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How to append a prefix to a flask blueprint that already has a blueprint? [duplicate]

I'm still new to Flask, so there may be an obvious way to accomplish this, but I haven't been able to figure it out so far from the documentation. My app is divided into several mostly disparate parts that share things like users/sessions/security and base template and everything but mostly do not interact much, and should be routed under different paths like /part1/.... I think this is pretty much exactly what blueprints are for. But what if I need to group routes and logic further under a blueprint?
For example, I have blueprint1 with url_prefix='/blueprint1' and maybe under that I want to have a collection of views revolving around a user sharing photos and other users commenting on them. I can't think of a better way of doing it than:
# app/blueprints/blueprint1/__init__.py
blueprint1 = Blueprint('blueprint1', __name__, template_folder='blueprint1')
#blueprint1.route('/photos')
def photos_index():
return render_template('photos/index.html')
#blueprint.route('/photos/<int:photo_id>')
def photos_show(photo_id):
photo = get_a_photo_object(photo_id)
return render_template('photos/show.html', photo=photo)
#blueprint.route('/photos', methods=['POST'])
def photos_post():
...
The problem here is that all the views related to the photos section of blueprint1 are located at the "top level," right with maybe blueprints for videos or audio or whatever (named videos_index()...). Is there any way to group them in a more hierarchical manner, like how the templates go under the 'blueprint1/photos' sub-directory? Of course I can put all the photo views in their own module to keep them organized separately, but what if I want to change the parent 'blueprint1/photos' path to something else? I'm sure I can invent a function or decorator that groups related routes under the same root path, but then I still have to name all the functions with the photos_ prefix and reference them like url_for('blueprint1.photos_show') It seems like blueprints are the answer when a Flask app gets large and you need to group and compartmentalize similar parts together, but you cannot do the same thing when the blueprints themselves get large.
For reference, in Laravel you can group related "views" under a Controller class where the views are methods. Controllers can reside in hierarchical namespaces like app\Http\Controllers\Blueprint1\Photocontroller, routes can be grouped together like
Route::group(['prefix' => 'blueprint1'], function() {
Route::group(['prefix' => 'photos'], function() {
Route::get('/', ['as' => 'blueprint.photos.index', 'uses' => 'ModelApiController#index']);
Route::post('/', ['as' => 'blueprint.photos.store', 'uses' => 'ModelApiController#store']);
Route::get('/{id}', ['as' => 'blueprint.photos.get', 'uses' => 'ModelApiController#get'])
->where('id', '[0-9]+');
});
});
and routes can be gotten like action('Blueprint1\PhotoController#index').
If only I could make a photos blueprint, then just do blueprint1.register_blueprint(photos_blueprint, url_prefix='/photos') or the like, these problems would pretty much be solved. Unfortunately Flask does not seem to support nesting blueprints like this. Is there an alternative way to handle this problem?

UPDATE
Flask 2 was released with support for nested blueprints.
[ START: Part from the docs ]
Nesting Blueprints
It is possible to register a blueprint on another blueprint.
parent = Blueprint('parent', __name__, url_prefix='/parent')
child = Blueprint('child', __name__, url_prefix='/child')
parent.register_blueprint(child)
app.register_blueprint(parent)
The child blueprint will gain the parent’s name as a prefix to its name, and child URLs will be prefixed with the parent’s URL prefix.
url_for('parent.child.create')
/parent/child/create
Blueprint-specific before request functions, etc. registered with the parent will trigger for the child. If a child does not have an error handler that can handle a given exception, the parent’s will be tried.
[ END: Part from the docs ]
Source: https://flask.palletsprojects.com/en/2.0.x/blueprints/#nesting-blueprints
OLD ANSWER
My hacky work around is that I made a class called ParentBP that has the following code
from typing import List
from flask import Blueprint
class ParentBP(object):
name: str
url_prefix: str
subdomain: str
blueprints: List[Blueprint]
def __init__(self, name="", url_prefix="", subdomain="") -> None:
self.name = name
self.url_prefix = url_prefix
self.subdomain = subdomain
self.blueprints = []
def register_blueprint(self, bp: Blueprint) -> None:
bp.name = self.name + "-" + bp.name
bp.url_prefix = self.url_prefix + (bp.url_prefix or "")
if self.subdomain:
bp.subdomain = self.subdomain
self.blueprints.append(bp)
so you can call it similar to a blueprint like below
blueprint1 = Blueprint("blueprint1", __name__)
blueprint2 = Blueprint("blueprint2", __name__, url_prefix="/bp2")
api_v1 = ParentBP("api-v1", url_prefix="/api/v1")
api_v1.register_blueprint(blueprint1)
api_v1.register_blueprint(blueprint)
to make the interface similar to normal registering of blueprints to the flask app, I extended the Flask class as follows
class ExtendedFlask(Flask):
def register_blueprint(self, blueprint: Union[Blueprint, ParentBP], **options: Any) -> None:
if isinstance(blueprint, ParentBP):
for bp in blueprint.blueprints:
super().register_blueprint(bp, **options)
else:
return super().register_blueprint(blueprint, **options)
now you can normally do the following
app = ExtendedFlask(__name__)
app.register_blueprint(api_v1)

