R client

EVA ICS machine learning kit R library can work both with and with no server installed. If there is no server installed, data is processed on the client side.

Installation

With remotes/devtools

install.packages("remotes")
remotes::install_github("eva-ics/eva-ics-ml-R")

Manual

In the system shell type:

git clone https://github.com/eva-ics/eva-ics-ml-R
cd eva-ics-ml-R
(
cat << EOF
install.packages("curl")
install.packages("httr")
install.packages("jsonlite")
install.packages("readr")
install.packages('.', repos=NULL, type='source', dependencies=TRUE)
EOF
) | R --no-save

Querying data

Note

When used with ML kit server, R client downloads data using CSV streams only.

library(evaics)
session <- eva.session('http://127.0.0.1:7727',
    user='admin', password='xxx', mlkit='http://localhost:8811')
req <- eva.history.request()
req <- eva.history.append_oid(req, 'sensor:tests/temp', value='temp1')
data <- eva.history.fetch(session, req,
    t_start='2023-02-22 23:23:34',
    t_end='2023-02-23 03:33:19', fill='15T')

If Machine learning kit server is used with a front-end and API methods are mapped to the same port, the argument “mlkit” of eva.session function can be just set to TRUE. If Machine learning kit server is not installed, do not set this argument or set it to FALSE.

A client can read mapping from a CSV file with fields “oid”, “status”, “value” and “database” (can be omitted if ML kit server is used):

req <- eva.history.request('params.csv')

Uploading data

Prepare a request the same way as querying (database parameter for OIDs is ignored). Then use “push” method to push a file. The file extension must match:

.arrows for Arrow streams
.arrow for Arrow files
.csv for CSV files

Instead of a file, a data frame can be submitted (in this case the data is uploaded as a CSV stream). The database service can be specified in a short manner (e.g. “id” for “eva.db.id”) or in full. Example:

eva.history.push(session, req, '/path/to/file.csv', database='mydb')

eva.session(
  url = "http://localhost:7727",
  user = NULL,
  password = NULL,
  key = NULL,
  timeout = 120,
  mlkit = FALSE
)

Arguments

Argument	Description
`url`	HMI or front-end server URL
`user`	user login (for login/password authentication)
`password`	user password
`key`	API key (for API key authentication)
`timeout`	timeout for HTTP requests
`mlkit`	if ML Kit server is installed: TRUE (if front-end server is used) or ML Kit server URL

eva.authenticate(session)

Arguments

Argument	Description
`session`

eva.call(session, method, params = list())

Arguments

Argument	Description
`session`
`method`	RPC method
`params`	method params

eva.credentials(session, user, password)

Arguments

Argument	Description
`session`
`user`	user login
`password`	user password

eva.test(session)

Arguments

Argument	Description
`session`

eva.history.request(params_csv = NULL)

Arguments

Argument	Description
`params_csv`	Load oid map params from a CSV file

eva.history.append_oid(
  request,
  oid,
  status = FALSE,
  value = FALSE,
  database = NULL,
  xopts = NULL
)

Arguments

Argument	Description
`request`
`oid`	item OID
`status`	status mapping: TRUE or col name
`value`	value mapping: TRUE or col name
`database`	database service to load state from
`xopts`	extra database request options

eva.history.fetch(
  session,
  request,
  t_start = NULL,
  t_end = NULL,
  fill = NULL,
  limit = NULL,
  database = NULL,
  xopts = NULL,
  t_col = "keep",
  tz = NULL
)

Arguments

Argument	Description
`session`
`request`	Request object
`t_start`	start time: date/time or unix timestamp
`t_end`	end time: date/time or unix timestamp
`fill`	fill: NX, where X: S for seconds, T for minutes, H for hours, D for days, W for weeks, e.g. 15T
`limit`	limit result records to
`database`	database service to perform request on
`xopts`	extra options
`t_col`	time column processing: keep (default) or drop
`tz`	time zone

eva.history.push(session, request, data, database = "default")

Arguments

Argument	Description
`session`
`request`	request object
`data`	file path or a data frame
`database`	database to push data to (default: default)