Latest revision as of 11:07, 14 August 2020

Install a REST client

• For this section, you need a REST client to send HTTP request (GET, POST, UPDATE, DELETE) to the OM2M platform.
• Install Postman extension on google chrome browser: http://www.postman.com
• The tutorial postman collection is available here: https://www.getpostman.com/collections/41fad4dcdaca7a90325e

Retrieve a resource

• HTTP request:

• HTTP response:

<?xml version="1.0" encoding="UTF-8"?>
<m2m:cb xmlns:m2m="http://www.onem2m.org/xml/protocols" rn="in-name">
    <ty>5</ty>
    <ri>/in-cse</ri>
    <ct>20151104T150228</ct>
    <lt>20151104T150228</lt>
    <acpi>/in-cse/acp-563660429</acpi>
    <cst>1</cst>
    <csi>in-cse</csi>
    <srt>1 2 3 4 5 9 14 15 16 17 23</srt>
    <poa>http://127.0.0.1:8080/</poa>
</m2m:cb>

You can set the Accept header to application/json if you want a response in JSON format instead of XML.

Create a "MY_SENSOR" application

• Send a HTTP request with the following parameters to create a MY_SENSOR application on the gateway.

• In the creation we have two important headers:
  • Content-Type: this header has 2 informations seperated by a semicolon
    • The format of the exchange, here "application/xml"
    • The resource type to be created, here "ty=2" (2 for AE, see oneM2M spec TS-0004 (V2.7.1), Table 6.3.4.2.1-1)

<m2m:ae xmlns:m2m="http://www.onem2m.org/xml/protocols" rn="MY_SENSOR" >
    <api>app-sensor</api>
    <lbl>Type/sensor Category/temperature Location/home</lbl>
    <rr>false</rr>
</m2m:ae>

• HTTP response:

<?xml version="1.0" encoding="UTF-8"?>
<m2m:ae xmlns:m2m="http://www.onem2m.org/xml/protocols" rn="MY_SENSOR">
    <ty>2</ty>
    <ri>ae-CAE449907766</ri>
    <pi>/in-cse</pi>
    <ct>20151104T151858</ct>
    <lt>20151104T151858</lt>
    <lbl>Type/sensor Category/temperature Location/home</lbl>
    <acpi>/in-cse/acp-89704715</acpi>
    <api>app-sensor</api>
    <aei>CAE449907766</aei>
    <rr>false</rr>
</m2m:ae>

• You can check the created application on the web interface.

Discover resources based on their labels

• You can discover available resources based on their search strings using the discovery resource. The fu parameter (stands for "Filter Usage") indicate that it is a discovery request. The lbl ("Label") indicate the specific label you what to filter.
• HTTP request:

• HTTP response:

<?xml version="1.0" encoding="UTF-8"?>
<m2m:disres xmlns:m2m="http://www.onem2m.org/xml/protocols">
    <ref ty="2"> <uri-of-the-resource> </ref>
</m2m:disres>

Create a DESCRIPTOR container

• Send a HTTP request with the following parameters to create a DESCRIPTOR container resource under the MY_SENSOR application.

<m2m:cnt xmlns:m2m="http://www.onem2m.org/xml/protocols" rn="DESCRIPTOR">
</m2m:cnt>

• HTTP response

<?xml version="1.0" encoding="UTF-8"?>
<m2m:cnt xmlns:m2m="http://www.onem2m.org/xml/protocols" rn="DESCRIPTOR">
    <ty>3</ty>
    <ri>cnt-478855064</ri>
    <pi>/in-cse/ae-CAE449907766</pi>
    <ct>20151104T155844</ct>
    <lt>20151104T155844</lt>
    <acpi>/in-cse/acp-89704715</acpi>
    <cni>0</cni>
    <cbs>0</cbs>
</m2m:cnt>

• Check the created container on the web interface.

Create a description contentInstance

• Send a HTTP request with the following parameters to create a description content instance resource under the "DESCRIPTOR" container.

	
<m2m:cin xmlns:m2m="http://www.onem2m.org/xml/protocols">
    <cnf>application/xml</cnf>
    <con>
        &lt;obj&gt;
            &lt;str name=&quot;type&quot; val=&quot;Temperature_Sensor&quot;/&gt;
            &lt;str name=&quot;location&quot; val=&quot;Home&quot;/&gt;
            &lt;str name=&quot;appId&quot; val=&quot;MY_SENSOR&quot;/&gt;
            &lt;op name=&quot;getValue&quot; href=&quot;/in-cse/in-name/MY_SENSOR/DATA/la&quot; 
         in=&quot;obix:Nil&quot; out=&quot;obix:Nil&quot; is=&quot;retrieve&quot;/&gt;
        &lt;/obj&gt;
    </con>
</m2m:cin>

• Check the created content instance on the web interface.