Unfortunately, nested blueprints are not a current feature in Flask. You'll have to do it manually. You could probably code something that works for your specific case, but a general solution has not been added to Flask. There has been some discussion on the issue tracker:
https://github.com/mitsuhiko/flask/issues/593
https://github.com/mitsuhiko/flask/issues/1548
https://github.com/pallets/flask/issues/3215
Adding nestable blueprints into Flask is not as trivial as automatically appending a prefix to routes. There are many other features of blueprints that need to be considered when nesting that make a general implementation significantly more complicated. The reason this has not been implemented yet is that no one in the community has had a great enough need for it that wasn't solved by a quick workaround vs contributing a general implementation.

I made a class called NestedBlueprint to hack it.
class NestedBlueprint(object):
def __init__(self, blueprint, prefix):
super(NestedBlueprint, self).__init__()
self.blueprint = blueprint
self.prefix = '/' + prefix
def route(self, rule, **options):
rule = self.prefix + rule
return self.blueprint.route(rule, **options)
Here is my base file which contains the blueprint: panel/__init__.py
from flask import Blueprint
panel_blueprint = Blueprint(PREFIX, __name__, url_prefix='/panel')
from . import customize
Here is the specific/nested file which contains nested blueprint: panel/customize.py
from rest.api.panel import panel_blueprint
from rest.api.util.nested_blueprint import NestedBlueprint
nested_blueprint = NestedBlueprint(panel_blueprint, 'customize')
#nested_blueprint.route('/test', methods=['GET'])
def test():
return ':)'
You can then call like this:
$ curl http://localhost:5000/panel/customize/test
:)

Here is my workaround:
When importing a blueprint, I define my nested routes:
app.register_blueprint(product_endpoints, url_prefix='/sites/<int:site_id>/menus/<int:menu_id>/categories/<int:category_id>/products/<int:product_id>')
app.register_blueprint(category_endpoints, url_prefix='/sites/<int:site_id>/menus/<int:menu_id>/categories/<int:category_id>')
app.register_blueprint(menu_endpoints, url_prefix='/sites/<int:site_id>/menus/<int:menu_id>')
app.register_blueprint(site_endpoints, url_prefix='/sites/<int:site_id>')
And inside the blueprints, I'm reusing route parse functions. For example, in the product_endpoints file:
from category_endpoints import get_category_data
product_endpoints = Blueprint('product_endpoints', __name__)
#product_endpoints.url_value_preprocessor
def get_product_data(endpoint, values):
if 'category_id' in values:
get_category_data(endpoint, values)
product = Product.get_by_id(int(values.pop('product_id')))
if not product:
abort(404)
g.product = product
and in category_endpoints file:
from menu_endpoints import get_menu_data
category_endpoints = Blueprint('category_endpoints', __name__)
#category_endpoints.url_value_preprocessor
def get_category_data(endpoint, values):
if 'menu_id' in values:
get_menu_data(endpoint, values)
category = ProductCategory.get_by_id(int(values.pop('category_id')))
if not category:
abort(404)
g.category = category
etc... With that approach, my blueprint is also usable with direct routes like /products/<int:product_id>.
This approach worked for me very well. I hope it can also help you.

