使用 msgspec（或 pydantic）在 Python 中注释 JSON 模式属性

Question

在从

msgspec

结构生成的 JSON 模式中，我想将结构中保存的属性的一些文本描述输出到模式，就像结构的文档字符串显示在 JSON 模式中一样。

这个小玩具示例（从 https://jcristharif.com/msgspec/jsonschema.html 截取）：

import json
import msgspec
from msgspec import Struct

def print_schema(schema):
    encoded_schema = msgspec.json.encode(schema)
    formatted_schema = json.dumps(json.loads(encoded_schema), indent=4)
    print(formatted_schema)

class Product(Struct):
    """A product in a catalog"""
    id: int
    name: str
    price: float

schema = msgspec.json.schema(Product)
print_schema(schema)

输出：

{
    "$ref": "#/$defs/Product",
    "$defs": {
        "Product": {
            "title": "Product",
            "description": "A product in a catalog",
            "type": "object",
            "properties": {
                "id": {
                    "type": "integer"
                },
                "name": {
                    "type": "string"
                },
                "price": {
                    "type": "number"
                }
            },
            "required": [
                "id",
                "name",
                "price"
            ]
        }
    }
}

with

description

包含文档字符串。我想做类似的事情

class Product(Struct):
    """A product in a catalog"""
    id: int      # DB uid
    name: str    # Name of product
    price: float # Price of product

并让注释显示在 JSON 模式中针对适当属性的位置。也许是这样的：

{
    "$ref": "#/$defs/Product",
    "$defs": {
        "Product": {
            "title": "Product",
            "description": "A product in a catalog",
            "type": "object",
            "properties": {
                "id": {
                    "description": "DB uid"
                    "type": "integer"
                },
                "name": {
                    "description": "Name of product"
                    "type": "string"
                },
                "price": {
                    "description": "Price of product"
                    "type": "number"
                }
            },
            "required": [
                "id",
                "name",
                "price"
            ]
        }
    }
}

但是，我对 JSON 模式了解不够，不知道这是否正确或有效，尽管查看 https://json-schema.org/learn/getting-started-step-by-step 似乎是正确的.

如何使用

msgspec

做到这一点？或者重写我的代码以使用

pydantic

？谢谢。

Answer 1

这个看起来像您要找的吗？

import json

from pydantic import BaseModel, Field


class Product(BaseModel):
    """A product in a catalog"""

    id: int = Field(description="DB uid")
    name: str = Field(description="Name of product")
    price: float = Field(description="Price of product")


product_schema = Product.model_json_schema()
json_product_schema = json.dumps(product_schema, indent=2)