flask extension that responses flexible result with negotiates accept header and checks permission

web.py

import json
from functools import wraps
from flask import render_template, url_for, request, redirect, session
from flask import Response

def require_role(role='student'):
    def decorate(f):
        @wraps(f)
        def check(*args, **kwargs):
            if session.get('role') != role:
                return redirect(url_for('user.signin', role=role, redir=request.url))
            return f(*args, **kwargs)
        return check
    return decorate

class WebApp(object):

    def __init__(self, app_or_blueprint):
        self.parent = app_or_blueprint

    def route(self, rule, template=None, role=None, use_ext=False, **options):
        types = ['application/json', 'text/html']
        def decorate(f):
            @wraps(f)
            def wrap(*args, **kwargs):
                result = f(*args, **kwargs)
                if isinstance(result, Response) or isinstance(result, unicode):
                    return result
                content_type = request.accept_mimetypes.best_match(types)
                if content_type == 'text/html':
                    if '__redirect__' in result:
                        return redirect(result['__redirect__'])
                    if template:
                        return render_template(template, **result)
                return json.dumps(result)
            if role: 
                wrap = require_role(role)(wrap)
            return self.parent.route(rule, **options)(wrap)
        return decorate