added exception handling

Author: SuRu

app/__init__.py

@@ -0,0 +1,34 @@
+from fastapi import FastAPI, Request, status
+from fastapi.responses import JSONResponse
+
+from app.exceptions import EntityNotFoundException
+from app.routers import branch, student
+
+app = FastAPI(
+    title='Students API',
+    description='Simple python students API',
+    version='1.0.0',
+    contact={
+        'name': 'SuRu',
+        'url': 'https://github.com/suru33/students-api-python',
+        'email': '33urus@gmail.com'
+    },
+    license_info={
+        'name': 'GNU General Public License v2.0',
+        'url': 'https://github.com/suru33/students-api-python/blob/master/LICENSE'
+    }
+)
+
+app.include_router(branch.router)
+app.include_router(student.router)
+
+
+@app.exception_handler(EntityNotFoundException)
+async def entity_not_found_exception_handler(request: Request, ex: EntityNotFoundException):
+    return JSONResponse(
+        status_code=status.HTTP_404_NOT_FOUND,
+        content={
+            "path": request.url.path,
+            "message": f"{ex.name}: {ex.value} does not exist"
+        },
+    )

app/exceptions.py

@@ -0,0 +1,7 @@
+from uuid import UUID
+
+
+class EntityNotFoundException(Exception):
+    def __init__(self, name: str, value: UUID):
+        self.name = name
+        self.value = value

app/models.py

@@ -19,7 +19,7 @@ class Student(Base):
 
     id = Column(name='s_id', type_=UUID(as_uuid=True), primary_key=True, index=True)
     name = Column(name='s_name', type_=String, nullable=False)
-    branch = Column(name='s_branch', type_=UUID, nullable=False)
+    branch = Column(name='s_branch', type_=UUID(as_uuid=True), nullable=False)
     year = Column(name='s_year', type_=Integer, nullable=False)
     dob = Column(name='s_dob', type_=DATE, nullable=False)
     email = Column(name='s_email', type_=String, nullable=False)

app/repositories/branch_repository.py

@@ -1,8 +1,9 @@
 from datetime import datetime
-from uuid import uuid4
+from uuid import UUID, uuid4
 
 from sqlalchemy.orm import Session
 
+from app.exceptions import EntityNotFoundException
 from app.models import Branch
 from app.schemas import BranchRequest
 
@@ -21,8 +22,12 @@ def create_branch(db: Session, request: BranchRequest):
     return branch
 
 
-def get_branch_by_id(db: Session, branch_id: str):
-    return db.query(Branch).filter(Branch.id == branch_id).first()
+def get_branch_by_id(db: Session, branch_id: UUID):
+    branch = db.query(Branch).filter(Branch.id == branch_id).first()
+    if branch:
+        return branch
+
+    raise EntityNotFoundException('branch', branch_id)
 
 
 def get_all_branches(db: Session):

app/repositories/student_repository.py

@@ -1,17 +1,21 @@
 from datetime import datetime
-from uuid import uuid4
+from uuid import UUID, uuid4
 
 from sqlalchemy.orm import Session
 
+from app.exceptions import EntityNotFoundException
 from app.models import Student
+from app.repositories import branch_repository
 from app.schemas import StudentRequest
 
 
-def create_student(db: Session, request: StudentRequest):
+def create_student(db: Session, branch_id: UUID, request: StudentRequest):
+    branch = branch_repository.get_branch_by_id(db, branch_id)
+
     student = Student(
         id=uuid4(),
         name=request.name,
-        branch=request.branch,
+        branch=branch.id,
         year=request.year,
         dob=request.dob,
         email=request.email,
@@ -25,8 +29,12 @@ def create_student(db: Session, request: StudentRequest):
     return student
 
 
-def get_student_by_id(db: Session, student_id: str):
-    return db.query(Student).filter(Student.id == student_id).first()
+def get_student_by_id(db: Session, student_id: UUID):
+    student = db.query(Student).filter(Student.id == student_id).first()
+    if student:
+        return student
+
+    raise EntityNotFoundException('student', student_id)
 
 
 def get_all_students(db: Session):

app/routers/branch.py

@@ -1,11 +1,12 @@
 from typing import List
+from uuid import UUID
 
-from fastapi import APIRouter, Depends, HTTPException
+from fastapi import APIRouter, Depends, HTTPException, status
 from sqlalchemy.orm import Session
 
 from app.dependencies import get_db
-from app.repositories import branch_repository as repository
-from app.schemas import BranchRequest, BranchResponse
+from app.repositories import branch_repository as repository, student_repository
+from app.schemas import BranchRequest, BranchResponse, StudentRequest, StudentResponse
 
 router = APIRouter(prefix="/branch", tags=["branch"])
 
