f-strings everywhere

docs/api.rst

@@ -58,12 +58,12 @@ Incoming Request Data
       the following:
 
       ============= ======================================================
-      `path`        ``u'/π/page.html'``
-      `full_path`   ``u'/π/page.html?x=y'``
-      `script_root` ``u'/myapplication'``
-      `base_url`    ``u'http://www.example.com/myapplication/π/page.html'``
-      `url`         ``u'http://www.example.com/myapplication/π/page.html?x=y'``
-      `url_root`    ``u'http://www.example.com/myapplication/'``
+      `path`        ``'/π/page.html'``
+      `full_path`   ``'/π/page.html?x=y'``
+      `script_root` ``'/myapplication'``
+      `base_url`    ``'http://www.example.com/myapplication/π/page.html'``
+      `url`         ``'http://www.example.com/myapplication/π/page.html?x=y'``
+      `url_root`    ``'http://www.example.com/myapplication/'``
       ============= ======================================================
 
 

docs/config.rst

@@ -596,8 +596,8 @@ your configuration classes::
         DB_SERVER = '192.168.1.56'
 
         @property
-        def DATABASE_URI(self):         # Note: all caps
-            return 'mysql://user@{}/foo'.format(self.DB_SERVER)
+        def DATABASE_URI(self):  # Note: all caps
+            return f"mysql://user@{self.DB_SERVER}/foo"
 
     class ProductionConfig(Config):
         """Uses production database server."""

docs/patterns/flashing.rst

@@ -103,7 +103,7 @@ error messages could be displayed with a red background.
 To flash a message with a different category, just use the second argument
 to the :func:`~flask.flash` function::
 
-    flash(u'Invalid password provided', 'error')
+    flash('Invalid password provided', 'error')
 
 Inside the template you then have to tell the
 :func:`~flask.get_flashed_messages` function to also return the

docs/patterns/lazyloading.rst

@@ -93,7 +93,7 @@ write this by having a function that calls into
 name and a dot, and by wrapping `view_func` in a `LazyView` as needed.  ::
 
     def url(import_name, url_rules=[], **options):
-        view = LazyView('yourapplication.' + import_name)
+        view = LazyView(f"yourapplication.{import_name}")
         for url_rule in url_rules:
             app.add_url_rule(url_rule, view_func=view, **options)
 

docs/patterns/requestchecksum.rst

@@ -52,4 +52,4 @@ Example usage::
         files = request.files
         # At this point the hash is fully constructed.
         checksum = hash.hexdigest()
-        return 'Hash was: %s' % checksum
+        return f"Hash was: {checksum}"

docs/patterns/sqlalchemy.rst

@@ -104,9 +104,9 @@ You can insert entries into the database like this:
 Querying is simple as well:
 
 >>> User.query.all()
-[<User u'admin'>]
+[<User 'admin'>]
 >>> User.query.filter(User.name == 'admin').first()
-<User u'admin'>
+<User 'admin'>
 
 .. _SQLAlchemy: https://www.sqlalchemy.org/
 .. _declarative:
@@ -200,19 +200,19 @@ SQLAlchemy will automatically commit for us.
 To query your database, you use the engine directly or use a connection:
 
 >>> users.select(users.c.id == 1).execute().first()
-(1, u'admin', u'admin@localhost')
+(1, 'admin', 'admin@localhost')
 
 These results are also dict-like tuples:
 
 >>> r = users.select(users.c.id == 1).execute().first()
 >>> r['name']
-u'admin'
+'admin'
 
 You can also pass strings of SQL statements to the
 :meth:`~sqlalchemy.engine.base.Connection.execute` method:
 
 >>> engine.execute('select * from users where id = :1', [1]).first()
-(1, u'admin', u'admin@localhost')
+(1, 'admin', 'admin@localhost')
 
 For more information about SQLAlchemy, head over to the
 `website <https://www.sqlalchemy.org/>`_.

docs/patterns/streaming.rst

@@ -21,7 +21,7 @@ data and to then invoke that function and pass it to a response object::
     def generate_large_csv():
         def generate():
             for row in iter_all_rows():
-                yield ','.join(row) + '\n'
+                yield f"{','.join(row)}\n"
         return Response(generate(), mimetype='text/csv')
 
