R and Database URLs

Note: This approach is now built into the dbx package

To use a DATABASE_URL with R, do:

Postgres

library(RPostgreSQL)
library(httr)

establishConnection <- function(url=Sys.getenv("DATABASE_URL"))
{
  cred <- parse_url(url)
  if (!identical(cred$scheme, "postgres")) stop("Invalid database url")
  if (is.null(cred$username)) cred$username <- ""
  if (is.null(cred$password)) cred$password <- ""
  if (is.null(cred$port)) cred$port <- 5432
  dbConnect(PostgreSQL(), host=cred$hostname, port=cred$port,
    user=cred$username, password=cred$password, dbname=cred$path)
}

con <- establishConnection()
dbGetQuery(con, "SELECT true AS success")

MySQL

library(RMySQL)
library(httr)

establishConnection <- function(url=Sys.getenv("DATABASE_URL"))
{
  cred <- parse_url(url)
  if (!identical(cred$scheme, "mysql")) stop("Invalid database url")
  if (is.null(cred$username)) cred$username <- "root"
  if (is.null(cred$password)) cred$password <- ""
  if (is.null(cred$port)) cred$port <- 3306
  dbConnect(MySQL(), host=cred$hostname, port=cred$port,
    user=cred$username, password=cred$password, dbname=cred$path)
}

con <- establishConnection()
dbGetQuery(con, "SELECT true AS success")