src/higher_lower/presentation/web/app.py

@@ -3,7 +3,7 @@
 @brief Routes that map a URL path to a guess and show the matching page.
 """
 
-from flask import Flask
+from flask import Blueprint, Flask, current_app
 
 from higher_lower.application.guess_game import GuessGame
 from higher_lower.constants import MAX_NUMBER, MIN_NUMBER
@@ -15,6 +15,43 @@ from higher_lower.presentation.web.page import (
 )
 from higher_lower.presentation.web.view import render_page
 
+## Key under which the game is stored in the Flask extensions registry.
+_GAME_KEY = "guess_game"
+
+## Blueprint that holds the views of the game.
+_blueprint = Blueprint("higher_lower", __name__)
+
+
+def _current_game() -> GuessGame:
+    """Find the game stored in the running application.
+
+    @return The game created by create_app.
+    """
+    game: GuessGame = current_app.extensions[_GAME_KEY]
+    return game
+
+
+@_blueprint.route("/")
+def home() -> str:
+    """Show the home page.
+
+    @return The home page HTML.
+    """
+    return render_page(HOME_PAGE)
+
+
+@_blueprint.route("/<int:guess>")
+def guess_number(guess: int) -> str:
+    """Judge the guess in the URL path.
+
+    @param guess The number the player guessed.
+    @return The page for a low, high, correct or out of range guess.
+    """
+    game = _current_game()
+    if not game.is_in_range(guess):
+        return render_page(OUT_OF_RANGE_PAGE)
+    return render_page(page_for_result(game.check(guess)))
+
 
 def create_app(secret_number: int | None = None) -> Flask:
     """Build the Flask application.
@@ -25,26 +62,7 @@ def create_app(secret_number: int | None = None) -> Flask:
     """
     if secret_number is None:
         secret_number = random_secret_number(MIN_NUMBER, MAX_NUMBER)
-    game = GuessGame(secret_number)
     app = Flask(__name__)
-
-    @app.route("/")
-    def home() -> str:
-        """Show the home page.
-
-        @return The home page HTML.
-        """
-        return render_page(HOME_PAGE)
-
-    @app.route("/<int:guess>")
-    def guess_number(guess: int) -> str:
-        """Judge the guess in the URL path.
-
-        @param guess The number the player guessed.
-        @return The page for a low, high, correct or out of range guess.
-        """
-        if not game.is_in_range(guess):
-            return render_page(OUT_OF_RANGE_PAGE)
-        return render_page(page_for_result(game.check(guess)))
-
+    app.extensions[_GAME_KEY] = GuessGame(secret_number)
+    app.register_blueprint(_blueprint)
     return app