[FIXED] werkzeug.routing.exceptions.BuildError: Could not build url for endpoint 'add_user_confirm' with values

Issue

Im trying to create an invite url for a project I'm working on and I have seen a few versions on line when it comes to creating a token URL for that to work.

I have an error when it comes to creating a URL

           ^^^^^^^^^^^^^^^^^^^^
  File "/Users/grahammorby/Documents/GitHub/tagr-api/venv/lib/python3.12/site-packages/flask/app.py", line 1071, in url_for
    return self.handle_url_build_error(error, endpoint, values)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/grahammorby/Documents/GitHub/tagr-api/venv/lib/python3.12/site-packages/flask/app.py", line 1060, in url_for
    rv = url_adapter.build(  # type: ignore[union-attr]
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/grahammorby/Documents/GitHub/tagr-api/venv/lib/python3.12/site-packages/werkzeug/routing/map.py", line 919, in build
    raise BuildError(endpoint, values, method, self)
werkzeug.routing.exceptions.BuildError: Could not build url for endpoint 'add_user_confirm' with values ['token']. Did you mean 'users_blueprint.add_user_confirm' instead?

I have two routes under a blueprint which look as follows:

@users_blueprint.route("/invite_user", methods=["GET", "POST"])
def invite_user():
    email = request.json["email"]

    if email:
        ts = URLSafeTimedSerializer("JWT_SECRET_KEY")
        salt = "12345"

        token = ts.dumps(email, salt)

        confirm_url = url_for("add_user_confirm", token=token, _external=True)

        try:
            msg = Message(
                "Welcome to TAGR",
                sender="[email protected]",
                html="You have been invited to set up an account on PhotogApp. Click here: "
                + confirm_url,
                recipients=[email],
            )
            mail.send(msg)

        except Exception as e:
            print(e)


@users_blueprint.route("/add_user_confirm/<token>", methods=["GET", "POST"])
def add_user_confirm(token):
    print(token)

Im new to this way of working and would welcome some help

Solution

You are trying to make a url for a route within your users_blueprint blueprint. Flask blueprint routes are defined in the format, <blueprint_name>.<route_name>. This means, to access a route within your blueprint, you would need to modify the following line,

confirm_url = url_for("add_user_confirm", token=token, _external=True)

to this:

confirm_url = url_for("users_blueprint.add_user_confirm", token=token, _external=True)

Without blueprints, you would not need to put the blueprint name before the route, and url_for("add_user_confirm", ...) would be fine. But because you defined the 'add_user_confirm' route under a blueprint with @users_blueprint.route(...) instead of @app.route(...), you need to specify this blueprint whenever you want to access that route.

Answered By - Patrick Yoder