# 109 Lab4 - GPS tracking using OM2M, node-red and app inventor 2
###### tags: `109 物聯網核心網路技術`
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## oneM2M 架構圖
Mca: the interface point between AE and CSE which provides the applications access to the common services.
Mcc: the reference point between two CSEs.
Mcn: the reference point between CSE and underlying NSE like transport and connectivity services.
Mcc’: the interface between two M2M service providers.
IN: Infrastructure Node
NoDN: Non-oneM2M Device Node
## A. Pre-work
* Start the OM2M IN-CSE
* Start the OM2M MN-CSE
* Start node-red
* Start App Inventor 2
:::danger
Lab4-1
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:::warning
因為 MN-CSE 可以透過 redirector(MCC) 到 IN-CSE
所以這邊 127.0.0.1:8282 可以存取到 IN-CSE 的資料
:::
## B. Create a MN-AE with Node-RED.
### 1. Application
:::info
在 mn-cse 上新增一個 Application resource
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#### Properties
* **Platform** : Destination CSE.

* **Application** : AE Id (application name).

* **Point of Access** : PoA URL.
* **Announce** : whether this resource is announced to other CSE or not.
* **Labels** : labels to describe this application.

#### om2m resource tree

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### 2. Container
:::info
Creates a Container resource to store content instances.
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#### Properties
* **Platform** : Destination CSE.
(選剛剛新增的 **"mn-cse"**)
* **Application** : AE Id (application name)
(選剛剛新增的 **"LOCATION_GATEWAY_APPLICATION"**)
* **Container** : Name of the container (choose among DESCRIPTOR, DATA, or input your own container’s name).

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* 
#### om2m resource tree
* 

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### 3. ContentInstance
:::info
Creates a ContentInstance resource to store application’s data.
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#### Properties
* Platform: Destination CSE.
(選剛剛新增的 **"mn-cse"**)
* Application: AE Id (application name).
(選剛剛新增的 **"LOCATION_GATEWAY_APPLICATION"**)
* Container: Name of the container.
(填入剛剛新增的 **"DATA"**)
* Labels: The data you want to store. You must describe three fields: Type (str, int, bool, etc.), Name (the name of the attribute), Value (the value of the attribute).
* 
#### om2m resource tree

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### 4. NotificationHandler(用http in取代)
om2m 1.3 訂閱時會先確認要通知的位置是否存在，但這顆node不太好用
("NotificationHandler"會把port佔住，要重啟node-red才能進行後面的測試)
建議使用node-red內建的 **"http in"**，或者直接開啟http server

這邊用 **input ->"http in"** 來示範
1. 將第一顆node(http in)改成以下內容
2. 中間那顆是個http response，在訂閱時需要回傳訊息，讓om2m知道這個位置存在

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### 5. Subscription
Creates a Subscription source.
* Platform: Destination CSE.
(選剛剛新增的 **"mn-cse"**)
* Application: AE Id (application name).
(選剛剛新增的 **"LOCATION_GATEWAY_APPLICATION"**)
* Container: Name of the container you want to subscribe to.
(填入剛剛新增的 **"DATA"**)
* Path: URL of the webservice that will handle the notification of this subscription.

* om2m resource tree

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## C. 測試&處理Notification
:::warning
把剛才用來確認訂閱的flow稍微改一下
:::
* "switch" node
* 取出狀態

    var data = msg.payload["m2m:sgn"].nev[0].rep[0]["m2m:cin"][0].con[0];
	msg.payload = data
	return msg;

* 設定object

    var New = {latitude:null,longitude:null};
	New.latitude = msg.payload.obj.str[0].$.val;
	New.longitude = msg.payload.obj.str[1].$.val;
	msg.payload = New;
	return msg;

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## D. 在MN-AE新增一個處理建立om2m resource任務的功能
* http in node
* set payload and headers

	/*jshint multistr: true */
	var data = '<m2m:cin xmlns:m2m="http://www.onem2m.org/xml/protocols">\
		<cnf>message</cnf>\
		<con>\
		  &lt;obj&gt;\
			&lt;str name=&quot;latitude&quot; val=&quot;'+msg.payload.latitude+'&quot;/&gt;\
			&lt;str name=&quot;longitude&quot; val=&quot;'+msg.payload.longitude+'&quot;/&gt;\
		  &lt;/obj&gt;\
		</con>\
	</m2m:cin>';

	msg.payload = data;
	msg.headers = {};
	msg.headers['X-M2M-Origin'] = 'admin:admin';
	msg.headers['Content-Type'] = 'application/xml;ty=4';

	return msg;

格式參考 : https://wiki.eclipse.org/OM2M/one/REST_API#Create_a_data_contentInstance
* post to mn-cse
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## E. Sending Location Data to MN-AE using App inventor 2
1. Create a new project and draw the components in the GUI as shown below.
2. In the blocks area, draw the corresponding objects for:

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:::danger
Lab4-2
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## F. Getting Location Data from IN-AE using App Inventor 2
1. Use node-red to create resources in in-cse
* create ae(application)




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* create container



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* create ContentInstance



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* handle the request from app inventor (om2m 自行編譯版)
第四條 第二顆 node
第四條 第四顆 node
第四條 第六顆 node
* handle the request from app inventor (om2m 下載版)
* 在 `[get]/locations` node 後，新增一function node

		msg.headers = {};
		msg.headers['X-M2M-Origin'] = 'admin:admin';
		return msg;

* `get from in cse` node 取消勾選 Use authentication

2. create a new project and draw the components in the GUI as shown below.
3. In the blocks area, draw the corresponding objects for: