Complete mongo db integration for get /books/{id})

app/routes.py

@@ -2,6 +2,7 @@
 
 import copy
 
+from bson.objectid import ObjectId
 from flask import jsonify, request
 from pymongo.errors import ConnectionFailure
 from werkzeug.exceptions import HTTPException, NotFound
@@ -88,7 +89,6 @@ def add_book():
         host = request.host_url
         # Send the host and new book_id to the helper function to generate links
         final_book_for_api = append_hostname(book_from_db, host)
-        print("final_book_for_api", final_book_for_api)
 
         # Transform _id to id and remove the internal _id
         final_book_for_api["id"] = str(final_book_for_api["_id"])
@@ -141,20 +141,36 @@ def get_book(book_id):
         """
         Retrieve a specific book by its unique ID.
         """
-        if not books:
-            return jsonify({"error": "Book collection not initialized"}), 500
+        # get the collection
+        collection = get_book_collection()
 
-        # extract host from the request
+        if collection is None:
+            return jsonify({"error": "Book collection not found"}), 500
+
+        # sanity check book_id
+        if not ObjectId.is_valid(book_id):
+            return jsonify({"error": "Invalid book ID format"}), 400
+        obj_id = ObjectId(book_id)
+
+        # Query db for a non-deleted book
+        query = {"_id": obj_id, "state": {"$ne": "deleted"}}
+        # look it up in MongoDB
+        book = collection.find_one(query)
+        # also equivalent to Key version
+        # book = raw_books.find_one(_id=obj_id, state={"$ne": "deleted"})
+
+        if book is None:
+            return jsonify({"error": "Book not found"}), 404
+
+        # Format for API response
         host = request.host_url
+        formatted_book = append_hostname(book, host)
 
-        for book in books:
-            if book.get("id") == book_id and book.get("state") != "deleted":
-                # copy the book
-                book_copy = copy.deepcopy(book)
-                book_copy.pop("state", None)
-                # Add the hostname to the book_copy object and return it
-                return jsonify(append_hostname(book_copy, host)), 200
-        return jsonify({"error": "Book not found"}), 404
+        formatted_book["id"] = str(formatted_book["_id"])
+        formatted_book.pop("state", None)
+        formatted_book.pop("_id", None)
+
+        return jsonify(formatted_book), 200
 
     # ----------- DELETE section ------------------
     @app.route("/books/<string:book_id>", methods=["DELETE"])

openapi.yml

@@ -135,6 +135,15 @@ components:
       required:
         - error
 
+    SimpleError:
+      type: object
+      properties:
+        error:
+          type: string
+          description: A brief error message.
+      required:
+        - error
+
   # API Error: Reusable responses for common errors  
   responses:
     BadRequest:
@@ -263,10 +272,32 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/BookOutput' 
+        '400':
+          description: |-
+            Bad Request. The provided book_id is not a valid 24-character hexadecimal string.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/SimpleError'
+              example:
+                error: "Invalid book ID format"
         '404': 
-          $ref: '#/components/responses/NotFound' 
-        '500': 
-          $ref: '#/components/responses/InternalServerError' 
+          description: A book with the specified ID was not found.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/SimpleError'
+              example:
+                error: "Book not found" 
+        '500':
+          description: |-
+            Service Unavailable. The server cannot connect to the database.
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/SimpleError'
+              example:
+                error: "Book collection not found" 
      # --------------------------------------------
 
     put:

tests/conftest.py

@@ -10,6 +10,7 @@
 import pytest
 
 from app import create_app
+from app.datastore.mongo_db import get_book_collection
 
 
 @pytest.fixture(name="_insert_book_to_db")
@@ -84,3 +85,23 @@ def test_app():
 def client(test_app):  # pylint: disable=redefined-outer-name
     """A test client for the app."""
     return test_app.test_client()
+
+
+@pytest.fixture(scope="function")
+def db_setup(test_app):  # pylint: disable=redefined-outer-name
+    """
+    Sets up and tears down the database for a test.
+    Scope is "function" to ensure a clean DB for each test.
+    """
+    # Use app_context to access the database
+    with test_app.app_context():
+        collection = get_book_collection()
+
+        collection.delete_many({})
+    # Pass control to the test function
+    yield
+
+    # Teardown: code runs after the test is finished
+    with test_app.app_context():
+        collection = get_book_collection()
+        collection.delete_many({})