Using R to send an Outlook email with an inline image
If you work in a corporate environment, there’s a good chance you’re using Microsoft Office. I wanted to set up a way to email tables and plots from R using Outlook. Sending an email is simple enough with the RDCOMClient library, but inserting a plot inline—rather than as an attachment—took a little bit of working out. I’m sharing my code here in case anyone else wants to do something similar. The trick is to save your plot as an image with a temporary file, attach it to the email, and then insert it inline using a cid (Content-ID).
library(ggplot2)
# Create a simple scatterplot with ggplo2
SimplePlot <- ggplot(mtcars, aes(x=wt, y=mpg)) + geom_point()
# Create a temporary file path for the image that we will attach to our email
SimplePlot.file <- tempfile(fileext = ".png")
# Save the ggplot we just created as an image with the temporary file path
ggsave(plot = SimplePlot, file = SimplePlot.file,
device = "png", width = 4, height = 4)
# Create an Outlook object, a new email, and set the parameters.
Outlook <- RDCOMClient::COMCreate("Outlook.Application")
Email <- Outlook$CreateItem(0)
Email[["To"]] <- "johnsmith@example.com"
Email[["subject"]] <- "A simple scatterplot"
# Some text before we insert our plot
Body <- "<p>Your scatterplot is here:</p>"
# First add the temporary file as an attachment.
Email[["Attachments"]]$Add(SimplePlot.file)
# Refer to the attachment with a cid
# "basename" returns the file name without the directory.
SimplePlot.inline <- paste0( "<img src='cid:",
basename(SimplePlot.file),
"' width = '400' height = '400'>")
# Put the text and plot together in the body of the email.
Email[["HTMLBody"]] <- paste0(Body, SimplePlot.inline)
# Either display the email in Outlook or send it straight away.
# Comment out either line.
Email$Display()
#Email$Send()
# Delete the temporary file used to attach images.
unlink(SimplePlot.file)devtools::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#> setting value
#> version R version 4.0.0 (2020-04-24)
#> os Ubuntu 20.04 LTS
#> system x86_64, linux-gnu
#> ui X11
#> language en_AU:en
#> collate en_AU.UTF-8
#> ctype en_AU.UTF-8
#> tz Australia/Melbourne
#> date 2020-06-13
#>
#> ─ Packages ───────────────────────────────────────────────────────────────────
#> package * version date lib source
#> assertthat 0.2.1 2019-03-21 [1] CRAN (R 4.0.0)
#> backports 1.1.7 2020-05-13 [1] CRAN (R 4.0.0)
#> callr 3.4.3 2020-03-28 [1] CRAN (R 4.0.0)
#> cli 2.0.2 2020-02-28 [1] CRAN (R 4.0.0)
#> crayon 1.3.4 2017-09-16 [1] CRAN (R 4.0.0)
#> desc 1.2.0 2018-05-01 [1] CRAN (R 4.0.0)
#> devtools 2.3.0 2020-04-10 [1] CRAN (R 4.0.0)
#> digest 0.6.25 2020-02-23 [1] CRAN (R 4.0.0)
#> downlit 0.0.0.9000 2020-06-12 [1] Github (r-lib/downlit@87fb1af)
#> ellipsis 0.3.1 2020-05-15 [1] CRAN (R 4.0.0)
#> evaluate 0.14 2019-05-28 [1] CRAN (R 4.0.0)
#> fansi 0.4.1 2020-01-08 [1] CRAN (R 4.0.0)
#> fs 1.4.1 2020-04-04 [1] CRAN (R 4.0.0)
#> glue 1.4.1 2020-05-13 [1] CRAN (R 4.0.0)
#> htmltools 0.4.0 2019-10-04 [1] CRAN (R 4.0.0)
#> hugodown 0.0.0.9000 2020-06-12 [1] Github (r-lib/hugodown@6812ada)
#> knitr 1.28 2020-02-06 [1] CRAN (R 4.0.0)
#> magrittr 1.5 2014-11-22 [1] CRAN (R 4.0.0)
#> memoise 1.1.0.9000 2020-05-09 [1] Github (hadley/memoise@4aefd9f)
#> pkgbuild 1.0.7 2020-04-25 [1] CRAN (R 4.0.0)
#> pkgload 1.0.2 2018-10-29 [1] CRAN (R 4.0.0)
#> prettyunits 1.1.1 2020-01-24 [1] CRAN (R 4.0.0)
#> processx 3.4.2 2020-02-09 [1] CRAN (R 4.0.0)
#> ps 1.3.3 2020-05-08 [1] CRAN (R 4.0.0)
#> R6 2.4.1 2019-11-12 [1] CRAN (R 4.0.0)
#> Rcpp 1.0.4.6 2020-04-09 [1] CRAN (R 4.0.0)
#> remotes 2.1.1 2020-02-15 [1] CRAN (R 4.0.0)
#> rlang 0.4.6 2020-05-02 [1] CRAN (R 4.0.0)
#> rmarkdown 2.2.3 2020-06-12 [1] Github (rstudio/rmarkdown@4ee96c8)
#> rprojroot 1.3-2 2018-01-03 [1] CRAN (R 4.0.0)
#> sessioninfo 1.1.1 2018-11-05 [1] CRAN (R 4.0.0)
#> stringi 1.4.6 2020-02-17 [1] CRAN (R 4.0.0)
#> stringr 1.4.0 2019-02-10 [1] CRAN (R 4.0.0)
#> testthat 2.3.2 2020-03-02 [1] CRAN (R 4.0.0)
#> usethis 1.6.1 2020-04-29 [1] CRAN (R 4.0.0)
#> withr 2.2.0 2020-04-20 [1] CRAN (R 4.0.0)
#> xfun 0.14 2020-05-20 [1] CRAN (R 4.0.0)
#> yaml 2.2.1 2020-02-01 [1] CRAN (R 4.0.0)
#>
#> [1] /home/mdneuzerling/R/x86_64-pc-linux-gnu-library/4.0
#> [2] /usr/local/lib/R/site-library
#> [3] /usr/lib/R/site-library
#> [4] /usr/lib/R/library