Overview
- Evgeny Aleshin
Introduction
To send data over HTTP, device messages have to be transformed into an HTTP request. The blueprint for transforming a device message into an HTTP request is known as a template. Sensors send different types of messages with different sets of fields, therefore a Template has to be defined for each message type. Templates are grouped together into Template Suites and in order for messages to be sent, template suites have to be connected to zones.
Template Suites
Template suites:
Store a collection of templates
Connect to zones with devices
Used for monitoring HTTP calls
TemplateÂ
A template is a blueprint for building an HTTP request for a single message type.
Each template has the following fields:
Field | Description |
|---|---|
Name | A unique reference for a template in a template suite |
Message Type | Type of message that this template will be applied to. |
Method | HTTP method that will be used for in a request |
URL | URL to which a request is made |
Header | Request headers, typically used for authorization |
Body | Request body defined as a JSON string |
Authorization Methods
Basic HTTP(s) Authentication using authorization header in the format of "Basic " + Base64 (username: password)
API-Key
Message Types
Different message types have a set of common and distinct attributes that can be used in the template.
Message types have two main categories – Direct and Smart.
The main difference between these two categories is that Smart message types have a pre-defined template body that cannot be changed. The resulting message structure is identical to RabbitMQ protocols (RTA & Parking Sessions) and supports Parking Session messages that are crucial for unmarked parking bays and useful for payment applications. It also allows for an easier transition to RabbitMQ.
Category | Message Type | Â |
|---|---|---|
Direct | Status Change | status change message is sent from a sensor when its value has been changed (occupancy state for parking sensor or number of detected cars for car counters |
Heartbeat | heartbeat message is sent after every constant time period of unchanging sensor state | |
User Registration | user registration message is sent when a user is authorized on the sensor using a Bluetooth-tag | |
Smart | Group Availability | status change message in a group format with group summary |
Parking Sessions | smart parking session messages formed by Nwave’s backend, with auto-correction for lost messages |
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