Create a DATA container

• Send a HTTP request with the following parameters to create a "DATA" container resource under the "MY_SENSOR" application.

<m2m:cnt xmlns:m2m="http://www.onem2m.org/xml/protocols" rn="DATA">
</m2m:cnt>

• Check the created container on the web interface.

Create a data contentInstance

• Send a HTTP request with the following parameters to create a data content instance resource under the "DATA" container.

	
<m2m:cin xmlns:m2m="http://www.onem2m.org/xml/protocols">
    <cnf>message</cnf>
    <con>
      &lt;obj&gt;
        &lt;str name=&quot;appId&quot; val=&quot;MY_SENSOR&quot;/&gt;
        &lt;str name=&quot;category&quot; val=&quot;temperature &quot;/&gt;
        &lt;int name=&quot;data&quot; val=&quot;27&quot;/&gt;
        &lt;int name=&quot;unit&quot; val=&quot;celsius&quot;/&gt;
      &lt;/obj&gt;
    </con>
</m2m:cin>

• Check the created content instance on the web interface.

Create a "MY_SENSOR" application using JSON

• Since OM2M supports JSON, you can send an HTTP request with the following parameters to create a MY_SENSOR application on the gateway using JSON instead of XML.

 {
   "m2m:ae": {
     "api": "app-sensor",
     "rr": "false",
     "lbl": ["Type/sensor", "Category/temperature", "Location/home"],
     "rn": "MY_SENSOR"
   }
 }

You can interact with the system in the same way using JSON instead of XML with an equivalent of the XML body. (Be careful for the Labels to use a JSON array for instance: "lbl":"["label-1", "label-2"].)

Subscribe to MY_SENSOR data

• Download the monitor server sample from this link: Monitor.
• Start the Monitor server using the following command:

> java -jar monitor.jar

• The monitor starts listening on port=1400 and context=/monitor.

Monitor console: the server is started

• Send a HTTP request with the following parameters to create a "Subscription" resource for receive asynchronously events from "MY_SENSOR" application.
• The monitor listening URL (http://127.0.0.1:1400/monitor) should be added on the "nu" tag of the subscription representation.

<m2m:sub xmlns:m2m="http://www.onem2m.org/xml/protocols" rn="SUB_MY_SENSOR">
    <nu>http://localhost:1400/monitor</nu>
    <nct>2</nct>
</m2m:sub>

• Check the created subscription on the web interface.

• Create a new event content instance resource under the "DATA" container.
• The new event is published to interested subscribers by the gateway.
• Here is an example of the "Notify" XML representation:

<?xml version="1.0" encoding="UTF-8"?>
<m2m:sgn xmlns:m2m="http://www.onem2m.org/xml/protocols">
   <nev>
      <rep rn="cin_name1">
         <ty>4</ty>
         <ri>cin-46677406</ri>
         <pi>/in-cse/cnt-397256037</pi>
         <ct>20151104T162611</ct>
         <lt>20151104T162611</lt>
         <st>0</st>
         <cnf>message</cnf>
         <cs>11</cs>
         <con>hello world</con>
      </rep>
      <rss>1</rss>
   </nev>
   <sud>false</sud>
   <sur>/in-cse/in-name/MY_SENSOR/DATA/SUB_MY_SENSOR</sur>
</m2m:sgn>

• The Monitor receives a "Notify" resource including the new "ContentInstance".
• Remember that the "Notify" resource has a generic structure to support notifications for other type of resources such as "AE", "Container", "Group", "AccessControlPolicy", etc.

Short Names

• ae: Application Entity
• cnt: Container
• cin: Content Instance
• sub: Subscription
• sgn: Agregated Notification
• rn: Resource Name
• ty: Type
• ri: Resource ID
• pi: Parent Id
• Acpi: Access Control Policies IDs
• uril: URI List
• ct: Creation Time
• et: Expiration Time
• lt: Last Modified Time
• lbl: Label
• cnf: Content Format
• con: Content
• mni: Maximum Number of Instance
• st: State Tag
• cs: Content Size
• aei: Application Entity Id
• api: Application Id
• poa: Point of Access
• rr: Request Reachability
• nev: Notification Event
• nep: Representation
• sur: Subscription URI
• Enc: Event Notification Criteria