src/higher_lower/presentation/lectures/step_02_url_paths.py

@@ -4,11 +4,47 @@
 converter.
 """
 
-from flask import Flask
+from flask import Blueprint, Flask
 from markupsafe import escape
 
 from higher_lower.constants import HOST, PORT
 
+## Blueprint that holds the views of this lecture step.
+_blueprint = Blueprint("step_02_url_paths", __name__)
+
+
+@_blueprint.route("/")
+def home() -> str:
+    """Answer the home route."""
+    return "Hello, World!"
+
+
+@_blueprint.route("/bye")
+def say_bye() -> str:
+    """Answer the fixed route /bye."""
+    return "Bye"
+
+
+@_blueprint.route("/username/<name>")
+def greet(name: str) -> str:
+    """Greet the user whose name is the variable section of the URL.
+
+    @param name The text found in the URL after /username/.
+    @return The greeting, with the name escaped so it cannot inject HTML.
+    """
+    return f"Hello there {escape(name)}!"
+
+
+@_blueprint.route("/username/<name>/<int:number>")
+def greet_with_number(name: str, number: int) -> str:
+    """Greet the user and use the converter <int:number> for a number.
+
+    @param name The text found in the URL after /username/.
+    @param number The integer found after the name; other text gives 404.
+    @return The greeting that repeats the name and the number.
+    """
+    return f"Hello there {escape(name)}, you are {number} years old!"
+
 
 def create_app() -> Flask:
     """Build the Flask application of this lecture step.
@@ -16,36 +52,7 @@ def create_app() -> Flask:
     @return The configured Flask application.
     """
     app = Flask(__name__)
-
-    @app.route("/")
-    def home() -> str:
-        """Answer the home route."""
-        return "Hello, World!"
-
-    @app.route("/bye")
-    def say_bye() -> str:
-        """Answer the fixed route /bye."""
-        return "Bye"
-
-    @app.route("/username/<name>")
-    def greet(name: str) -> str:
-        """Greet the user whose name is the variable section of the URL.
-
-        @param name The text found in the URL after /username/.
-        @return The greeting, with the name escaped so it cannot inject HTML.
-        """
-        return f"Hello there {escape(name)}!"
-
-    @app.route("/username/<name>/<int:number>")
-    def greet_with_number(name: str, number: int) -> str:
-        """Greet the user and use the converter <int:number> for a number.
-
-        @param name The text found in the URL after /username/.
-        @param number The integer found after the name; other text gives 404.
-        @return The greeting that repeats the name and the number.
-        """
-        return f"Hello there {escape(name)}, you are {number} years old!"
-
+    app.register_blueprint(_blueprint)
     return app
 
 

src/higher_lower/presentation/lectures/step_03_html.py

@@ -3,7 +3,7 @@
 @brief A route that returns a heading, a paragraph and two images as HTML.
 """
 
-from flask import Flask
+from flask import Blueprint, Flask
 
 from higher_lower.constants import HOST, LECTURE_IMAGE_WIDTH, PORT, STILL_IMAGE
 
@@ -11,29 +11,34 @@ from higher_lower.constants import HOST, LECTURE_IMAGE_WIDTH, PORT, STILL_IMAGE
 ANIMATED_IMAGE: str = STILL_IMAGE.replace("_s.gif", ".gif")
 
 
+## Blueprint that holds the views of this lecture step.
+_blueprint = Blueprint("step_03_html", __name__)
+
+
+@_blueprint.route("/")
+def home() -> str:
+    """Return structured HTML instead of a plain string.
+
+    The Python string uses double quotes and the HTML attributes use single
+    quotes, so the two never end each other.
+
+    @return A centred heading, a paragraph, a still picture and a GIF.
+    """
+    return (
+        "<h1 style='text-align: center'>Hello, World!</h1>"
+        "<p>This is a paragraph.</p>"
+        f"<img src='{STILL_IMAGE}' width={LECTURE_IMAGE_WIDTH}>"
+        f"<img src='{ANIMATED_IMAGE}' width={LECTURE_IMAGE_WIDTH}>"
+    )
+
+
 def create_app() -> Flask:
     """Build the Flask application of this lecture step.
 
