A config setting containing list of WSGI middleware applications which, in order, process the incoming requests made to the server. These applications can extract, add, or filter information associated with the web request, as necessary. The defaults provide query string processing, content negotiation and establish environ settings.

Plugins can add additional middleware by adding to this config setting. Note that the values of the list are references to the middleware classes, not strings.

The default value is:

    'server_request_filters': [
        Query,        # extract query string
        StoreSet,     # establish a reference to the store
        UserExtract,  # determine the current user
        Header,       # process HEAD requests
        Negotiate],   # do content negotation