@@ -16,13 +17,18 @@ async def get_all_branches(db: Session = Depends(get_db)):
 
 
 @router.get("/{branch_id}", response_model=BranchResponse)
-async def get_branch_by_id(branch_id, db: Session = Depends(get_db)):
+async def get_branch_by_id(branch_id: UUID, db: Session = Depends(get_db)):
     branch = repository.get_branch_by_id(db, branch_id)
     if branch is None:
         raise HTTPException(status_code=404, detail="Branch not found")
     return branch
 
 
-@router.post("/", response_model=BranchResponse)
+@router.post("/", response_model=BranchResponse, status_code=status.HTTP_201_CREATED)
 async def create_branch(request: BranchRequest, db: Session = Depends(get_db)):
     return repository.create_branch(db, request)
+
+
+@router.post("/{branch_id}/student", response_model=StudentResponse, status_code=status.HTTP_201_CREATED)
+async def create_student(request: StudentRequest, branch_id: UUID, db: Session = Depends(get_db)):
+    return student_repository.create_student(db, branch_id, request)

app/routers/student.py

@@ -1,11 +1,12 @@
 from typing import List
+from uuid import UUID
 
 from fastapi import APIRouter, Depends, HTTPException
 from sqlalchemy.orm import Session
 
 from app.dependencies import get_db
 from app.repositories import student_repository as repository
-from app.schemas import StudentRequest, StudentResponse
+from app.schemas import StudentResponse
 
 router = APIRouter(prefix="/student", tags=["student"])
 
@@ -16,13 +17,11 @@ async def get_all_students(db: Session = Depends(get_db)):
 
 
 @router.get("/{student_id}", response_model=StudentResponse)
-async def get_student_by_id(student_id, db: Session = Depends(get_db)):
+async def get_student_by_id(student_id: UUID, db: Session = Depends(get_db)):
     student = repository.get_student_by_id(db, student_id)
     if student is None:
         raise HTTPException(status_code=404, detail="Student not found")
     return student
 
 
-@router.post("/", response_model=StudentResponse)
-async def create_student(request: StudentRequest, db: Session = Depends(get_db)):
-    return repository.create_student(db, request)
+

app/schemas.py

@@ -1,12 +1,12 @@
 from datetime import date, datetime
 from uuid import UUID
 
-from pydantic import BaseModel
+from pydantic import BaseModel, EmailStr, conint, constr
 
 
 class BranchRequest(BaseModel):
-    short_name: str
-    name: str
+    short_name: constr(strict=True, min_length=3, max_length=10)
+    name: constr(strict=True, min_length=3, max_length=100)
 
 
 class BranchResponse(BaseModel):
@@ -21,21 +21,20 @@ class Config:
 
 
 class StudentRequest(BaseModel):
-    name: str
-    branch: str
-    year: int
-    dob: str
-    email: str
-    phone: str
+    name: constr(strict=True, min_length=3, max_length=100)
+    year: conint(strict=True, ge=1, le=4)
+    dob: date
+    email: EmailStr
+    phone: constr(strict=True, min_length=5, max_length=20)
 
 
 class StudentResponse(BaseModel):
     id: UUID
     name: str
-    branch: str
-    year: int
+    branch: UUID
+    year: conint(strict=True, ge=1, le=4)
     dob: date
-    email: str
+    email: EmailStr
     phone: str
     created_at: datetime
     updated_at: datetime

main.py

@@ -1,24 +1,4 @@
-from fastapi import FastAPI
-
-from app.routers import branch, student
-
-app = FastAPI(
-    title='Students API',
-    description='Simple python students API',
-    version='1.0.0',
-    contact={
-        'name': 'SuRu',
-        'url': 'https://github.com/suru33/students-api-python',
-        'email': '33urus@gmail.com'
-    },
-    license_info={
-        'name': 'GNU General Public License v2.0',
-        'url': 'https://github.com/suru33/students-api-python/blob/master/LICENSE'
-    }
-)
-
-app.include_router(branch.router)
-app.include_router(student.router)
+from app import app
 
 
 @app.get("/")