Pydantic-resolve is a schema based solution for data management.

1. It manages the deep data inside each schema, instead of visiting from outside by manual traversal.
2. It runs a Level Order Traversal (BFS) inside and execute resolve and post during this process.
3. It describes the relationship between data in a form close to ERD (entity relationship diagram)

Install

User of pydantic v2, please use pydantic2-resolve instead.

This lib now supports both pydantic v1 and v2 starts from v1.11.0

pip install pydantic-resolve

Hello world

manage your data inside the schema.

class Tree(BaseModel):
    name: str
    number: int
    description: str = ''
    def resolve_description(self):
        return f"I'm {self.name}, my number is {self.number}"
    children: list['Tree'] = []


tree = dict(
    name='root',
    number=1,
    children=[
        dict(
            name='child1',
            number=2,
            children=[
                dict(
                    name='child1-1',
                    number=3,
                ),
                dict(
                    name='child1-2',
                    number=4,
                ),
            ]
        )
    ]
)

async def main():
    t = Tree.parse_obj(tree)
    t = await Resolver().resolve(t)
    print(t.json(indent=4))

import asyncio
asyncio.run(main())

output

{
  "name": "root",
  "number": 1,
  "description": "I'm root, my number is 1",
  "children": [
    {
      "name": "child1",
      "number": 2,
      "description": "I'm child1, my number is 2",
      "children": [
        {
          "name": "child1-1",
          "number": 3,
          "description": "I'm child1-1, my number is 3",
          "children": []
        },
        {
          "name": "child1-2",
          "number": 4,
          "description": "I'm child1-2, my number is 4",
          "children": []
        }
      ]
    }
  ]
}

Composing a subset from ERD definitions

define elements of ERD, schema (entity), dataloader (relationship).

then pick and compose them together according to your requirement and get the result.

import asyncio
import json
from typing import Optional
from pydantic import BaseModel
from pydantic_resolve import Resolver, build_object, build_list, LoaderDepend
from aiodataloader import DataLoader

# Schema/ Entity
class Comment(BaseModel):
    id: int
    content: str
    user_id: int

class Blog(BaseModel):
    id: int
    title: str
    content: str

class User(BaseModel):
    id: int
    name: str


# Loaders/ relationships
class CommentLoader(DataLoader):
    async def batch_load_fn(self, comment_ids):
        comments = [
            dict(id=1, content="world is beautiful", blog_id=1, user_id=1),
            dict(id=2, content="Mars is beautiful", blog_id=2, user_id=2),
            dict(id=3, content="I love Mars", blog_id=2, user_id=3),
        ]
        return build_list(comments, comment_ids, lambda c: c['blog_id'])

class UserLoader(DataLoader):
    async def batch_load_fn(self, user_ids):
        users = [ dict(id=1, name="Alice"), dict(id=2, name="Bob"), ]
        return build_object(users, user_ids, lambda u: u['id'])


# Compose schemas and dataloaders together
class CommentWithUser(Comment):
    user: Optional[User] = None
    def resolve_user(self, loader=LoaderDepend(UserLoader)):
        return loader.load(self.user_id)

class BlogWithComments(Blog):
    comments: list[CommentWithUser] = []
    def resolve_comments(self, loader=LoaderDepend(CommentLoader)):
        return loader.load(self.id)


# Run
async def main():
    raw_blogs =[
        dict(id=1, title="hello world", content="hello world detail"),
        dict(id=2, title="hello Mars", content="hello Mars detail"),
    ]
    blogs = await Resolver().resolve([BlogWithComments.parse_obj(b) for b in raw_blogs])
    print(json.dumps(blogs, indent=2, default=lambda o: o.dict()))

asyncio.run(main())

output

[
  {
    "id": 1,
    "title": "hello world",
    "content": "hello world detail",
    "comments": [
      {
        "id": 1,
        "content": "world is beautiful",
        "user_id": 1,
        "user": {
          "id": 1,
          "name": "Alice"
        }
      }
    ]
  },
  {
    "id": 2,
    "title": "hello Mars",
    "content": "hello Mars detail",
    "comments": [
      {
        "id": 2,
        "content": "Mars is beautiful",
        "user_id": 2,
        "user": {
          "id": 2,
          "name": "Bob"
        }
      },
      {
        "id": 3,
        "content": "I love Mars",
        "user_id": 3,
        "user": null
      }
    ]
  }
]

Documents

• Quick start: https://allmonday.github.io/pydantic-resolve/about/
• API: https://allmonday.github.io/pydantic-resolve/reference_api/
• Demo: https://github.com/allmonday/pydantic-resolve-demo
• Composition oriented pattern: https://github.com/allmonday/composition-oriented-development-pattern

Test and coverage

tox

tox -e coverage
python -m http.server

latest coverage: 98%

Sponsor

If this code helps and you wish to support me

Paypal: https://www.paypal.me/tangkikodo

Discussion

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