HTTP Server

Overview

The HTTP Server resource offers access to data points through a HTTP/REST interface.

• This server will accept JSON data via POST or PUT and forwarding that data to corresponding MQTT topic.

• User access and authentication can be configured using the existing connectware functionalities for HTTP permissions.

• The listening port is the same port 443 which is also used for HTTPS access to the other REST interfaces of the Connectware, where each request with the path /data refers to the internal HTTP server for data access.

The HTTP server can be configured using the Cybus::Server::Http resource. The server resource defines an optional base path prefix in addition to the standard /data prefix.

Each HTTP route is described by a Cybus::Node::Http resource that defines the path and http method as parameters to specify the route.

Permissions

User access and authentication can be configured using the existing connectware functionalities for HTTP permissions, see Roles and Permissions. For the example below where the user should PUT or POST to the route data/cybustest/postRoute, the user must be granted matching write permissions, e.g. data/cybustest/# or data/+/postRoute.

Commissioning File Specifics

Custom Server Properties

basePath (string)

Any additional base URL path in addition to the default /data/ base URL path

Default: ""

Examples: "/my/custom/path", "/"

requestMaxBodySize (integer)

Default: 100000

Example: 100000

Additional restrictions:

• Minimum: 1

• Maximum: 512000

Custom Node Properties

method (string, enum)

The HTTP method to be offered by this particular route node

This element must be one of the following enum values:

• POST

• PUT

• GET

route (string)

The additional route path of this particular HTTP node, preceded by the server’s base url

Examples: "/my/individual/route", "/testroute"

Sending data to the HTTP Server

JSON

If the server receives a messages with the header Content-type=application/json, it will parse the HTTP message body in JSON format, then transform the content into the internal message convention where the message body is in the value property. Example:

// Original message sent to HTTP server
{
  "machineState": "okay",
  "temperature": 23,
  "logs": [
    "message1",
    "message2"
  ]
}

// Resulting protocol-mapper output at the MQTT broker
{
   "timestamp": 12391238123, // milliseconds since epoch
   "value": {
      "machineState": "okay",
      "temperature": 23,
      "logs": [
        "message1",
        "message2"
      ]
    }
}

If the request sent to the server is not parseable as JSON, it will be dropped and not forwarded to the MQTT broker.

Other Formats

Other supported mime-types in the Content-type header are:

• application/octet-stream

• text/plain

• text/xml

• text/csv

In all of these cases, the HTTP message body is forwarded to the specified topic without any further modification (no timestamp, no value property).

Receiving data from the HTTP Server

JSON

Each Node with method = GET has an internal cache, which will store any date written to it using the */write topic. The cache has a depth of 1, so only the latest data is being stored.

Data will always be in the format of a JSON object containing value and timestamp. If no timestamp is provided, one will be generated.

If no data is available, the server will respond with status of 204.

// Original message sent to MQTT broker
{
  "value": "Cybus"
}

// Resulting protocol-mapper output at the MQTT broker
{
   "timestamp": 12391238123, // milliseconds since epoch
   "value": "Cybus"
}

Sample Commissioning File

The endpoints from the commissioning file can be accessed using the following curl commands. It is assumed that the Connectware is configured so that the data route is accessible by basic auth authentication, and that the user has sufficient HTTP permission to write to the path data/cybustest/postRoute.

The POST based demo endpoint:

curl --location --request POST 'https://my.connectwareurl.com/data/cybustest/postRoute' \
--header 'Authorization: Basic <BASIC AUTH TOKEN>' \
--header 'Content-Type: application/json' \
--data-raw '{
    "test1": "testdata send via POST Route"
}'

The PUT based demo endpoint:

curl --location --request PUT 'https://my.connectwareurl.com/data/cybustest/putRoute' \
--header 'Authorization: Basic <BASIC AUTH TOKEN>' \
--header 'Content-Type: application/json' \
--data-raw '{
    "test2": "testdata send via PUT Route"
}'

The GET based demo endpoint:

curl --location --request GET 'https://my.connectwareurl.com/data/cybustest/getRoute' \
--header 'Authorization: Basic <BASIC AUTH TOKEN>'

Download: http-server-example.yml

---
  description: Provides a demonstration structure for a http server configured in the protocol mapper

  metadata:
    name: Definition By Example for HTTP Endpoints

  parameters: {}

  resources:
    httpServer:
      type: Cybus::Server::Http
      properties:
        basePath: /cybustest

    postRoute:
      type: Cybus::Node::Http
      properties:
        parent: !ref httpServer
        method: POST
        route: /postRoute

    putRoute:
      type: Cybus::Node::Http
      properties:
        parent: !ref httpServer
        method: PUT
        route: /putRoute

    getRoute:
      type: Cybus::Node::Http
      properties:
        parent: !ref httpServer
        method: GET
        route: /getRoute

    httpMapping:
      type: Cybus::Mapping
      properties:
        mappings:
          - subscribe:
              endpoint: !ref postRoute
            publish:
              topic: output/postroute
          - subscribe:
              endpoint: !ref putRoute
            publish:
              topic: output/putroute
          - subscribe:
              topic: input/getRoute
            publish:
              endpoint: !ref getRoute