In Tornado, how to decorate the GOT coroutine function
I want to decorate the coroutine GET method that determines whether to read data from cache and set data caching. But I don't know how to wrap a coroutine. This is how I am doing it now:
def cache_it(f):
@functools.wraps(f)
@coroutine
def wrapper(self, *args, **kwargs):
key = self.get_cache_key()
result = cache.get(key)
if not result:
yield f(self, *args, **kwargs)
if self._result_buffer:
cache.set(key, self._result_buffer)
else:
self._result_buffer = result
class BaseHandler(RequestHandler):
def __init__(self, *args, **kwargs):
super(BaseHandler, self).__init__(*args, **kwargs)
self._result_buffer = []
def write(self, chunk):
self._result_buffer.append(chunk)
def flush(self, include_footers=False, callback=None):
self._flush_result_buffer()
super(BaseHandler, self).flush(include_footers)
def finish(self, chunk=None):
if chunk is not None:
self.write(chunk)
self._flush_result_buffer()
super(BaseHandler, self).finish()
def _flush_result_buffer(self):
for r in self._result_buffer:
super(BaseHandler, self).write(r)
self._result_buffer = []
class IndexHandler(RequestHandler):
@cache_it
@coroutine
def get(self):
...
self.write({'data': data})
But it doesn't work. Please let me know how to do this and where am I going wrong.
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1 answer
Af first. coroutine should be fixed (just add return):
def cache_it(f):
@functools.wraps(f)
@coroutine
def wrapper(self, *args, **kwargs):
key = self.get_cache_key()
result = cache.get(key)
if not result:
yield f(self, *args, **kwargs)
if self._result_buffer:
cache.set(key, self._result_buffer)
else:
self._result_buffer = result
return wrapper
And here too should be fixed:
class IndexHandler(BaseHandler):
You can now cache the resulting buffer (note: its list).
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