Introduction to cumulocityr

library(cumulocityr)
library(knitr)

Introduction

This vignette introduces the main functions with a few examples.

Authentication

Credentials and base url for cumulocity are stored in a user’s private .Renviron file.

The credentials are defined as follows:

CUMULOCITY_base_url = "[tenant url]"
CUMULOCITY_usr = "[username]"
CUMULOCITY_pwd = "[password]"
CUMULOCITY_device_id = "[an example device id]"

The tenant url should be of the form “https://tenant_name.cumulocity.com”. CUMULOCITY_device_id is provided for convenience, but is not required by any of the main functions.

The file .Renviron can be edited with usethis::edit_r_environ().

Get devices

Get devices for the tenant and display a few columns. If no arguments are passed, get_devices() returns all devices.

devices <- get_devices()
print(devices[,c("type", "name", "id")])
#>              type           name    id
#> 1 c8y_SensorPhone     Pixel 2 XL  1200
#> 2        c8y_Demo  A demo device   200
#> 3            <NA>     DemoDevice 51868
#> 4  c8y_MQTTDevice Temperature #1 53700

Get measurements

Get measurements for device “Temperature #1” and plot the result. Datetimes are returned as character strings; we first convert to POSIXct before plotting.

meas <- get_measurements(device_id = 53700,
                         num_rows = 100,
                         date_from = "2019-09-30T19:59:00Z")
kable(head(meas[c("time", "type", "c8y_Temperature.T.value")]))

time	type	c8y_Temperature.T.value
2019-09-30T19:59:00.850Z	c8y_Temperature	2.079117
2019-09-30T19:59:05.851Z	c8y_Temperature	9.135455
2019-09-30T19:59:10.850Z	c8y_Temperature	8.090170
2019-09-30T19:59:15.851Z	c8y_Temperature	6.691306
2019-09-30T19:59:20.853Z	c8y_Temperature	5.000000
2019-09-30T19:59:25.851Z	c8y_Temperature	3.090170

time_parsed <- as.POSIXct(meas$time, format = "%Y-%m-%dT%H:%M:%OSZ", tz = "Z")

plot(time_parsed, meas$c8y_Temperature.T.value, type = "l",
     xlab = "Time", ylab = "Temperature (deg C)")

Get events

Similarly, we can get events for the same device:

events <- get_events(device_id = 53700,
                     num_rows = 6,
                     date_from = "2019-09-30T19:59:00Z")

kable(events[c("type", "time", "c8y_Position.lng", "c8y_Position.alt")])

type	time	c8y_Position.lng	c8y_Position.alt
c8y_LocationUpdate	2019-10-01T04:53:57.435Z	77	88
c8y_LocationUpdate	2019-10-01T04:53:52.435Z	33	44
c8y_LocationUpdate	2019-10-01T04:53:47.434Z	22	33
3	2019-10-01T04:53:42.432Z	NA	NA
c8y_LocationUpdate	2019-10-01T04:51:27.419Z	77	88
c8y_LocationUpdate	2019-10-01T04:51:22.418Z	33	44

Unparsed data

By default, the content is parsed, but it is possible to return a list of JSON objects.

meas_03 <- get_measurements(device_id = 53700,
                            num_rows = 2,
                            date_from = "2019-09-30T19:59:00Z",
                            parse_json = FALSE)

print(meas_03)
#> [[1]]
#> [1] "{\"next\":\"https://mg.cumulocity.com/measurement/measurements?dateTo=2019-10-16T15:31:16Z&pageSize=2&source=53700&dateFrom=2019-09-30T19:59:00Z&currentPage=2\",\"self\":\"https://mg.cumulocity.com/measurement/measurements?dateTo=2019-10-16T15:31:16Z&pageSize=2&source=53700&dateFrom=2019-09-30T19:59:00Z&currentPage=1\",\"statistics\":{\"totalPages\":null,\"currentPage\":1,\"pageSize\":2},\"measurements\":[{\"self\":\"https://mg.cumulocity.com/measurement/measurements/53701\",\"time\":\"2019-09-30T19:59:00.850Z\",\"id\":\"53701\",\"source\":{\"self\":\"https://mg.cumulocity.com/inventory/managedObjects/53700\",\"id\":\"53700\"},\"type\":\"c8y_Temperature\",\"c8y_Temperature\":{\"T\":{\"unit\":\"\\u00baC\",\"value\":2.0791169082}}},{\"self\":\"https://mg.cumulocity.com/measurement/measurements/53702\",\"time\":\"2019-09-30T19:59:05.851Z\",\"id\":\"53702\",\"source\":{\"self\":\"https://mg.cumulocity.com/inventory/managedObjects/53700\",\"id\":\"53700\"},\"type\":\"c8y_Temperature\",\"c8y_Temperature\":{\"T\":{\"unit\":\"\\u00baC\",\"value\":9.1354545764}}}]}"