Modify expand_login_view to allow for subdomain and host matching for login_view

[travispaxton]

The current implementation will throw the following error when using dynamic subdomain or host matching in Flask:

werkzeug.routing.BuildError: Could not build url for endpoint 'login'. Did you forget to specify values ['tenant_name']?

This change will allow for the following:

login_manager.login_view = 'login'


@app.route('/', subdomain='<tenant_name>')
@login_required
def dashboard(tenant_name):
    ...


@app.route('/login', methods=['GET', 'POST'], subdomain='<tenant_name>')
def login(tenant_name):
    ...

[coveralls]

Coverage remained the same at 100.0% when pulling 425a839 on travispaxton:master into 5fce013 on maxcountryman:master.

[davidism]

I don't think this should have been merged. For some "global" variables in URL rules, like multi-tennant, locale, etc., you should use app.url_value_preprocessor and app.url_defaults to extract to g at the beginning of the request and inject in url building.

This change added all URL values as query args to the login view, not just subdomain and host. #663 addressed that, but had to use an internal Werkzeug API to inspect the URL rule each time (overhead), and was broken when it was removed from Werkzeug.

@app.url_value_preprocessor
def store_tennant(endpoint, values):
    g.tennant = values.pop("tennant", None)

@app.url_defaults
def set_tennant(endpoint, values):
    values.setdefault("tennant", g.tennant)

[maxcountryman]

Agree. This seems like the wrong approach. We should revert this.

[davidism]

I'll revert it and release 0.6.2.