Migration to NestJS

[nitrosx]

Summary key items for migration to Loopback 4:

• no matter which framework we are going looking to a complete refactoring of the code base
• Each endpoint will require a considerable amount work, even after we have developed the knowhow
• User management should require work only at the beginning while we set it up. It should require minimal effort to integrate it in each end point.
• Documentation is fragmented and it is not easy to find an end-to-end tutorial
• As of now, LB4 is still a viable option

Valid reasons to change framework:

• longer long term support
• better and easier documentation
• better tutorials and how-tos
• wider user base

Notes

There are many frameworks out there, as illustrated by this post:
In one of the posts that I came across, I read about nestjs and next.js, which apparently have wider user base.
I checked nestjs web page, I could not find any info on End-Of-Life and support. I did find their documentation a little easier to read and follow (here is the authentication documentation: )
I also find this post where they compare nestjs with other frameworks, but not with loopback.
This post provide a little info on differences between LB3, LB4 and nestjs:

[nitrosx]

@henrikjohansson712 and @nitrosx (myself) agreed that a migration to a Loopback4 requires a considerable code refactoring.

We decided to explore implementing datasets endpoint in express.js and nest.js.

This experience allowed us to conclude the following:

• using either express.js and nest.js was easier to understand the workflow and the framework/library used
• in both cases, we were able to write code that was easier to understand
• with nest,js is easier to access the lower level functionalities and data structure than in LB4
• nest.js documentation is complete although it lack coverage of edge use cases.

We therefore decided to explore nest.js so we could leverage higher level functionalities already present in the framework.

[nitrosx]

WE continued our exploration of nest.js and implemented a proof-of-concept of the full Datasets endpoint without changing the underline database.
We also implemented authentication.

Implementation of scicat-nestjs is available in nestjs branch

[nitrosx]

We just successfully tested the scicat migration middleware (S2M for short).
Here is the configuration:

• S2M configured to listen on port 3000 directing Datasets end point to scicat-nestjs and all other requests to scicat-lb3 (current implementation).
• scicat-nestjs listening on port 3002
• scicat-lb3 listening on port 3001
• common database accessed by scicat-nestjs and scicat-lb3

Tested performed:

• login (authentication on both backends and tokens management)
• retrieved all datasets list (directed to and answered by scicat-nestjs)
• retrieved one dataset by id (directed to and answered by scicat-nestjs)
• retrieved all proposals list (directed to and answered by scicat-lb3)
• retrieved one proposal by id (directed to and answered by scicat-lb3)

[stephan271]

Congratulations ! Looks like a promising approach .

[nitrosx]

We are now working to have a functional nestjs endpoint for datasets with authentication and authorization.
Renaming the ticket to Migration to NestJS

[nguyenlinhlinh]

I can volunteer to migrate the job endpoint.