Validation Module¶

forge.validation — Pydantic-integrated input validation with consistent error responses.

Overview¶

The Validation module validates function input against Pydantic schemas with zero boilerplate. It integrates with FastAPI to return structured 422 error responses that are consistent across your entire API.

Installation¶

pip install forge-kaif

Quick Start¶

from pydantic import BaseModel
from forge.validation import validate

class CreateUserRequest(BaseModel):
    name: str
    email: str
    age: int

@validate(schema=CreateUserRequest)
async def create_user(data: CreateUserRequest):
    # data is already a validated CreateUserRequest instance
    return await db.insert_user(data)

Key Features¶

Structured Error Responses¶

When validation fails, the module returns a consistent error format:

{
  "detail": [
    {
      "loc": ["body", "email"],
      "msg": "value is not a valid email address",
      "type": "value_error"
    }
  ]
}

Automatic Error Formatting¶

from pydantic import ValidationError
from forge.validation import format_validation_error

try:
    validated = schema.model_validate(data)
except ValidationError as exc:
    error_response = format_validation_error(exc)
    # error_response is a ValidationErrorResponse with structured detail

FastAPI Integration¶

The validation decorator works seamlessly with FastAPI routes, raising HTTPException(422) with structured error details that FastAPI converts to proper JSON responses.

API Reference¶

Classes¶

ValidationErrorDetail ¶

Details of a single validation error.

ValidationErrorResponse ¶

Standard error response for validation failures.