Merge pull request #509 from hfhoffman1144/python-pydantic

Materials for Pydantic: Simplifying Data Validation in Python

Author: brendaweles

python-pydantic/README.md

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+# Pydantic: Simplifying Data Validation in Python
+
+Supporting code for the Real Python tutorial [Pydantic: Simplifying Data Validation in Python](https://realpython.com/pydantic-simplifying-data-validation-in-python/). 
+
+To run the code in this tutorial, install Pydantic with its `email` dependency:
+
+```console
+(venv) $ python -m pip install "pydantic[email]"
+```
+
+Pydantic has a separate package for [settings management](https://docs.pydantic.dev/latest/concepts/pydantic_settings/), which you'll also cover in this tutorial. To install this, run the following command:
+
+```console
+(venv) $ python -m pip install pydantic-settings
+```

python-pydantic/pydantic_models.py

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+from typing import Self
+from datetime import date
+from uuid import UUID, uuid4
+from enum import Enum
+from pydantic import (
+    BaseModel,
+    EmailStr,
+    Field,
+    field_validator,
+    model_validator,
+)
+
+
+class Department(Enum):
+    HR = "HR"
+    SALES = "SALES"
+    IT = "IT"
+    ENGINEERING = "ENGINEERING"
+
+
+class Employee(BaseModel):
+    employee_id: UUID = Field(default_factory=lambda: uuid4(), frozen=True)
+    name: str = Field(min_length=1, frozen=True)
+    email: EmailStr = Field(pattern=r".+@example\.com$")
+    date_of_birth: date = Field(alias="birth_date", repr=False, frozen=True)
+    salary: float = Field(alias="compensation", gt=0, repr=False)
+    department: Department
+    elected_benefits: bool
+
+    @field_validator("date_of_birth")
+    @classmethod
+    def check_valid_age(cls, date_of_birth: date) -> date:
+        date_delta = date.today() - date_of_birth
+        age = date_delta.days / 365
+
+        if age < 18:
+            raise ValueError("Employees must be at least 18 years old.")
+
+        return date_of_birth
+
+    @model_validator(mode="after")
+    def check_it_benefits(self) -> Self:
+        department = self.department
+        elected_benefits = self.elected_benefits
+
+        if department == Department.IT and elected_benefits:
+            raise ValueError(
+                "IT employees are contractors and don't qualify for benefits."
+            )
+        return self

python-pydantic/settings_management.py

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+from pydantic import HttpUrl, Field
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+class AppConfig(BaseSettings):
+    model_config = SettingsConfigDict(
+        env_file=".env",
+        env_file_encoding="utf-8",
+        case_sensitive=True,
+        extra="forbid",
+    )
+
+    database_host: HttpUrl
+    database_user: str = Field(min_length=5)
+    database_password: str = Field(min_length=10)
+    api_key: str = Field(min_length=20)

python-pydantic/validate_functions.py

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+import time
+from typing import Annotated
+from pydantic import PositiveFloat, validate_call, Field, EmailStr
+
+
+@validate_call
+def send_invoice(
+    client_name: Annotated[str, Field(min_length=1)],
+    client_email: EmailStr,
+    items_purchased: list[str],
+    amount_owed: PositiveFloat,
+) -> str:
+    email_str = f"""
+    Dear {client_name}, \n
+    Thank you for choosing xyz inc! You
+    owe ${amount_owed:,.2f} for the following items: \n
+    {items_purchased}
+    """
+
+    print(f"Sending email to {client_email}...")
+    time.sleep(2)
+
+    return email_str