RegisteringBlueprint.py

from flask import Blueprint

shared_value = None

class RegisteringExampleBlueprint(Blueprint):
    '''
    Example showing how to access a value for routes
    saved in flask's configuration section for all routes in
    blueprint.
    
    Note if you tried simply saying api = app.config['value']
    you would get a context error.
    '''
    def register(self, app, options, first_registration=False):
        global shared_value
        shared_value = app.config['value']

        super(RegisteringExampleBlueprint,
              self).register(app, options, first_registration)
              
the_blueprint = RegisteringExampleBlueprint('example', __name__)

### Alternate with standard Blueprint ###
@the_blueprint.record
def record_example(setup_state):
    global shared_value
    app = setup_state.app

    shared_value = app.config['value']