tornado coroutine使用

工作中想在tornado里面封装个异步发送http请求的公共方法，代码如下：

@tornado.gen.enginedef asyn_send_http_req(reqUrl, parm):        try:            client = tornado.httpclient.AsyncHTTPClient()            httpReq = tornado.httpclient.HTTPRequest(reqUrl,method="POST",body=parm,connect_timeout=3)            response = yield tornado.gen.Task(client.fetch,httpReq)            response = response.body            logging.info(response)        except Exception:            response = None        if response and response.strip():            pass        else:            response = None

    yield response

response = asyn_send_http_req(reqUrl,parm)

获取响应总是报错，后来查了下资料，原来是generator里面不能return。需要使用tornado的 

tornado.gen.Task 来返回响应，代码如下：

@tornado.gen.enginedef asyn_send_http_req(reqUrl, parm,callback=None):        try:            client = tornado.httpclient.AsyncHTTPClient()            httpReq = tornado.httpclient.HTTPRequest(reqUrl,method="POST",body=parm,connect_timeout=3)            response = yield tornado.gen.Task(client.fetch,httpReq)            response = response.body            logging.info(response)        except Exception:            response = None        if response and response.strip():            pass        else:            response = None        callback(response)
response = yield tornado.gen.Task(asyn_send_http_req,reqUrl,parm)
使用callback返回响应。
@tornado.gen.engine 是3.0 版本前使用，现在不建议使用，3.0后使用@tornado.gen.coroutine替代。
@tornado.gen.coroutinedef asyn_send_http_req(reqUrl, parm):        try:            client = tornado.httpclient.AsyncHTTPClient()            httpReq = tornado.httpclient.HTTPRequest(reqUrl,method="POST",body=parm,connect_timeout=3)            response = yield tornado.gen.Task(client.fetch,httpReq)            response = response.body            logging.info(response)        except Exception:            response = None        if response and response.strip():            pass        else:            response = None        raise gen.Return(response)
同时使用gen.Return（）方法返回响应。
OK，问题解决。