====== GMS ======

The GMS has several interfaces that can be accessed through APIs.

{{:wiki3:gms_overview_3x.png|}}

===== REST =====

A RESTful Web services architecture follows basic design principles:

  * It exposes a tree of resources via URI 
  * It is stateless. Each request from any client contains all the information necessary to service the request, and session state is held in the client. 
  * A resource is represented by an hypermedia type, for example JSON 
  * It uses HTTP methods explicitly (''GET'', ''POST'', ''PUT'', ''DELETE'', …) and other HTTP standards 
  * hypertext links to reference state 
  * hypertext links to reference-related resources

The API version level is requested by the client using the //accept// HTTP header, for example here with API v1:

<code>Accept: application/vnd.kerlink.iot-v1+json</code>

<note important>
Many changes have been done between GMS API (WMC 3.0) and OSS API (WMC 2.3.x).    \\
Refer to the [[.documentation|Documentation]] section to get details of all methods available for this new WMC release.
</note> 


==== Example ====

<code>GET https://kerlink.wanesy.fr/gms/application/customers/198/fleets?page=3&PageSize=40</code>

This web service allows to get the page number 3 of the list of fleets of the customer 198.

| VERB | PROTOCOL | DOMAIN | PATH | QUERY STRING |
| GET  |http    |kerlink.wanesy.fr |/gms/application/customers/1/fleets |?page=3&PageSize=40 |



The list of possible verbs is : ''GET'', ''POST'', ''PUT'', ''DELETE'', ''PATCH'' 

  * ''POST'': creates a new resource. 
  * ''GET'': gets a resource. 
  * ''PUT'': updates an existing resource. 
  * ''DELETE'': deletes a resource. 
  * ''PATCH'': updates a subset of fields of an existing resource. 

==== Using the command-line ====

These examples use the command-line program ''curl'' to make HTTP requests.



=== Logging in ===

The use of the API is bound to a fresh token. Here is how you can request for a new token:

<code bash>
curl -s 'https://kerlink.wanesy.fr/gms/application/login' \
  -H 'Accept: application/vnd.kerlink.iot-v1+json' \
  -X POST \
  -d '{"login":"jdoe","password":"P@ssW0rd5ecRe7"}' \
  -H 'Content-Type: application/vnd.kerlink.iot-v1+json' \
  | jq .
</code>

Here ''jq'' is used to prettify the JSON output so that it is readable and indented:

<code javascript>
{
  "expiredDate": 1500537180050,
  "tokenType": "Bearer",
  "token": "eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJzdXBlcmFkbW ... n6i5WboHR-I"
}
</code>

=== Requesting the customers list ===

<code bash>
curl -s 'https://kerlink.wanesy.fr/gms/application/customers' \
  -H 'Accept: application/vnd.kerlink.iot-v1+json' \
  -H 'Authorization: Bearer eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJzdXBlcmFkbW ... n6i5WboHR-I' \
  | jq .
</code>

Result:

<code javascript>
{
  "count": 2,
  "pageSize": 50,
  "page": 1,
  "totalCount": 2,
  "list": [
    {
      "id": 130,
      ...
    }
  ],
  "nbPages": 1
}
</code>

=== Requesting the customer ID ===

<code bash>
$ curl -s 'https://kerlink.wanesy.fr/gms/application/authenticatedUser' \
  -H 'Authorization: Bearer eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJzdXBlcmFkbW ... n6i5WboHR-I' \
  -H 'Content-Type: application/vnd.kerlink.iot-v1+json;charset=UTF-8' \
  -H 'Accept: application/json, text/plain, */*' \
  | jq  '.links[] | select(.rel=="customer") | .href'
</code>

The ''jq'' filter is used to show only customer ID information. In fact, it will display the ''href'' value for all ''links'' objects for which the ''rel'' key has the ''customer'' value.

Example result with customer ID number ''23'':

<code javascript>
"/application/customers/23"
</code>

=== Sending data to an endpoint ===

Not all fields in ''TxMessageDto'' are required when creating a new TX message. The actual parameters to send are:

  * ''confirmed'': boolean, whether the TX message should be acknowledged (confirmed data transfer) 
  * ''contentType'': enum { TEXT, HEXA }, describes how the payload is encoded
  * ''port'': integer, LoRaWAN application port number
  * ''payload'': string, data payload, either encoded as an hex string or binary data in base64
  * ''maxAttempts'': integer (optional), maximum number of transmission attempts. Only required if confirmed is true. 
  * ''ttl'': integer (optional), time to live. Only required if confirmed is true.


No other parameter is supported.