I am trying to use imageattach, and I do not really understand how it should work, how dis/similar it is to just a normal relationship.
Below is a snippet of code, which is mimicking something like a StackOverflow question board, where users could post questions and the questions could have images attached to them. I am following a style quite similar to FastAPI's SQLAlchemy tutorial.
I am able to get users, create users, and get questions. But when I try to create a question (POST a question), I get the following pydantic validation error:
pydantic.error_wrappers.ValidationError: 1 validation error for Question
response -> pictures
value is not a valid list (type=type_error.list)
I am fairly sure this is an issue with pydantic having trouble understanding the relationship that sqlalchemy-imageattach creates, which is why I am posting here.
schemas.py (Pydantic models)
from typing import List, Optional
from pydantic import BaseModel
class QuestionPictureBase(BaseModel):
pass
class QuestionPicture(QuestionPictureBase):
id: int
question_id: int
class Config:
orm_mode = True
class QuestionBase(BaseModel):
header: str
details: str
class QuestionCreate(QuestionBase):
pass
class Question(QuestionBase):
id: int
creator_id: int
pictures: List[QuestionPicture] = []
class Config:
orm_mode = True
class UserBase(BaseModel):
email: Optional[str] = None
name: str # This is the nickname they want to go by
username: str # This is the unique user name
class UserCreate(UserBase):
password: str
class User(UserBase):
id: int
is_active: bool
questions: List[Question] = []
class Config:
orm_mode = TrueThen the SQL ORM models:
models.py
from sqlalchemy import Boolean, Column, ForeignKey, Integer, String, Text
from sqlalchemy.orm import relationship
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy_imageattach.entity import Image, image_attachment
from .database import Base
class User(Base):
__tablename__ = "users"
id = Column(Integer, primary_key=True, index=True)
name = Column(String)
username = Column(String, unique=True, index=True)
email = Column(String)
hashed_password = Column(String)
is_active = Column(Boolean, default=True)
questions = relationship("Question", back_populates="creator", uselist=True)
class Question(Base):
__tablename__ = "questions"
id = Column(Integer, primary_key=True, index=True)
header = Column(String, index=True)
details = Column(String, index=True)
creator_id = Column(Integer, ForeignKey("users.id"))
pictures = image_attachment("QuestionPicture", uselist=True)
creator = relationship("User", back_populates="questions")
class QuestionPicture(Base, Image):
"""Model for pictures associated with the question."""
__tablename__ = "question_pictures"
id = Column(Integer, primary_key=True)
question_id = Column(Integer, ForeignKey("questions.id"))
question = relationship("Question", back_populates="pictures")Then the CRUD module (edited down to just the function of interest):
crud.py
from sqlalchemy.orm import Session
from . import models, schemas
def create_user_question(db: Session, question: schemas.QuestionCreate, username: str):
user = get_user_by_username(db=db, username=username)
db_item = models.Question(**question.dict(), creator_id=user.id)
db.add(db_item)
db.commit()
db.refresh(db_item)
return db_itemAnd finally, the main.py module, again edited just to focus upon question creation.
from typing import List
from fastapi import Depends, FastAPI, HTTPException
from sqlalchemy.orm import Session
from . import crud, models, schemas
from .database import SessionLocal, engine
app = FastAPI()
def get_db():
db = SessionLocal()
try:
yield db
finally:
db.close()
@app.post("/users/{username}/questions/", response_model=schemas.Question)
def create_question_for_user(
username: str, question: schemas.QuestionCreate, db: Session = Depends(get_db)
):
return crud.create_user_question(db=db, question=question, username=username)
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