RStudio Connections

RStudio connections can be extended through:

  1. Snippet Files that provide support for new connections using R templates that enable users and system administrators to list and create new connections.
  2. Packages that do one or more of the following:
    • Implement the Connections Contract to manage and explore data in RStudio’s Connections Pane and/or
    • Supply Snippet Files or a Shiny Application to extend RStudio’s New Connection dialog.

Snippet Files

A Connection Snippet File is an R code snippet with additional metadata which is intended to initialize a connection. This file can be as simple as:

library(readr)
data <- read_csv(readr_example("mtcars.csv"))

Once this file is saved under /etc/rstudio/connections/ as Motor Trend Cars.R, RStudio will make this connection as available as:

The path is configurable through the connections-path environment variable and multiple connection files can be specified.

In order to parameterize this connection, one can create fields using using the ${Position:Label=Default} syntax:

  • Position: The row position starting at zero.
  • Label: The label assigned to this field.
  • Default: An optional default value.

For example, we can filter out this dataframe to produce the following connection interface:

library(readr)
data <- read_csv(readr_example("mtcars.csv"))
data[data$mpg == ${0:Miles per Gallon=21.4} | data$cyl == ${1:Cylinders=6}, ]

In order to create a ; separated list of values, one can use the syntax ${Position:Label=Default:Key}. Semicolon-separated list are common in database connections and therefore, natively supported in snippet files, for instance:

"${2:Letters=ABC:LettersKey}${3:Numbers=123:NumbersKey}"

There are a couple escape characters supported: $colon$ to escape : and $equal to escape =.

R Packages

Package Structure

A package supporting connections defines the following components:

  • Connections File: A DCF file must be created under inst/rstudio/connections.dcf to enumerate each connection supported in the package.
  • Snippet Files: Snippet files are stored under inst/rstudio/connections/.

As a quick start, the Rstudio Connections Example GitHub repo contains a working example of this structure.

Connections Contract

You can integrate with RStudio’s Connection Pane to allow users to explore connections created with your R package by using the Connections Contract.

Snippet Files

Snippet Files are specified under the /inst/rstudio/connections and follow the same syntax mentioned in the “Snippet Files” section.

Shiny Application

For advanced connection interfaces, a shiny application can be specified. See sparklyr for a working application.