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Using as module

datamodel-code-generator is a CLI. But, it has another side as a python module.

You can call this code-generator in your python code.

How to use it as module

You can generate models with datamodel_code_generator.generate into a temporary directory.

And, you can read files from the directory.

Installation

pip install "datamodel-code-generator[http]"

Example

from pathlib import Path
from tempfile import TemporaryDirectory
from datamodel_code_generator import InputFileType, generate

json_schema: str = """{
    "type": "object",
    "properties": {
        "number": {"type": "number"},
        "street_name": {"type": "string"},
        "street_type": {"type": "string",
                        "enum": ["Street", "Avenue", "Boulevard"]
                        }
    }
}"""

with TemporaryDirectory() as temporary_directory_name:
    temporary_directory = Path(temporary_directory_name)
    output = Path(temporary_directory / 'model.py')
    generate(
        json_schema,
        input_file_type=InputFileType.JsonSchema,
        input_filename="example.json",
        output=output,
    )
    model: str = output.read_text()
print(model)

The result of print(model)

# generated by datamodel-codegen:
#   filename:  example.json
#   timestamp: 2020-12-21T08:01:06+00:00

from __future__ import annotations

from enum import Enum
from typing import Optional

from pydantic import BaseModel


class StreetType(Enum):
    Street = 'Street'
    Avenue = 'Avenue'
    Boulevard = 'Boulevard'


class Model(BaseModel):
    number: Optional[float] = None
    street_name: Optional[str] = None
    street_type: Optional[StreetType] = None

Why doesn't the function return str?

If generated code are modular files then, str can't reproduce the structure of modules.

Also, TemporaryDirectory and Path provide an easy way to read files.

There is an example when a generated model file is only one.

Otherwise, You should walk in a directory to find modular files.

fastapi-code-generator uses datamodel-code-generator as module to create models from OpenAPI.