On Jun 4, 2:54 am, Gustavo Narea <[email protected]> wrote:
> Hi, Wyatt.
>
> Wyatt said:
>
> > I want to get access to the "root" WSGI middleware, the one that is
> > hit first when a request is made. In this example:
>
> > [pipeline:main]
> > pipeline = somefilter auth urlmap
>
> > ...I want access to `somefilter`. I couldn't find a reference to the
> > root app anywhere in the environ. Does anyone know how to access this?
>
> You can't, because it works like this:
> """
> class Middleware1(object):
> def __init__(self, app):
> self.app = app
> def __call__(self, environ, start_response):
> # ... do something ...
> return self.app(environ, start_response)
>
> class Middleware2(object):
> def __init__(self, app):
> self.app = app
> def __call__(self, environ, start_response):
> # ... do something ...
> return self.app(environ, start_response)
>
> class Middleware3(object):
> foo = "some value"
> def __init__(self, app):
> self.app = app
> def __call__(self, environ, start_response):
> # ... do something ...
> return self.app(environ, start_response)
>
> pylonsapp = make_app(...)
> pylonsapp = Middleware1(pylonsapp)
> pylonsapp = Middleware2(pylonsapp)
> pylonsapp = Middleware3(pylonsapp)
> """
>
> So in Middleware1, for example, you cannot access Middleware3 and vice versa.
Right. In your example, I want access to the `Middleware3` instance--
the WSGI app that is directly served by Paste (or your favorite WSGI
server, X). What I was thinking was that the server machinery could
place a reference to this "root" app in the WSGI environ. I haven't
really thought it through, so perhaps this is a bad idea.
> > For now, I created a wrapper app that saves a reference to itself in
> > the environ.
>
> If you really want it, the standard way to do it is to put in the environ
> whatever you need from that middleware, not the whole middleware.
Well, since it's just a reference, and the object it refers to lives
until the app server dies anyway, I don't think there should be any
issue with sticking it in the environ.
What I'm trying to *do* is a subrequest, based on the original
request:
req = request.copy()
# ...modify req.environ here, with a different PATH_INFO, say...
response = req.get_response(request.environ['wsgi.root_app']) #
root app gets __call__'ed here with new environ
return json.loads(response.body)
Maybe our discussion is moot because there's a better way to do
subrequests? I might just need to RTFM a bit more. In the meantime, my
simple wrapper app seems to work fine.
> For example, if what you need is the "foo" argument of Middleware3 in
> Middleware1, you can use this:
> """
> class Middleware1(object):
> def __init__(self, app):
> self.app = app
> def __call__(self, environ, start_response):
> # ... do something ...
> if "middleware3.foo" in environ:
> # here it is!
> return self.app(environ, start_response)
>
> class Middleware2(object):
> def __init__(self, app):
> self.app = app
> def __call__(self, environ, start_response):
> # ... do something ...
> return self.app(environ, start_response)
>
> class Middleware3(object):
> foo = "some value"
> def __init__(self, app):
> self.app = app
> def __call__(self, environ, start_response):
> # ... do something ...
> environ["middleware3.foo"] = self.foo
> return self.app(environ, start_response)
>
> pylonsapp = make_app(...)
> pylonsapp = Middleware1(pylonsapp)
> pylonsapp = Middleware2(pylonsapp)
> pylonsapp = Middleware3(pylonsapp)
> """
>
> Then this value will be available in any middleware* and the application
> itself.
>
> HTH,
>
> PS: Not exactly "any middleware"; it will be available for any middleware
> under it... So if we had a fourth middleware, it wouldn't be able to access
> environ["middleware3.foo"].
> --
> Gustavo Narea <xri://=Gustavo>.
> | Tech blog: =Gustavo/(+blog)/tech ~ About me: =Gustavo/about |
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