 Each ``yield`` expression is directly sent to the browser.  Note though

docs/patterns/viewdecorators.rst

@@ -142,8 +142,7 @@ Here is the code for that decorator::
             def decorated_function(*args, **kwargs):
                 template_name = template
                 if template_name is None:
-                    template_name = request.endpoint \
-                        .replace('.', '/') + '.html'
+                    template_name = f"'{request.endpoint.replace('.', '/')}.html'"
                 ctx = f(*args, **kwargs)
                 if ctx is None:
                     ctx = {}

docs/quickstart.rst

@@ -447,11 +447,11 @@ Here is a basic introduction to how the :class:`~markupsafe.Markup` class works:
 
     >>> from markupsafe import Markup
     >>> Markup('<strong>Hello %s!</strong>') % '<blink>hacker</blink>'
-    Markup(u'<strong>Hello &lt;blink&gt;hacker&lt;/blink&gt;!</strong>')
+    Markup('<strong>Hello &lt;blink&gt;hacker&lt;/blink&gt;!</strong>')
     >>> Markup.escape('<blink>hacker</blink>')
-    Markup(u'&lt;blink&gt;hacker&lt;/blink&gt;')
+    Markup('&lt;blink&gt;hacker&lt;/blink&gt;')
     >>> Markup('<em>Marked up</em> &raquo; HTML').striptags()
-    u'Marked up \xbb HTML'
+    'Marked up \xbb HTML'
 
 .. versionchanged:: 0.5
 
@@ -609,8 +609,8 @@ Werkzeug provides for you::
     @app.route('/upload', methods=['GET', 'POST'])
     def upload_file():
         if request.method == 'POST':
-            f = request.files['the_file']
-            f.save('/var/www/uploads/' + secure_filename(f.filename))
+            file = request.files['the_file']
+            file.save(f"/var/www/uploads/{secure_filename(f.filename)}")
         ...
 
 For some better examples, checkout the :ref:`uploading-files` pattern.

docs/templating.rst

@@ -222,8 +222,8 @@ functions)::
 
     @app.context_processor
     def utility_processor():
-        def format_price(amount, currency=u'€'):
-            return u'{0:.2f}{1}'.format(amount, currency)
+        def format_price(amount, currency="€"):
+            return f"{amount:.2f}{currency}"
         return dict(format_price=format_price)
 
 The context processor above makes the `format_price` function available to all

docs/testing.rst

@@ -165,16 +165,19 @@ invalid credentials.  Add this new test function::
     def test_login_logout(client):
         """Make sure login and logout works."""
 
-        rv = login(client, flaskr.app.config['USERNAME'], flaskr.app.config['PASSWORD'])
+        username = flaskr.app.config["USERNAME"]
+        password = flaskr.app.config["PASSWORD"]
+
+        rv = login(client, username, password)
         assert b'You were logged in' in rv.data
 
         rv = logout(client)
         assert b'You were logged out' in rv.data
 
-        rv = login(client, flaskr.app.config['USERNAME'] + 'x', flaskr.app.config['PASSWORD'])
+        rv = login(client, f"{username}x", password)
         assert b'Invalid username' in rv.data
 
-        rv = login(client, flaskr.app.config['USERNAME'], flaskr.app.config['PASSWORD'] + 'x')
+        rv = login(client, username, f'{password}x')
         assert b'Invalid password' in rv.data
 
 Test Adding Messages

docs/tutorial/blog.rst

@@ -207,7 +207,7 @@ it from each view.
         ).fetchone()
 
         if post is None:
-            abort(404, "Post id {0} doesn't exist.".format(id))
+            abort(404, f"Post id {id} doesn't exist.")
 
         if check_author and post['author_id'] != g.user['id']:
             abort(403)

docs/tutorial/views.rst

@@ -94,7 +94,7 @@ write templates to generate the HTML form.
             elif db.execute(
                 'SELECT id FROM user WHERE username = ?', (username,)
             ).fetchone() is not None:
-                error = 'User {} is already registered.'.format(username)
+                error = f"User {username} is already registered."
 
             if error is None:
                 db.execute(