Flask Create global response function to be called from every where in the web app

new to flask , i have web app that containes few parts
for example:
utils/
-- utils.py
db/
-- oracle.py
main.py
My Question is how can i make global_response function/handler that can be called from : utils.py,oracle.py,main.py without threading problem
for example:
in utils.py
clas Utils():
def A(self):
return global_response("error","a")
oracle.py
clas Utils():
def ORA(self):
return global_response("error ora","b")
main.py
def some_fun(self):
return global_response("error main","c")
and here is the response function which was in main.py but now needs to be called from any where :
def global_response(error_msg, title,*options):
res = {"status": error_msg, "title": title}
for option in options:
res.update(option)
return json.dumps(res)

Instead of creating a response function, you can create a custom response class which will replace flask's builtin Response class.
The class will inherit flask's Response class, meaning:
class GlobalResponse(Response):
pass
In order to generate the generic response, you should call the app.make_response method.
You can view This link for a walk through of how to create a response class.
Side notes
I would recommended you to check out flask's jsonify function which wraps the json.dumps and is considered "stronger" (works for more cases).
You may want to look at flask's make_response method.

Expose a Django app's models at the module level

I've made a django app, which is designed to be easily pluggable, and only has 1 view, and 1 model that project planning to use the app need to be aware of.
For ease, I'd like to just make the view and model available from the app-level. So rather than:
from mything.views import MyView
from mything.models import MyModel
You can instead just do:
from mything import MyView, MyModel
I changed the __init__.py file in the app to be like this:
from .views import MyView
from .models import MyModel
Of course I get the old django.core.exceptions.AppRegistryNotReady raised, since it's attempting to run the models.py code before the apps are loaded.
So I came up with the following workaround, and I'm wondering if it's a reasonable pattern to use or not. Now in __init__.py I have:
def _expose_items():
from .views import MyView
from .models import MyModel
globals()['MyView'] = MyView
globals()['MyModel'] = MyModel
And in my app's apps.py:
from . import _expose_items
class MyThingConfig(AppConfig):
name = 'mything'
def ready(self):
_expose_items()
So now indeed, I can directly import the view and model from the outside. Is this useful, or horrible?

Most Django apps do not collect views or models to the top level module. Refer to django.contrib.auth as an example.

Most Django apps do not collect views or models to the top level module. Use clear documentation to demonstrate how to import from your app. Hacks including globals() will probably create more trouble than help.
Refer to django.contrib.auth as an example.

Nested Blueprints in Flask?

I'm still new to Flask, so there may be an obvious way to accomplish this, but I haven't been able to figure it out so far from the documentation. My app is divided into several mostly disparate parts that share things like users/sessions/security and base template and everything but mostly do not interact much, and should be routed under different paths like /part1/.... I think this is pretty much exactly what blueprints are for. But what if I need to group routes and logic further under a blueprint?
For example, I have blueprint1 with url_prefix='/blueprint1' and maybe under that I want to have a collection of views revolving around a user sharing photos and other users commenting on them. I can't think of a better way of doing it than:
# app/blueprints/blueprint1/__init__.py
blueprint1 = Blueprint('blueprint1', __name__, template_folder='blueprint1')
#blueprint1.route('/photos')
def photos_index():
return render_template('photos/index.html')
#blueprint.route('/photos/<int:photo_id>')
def photos_show(photo_id):
photo = get_a_photo_object(photo_id)
return render_template('photos/show.html', photo=photo)
#blueprint.route('/photos', methods=['POST'])
def photos_post():
...
The problem here is that all the views related to the photos section of blueprint1 are located at the "top level," right with maybe blueprints for videos or audio or whatever (named videos_index()...). Is there any way to group them in a more hierarchical manner, like how the templates go under the 'blueprint1/photos' sub-directory? Of course I can put all the photo views in their own module to keep them organized separately, but what if I want to change the parent 'blueprint1/photos' path to something else? I'm sure I can invent a function or decorator that groups related routes under the same root path, but then I still have to name all the functions with the photos_ prefix and reference them like url_for('blueprint1.photos_show') It seems like blueprints are the answer when a Flask app gets large and you need to group and compartmentalize similar parts together, but you cannot do the same thing when the blueprints themselves get large.
For reference, in Laravel you can group related "views" under a Controller class where the views are methods. Controllers can reside in hierarchical namespaces like app\Http\Controllers\Blueprint1\Photocontroller, routes can be grouped together like
Route::group(['prefix' => 'blueprint1'], function() {
Route::group(['prefix' => 'photos'], function() {
Route::get('/', ['as' => 'blueprint.photos.index', 'uses' => 'ModelApiController#index']);
Route::post('/', ['as' => 'blueprint.photos.store', 'uses' => 'ModelApiController#store']);
Route::get('/{id}', ['as' => 'blueprint.photos.get', 'uses' => 'ModelApiController#get'])
->where('id', '[0-9]+');
});
});
and routes can be gotten like action('Blueprint1\PhotoController#index').
If only I could make a photos blueprint, then just do blueprint1.register_blueprint(photos_blueprint, url_prefix='/photos') or the like, these problems would pretty much be solved. Unfortunately Flask does not seem to support nesting blueprints like this. Is there an alternative way to handle this problem?