     @return The configured Flask application.
     """
     app = Flask(__name__)
-
-    @app.route("/")
-    def home() -> str:
-        """Return structured HTML instead of a plain string.
-
-        The Python string uses double quotes and the HTML attributes use single
-        quotes, so the two never end each other.
-
-        @return A centred heading, a paragraph, a still picture and a GIF.
-        """
-        return (
-            "<h1 style='text-align: center'>Hello, World!</h1>"
-            "<p>This is a paragraph.</p>"
-            f"<img src='{STILL_IMAGE}' width={LECTURE_IMAGE_WIDTH}>"
-            f"<img src='{ANIMATED_IMAGE}' width={LECTURE_IMAGE_WIDTH}>"
-        )
-
+    app.register_blueprint(_blueprint)
     return app
 
 

src/higher_lower/presentation/lectures/step_04_decorators.py

@@ -7,7 +7,7 @@ the /bye route.
 from collections.abc import Callable
 from functools import wraps
 
-from flask import Flask
+from flask import Blueprint, Flask
 
 from higher_lower.constants import HOST, PORT
 
@@ -54,26 +54,32 @@ def make_underlined(function: Callable[..., str]) -> Callable[..., str]:
     return _wrap_in_tag(function, "u")
 
 
+## Blueprint that holds the views of this lecture step.
+_blueprint = Blueprint("step_04_decorators", __name__)
+
+
+@_blueprint.route("/")
+def home() -> str:
+    """Answer the home route."""
+    return "Hello, World!"
+
+
+@_blueprint.route("/bye")
+@make_bold
+@make_emphasis
+@make_underlined
+def say_bye() -> str:
+    """Answer /bye with bold, emphasised and underlined text."""
+    return "Bye"
+
+
 def create_app() -> Flask:
     """Build the Flask application of this lecture step.
 
     @return The configured Flask application.
     """
     app = Flask(__name__)
-
-    @app.route("/")
-    def home() -> str:
-        """Answer the home route."""
-        return "Hello, World!"
-
-    @app.route("/bye")
-    @make_bold
-    @make_emphasis
-    @make_underlined
-    def say_bye() -> str:
-        """Answer /bye with bold, emphasised and underlined text."""
-        return "Bye"
-
+    app.register_blueprint(_blueprint)
     return app
 
 

src/higher_lower/presentation/lectures/step_05_authenticated.py

@@ -7,7 +7,7 @@ only for a logged-in user.
 from collections.abc import Callable
 from functools import wraps
 
-from flask import Flask
+from flask import Blueprint, Flask
 from markupsafe import escape
 
 from higher_lower.constants import HOST, PORT
@@ -57,28 +57,33 @@ def create_blog_post(user: User) -> str:
     return f"This is {user.name}'s new blog post."
 
 
+## Blueprint that holds the views of this lecture step.
+_blueprint = Blueprint("step_05_authenticated", __name__)
+
+
+@_blueprint.route("/")
+def home() -> str:
+    """Show the result of create_blog_post for a user in and out."""
+    lines = []
+    for name, logged_in in (("Angela", True), ("Bob", False)):
+        user = User(name)
+        user.is_logged_in = logged_in
+        state = "logged in" if logged_in else "logged out"
+        post = create_blog_post(user)
+        lines.append(
+            f"<p>{escape(name)} is {state}: "
+            f"{escape(post) if post else 'no post created'}</p>"
+        )
+    return "<h1>is_authenticated</h1>" + "".join(lines)
+
+
 def create_app() -> Flask:
     """Build the Flask application of this lecture step.
 
     @return The configured Flask application.
     """
     app = Flask(__name__)
-
-    @app.route("/")
-    def home() -> str:
-        """Show the result of create_blog_post for a user in and out."""
-        lines = []
-        for name, logged_in in (("Angela", True), ("Bob", False)):
-            user = User(name)
-            user.is_logged_in = logged_in
-            state = "logged in" if logged_in else "logged out"
-            post = create_blog_post(user)
-            lines.append(
-                f"<p>{escape(name)} is {state}: "
-                f"{escape(post) if post else 'no post created'}</p>"
-            )
-        return "<h1>is_authenticated</h1>" + "".join(lines)
-
+    app.register_blueprint(_blueprint)
     return app