Package 'blastula'

Title: Easily Send HTML Email Messages
Description: Compose and send out responsive HTML email messages that render perfectly across a range of email clients and device sizes. Helper functions let the user insert embedded images, web link buttons, and 'ggplot2' plot objects into the message body. Messages can be sent through an 'SMTP' server, through the 'Posit Connect' service, or through the 'Mailgun' API service <https://www.mailgun.com/>.
Authors: Richard Iannone [aut, cre] , Joe Cheng [aut], Jeroen Ooms [ctb] , Ted Goas [cph] (cerberus-meta.html), Posit Software, PBC [cph, fnd]
Maintainer: Richard Iannone <[email protected]>
License: MIT + file LICENSE
Version: 0.3.5.9000
Built: 2024-11-07 05:13:18 UTC
Source: https://github.com/rstudio/blastula

Help Index


The magrittr pipe

Description

The blastula package uses the pipe function, ⁠\%>\%⁠, to turn function composition into a series of imperative statements.


Add a file attachment to an email message

Description

This gives us a simple interface for attaching a file to the email object. When it comes time to send the email through smtp_send(), all attachments (specified by individual calls to add_attachment()) will be faithfully transmitted along with the message.

Usage

add_attachment(
  email,
  file,
  content_type = mime::guess_type(file),
  filename = basename(file)
)

Arguments

email

The email message object, as created by the compose_email() function. The object's class is email_message.

file

The filename for the file to be attached.

content_type

The MIME type for the attachment. By default, this is guessed by the mime::guess_type() function on the basis of the file's extension. The available MIME types that can be guessed are available in the mime::mimemap named character vector.

filename

the filename for the attachment. This can be different than the basename provided to file for the purpose of customization. By default, the basename of file is taken to be the attachment's filename.

Details

There are options available to specify the attachment's MIME type, its disposition, and customize the attachment's recipient-facing filename.


Create an HTML fragment for a CTA button

Description

Create the HTML fragment for a call to action button. This can be used as part of the email body but, since this HTML, it must be contained within md(). There are options to specify the button text, the URL, and the button's alignment.

Usage

add_cta_button(url, text, align = "center")

Arguments

url

A URL for the button.

text

The text that is placed atop the CTA button.

align

The alignment of the button inside the main content area. Options are "center" (the default), "left", and "right".

Value

A character object with an HTML fragment that can be placed inside the message body wherever the CTA button should appear.

Examples

# Create the button as an HTML fragment
cta_button <-
  add_cta_button(
    url = "http://www.website.net",
    text = "Press This Button"
  )

# Include the button in the email
# message body by using it as part of
# a vector inside of `md()`
email <-
  compose_email(
    body = md(
      c(
  "Pressing the button will take
  you to an example website",
  cta_button
      )
    )
  )

if (interactive()) email

Create an HTML fragment for an embedded ggplot image

Description

Add an ggplot plot inside the body of the email with this helper function.

Usage

add_ggplot(
  plot_object,
  width = 5,
  height = 5,
  alt = NULL,
  align = c("center", "left", "right", "inline"),
  float = c("none", "left", "right")
)

Arguments

plot_object

The ggplot2 plot object.

width

The width of the output plot in inches.

height

The height of the output plot in inches.

alt

Text description of image passed to the alt attribute inside of the image (⁠<img>⁠) tag for use when image loading is disabled and on screen readers. Defaults to the ggplot2 plot object's title, if exists. Override by passing a custom character string or "" for no text.

align

The alignment to be used for the image. If not "inline", the image will appear in its own block, i.e. there will not be text to the left or right of it.

float

The float value to be used for the image. If not "none", text will flow around the image, and the align argument will be ignored.

Value

An HTML fragment that can be placed inside the message body wherever the plot image should appear.

Examples

library(ggplot2)

# Create a ggplot plot
plot <-
  ggplot(
    data = mtcars,
    aes(x = disp, y = hp,
        color = wt, size = mpg)) +
  geom_point()

# Create an HTML fragment that
# contains an the ggplot as an
# embedded plot
plot_html <-
  add_ggplot(plot_object = plot)

# Include the plot in the email
# message body by simply referencing
# the `plot_html` object
email <-
  compose_email(
    body = md(
      c(
"Hello!