UPDATE
Flask 2 was released with support for nested blueprints.
[ START: Part from the docs ]
Nesting Blueprints
It is possible to register a blueprint on another blueprint.
parent = Blueprint('parent', __name__, url_prefix='/parent')
child = Blueprint('child', __name__, url_prefix='/child')
parent.register_blueprint(child)
app.register_blueprint(parent)
The child blueprint will gain the parent’s name as a prefix to its name, and child URLs will be prefixed with the parent’s URL prefix.
url_for('parent.child.create')
/parent/child/create
Blueprint-specific before request functions, etc. registered with the parent will trigger for the child. If a child does not have an error handler that can handle a given exception, the parent’s will be tried.
[ END: Part from the docs ]
Source: https://flask.palletsprojects.com/en/2.0.x/blueprints/#nesting-blueprints
OLD ANSWER
My hacky work around is that I made a class called ParentBP that has the following code
from typing import List
from flask import Blueprint
class ParentBP(object):
name: str
url_prefix: str
subdomain: str
blueprints: List[Blueprint]
def __init__(self, name="", url_prefix="", subdomain="") -> None:
self.name = name
self.url_prefix = url_prefix
self.subdomain = subdomain
self.blueprints = []
def register_blueprint(self, bp: Blueprint) -> None:
bp.name = self.name + "-" + bp.name
bp.url_prefix = self.url_prefix + (bp.url_prefix or "")
if self.subdomain:
bp.subdomain = self.subdomain
self.blueprints.append(bp)
so you can call it similar to a blueprint like below
blueprint1 = Blueprint("blueprint1", __name__)
blueprint2 = Blueprint("blueprint2", __name__, url_prefix="/bp2")
api_v1 = ParentBP("api-v1", url_prefix="/api/v1")
api_v1.register_blueprint(blueprint1)
api_v1.register_blueprint(blueprint)
to make the interface similar to normal registering of blueprints to the flask app, I extended the Flask class as follows
class ExtendedFlask(Flask):
def register_blueprint(self, blueprint: Union[Blueprint, ParentBP], **options: Any) -> None:
if isinstance(blueprint, ParentBP):
for bp in blueprint.blueprints:
super().register_blueprint(bp, **options)
else:
return super().register_blueprint(blueprint, **options)
now you can normally do the following
app = ExtendedFlask(__name__)
app.register_blueprint(api_v1)

Unfortunately, nested blueprints are not a current feature in Flask. You'll have to do it manually. You could probably code something that works for your specific case, but a general solution has not been added to Flask. There has been some discussion on the issue tracker:
https://github.com/mitsuhiko/flask/issues/593
https://github.com/mitsuhiko/flask/issues/1548
https://github.com/pallets/flask/issues/3215
Adding nestable blueprints into Flask is not as trivial as automatically appending a prefix to routes. There are many other features of blueprints that need to be considered when nesting that make a general implementation significantly more complicated. The reason this has not been implemented yet is that no one in the community has had a great enough need for it that wasn't solved by a quick workaround vs contributing a general implementation.

I made a class called NestedBlueprint to hack it.
class NestedBlueprint(object):
def __init__(self, blueprint, prefix):
super(NestedBlueprint, self).__init__()
self.blueprint = blueprint
self.prefix = '/' + prefix
def route(self, rule, **options):
rule = self.prefix + rule
return self.blueprint.route(rule, **options)
Here is my base file which contains the blueprint: panel/__init__.py
from flask import Blueprint
panel_blueprint = Blueprint(PREFIX, __name__, url_prefix='/panel')
from . import customize
Here is the specific/nested file which contains nested blueprint: panel/customize.py
from rest.api.panel import panel_blueprint
from rest.api.util.nested_blueprint import NestedBlueprint
nested_blueprint = NestedBlueprint(panel_blueprint, 'customize')
#nested_blueprint.route('/test', methods=['GET'])
def test():
return ':)'
You can then call like this:
$ curl http://localhost:5000/panel/customize/test
:)

