diff options
Diffstat (limited to 'studio/static/doc/flask-docs/_sources/patterns/appfactories.txt')
| -rw-r--r-- | studio/static/doc/flask-docs/_sources/patterns/appfactories.txt | 75 |
1 files changed, 0 insertions, 75 deletions
diff --git a/studio/static/doc/flask-docs/_sources/patterns/appfactories.txt b/studio/static/doc/flask-docs/_sources/patterns/appfactories.txt deleted file mode 100644 index 2a6190e..0000000 --- a/studio/static/doc/flask-docs/_sources/patterns/appfactories.txt +++ /dev/null @@ -1,75 +0,0 @@ -.. _app-factories: - -Application Factories -===================== - -If you are already using packages and blueprints for your application -(:ref:`blueprints`) there are a couple of really nice ways to further improve -the experience. A common pattern is creating the application object when -the blueprint is imported. But if you move the creation of this object, -into a function, you can then create multiple instances of this and later. - -So why would you want to do this? - -1. Testing. You can have instances of the application with different - settings to test every case. -2. Multiple instances. Imagine you want to run different versions of the - same application. Of course you could have multiple instances with - different configs set up in your webserver, but if you use factories, - you can have multiple instances of the same application running in the - same application process which can be handy. - -So how would you then actually implement that? - -Basic Factories ---------------- - -The idea is to set up the application in a function. Like this:: - - def create_app(config_filename): - app = Flask(__name__) - app.config.from_pyfile(config_filename) - - from yourapplication.views.admin import admin - from yourapplication.views.frontend import frontend - app.register_blueprint(admin) - app.register_blueprint(frontend) - - return app - -The downside is that you cannot use the application object in the blueprints -at import time. You can however use it from within a request. How do you -get access to the application with the config? Use -:data:`~flask.current_app`:: - - from flask import current_app, Blueprint, render_template - admin = Blueprint('admin', __name__, url_prefix='/admin') - - @admin.route('/') - def index(): - return render_template(current_app.config['INDEX_TEMPLATE']) - -Here we look up the name of a template in the config. - -Using Applications ------------------- - -So to use such an application you then have to create the application -first. Here an example `run.py` file that runs such an application:: - - from yourapplication import create_app - app = create_app('/path/to/config.cfg') - app.run() - -Factory Improvements --------------------- - -The factory function from above is not very clever so far, you can improve -it. The following changes are straightforward and possible: - -1. make it possible to pass in configuration values for unittests so that - you don't have to create config files on the filesystem -2. call a function from a blueprint when the application is setting up so - that you have a place to modify attributes of the application (like - hooking in before / after request handlers etc.) -3. Add in WSGI middlewares when the application is creating if necessary. |