adding validator to disallow duplicate books

Author: yoandysse

models.py

@@ -19,6 +19,35 @@ class Config:
             }
         }
 
+class BookCreate(BaseModel):
+    id: str = Field(default_factory=uuid.uuid4, alias="_id")
+    title: str = Field(...)
+    author: str = Field(...)
+    synopsis: str = Field(...)
+
+    class Config:
+        allow_population_by_field_name = True
+        schema_extra = {
+            "example": {
+                "title": "Don Quixote",
+                "author": "Miguel de Cervantes",
+                "synopsis": "..."
+            }
+        }
+class BookCreate(BaseModel):
+    title: str = Field(...)
+    author: str = Field(...)
+    synopsis: str = Field(...)
+
+    class Config:
+        allow_population_by_field_name = True
+        schema_extra = {
+            "example": {
+                "title": "Don Quixote",
+                "author": "Miguel de Cervantes",
+                "synopsis": "..."
+            }
+        }
 
 class BookUpdate(BaseModel):
     title: Optional[str]

routes.py

@@ -1,14 +1,21 @@
 from fastapi import APIRouter, Body, Request, Response, HTTPException, status
 from fastapi.encoders import jsonable_encoder
 from typing import List
-
-from models import Book, BookUpdate
+import uuid
+from models import Book, BookUpdate, BookCreate
 
 router = APIRouter()
 
 @router.post("/", response_description="Create a new book", status_code=status.HTTP_201_CREATED, response_model=Book)
-def create_book(request: Request, book: Book = Body(...)):
+def create_book(request: Request, book: BookCreate = Body(...)):
     book = jsonable_encoder(book)
+    book["_id"] = str(uuid.uuid4())
+
+    # verify if book title already exists
+    if request.app.database["books"].find_one({"title": book["title"]}):
+        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail=f"Book with title {book['title']} already exists")
+
+
     new_book = request.app.database["books"].insert_one(book)
     created_book = request.app.database["books"].find_one(
         {"_id": new_book.inserted_id}