参考：http://flask.pocoo.org/docs/0.12/patterns/streaming/#streaming-from-templates
目录结构：
.
├── app.py
└── templates
└── the_template.html
run
FLASK_APP=app.py flask run
app.py
from flask import Response, Flask
app = Flask(__name__)
def stream_template(template_name, **context):
app.update_template_context(context)
t = app.jinja_env.get_template(template_name)
rv = t.stream(context)
rv.disable_buffering()
return rv
@app.route('/t')
def render_large_template():
rows = [1,2,3,4]
return Response(stream_template('the_template.html', rows=rows))
the_templates.html
{% for row in rows %}
{{ row }}
{% endfor %}