A regex parser for Pydantic, using pythons regex validator.

Since pydantic V2, pydantics regex validator has some limitations. It cannot do look arounds. There is some documenation on how to get around this. This package simplifies things for developers

We provide the class, Regex, which can be used.

Usage in Pydantic

To use simply do:

from pydantic_python_regex_validator import Regex
from pydantic import BaseModel
from typing import Annotated

class MyModel(BaseModel):
    my_field: Annotated[str, Regex(r'^foo')]

This will then have field, my_field, which will have the regex constraint ^foo

Usage in FastAPI

This can also be used with fastapi.

from pydantic_python_regex_validator import RegexQuery, RegexBody
from fastapi import FastAPI

app = FastAPI()

@app.get("/test")
async def get_endpoint(my_param: RegexQuery("^foo")):
    return my_param

@app.post("/test")
async def post_endpoint(my_param: RegexBody("^foo")):
    return my_param

This then has an endpoint at /test which takes a param, my_param, which has the regex constraint ^foo