Creating a Table for Post Likes

To allow users to like or dislike posts in your social media application, you’ll need to create a separate table to store these interactions. This table will typically have a foreign key referencing the user and the post involved.

Creating the PostLikes Table

Python

from sqlalchemy import Column, Integer, ForeignKey

class PostLike(Base):
    __tablename__ = "post_likes"

    id = Column(Integer, primary_key=True, index=True)
    user_id = Column(Integer, ForeignKey("users.id"))   
    post_id = Column(Integer, ForeignKey("posts.id"))

    user = relationship("User", back_populates="liked_posts")
    post = relationship("Post", back_populates="likes")   

Explanation:

• The PostLike model represents a like or dislike interaction between a user and a post.
• The user_id and post_id columns reference the corresponding User and Post records.
• The relationship statements define the relationships between the PostLike model and the User and Post models.

Creating Endpoints for Liking and Disliking Posts

Python

@router.post("/posts/{post_id}/like")
async def like_post(post_id: int, current_user: User = Depends(get_current_user), db: Session = Depends(get_db)):
    # Check if the user has already liked or disliked the post
    existing_like = await db.query(PostLike).filter(PostLike.user_id == current_user.id, PostLike.post_id == post_id).first()
    if existing_like:
        return {"message": "You have already liked or disliked this post"}

    # Create a new like
    like = PostLike(user_id=current_user.id, post_id=post_id)
    db.add(like)
    await db.commit()
    await db.refresh(like)
    return {"message": "Post liked"}

@router.delete("/posts/{post_id}/like")
async def unlike_post(post_id: int, current_user: User = Depends(get_current_user), db: Session = Depends(get_db)):
    # Find the existing like
    existing_like = await db.query(PostLike).filter(PostLike.user_id == current_user.id, PostLike.post_id == post_id).first()
    if not existing_like:
        return {"message": "You have not liked or disliked this post"}

    # Delete the like
    db.delete(existing_like)
    await db.commit()
    return {"message": "Post unliked"}

Retrieving Post Likes

Python

@router.get("/posts/{post_id}/likes")
async def get_post_likes(post_id: int, db: Session = Depends(get_db)):
    likes = await db.query(PostLike).filter(PostLike.post_id == post_id).all()
    return likes

By following these steps, you can effectively implement post liking functionality in your FastAPI application, allowing users to interact with and engage with the content on your platform.