Show Todo

We need a route for showing an individual todo. Let’s use this as a chance to show more about running Python code in PyCharm. Namely, let’s look more at PyCharm’s Run Configurations.

Source for this step View video/audio walkthrough

Steps

  1. In app.py, let’s add a route. On the empty line after the list_todos function, add:

    @app.route('/todo/<todo_id>')
def show_todo(todo_id):
    return 'ToDo {todo_id}'.format()

  2. Now for the return value. Put the cursor inside the parentheses for the format(). Using PyCharm’s autocompletion, press t and PyCharm suggests todo_id. Press enter to accept. Press =t then accept todo_id again.

  3. Our route should look like this:

    @app.route('/todo/<todo_id>')
def show_todo(todo_id):
    return 'ToDo {todo_id}'.format(todo_id=todo_id)

  4. Click 4. Run in the bottom of PyCharm to open the Run Tool window. Our Flask application should be running. If not, click the green play arrow in the Run Tool’s window.

  5. In PyCharm’s toolbar, near the top, click the green play arrow. We wind up with a second Flask application listening on the same port. Can PyCharm help us prevent this?

  6. In the Run Tool window, close the second tab by right-clicking on it and choosing Close Tab.

  7. Click Run -> Edit Configurations to edit the epc run configuration.

  8. Near the top right, there is a checkbox for Single instance only. Change it to checked and click Ok to save your changes.

  9. Now click the green play arrow in the toolbar again. PyCharm warns us that we already have an instance of this run configuration running.

  10. One last housekeeping: we need a web link to get to this view. Change list_todos to return a link to a todo page:

    return 'Todo List <a href="/todo/1">First Todo</a>'

  11. Reload our browser and confirm that our 3 routes work ok.

  12. Our app.py file should match the following:

    app.py in Show Todo
    from flask import Flask

app = Flask(__name__)


@app.route('/')
def home_page():
    return 'Hello World! <a href="/todo/">Todos</a>'


@app.route('/todo/')
def list_todos():
    return 'Todo List <a href="/todo/1">First Todo</a>'


@app.route('/todo/<todo_id>')
def show_todo(todo_id):
    return 'ToDo {todo_id}'.format(todo_id=todo_id)

if __name__ == '__main__':
    app.run(debug=True)

Analysis

PyCharm doesn’t just run Python code. It provides a configurable, managed way to run your code in a smart output window.

  • Run Configurations. A list of different configurations for running some of your code, including settings.

  • Run Tool Window. Like other tools in PyCharm, the Run Tool has a window with tabs for each run configuration that is running or has been run.

  • Buttons and Shortcuts. Running, stopping, and re-running can all happen from multiple places, including keyboard shortcuts.

    Note

    You can get to the list of shortcuts with Help -> Keymap Reference.

We also saw some other smart PyCharm help in action:

  • Flask-aware Live Templates speed up common tasks, such as adding a route.
  • PyCharm was smart about the Flask route parameter not appearing in the view function’s signature.
  • Code Insight flagged us when we made mistakes.
  • Code Completion helped us avoid extra (and error-prone) typing via autocomplete.

Extra Credit

  1. What flavors of run configurations are supported in PyCharm Professional?
  2. Is there a special run configuration for Flask?
  3. How did we get this
  4. Can run configurations be shared?
  5. Does PyCharm use different configurations for running code versus debugging code?
  6. How do you clear all the lines of output in the run tool window?
  7. Did PyCharm have a Quick Fix for the route string warning?