我在当地运行Fiware IoT Agent example。计划是将它连接到某种设备并进行演示。我正在使用request bin来检查IoT代理发送的请求。
用./services start
启动环境后,我调用这个shell脚本在代理中注册一个铃声设备,然后触发“ring”命令。
curl -iX POST \
'http://localhost:4041/iot/devices' \
-H 'Content-Type: application/json' \
-H 'fiware-service: openiot' \
-H 'fiware-servicepath: /' \
-d '{
"devices": [
{
"device_id": "bell001",
"entity_name": "urn:ngsi-ld:Bell:001",
"entity_type": "Bell",
"protocol": "PDI-IoTA-UltraLight",
"transport": "HTTP",
"endpoint": "https://requestbin.fullcontact.com/zhygotzh/iot/bell001",
"commands": [
{ "name": "ring", "type": "command" }
],
"static_attributes": []
}
]
}
'
curl -iX POST \
'http://localhost:4041/v1/updateContext' \
-H 'Content-Type: application/json' \
-H 'fiware-service: openiot' \
-H 'fiware-servicepath: /' \
-d '{
"contextElements": [
{
"type": "Bell",
"isPattern": "false",
"id": "urn:ngsi-ld:Bell:001",
"attributes": [
{ "name": "ring", "type": "command", "value": "" }
],
"static_attributes": []
}
],
"updateAction": "UPDATE"
}'
这很好用,我得到200响应,我可以在请求bin中看到请求。
$ ./setup-ul.sh
HTTP/1.1 201 Created
X-Powered-By: Express
Fiware-Correlator: 8298b65a-8550-4b6e-8a4d-21bc32abdf8a
Content-Type: application/json; charset=utf-8
Content-Length: 2
ETag: W/"2-vyGp6PvFo4RvsFtPoIWeCReyIC8"
Date: Fri, 29 Mar 2019 11:34:05 GMT
Connection: keep-alive
{}HTTP/1.1 200 OK
X-Powered-By: Express
Fiware-Correlator: c79a1146-05d8-4eb1-8e1c-bf19661cb403
Content-Type: application/json; charset=utf-8
Content-Length: 208
ETag: W/"d0-6+Ce6hwRVmP90ZI667iON6zHtdA"
Date: Fri, 29 Mar 2019 11:34:07 GMT
Connection: keep-alive
{"contextResponses":[{"contextElement":{"attributes":[{"name":"ring","type":"command","value":""}],"id":"urn:ngsi-ld:Bell:001","isPattern":false,"type":"Bell"},"statusCode":{"code":200,"reasonPhrase":"OK"}}]}
但是,请求是Ultra Light格式。我更喜欢JSON格式。所以我想我只是替换docker compose文件中的图像。
iot-agent:
image: fiware/iotagent-ul:1.8.0
hostname: iot-agent
变为
iot-agent:
image: fiware/iotagent-json
hostname: iot-agent
在docker-compose.yml
。
现在,当我使用更新的docker-compose文件尝试相同的操作时,我得到以下结果:
$ ./setup.sh
HTTP/1.1 201 Created
X-Powered-By: Express
Fiware-Correlator: 69d6a6ad-a44a-4e57-87dd-4e512d499fee
Content-Type: application/json; charset=utf-8
Content-Length: 2
ETag: W/"2-vyGp6PvFo4RvsFtPoIWeCReyIC8"
Date: Fri, 29 Mar 2019 11:44:36 GMT
Connection: keep-alive
{}HTTP/1.1 400 Bad Request
X-Powered-By: Express
Fiware-Correlator: 6c9a28b5-0505-456c-bcdb-841df2bc6f62
Content-Type: application/json; charset=utf-8
Content-Length: 388
ETag: W/"184-RqfzTJc6iD9nXX3kAbxZqwruJC0"
Date: Fri, 29 Mar 2019 11:44:37 GMT
Connection: keep-alive
{"contextResponses":[{"contextElement":{"contextElements":[{"type":"Bell","isPattern":"false","id":"urn:ngsi-ld:Bell:001","attributes":[{"name":"ring","type":"command","value":""}],"static_attributes":[]}],"updateAction":"UPDATE"},"statusCode":{"code":400,"reasonPhrase":"HTTP_COMMAND_RESPONSE_ERROR","details":"There was an error in the response of a device to a command [400 ]:null"}}]}
这似乎是相关部分:There was an error in the response of a device to a command [400 ]:null
。这是否意味着物联网代理期待来自“设备”的更具体的响应?
请求可以在请求bin中看到,因此它可以工作到那么远。但为什么代理人认为存在问题?它是否期望某种特定的响应格式?
我已经尝试将设备注册步骤中的“协议”转换为“PDI-IoTA-JSON”。这没有用。
问题是IoT代理假定设备将使用JSON进行响应。 Requestbin的默认答案是字符串“ok”。这导致代理崩溃。
如果设备返回{}
,请求成功,如果它返回命令结果的某些信息,则更成功。例如。
{
"ring": "successfully rung"
}