Overwrite route in flask blueprint

There is a blueprint with a lot of useful routes defined, but I have no control over it (can not change it's code in any way) Trying to reuse it in a different app but one of the blueprint's endpoints must be overloaded. How can I achieve that?

I tried just adding a new route to blueprint on top of the existing one:

@blueprint.route('/my/route', methods=['PUT', 'POST']) def my_new_view_func(program, project): # some new behavior for the endpoint 

As the result there is duplicate url_rule in app.url_map.iter_rules():

<Rule '/my/route' (PUT, POST) -> my_view_func>, <Rule '/my/route' (PUT, POST) -> my_new_view_func>, 

and when requesting /my/route old viewer my_view_func gets executed

Can I somehow get rid of the old url rule? Or maybe there is a better way to overwrite the route?

1 Answer

There are 2 solutions which I found. First:

from flask import Flask, Blueprint simple_page = Blueprint('simple_page', __name__, ) @simple_page.route('/my/route/') def my(): # for example it's a registered route somewhere... return 'default' @simple_page.route('/my/route/') def new_my(): # new endpoint / should works instead my() return 'new' # map of views which we won't register in Flask app # you can store this somewhere in settings SKIP_VIEWS = ( # route, view function ('/my/route/', my, ), ) class CustomFlask(Flask): def add_url_rule(self, rule, endpoint=None, view_func=None, **options): # Flask registers views when an application starts # do not add view from SKIP_VIEWS for rule_, view_func_ in SKIP_VIEWS: # type: str, func if rule_ == rule and view_func == view_func_: return return super(CustomFlask, self).add_url_rule(rule, endpoint, view_func, **options) app = CustomFlask(__name__) app.register_blueprint(simple_page) app.run(debug=True) 

Second way:

two.py - default blueprint with endpoint

from flask import Blueprint bp_two = Blueprint('simple_page2', __name__, ) @bp_two.route('/my/route/') def default(): return 'default' 

test.py - your blueprint + app

from flask import Flask, Blueprint from two import bp_two your_bp = Blueprint('simple_page', __name__, ) @your_bp.route('/my/route/') def new_route(): return 'new' app = Flask(__name__) # register blueprint and turn off '/my/route/' endpoint app.register_blueprint(bp_two, **{'url_defaults': {'/my/route/': None}}) app.register_blueprint(your_bp) app.run(debug=True) 

Run app. Open /my/route/. You will see that default endpoint wasn't add/works.

Hope this helps.