Here is a plot that will change
the way you look at cars forever.\n",
plot_html,
"Let me know what you think
about it!"
      )
    )
  )

if (interactive()) email

Create an HTML fragment for an embedded image

Description

Add a local image inside the body of the email with this helper function.

Usage

add_image(
  file,
  alt = "",
  width = 520,
  align = c("center", "left", "right", "inline"),
  float = c("none", "left", "right")
)

Arguments

file

A path to an image file.

alt

Text description of image passed to the alt attribute inside of the image (⁠<img>⁠) tag for use when image loading is disabled and on screen readers. NULL default produces blank ("") alt text.

width

The width to be used for the image, in pixels.

align

The alignment to be used for the image. If not "inline", the image will appear in its own block, i.e. there will not be text to the left or right of it.

float

The float value to be used for the image. If not "none", text will flow around the image, and the align argument will be ignored.

Value

A character object with an HTML fragment that can be placed inside the message body wherever the image should appear.

Examples

# Create an HTML fragment that
# contains an image
img_file_path <-
  system.file(
    "example_files",
    "test_image.png",
    package = "blastula"
  )

img_file_html <-
  add_image(file = img_file_path)

# Include the image in the email
# message body by simply referencing
# the `img_file_html` object
email <-
  compose_email(
    body = md(
      c(
"Hello,

Here is an image:\n",
img_file_html
      )
    )
  )

if (interactive()) email

Deploy a local image to Imgur and create an image tag

Description

Getting images into email message bodies (and expecting them to appear for the recipient) can be a harrowing experience. External images (i.e., available at public URLs) work exceedingly well and most email clients will faithfully display these images. With the imgur_image() function, we can take a local image file or a ggplot2 plot object and send it to the Imgur service, and finally receive an image (⁠<img>⁠) tag that can be directly inserted into an email message using compose_email().

Usage

add_imgur_image(
  image,
  client_id = NULL,
  alt = NULL,
  width = 520,
  align = c("center", "left", "right", "inline"),
  float = c("none", "left", "right")
)

Arguments

image

The path to the local image we would like to deploy to Imgur and for which we'd like an image tag.

client_id

The Imgur Client ID value.

alt

Text description of image passed to the alt attribute inside of the image (⁠<img>⁠) tag for use when image loading is disabled and on screen readers. NULL default produces blank ("") alt text.

width

The width to be used for the image, in pixels.

align

The alignment to be used for the image. If not "inline", the image will appear in its own block, i.e. there will not be text to the left or right of it.

float

The float value to be used for the image. If not "none", text will flow around the image, and the align argument will be ignored.

Details

To take advantage of this, we need to first have an account with Imgur and then obtain a Client-ID key for the Imgur API. This can be easily done by going to ⁠https://api.imgur.com/oauth2/addclient⁠ and registering an application. Be sure to select the OAuth 2 authorization type without a callback URL.

Value

An HTML fragment that can be placed inside the message body wherever the image should appear.


Create a string with a more readable date/time

Description

Add a nicely-formatted date/time string inside the body of the email with this helper function. We can provide a POSIXct date-time object or use the current date/time/tz (based on the user's locale information at the time of the function call). There are options to specify whether the date, time, and time zone parts are to be included.

Usage

add_readable_time(time = NULL, use_date = TRUE, use_time = TRUE, use_tz = TRUE)

Arguments

time

The POSIXct time to use, and to make more readable for email recipients. If a time is not provided (the default), the current system time will be used.

use_date, use_time, use_tz

Logical value that indicate whether to include the date, time, or time zone components.

Value

A character object that can be placed inside any message component message wherever the function is called.

Examples

# Generate a date and time value using a specified date/time value
add_readable_time(
  time = ISOdatetime(
    year = 2022,
    month = 3,
    day = 15,
    hour = 8,
    min = 30,
    sec = 0,
    tz = "GMT"
   ),
  use_tz = FALSE
)

Specify the components of an article

Description

The article() function is used exclusively within block_articles(), and having one, two, or three calls will arrange the articles in a row (or as a column of articles at lower screen widths).

