Use Case 5 is dedicated to information related to special vehicles (dynamic events).

The objective of this use case is to collect and publish information in real time on the location of special transports that have previously been authorized by DGT.

The aim is to send the x, y coordinates to the platform by the special vehicle to allow it to be detected by other vehicles beyond the direct line of sight.

The platform has two different functionalities for the publication (sending) and for the subscription (reception) of information. The first is through a REST API and the second through a real-time MQTT service.

Both the publication and subscription functionality require different access certificates that must be requested and supplied by DGT 3.0. If these certificates have not already been requested, they should be requested from [email protected].

Below are the URLs with which each functionality is accessed:

The two functionalities are described below.

This use case has a REST API for the publication (sending) of the data by the companies that request it. Details of this can be found in the following sections:

• General details for making a request:

General · (cmobility30.es)

• The details of the master tables and data that can compose the event:

Master Tables

• The structure of the event can be seen here:

Event

This use case also has a subscription service (reception) to the data for the companies that request it through the MQTT protocol. Below you can find the details of this:

MQTT (MQ Telemetry Transport) is a messaging protocol used as a simple and lightweight method to transfer data to / from low-power devices.

The protocol supports a single messaging pattern, the Publish-Subscribe pattern: each message is published on a topic that must be subscribed to in order to receive the information.

Subscription to the service of this use case must be through the topic:

out_usecase5_v2

In the topic, the events are published in JSON format. Here you can see an example:

{
    "actionId": "14e1a280f261053b41aefd3197a100a96a551fad28e51e43a1266ff1e62fb488",
    "timestamp": "2024-09-03T07:26:02Z",
    "lon": -4.304818,
    "lat": 41.312456,
    "eventTypeId": 2
}

• actionId (text): unique identifier of the event

• timestamp (UTC time): date and time in UTC format of when the event was generated. It must be a maximum of 30 seconds old with respect to UTC time. The date must end with the character 'Z' that marks that it is in UTC

• lon (decimal number): longitude in WGS 84 coordinate system where the event was generated

• lat (decimal number): latitude in WGS 84 coordinate system where the event was generated

• eventTypeId (integer number): identifier of the event type. 1 = Activation, 2 = Actived, 3 = Deactivation

See more information and a connection example here.

As stated above, all HTTP responses other than 200 – OK, can be considered invalid. The format of the error response is like the following example:

{
    "status": 401,
    "code": 1,
    "message": "User not found or valid"
}

These errors will have three main categories:

• HTTP Status: 401 - Unauthorized

  Code	Message
  1	User not found or valid

• HTTP Status: 400 - Bad Request

  Code	Message
  0	Authenticate
  2	Entity ID not found
  3	Missing required property
  4	The entity received cannot be proccessed
  5	Incorrect token received
  6	Expired token received
  7	There is an error with the token provided. Please request a new one
  8	No token received
  9	Required request body is missing
  10	Event is marked as expired by timestamp
  11	Missing request header
  12	Access denied role

In the case of getting an error 3 - Missing required property, the response obtained will have a value in the message that will indicate the missing fields to send:

{
    "status": 400,
    "code": 3,
    "message": "[deviceTypeId: must not be null, deviceUseTypeId: must not be null, informationQualityId: must not be null]"
}

• HTTP Status: 500 - Internal Server Error

  Code	Message
  13	Internal error