Backend FastAPI

Usemos FastAPI para construir backend en Python

Configuremos el ambiente

requirements.txt

fastapi[all]
uvicorn[standard]

!pip install -r requirements.txt

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
async def root():
    return {"message": "Hello World"}

!uvicorn main:app --reload

Métodos Get - Post - Put - Delete

# @title Cargar Datos
users = [
    {
        "name": "John",
        "lastname": "Doe",
        "language": "English",
        "email": "john.doe@example.com",
        "location_id": 1,
        "password": "password123",
        "skill_id": 101
    },
    {
        "name": "Alice",
        "lastname": "Smith",
        "language": "Spanish",
        "email": "alice.smith@example.com",
        "location_id": 2,
        "password": "alicepwd456",
        "skill_id": 102
    },
    {
        "name": "Bob",
        "lastname": "Johnson",
        "language": "French",
        "email": "bob.johnson@example.com",
        "location_id": 3,
        "password": "bobbie789",
        "skill_id": 103
    },
    {
        "name": "Eva",
        "lastname": "Brown",
        "language": "German",
        "email": "eva.brown@example.com",
        "location_id": 4,
        "password": "evapass123",
        "skill_id": 104
    },
    {
        "name": "Michael",
        "lastname": "Davis",
        "language": "Italian",
        "email": "michael.davis@example.com",
        "location_id": 5,
        "password": "mdp7890",
        "skill_id": 105
    },
    {
        "name": "Sophia",
        "lastname": "Garcia",
        "language": "Portuguese",
        "email": "sophia.garcia@example.com",
        "location_id": 6,
        "password": "sophiapwd12",
        "skill_id": 106
    },
    {
        "name": "Daniel",
        "lastname": "Rodriguez",
        "language": "Chinese",
        "email": "daniel.rodriguez@example.com",
        "location_id": 7,
        "password": "dan1234",
        "skill_id": 107
    },
    {
        "name": "Olivia",
        "lastname": "Martinez",
        "language": "Japanese",
        "email": "olivia.martinez@example.com",
        "location_id": 8,
        "password": "oliviapass567",
        "skill_id": 108
    },
    {
        "name": "William",
        "lastname": "Lopez",
        "language": "Korean",
        "email": "william.lopez@example.com",
        "location_id": 9,
        "password": "willpwd90",
        "skill_id": 109
    },
    {
        "name": "Ava",
        "lastname": "Lee",
        "language": "Russian",
        "email": "ava.lee@example.com",
        "location_id": 10,
        "password": "avapass321",
        "skill_id": 110
    }
]

Documentación:

localhost:8000/docs

@app.get("/")
async def root():
    return {"message": "Hello World"}

from pydantic import BaseModel
class User(BaseModel):
    user_id = int
    name = str
    lastname = str
    language = str
    email = str
    location_id = int
    password = str
    skill_id = int

Probemos la API

@app.get("/items/{item_id}")
async def read_item(item_id: int):
    try:
        item = users[item_id]
        return User(**item)
    except:
        print ({"Error": "item_id"})

@app.post("/items/")
async def create_item(item: User):
    users.append(item)  # Agregar el nuevo registro a la base de datos (en este caso, una lista)
    return item

@app.put("/items/{item_id}")
async def update_item(item_id: int, item: User):
    if item_id < 0 or item_id >= len(users):
        return {"error": "El id del recurso no existe"}

    # Actualizar el recurso existente por su id
    users[item_id] = item.dict()

    return {"message": "Recurso actualizado correctamente"}

# Endpoint DELETE para eliminar un recurso por su id
@app.delete("/items/{item_id}")
async def delete_item(item_id: int):
    index_to_remove = None

    # Buscar el índice del recurso por su id
    for i, item in enumerate(users):
        if item["id"] == item_id:
            index_to_remove = i
            break

    if index_to_remove is not None:
        # Eliminar el recurso de la lista por su índice
        deleted_item = users.pop(index_to_remove)
        return {"message": f"Recurso con id {item_id} eliminado correctamente"}
    else:
        return {"error": f"El recurso con id {item_id} no existe"}

Hablemos de esquemas

esquemas.py

from pydantic import BaseModel
class User(BaseModel):
    user_id : int
    name : str
    lastname : str
    language : str
    email : str
    location_id : int
    password : str
    skill_id : int

Hablemos de ORM’s

database.py

sqlalchemy

from sqlalchemy import create_engine
engine = create_engine("sqlite:///test.db", echo=True)

from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base
session = sessionmaker(bind=engine)

Base = declarative_base()

Hablemos de modelos (ORM’s)

models.py

from sqlalchemy import Column, Integer, String, DateTime, Boolean, Float

from sqlalchemy import Column, Integer, String, DateTime, Boolean, Float

class User(Base):
    __tablename__ = "users"
    user_id = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String(50))
    lastname = Column(String(50))
    language = Column(String)
    email = Column(String)
    location_id = Column(Integer)
    password = Column(String)
    skill_id = Column(Integer)

Base.metadata.create_all(engine)

@app.post("/users")
async def create_user(user: User):
    session.add(user)
    session.commit()
    return user

@app.put("/items/{item_id}")
async def update_item(item_id: str, item: Item):
    return {"item_name": item.name, "item_id": item_id}


@app.get("/users")
async def get_users():
    users = session.query(User).all()
    return users

@app.get("/users/{user_id}")
async def get_user(user_id: int):
    user = session.query(User).filter(User.user_id == user_id).first()
    return user