Usage

article(image = NULL, title = NULL, content = NULL, link = NULL)

Arguments

image

An optional URL pointing to an image resource.

title

An optional title for the article.

content

An optional paragraph of text for the article.

link

An optional link to apply to the content elements.

Examples

# We can define an article with a link
# to an image, title text, some content,
# and a link to relevant content
article <-
  article(
    image = "https://i.imgur.com/dxSXzGb.jpg",
    title = "Hong Kong",
    content =
      "Once home to fishermen and farmers, \\
      modern Hong Kong is a teeming, \\
      commercially-vibrant metropolis where \\
      Chinese and Western influences fuse.",
    link = "http://www.discoverhongkong.com"
  )

if (interactive()) article

Associate an email when publishing an R Markdown document to Posit Connect

Description

This function is used to customize emails sent by Posit Connect in conjunction with publishing an R Markdown document. It associates a custom email message with the main R Markdown document, which Connect can send to selected recipients. The main input is a rendered email message, which can be produced by either the render_email() or render_connect_email() function.

Usage

attach_connect_email(
  email = NULL,
  subject = NULL,
  attachments = NULL,
  attach_output = FALSE,
  text = NULL,
  preview = TRUE
)

Arguments

email

A rendered email message. Normally, we'd want to use an associated .Rmd file with the blastula::blastula_email R Markdown output format in render_connect_email() call (where its input is the email .Rmd file).

subject

An option to specify the the email subject while attaching the email object.

attachments

A vector of attachments for the Connect email. These files can be any of those deployed when publishing to Posit Connect, and, any generated files (via R Markdown rendering).

attach_output

Should the rendered output of the main R Markdown document be included as an email attachment? By default, this is FALSE. If TRUE the main R Markdown document will be attached first (before any files specified in attachments) and the filename will be preserved.

text

Instead of using a rendered email document through the email option, we can use plain text here. However, if any email object is supplied then input to text is ignored.

preview

Should the email message display it's own preview window? If TRUE (the default), the rendered email message will be shown in the default browser.

Details

Since this function needs to be invoked within an R Markdown document, the chunk option echo=FALSE is useful here (so that viewers of the rendered document don't have to unnecessarily read code related to email inclusion). While the output is invisible, any errors related to rendering will be visible to the author.


The R Markdown blastula_email output format

Description

The R Markdown blastula_email output format

Usage

blastula_email(
  content_width = "1000px",
  toc = FALSE,
  toc_depth = 3,
  toc_float = FALSE,
  number_sections = FALSE,
  section_divs = TRUE,
  fig_width = 5.35,
  fig_height = 5,
  fig_retina = 2,
  fig_caption = TRUE,
  dev = "png",
  smart = TRUE,
  self_contained = TRUE,
  template = "blastula",
  includes = NULL,
  keep_md = FALSE,
  md_extensions = NULL,
  connect_footer = FALSE,
  ...
)

Arguments

content_width

The width of the rendered HTML content. By default, this is set to ⁠1000px⁠. Using widths less than ⁠600px⁠ is generally not advised but, if necessary, be sure to test such HTML emails with a wide range of email clients before sending to the intended recipients. The Outlook mail client (Windows, Desktop) does not respect content_width.

toc

If you would like an automatically-generated table of contents in the output email, choose TRUE. By default, this is FALSE where no table of contents will be generated.

toc_depth

The depth of headers to include in the table of contents ( should toc be set to TRUE).

toc_float

An option to float the table of contents to the left of the main document content. By default, this is FALSE.

number_sections

Sections can be sequentially numbered if this is set to TRUE. By default, this is FALSE.

section_divs

This wraps sections in ⁠<section>⁠ tags and attaches identifiers to the enclosing ⁠<section>⁠s. This is set to TRUE.

fig_width, fig_height

The figure width and height in units of inches.

fig_retina

The scaling factor for retina displays. The default value is 2, which is the preferred choice for most retina displays. This can be set to NULL to prevent retina scaling. Note that this will always be NULL if keep_md is set to TRUE.

