How to set static_url_path in Flask application

I want to do something like this:

app = Flask(__name__)
app.config.from_object(mypackage.config)
app.static_url_path = app.config['PREFIX']+"/static"

when I try:

print app.static_url_path

I get the correct static_url_path

But in my templates when I use url_for('static'), The html file generated using jinja2 still has the default static URL path /static with the missing PREFIX that I added.

If I hardcode the path like this:

app = Flask(__name__, static_url_path='PREFIX/static')

It works fine. What am I doing wrong?

Solution

Flask creates the URL route when you create the Flask() object. You'll need to re-add that route:

# remove old static map
url_map = app.url_map
try:
    for rule in url_map.iter_rules('static'):
        url_map._rules.remove(rule)
except ValueError:
    # no static view was created yet
    pass

# register new; the same view function is used
app.add_url_rule(
    app.static_url_path + '/<path:filename>',
    endpoint='static', view_func=app.send_static_file)

It'll be easier just to configure your Flask() object with the correct static URL path.

Demo:

>>> from flask import Flask
>>> app = Flask(__name__)
>>> app.url_map
Map([<Rule '/static/<filename>' (HEAD, OPTIONS, GET) -> static>])
>>> app.static_url_path = '/PREFIX/static'
>>> url_map = app.url_map
>>> for rule in url_map.iter_rules('static'):
...     url_map._rules.remove(rule)
... 
>>> app.add_url_rule(
...     app.static_url_path + '/<path:filename>',
...     endpoint='static', view_func=app.send_static_file)
>>> app.url_map
Map([<Rule '/PREFIX/static/<filename>' (HEAD, OPTIONS, GET) -> static>])