mitsuhiko/_error_

## _error_
Debugging middleware caught exception in streamed response at a point where response headers were already sent.
Traceback (most recent call last):
  File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/werkzeug/wsgi.py", line 513, in next
    return self._next()
  File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/werkzeug/wrappers.py", line 829, in iter_encoded
    for item in self.response:
  File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/jinja2/environment.py", line 918, in generate
    yield self.environment.handle_exception(exc_info, True)
  File "/home/max/Projekte/flask-testing-stuff/templates/index.html", line 1, in top-level template code
    {% extends "layout.html" %}
  File "/home/max/Projekte/flask-testing-stuff/templates/layout.html", line 8, in top-level template code
    <a href="{{ url_for('index') }}" class=""><h1>d'Anjou</h1></a>
  File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/flask/helpers.py", line 192, in url_for
    blueprint_name = request.blueprint
  File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/werkzeug/local.py", line 336, in __getattr__
    return getattr(self._get_current_object(), name)
  File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/werkzeug/local.py", line 295, in _get_current_object
    return self.__local()
  File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/flask/globals.py", line 19, in _lookup_object
    raise RuntimeError('working outside of request context')
RuntimeError: working outside of request context

## index.html
{% extends "layout.html" %}
{% block body %}
    <ul>
        {% for elem in mygenerator %}
        <li>
            <a href="{{ url_for('index') }}">{{ elem }}</a>
        </li>
        {% endfor %}
    </ul>
{% endblock %}

## layout.html
<!DOCTYPE html>
    <head>
        <meta charset="utf-8" />
        <title>Title</title>
    </head>
    <body>
            <p>
                <a href="{{ url_for('index') }}" class=""><h1>d'Anjou</h1></a>
            </p>
            {% block body %}
            {% endblock %}
    </body>
</html>

## server.py
from flask import Flask, Response, _request_ctx_stack
from jinja2 import Template
from time import sleep

app = Flask(__name__)

def get_generator():
    with _request_ctx_stack.top:
        for i in xrange(10):
            sleep(0.5)
            yield i

@app.before_request
def before_request(*args):
     print 'before_request'

@app.after_request
def after_request(response):
     print 'after_request'
     return response

@app.teardown_request
def teardown_request(error=None):
     print 'teardown_request'

@app.route('/')
def index():
    t = app.jinja_env.get_template('index.html')
    return Response(t.generate(mygenerator=get_generator()))

if __name__ == "__main__":
    app.run(debug=True)
	Debugging middleware caught exception in streamed response at a point where response headers were already sent.
	Traceback (most recent call last):
	File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/werkzeug/wsgi.py", line 513, in next
	return self._next()
	File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/werkzeug/wrappers.py", line 829, in iter_encoded
	for item in self.response:
	File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/jinja2/environment.py", line 918, in generate
	yield self.environment.handle_exception(exc_info, True)
	File "/home/max/Projekte/flask-testing-stuff/templates/index.html", line 1, in top-level template code
	{% extends "layout.html" %}
	File "/home/max/Projekte/flask-testing-stuff/templates/layout.html", line 8, in top-level template code
	<a href="{{ url_for('index') }}" class=""><h1>d'Anjou</h1></a>
	File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/flask/helpers.py", line 192, in url_for
	blueprint_name = request.blueprint
	File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/werkzeug/local.py", line 336, in __getattr__
	return getattr(self._get_current_object(), name)
	File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/werkzeug/local.py", line 295, in _get_current_object
	return self.__local()
	File "/home/max/.virtualenvs/flask/lib/python2.7/site-packages/flask/globals.py", line 19, in _lookup_object
	raise RuntimeError('working outside of request context')
	RuntimeError: working outside of request context
	{% extends "layout.html" %}
	{% block body %}
	<ul>
	{% for elem in mygenerator %}
	<li>
	<a href="{{ url_for('index') }}">{{ elem }}</a>
	</li>
	{% endfor %}
	</ul>
	{% endblock %}
	<!DOCTYPE html>
	<head>
	<meta charset="utf-8" />
	<title>Title</title>
	</head>
	<body>
	<p>
	<a href="{{ url_for('index') }}" class=""><h1>d'Anjou</h1></a>
	</p>
	{% block body %}
	{% endblock %}
	</body>
	</html>
	from flask import Flask, Response, _request_ctx_stack
	from jinja2 import Template
	from time import sleep

	app = Flask(__name__)

	def get_generator():
	with _request_ctx_stack.top:
	for i in xrange(10):
	sleep(0.5)
	yield i

	@app.before_request
	def before_request(*args):
	print 'before_request'

	@app.after_request
	def after_request(response):
	print 'after_request'
	return response

	@app.teardown_request
	def teardown_request(error=None):
	print 'teardown_request'

	@app.route('/')
	def index():
	t = app.jinja_env.get_template('index.html')
	return Response(t.generate(mygenerator=get_generator()))

	if __name__ == "__main__":
	app.run(debug=True)