fig_caption

An option to render figures with captions. By default, this is set to TRUE.

dev

The R graphics device for figures. By default, this is the png device.

smart

An option to produce typographically correct output. This will convert straight quotes to curly quotes, ⁠---⁠ to em dashes, ⁠--⁠ to en dashes, and instances of ... to ellipses. By default, this is TRUE.

self_contained

Should a self-contained output file be generated. By default, this is TRUE. The standalone HTML file will have no external dependencies, it will use URIs to incorporate the contents of linked scripts, stylesheets, images, and videos.

template

The Pandoc template to use for rendering. This is the "blastula" template by default.

includes

A named list of additional content to include within the document. This is typically created using the rmarkdown::includes() function. By default, this is set to NULL.

keep_md

Should you need the keep the intermediate Markdown (.md) file, set this to TRUE. By default, the .md file is not kept.

md_extensions

Markdown extensions to be added or removed from the default definition or R Markdown.

connect_footer

Should a prepared footer message with links be included in the rendered email?

...

Specify other options in rmarkdown::html_document().


Default template for compose_email()

Description

A template function that is suitable for using as the template argument of compose_email(). Template functions should generally not be called directly. When implementing your own template function, you must include parameters for html_body, html_header, html_footer, and title; you may also optionally add your own parameters, which callers to compose_email() can provide through the ... argument.

Usage

blastula_template(
  html_body,
  html_header,
  html_footer,
  title,
  content_width = "1000px",
  font_family = "Helvetica, sans-serif"
)

Arguments

html_body, html_header, html_footer

htmltools tag objects (e.g. htmltools::tags() or htmltools::HTML()), or NULL to omit.

title

Plain text title to be used for the ⁠<title>⁠ element; may be displayed in mobile phone notifications.

content_width

The width that should be used for the content area. By default, this is set to ⁠1000px⁠. Using widths less than ⁠600px⁠ is generally not advised but, if necessary, be sure to test such HTML emails with a wide range of email clients before sending to the intended recipients.

font_family

The CSS value to use for font-family.

Value

A string containing a complete HTML document.


A block of one, two, or three articles with a multicolumn layout

Description

With block_articles(), we can create a single- or multi-column layout of articles. The articles are responsive to the screen width, so side-by-side articles will collapse and any of the optional images will resize accordingly. The function can accept one to three article() calls, each with varying amounts of text and imagery. Like all ⁠block_*()⁠ functions, block_articles() must be placed inside of blocks() and the resultant blocks object can be provided to the body, header, or footer arguments of compose_email().

Usage

block_articles(...)

Arguments

...

One, two, or three calls to article().

Examples

# Create a block of three, side-by-side
# articles with three `article()`
# calls inside of `block_articles()`,
# itself placed in `blocks()`
email <-
  compose_email(
    body =
      blocks(
        block_articles(
          article(
            image = "https://i.imgur.com/XMU8yJa.jpg",
            title = "Taiwan",
            content =
              "It is a thriving mosaic of tradition,
              culture, and high-tech development,
              merging Eastern and Western influences."
          ),
          article(
            image = "https://i.imgur.com/aYOm3Tk.jpg",
            title = "Japan",
            content =
              "Japan is an archipelago consisting
              of 6,852 islands along East Asia's
              Pacific Coast."
          ),
          article(
             image = "https://i.imgur.com/ekjFVOL.jpg",
             title = "Singapore",
             content =
               "Singapore is an island city-state
               in Southeast Asia. It's lies at the
               southern tip of the Malay Peninsula."
          )
        )
      )
    )

if (interactive()) email

A spacer block

Description

With block_spacer() we can more easily define an area of whitespace in a block-based layout. This function is meant to be easily combined with other ⁠block_*()⁠ functions. Like all ⁠block_*()⁠ functions, block_spacer() must be placed inside of blocks() and the resultant blocks object can be provided to the body, header, or footer arguments of compose_email().