Here is my workaround:
When importing a blueprint, I define my nested routes:
app.register_blueprint(product_endpoints, url_prefix='/sites/<int:site_id>/menus/<int:menu_id>/categories/<int:category_id>/products/<int:product_id>')
app.register_blueprint(category_endpoints, url_prefix='/sites/<int:site_id>/menus/<int:menu_id>/categories/<int:category_id>')
app.register_blueprint(menu_endpoints, url_prefix='/sites/<int:site_id>/menus/<int:menu_id>')
app.register_blueprint(site_endpoints, url_prefix='/sites/<int:site_id>')
And inside the blueprints, I'm reusing route parse functions. For example, in the product_endpoints file:
from category_endpoints import get_category_data
product_endpoints = Blueprint('product_endpoints', __name__)
#product_endpoints.url_value_preprocessor
def get_product_data(endpoint, values):
if 'category_id' in values:
get_category_data(endpoint, values)
product = Product.get_by_id(int(values.pop('product_id')))
if not product:
abort(404)
g.product = product
and in category_endpoints file:
from menu_endpoints import get_menu_data
category_endpoints = Blueprint('category_endpoints', __name__)
#category_endpoints.url_value_preprocessor
def get_category_data(endpoint, values):
if 'menu_id' in values:
get_menu_data(endpoint, values)
category = ProductCategory.get_by_id(int(values.pop('category_id')))
if not category:
abort(404)
g.category = category
etc... With that approach, my blueprint is also usable with direct routes like /products/<int:product_id>.
This approach worked for me very well. I hope it can also help you.

blueprint of blueprints (Flask)

I have a series of blueprints I'm using, and I want to be able to bundle them further into a package I can use as seamlessly as possible with any number of other applications. A bundle of blueprints that provides an entire engine to an application. I sort of created my own solution, but it is manual and requires too much effort to be effective. It doesn't seem like an extension, and it is more than one blueprint(several that provide a common functionality).
Is this done? How?
(Application dispatching methods of tying together several programs might work isn't what I'm looking for)

Check this out: Nesting Blueprints → https://flask.palletsprojects.com/en/2.0.x/blueprints/#nesting-blueprints
parent = Blueprint('parent', __name__, url_prefix='/parent')
child = Blueprint('child', __name__, url_prefix='/child')
parent.register_blueprint(child)
app.register_blueprint(parent)

I wish the Blueprint object has a register_blueprint function just as the Flask object does. It would automatically place and registered blueprints under the current Blueprints' url.

The simplest way would be to create a function that takes an instance of a Flask application and registers all your blueprints on it in one go. Something like this:
# sub_site/__init__.py
from .sub_page1 import bp as sb1bp
from .sub_page2 import bp as sb2bp
# ... etc. ...
def register_sub_site(app, url_prefix="/sub-site"):
app.register_blueprint(sb1bp, url_prefix=url_prefix)
app.register_blueprint(sb2bp, url_prefix=url_prefix)
# ... etc. ...
# sub_site/sub_page1.py
from flask import Blueprint
bp = Blueprint("sub_page1", __name__)
#bp.route("/")
def sub_page1_index():
pass
Alternately, you could use something like HipPocket's autoload function (full disclosure: I wrote HipPocket) to simplify the import handling:
# sub_site/__init__.py
from hip_pocket.tasks import autoload
def register_sub_site(app,
url_prefix="/sub-site",
base_import_name="sub_site"):
autoload(app, base_import_name, blueprint_name="bp")
However, as it currently stands you couldn't use the same structure as example #1 (HipPocket assumes you are using packages for each Blueprint). Instead, your layout would look like this:
# sub_site/sub_page1/__init__.py
# This space intentionally left blank
# sub_site/sub_page1/routes.py
from flask import Blueprint
bp = Blueprint("sub_page1", __name__)
#bp.route("/")
def sub_page1_index():
pass

I have solution for myself how to load blueprints defined in configuration, so then you can have something like CORE_APPS = ('core', 'admin', 'smth') in config and when you construct app you can register those apps (of course those strings in CORE_APPS must be the names of the files you want to import in your python path).
So I'm using function to create app:
app = create_app()
def create_app():
app = Flask(__name__)
# I have class for my configs so configuring from object
app.config.from_object('configsClass')
# does a lot of different stuff but the main thing could help you:
from werkzeug.utils import import_string
for app in app.config['CORE_APPS']
real_app = import_string(app)
app.register_blueprint(real_app)
After that your blueprint should be registered. Of course you can have different format in configs to support custom url prefixes and so on and so on :)
Of course you can also do something like this in your main blueprint, so in the application creation you will need to register that one main blueprint.