Pydantic-resolve, a hierarchical solution for data fetching and processing

[navbaker]

I’ve used Pydantic with FastAPI, but can’t really get a solid feel for what this is doing. Can someone explain this to me like I’m 5?

[thornewolf]

say you have a model with two attributes profile_image_url: str and profile_image: bytes

it's expensive to fetch profile_image since it will involve a http call to profile_image_url. right now, i would resolve this by using the @property decorator

this library offers an alternative method for populating profile_image by explicitly giving the user a hook for when they want to resolve this dependency. they might want to do it before access time, they might want to batch requests to this external profile_image service to reduce roundtrip latency

this pattern has potential to become more powerful if we only have user_id in context initially. we might want to fetch the product_image_url from the database then fetch the actual product_image after. this dependency graph might be simplified/optimized using this tool

the repo provides its own concrete example of this form with batch_person_age_loader

[yen223]

If you know Django, this looks like a more general version of how Django does foreign-key fields.

[tangkikodo]

A powerful tool to build nested view data.

based on pydantic, pydantic-resolve uses declaretive way to define and resolve (fetch) data from top to bottom

and provides post-process hooks from bottom to top (friendly for aggregation & calculation)

it also provides visibility control over all fields.

concept diagram: https://raw.githubusercontent.com/allmonday/pydantic-resolve...

[tangkikodo]

inspired by graphql (define schema in declaretive way)

however gql itself only walks from top to bottom, which lack the ability to change data after it's descdenants are resolved.

pydantic-resolve is progressive, this means you don't need to introduce a big framework to build a nested view data, all you need to do is just:

- simpilify your query of root data (no complex sql any more, then you can reuse it)

- define the related data you wanted, and then let resolver to fetch it.

that's all~

[dlahoda]

There was COM/Corba like this. It was hanging/freezing. So somebody will have to refactor it back to normal.

[canadiantim]

Could this be used to efficiently model an hierichical comment thread for example, like HN or reddit?

[lucky_cloud]

The modeling could be done in pure Pydantic.

This project might be helpful in fetching the actual content from a database in an efficient way.

[malcolmgreaves]

Is this more-or-less functional reactive programming (FRP) using Pydantic?

[tangkikodo]

not really, it only traversal (with resolving descendants at the same time) once from top to bottom and then back.