If I nest blueprints such as:

a_bp = Blueprint('a', __name__)
b_bp = Blueprint('b', __name__)
c_bp = Blueprint('c', __name__)

b_bp.register_blueprint(c_bp, url_prefix="/c")
a_bp.register_blueprint(b_bp, url_prefix="/b")
app.register_blueprint(a_bp, url_prefix="/a")

how can I include a dynamic url identifier (a variable in the url, such as <int:variableName>) for each level?

For example:

a_bp = Blueprint('a', __name__)
a_id_bp = Blueprint('id', __name__)
b_bp = Blueprint('b', __name__)
b_id_bp = Blueprint('id', __name__)
c_bp = Blueprint('c', __name__)

b_id_bp.register_blueprint(c_bp, url_prefix="/c")
b_bp.register_blueprint(b_id_bp, url_prefix="/<int:b_id>")
a_id_bp.register_blueprint(b_bp, url_prefix="/b")
a_bp.register_blueprint(a_id_bp, url_prefix="/<int:a_id>")
app.register_blueprint(a_bp, url_prefix="/a")

such that htmls appear as:

/a/<int:a_id>/b/<int:b_id>/c/

If I nest blueprints such as:

a_bp = Blueprint('a', __name__)
b_bp = Blueprint('b', __name__)
c_bp = Blueprint('c', __name__)

b_bp.register_blueprint(c_bp, url_prefix="/c")
a_bp.register_blueprint(b_bp, url_prefix="/b")
app.register_blueprint(a_bp, url_prefix="/a")

how can I include a dynamic url identifier (a variable in the url, such as <int:variableName>) for each level?

For example:

a_bp = Blueprint('a', __name__)
a_id_bp = Blueprint('id', __name__)
b_bp = Blueprint('b', __name__)
b_id_bp = Blueprint('id', __name__)
c_bp = Blueprint('c', __name__)

b_id_bp.register_blueprint(c_bp, url_prefix="/c")
b_bp.register_blueprint(b_id_bp, url_prefix="/<int:b_id>")
a_id_bp.register_blueprint(b_bp, url_prefix="/b")
a_bp.register_blueprint(a_id_bp, url_prefix="/<int:a_id>")
app.register_blueprint(a_bp, url_prefix="/a")

such that htmls appear as:

/a/<int:a_id>/b/<int:b_id>/c/

• flask

Share Improve this question Follow edited Mar 5 at 12:25 kando asked Mar 4 at 15:13 kandokando 60511 gold badge77 silver badges1919 bronze badges 4

• Your example works as expected. What's the problem? – Detlef Commented Mar 4 at 20:42
• I was under the impression that variables in the url could not be submitted as url_prefix – kando Commented Mar 5 at 2:53
• The rules are combined into one and passed to Flask.add_url_rule(). It is important that your endpoint in the blueprint accepts all parameters. – Detlef Commented Mar 5 at 9:17
• (Updated question for clarity.) – kando Commented Mar 5 at 12:27

Add a comment  | 

1 Answer 1

Sorted by: Reset to default 1

You can also use a dynamic rule for the url_prefix attribute. When registering the blueprint, the individual rules are combined into one and passed to Flask.add_url_rule().

In the endpoint, it is important to note that all parameters defined by the assembled rule are also accepted as attributes.

from flask import Flask, Blueprint, request
from markupsafe import escape

app = Flask(__name__)

bp_a = Blueprint('a', __name__)
# You can set the attribute either when instantiating the blueprint.
bp_a_id = Blueprint('id', __name__, url_prefix='/<int:a_id>')

bp_b = Blueprint('b', __name__)
bp_b_id = Blueprint('id', __name__)

bp_c = Blueprint('c', __name__)

@bp_c.route('/')
def index(**kwargs):
    return escape(f'{request.endpoint} = {request.url_rule} : {kwargs}')

bp_b_id.register_blueprint(bp_c, url_prefix='/c')
# Or you can set the attribute when registering the blueprint. 
bp_b.register_blueprint(bp_b_id, url_prefix='/<int:b_id>')
bp_a_id.register_blueprint(bp_b, url_prefix='/b')
bp_a.register_blueprint(bp_a_id)
app.register_blueprint(bp_a, url_prefix='/a')

For example, calling http://localhost:5000/a/1/b/2/c/ produces the following output.

a.id.b.id.c.index = /a/<int:a_id>/b/<int:b_id>/c/ : {'a_id': 1, 'b_id': 2}