Update code in endpoints/book.post.py

endpoints/book.post.py

@@ -0,0 +1,90 @@
+Sure, here's an example of a FastAPI endpoint that saves data to a database using SQLAlchemy and Pydantic:
+
+```python
+from typing import List
+from fastapi import FastAPI, HTTPException
+from pydantic import BaseModel
+from sqlalchemy import Column, Integer, String, create_engine
+from sqlalchemy.orm import sessionmaker
+from sqlalchemy.ext.declarative import declarative_base
+
+# Create the database engine and session
+engine = create_engine('sqlite:///books.db', echo=True)
+Session = sessionmaker(bind=engine)
+session = Session()
+
+# Create the base class for SQLAlchemy models
+Base = declarative_base()
+
+# Define the SQLAlchemy model
+class Book(Base):
+    __tablename__ = 'books'
+
+    id = Column(Integer, primary_key=True)
+    title = Column(String)
+    author = Column(String)
+
+    def __repr__(self):
+        return f"Book(id={self.id}, title='{self.title}', author='{self.author}')"
+
+# Create the database table
+Base.metadata.create_all(engine)
+
+# Define the Pydantic model
+class BookSchema(BaseModel):
+    title: str
+    author: str
+
+    class Config:
+        orm_mode = True
+
+# Create the FastAPI app
+app = FastAPI()
+
+# Define the POST endpoint
+@app.post('/books', response_model=List[BookSchema])
+def create_book(book: BookSchema):
+    # Create a new book instance
+    new_book = Book(title=book.title, author=book.author)
+
+    # Add the new book to the session
+    session.add(new_book)
+
+    # Commit the changes to the database
+    session.commit()
+
+    # Retrieve all books from the database
+    books = session.query(Book).all()
+
+    # Convert the SQLAlchemy models to Pydantic models
+    return [BookSchema.from_orm(book) for book in books]
+
+# Run the app
+if __name__ == '__main__':
+    import uvicorn
+    uvicorn.run(app, host='0.0.0.0', port=8000)
+```
+
+Here's a breakdown of the code:
+
+1. We define the SQLAlchemy model `Book` with `id`, `title`, and `author` columns.
+2. We create the database table using `Base.metadata.create_all(engine)`.
+3. We define the Pydantic model `BookSchema` with `title` and `author` fields.
+4. We create the FastAPI app instance.
+5. We define the `POST` endpoint `/books` that accepts a `BookSchema` instance as input.
+6. Inside the endpoint function, we create a new `Book` instance using the data from the `BookSchema` instance.
+7. We add the new `Book` instance to the session and commit the changes to the database.
+8. We retrieve all books from the database using `session.query(Book).all()`.
+9. We convert the SQLAlchemy models to Pydantic models using `BookSchema.from_orm(book)`.
+10. We return the list of `BookSchema` instances as the response.
+
+To run the app, execute `uvicorn main:app --reload` in your terminal, and then you can send a POST request to `http://localhost:8000/books` with a JSON payload like:
+
+```json
+{
+    "title": "The Great Gatsby",
+    "author": "F. Scott Fitzgerald"
+}
+```
+
+This will create a new book in the database and return a list of all books in the database.