Pydantic Type Coercion

pydantic_coercion.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "dc7ad921-684f-4508-a8e8-8ab0b236a1a6",
   "metadata": {},
   "source": [
    "## Dict -> Object Coercion with pydantic and @validate_arguments\n",
    "\n",
    "https://docs.pydantic.dev/latest/usage/validation_decorator/"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "c1dacf4e-7f38-4913-9deb-c2137a7f01c8",
   "metadata": {
    "tags": []
   },
   "outputs": [],
   "source": [
    "from typing import Literal\n",
    "from pydantic import BaseModel, validate_arguments\n",
    "\n",
    "\n",
    "class MyClass(BaseModel):\n",
    "   foo: Literal[\"bar\"]\n",
    "   fizzbuzz: dict[str, list[int]]\n",
    "\n",
    "\n",
    "@validate_arguments\n",
    "def add_my_class(dict_or_object: MyClass):\n",
    "    print(repr(dict_or_object))\n",
    "    print()\n",
    "    print(dict_or_object.dict())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "0b81ecf6-defb-4733-b5ed-ade64e4c38d4",
   "metadata": {
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "MyClass(foo='bar', fizzbuzz={'buzz': [3, 6], 'fizz': [5, 10]})\n",
      "\n",
      "{'foo': 'bar', 'fizzbuzz': {'buzz': [3, 6], 'fizz': [5, 10]}}\n"
     ]
    }
   ],
   "source": [
    "add_my_class({\"foo\": \"bar\", \"fizzbuzz\": {\"buzz\": [3, \"6\"], \"fizz\": [\"5\", 10]}})"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "id": "9270a74d-660d-4936-9f3e-0cdd2b4e943d",
   "metadata": {
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "MyClass(foo='bar', fizzbuzz={})\n",
      "\n",
      "{'foo': 'bar', 'fizzbuzz': {}}\n"
     ]
    }
   ],
   "source": [
    "my_class = MyClass(foo=\"bar\", fizzbuzz={})\n",
    "add_my_class(my_class)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "efa38566-ab6f-4ccd-b2b3-fb7a17629ecb",
   "metadata": {
    "tags": []
   },
   "outputs": [
    {
     "ename": "ValidationError",
     "evalue": "2 validation errors for AddMyClass\ndict_or_object -> foo\n  unexpected value; permitted: 'bar' (type=value_error.const; given=BAR; permitted=('bar',))\ndict_or_object -> fizzbuzz\n  field required (type=value_error.missing)",
     "output_type": "error",
     "traceback": [
      "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[0;31mValidationError\u001b[0m                           Traceback (most recent call last)",
      "Cell \u001b[0;32mIn[4], line 1\u001b[0m\n\u001b[0;32m----> 1\u001b[0m \u001b[43madd_my_class\u001b[49m\u001b[43m(\u001b[49m\u001b[43m{\u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mmissing\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m:\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mfields\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m,\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mfoo\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m:\u001b[49m\u001b[43m \u001b[49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[38;5;124;43mBAR\u001b[39;49m\u001b[38;5;124;43m\"\u001b[39;49m\u001b[43m}\u001b[49m\u001b[43m)\u001b[49m\n",
      "File \u001b[0;32m~/.local/share/virtualenvs/cloud-dogfood-FpNSVJLB/lib/python3.10/site-packages/pydantic/decorator.py:40\u001b[0m, in \u001b[0;36mpydantic.decorator.validate_arguments.validate.wrapper_function\u001b[0;34m()\u001b[0m\n",
      "File \u001b[0;32m~/.local/share/virtualenvs/cloud-dogfood-FpNSVJLB/lib/python3.10/site-packages/pydantic/decorator.py:133\u001b[0m, in \u001b[0;36mpydantic.decorator.ValidatedFunction.call\u001b[0;34m()\u001b[0m\n",
      "File \u001b[0;32m~/.local/share/virtualenvs/cloud-dogfood-FpNSVJLB/lib/python3.10/site-packages/pydantic/decorator.py:130\u001b[0m, in \u001b[0;36mpydantic.decorator.ValidatedFunction.init_model_instance\u001b[0;34m()\u001b[0m\n",
      "File \u001b[0;32m~/.local/share/virtualenvs/cloud-dogfood-FpNSVJLB/lib/python3.10/site-packages/pydantic/main.py:341\u001b[0m, in \u001b[0;36mpydantic.main.BaseModel.__init__\u001b[0;34m()\u001b[0m\n",
      "\u001b[0;31mValidationError\u001b[0m: 2 validation errors for AddMyClass\ndict_or_object -> foo\n  unexpected value; permitted: 'bar' (type=value_error.const; given=BAR; permitted=('bar',))\ndict_or_object -> fizzbuzz\n  field required (type=value_error.missing)"
     ]
    }
   ],
   "source": [
    "add_my_class({\"missing\": \"fields\", \"foo\": \"BAR\"})"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3 (ipykernel)",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.10.10"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 5
}