带有Leshan LWM2M演示服务器的SSE

Question

我正在尝试与Leshan演示服务器进行交互的http api。我试图处理LWM2M中的OBSERVE，但是我需要使用http处理通知。我发现乐山使用SSE进行通知。因此，我试图使用请求和sseclient在python中实现sse客户端。

这是我的代码：

    response= requests.post(url_request , "format=TLV" , stream= True)    
    client = sseclient.SSEClient(response)
    for event in client.events():
        print(json.loads(event.data))

我尝试运行我的脚本，但似乎流没有打开，并且它立即关闭而没有等待服务器的响应，即使默认情况下请求对HTTP下的TCP连接实现keep_alive且流为True。

有人知道为什么吗？

Answer 1

阅读sseclient文档，因此使用SSEClient的正确方法似乎是：

from sseclient import SSEClient
messages = SSEClient('http://example.com/sse_stream/')
for msg in messages:
    do_something_useful(msg)

在Leshan Github上阅读answer，Leshan Server Demo的流URL似乎是http://your.leshan.server.org/event?ep=your_device_endpoint_name

所以我尝试了：

from sseclient import SSEClient
messages = SSEClient('http://localhost:8080/event?ep=my_device')
for msg in messages:
    print (msg.event, msg.data)

它对我有用🎉！当我观察Leshan Client Demo的温度实例时得到这种结果：

(u'NOTIFICATION', u'{"ep":"my_device","res":"/3303/0","val":{"id":0,"resources":[{"id":5601,"value":-18.9},{"id":5602,"value":31.2},{"id":5700,"value":-18.4},{"id":5701,"value":"cel"}]}}')
(u'COAPLOG', u'{"timestamp":1592296453808,"incoming":true,"type":"CON","code":"POST","mId":29886,"token":"889372029F81C124","options":"Uri-Path: \\"rd\\", \\"reWfKIgPYD\\"","ep":"my_device"}')
(u'COAPLOG', u'{"timestamp":1592296453809,"incoming":false,"type":"ACK","code":"2.04","mId":29886,"token":"889372029F81C124","ep":"my_device"}')
(u'UPDATED', u'{"registration":{"endpoint":"my_device","registrationId":"reWfKIgPYD","registrationDate":"2020-06-16T10:02:25+02:00","lastUpdate":"2020-06-16T10:34:13+02:00","address":"127.0.0.1:44400","lwM2mVersion":"1.0","lifetime":300,"bindingMode":"U","rootPath":"/","objectLinks":[{"url":"/","attributes":{"rt":"\\"oma.lwm2m\\""}},{"url":"/1/0","attributes":{}},{"url":"/3/0","attributes":{}},{"url":"/6/0","attributes":{}},{"url":"/3303/0","attributes":{}}],"secure":false,"additionalRegistrationAttributes":{}},"update":{"registrationId":"reWfKIgPYD","identity":{"peerAddress":{}},"additionalAttributes":{}}}')
(u'COAPLOG', u'{"timestamp":1592296455150,"incoming":true,"type":"NON","code":"2.05","mId":29887,"token":"3998C5DE2588F835","options":"Content-Format: \\"application/vnd.oma.lwm2m+tlv\\" - Observe: 2979","payload":"Hex:e3164563656ce8164408c03199999999999ae815e108c032e66666666666e815e208403f333333333333","ep":"my_device"}')

如果仅通过通知感兴趣，只需添加一个if msg.event == 'NOTIFICATION':块。