f.E. you can run the following commands in arangosh to install the foxx app "example" in the database "myDB":
db._useDatabase("myDB")
fm.install("example","/example")
your app will than be reachable at (assuming standard configuration):
http://localhost:8529/_db/myDB/example
It is intentionally not possible to access a different database from within a Foxx app.