Creating Posts in Our Social Media API

In this section, we’ll understand the process of building a feature to allow users to create posts in our social media API. We’ll utilize FastAPI’s powerful data validation and request body handling capabilities to ensure that posts are created correctly.

Setting Up the Data Model

First, we’ll define a data model for our posts using Pydantic:

Python

from pydantic import BaseModel

class Post(BaseModel):
    content: str
    user_id: int

This model ensures that posts have a content field and a user_id field.

Creating a POST Endpoint

Now, we’ll create a POST endpoint to handle the creation of new posts:

Python

from fastapi import APIRouter, HTTPException

router = APIRouter()

@router.post("/posts")
async def create_post(post: Post, db: Session = Depends(get_db)):
    new_post = PostModel(content=post.content, user_id=post.user_id)
    db.add(new_post)
    db.commit()
    db.refresh(new_post)
    return new_post

Explanation:

• The @router.post("/posts") decorator defines a POST endpoint for the /posts path.
• The post: Post argument indicates that the request body should be parsed as a Post object.
• The db: Session = Depends(get_db) argument injects a database session into the function.
• A new PostModel instance is created using the data from the request body.
• The new post is added to the database session.
• The changes are committed to the database.
• The new post is refreshed to get its assigned ID.
• The created post is returned as a response.

Handling Errors

You might want to add error handling to catch exceptions like database errors or validation errors:

Python

try:
    db.add(new_post)
    db.commit()
    db.refresh(new_post)
except Exception as e:
    raise HTTPException(status_code=400, detail=f"Error creating post: {e}")