Usage

block_spacer()

Examples

# Create a block of two, side-by-side
# articles with two `article()` calls
# inside of `block_articles()`, itself
# placed in `blocks()`; include some
# introductory text and place extra
# space around that text (with
# `block_spacer()`)
email <-
  compose_email(
    body =
      blocks(
        block_spacer(),
        block_text(
          "These are two of the cities I visited this year.
          I liked them a lot, so, I'll visit them again!"),
        block_spacer(),
        block_articles(
          article(
            image = "https://i.imgur.com/dig0HQ2.jpg",
            title = "Los Angeles",
            content =
              "I want to live in Los Angeles.
              Not the one in Los Angeles.
              No, not the one in South California.
              They got one in South Patagonia."
          ),
          article(
            image = "https://i.imgur.com/RUvqHV8.jpg",
            title = "New York",
            content =
              "Start spreading the news.
              I'm leaving today.
              I want to be a part of it.
              New York, New York."
          )
        )
      )
    )

if (interactive()) email

A block of text

Description

With block_text() we can define a text area and this can be easily combined with other ⁠block_*()⁠ functions. The text will take the entire width of the block and will resize according to screen width. Like all ⁠block_*()⁠ functions, block_text() must be placed inside of blocks() and the resultant blocks object can be provided to the body, header, or footer arguments of compose_email().

Usage

block_text(text, align = c("left", "center", "right", "justify"))

Arguments

text

Plain text or Markdown text (via md()).

align

The text alignment to be used for this block of text. The default is "left".

Examples

# Create a block of two, side-by-side
# articles with two `article()` calls
# inside of `block_articles()`, itself
# placed in `blocks()`; also, include some
# text at the top with `block_text()`
email <-
  compose_email(
    body =
      blocks(
        block_text(
          "These are two of the cities I visited this year.
          I liked them a lot, so, I'll visit them again!"),
        block_articles(
          article(
            image = "https://i.imgur.com/dig0HQ2.jpg",
            title = "Los Angeles",
            content =
              "I want to live in Los Angeles.
              Not the one in Los Angeles.
              No, not the one in South California.
              They got one in South Patagonia."
          ),
          article(
            image = "https://i.imgur.com/RUvqHV8.jpg",
            title = "New York",
            content =
              "Start spreading the news.
              I'm leaving today.
              I want to be a part of it.
              New York, New York."
          )
        )
      )
    )

if (interactive()) email

A block with large title text

Description

With block_title() we can define a title text area and this can be easily combined with other ⁠block_*()⁠ functions. The title will take the entire width of the block and will resize according to screen width. Like all ⁠block_*()⁠ functions, block_title() must be placed inside of blocks() and the resultant blocks object can be provided to the body, header, or footer arguments of compose_email().

Usage

block_title(title)

Arguments

title

Plain text or Markdown text (via md()) for the title.

Examples

# Create a block of two, side-by-side
# articles with two `article()` calls
# inside of `block_articles()`, itself
# placed in `blocks()`; also, include a
# title at the top with `block_title()`
email <-
  compose_email(
    body =
      blocks(
        block_title("Two Cities I Visited Recently"),
        block_articles(
          article(
            image = "https://i.imgur.com/dig0HQ2.jpg",
            title = "Los Angeles",
            content =
              "I want to live in Los Angeles.
              Not the one in Los Angeles.
              No, not the one in South California.
              They got one in South Patagonia."
          ),
          article(
            image = "https://i.imgur.com/RUvqHV8.jpg",
            title = "New York",
            content =
              "Start spreading the news.
              I'm leaving today.
              I want to be a part of it.
              New York, New York."
          )
        )
      )
    )

if (interactive()) email

An enclosure for all HTML block functions

Description

To contain all of the block-based HTML ⁠block_*()⁠ calls, we should use the blocks() function. We can pass the resulting blocks object to either of the body, header, and footer arguments of compose_email().

Usage

blocks(...)

Arguments

...

One or more ⁠block_*()⁠ calls.

Examples

# This is an example of how a
# title and text looks in each of
# the three content areas
email <-
  compose_email(
    header =
      blocks(
        block_title("This is a Title in the **Header**"),
        block_text("This is text in the **Header**.")
      ),
    body =
      blocks(
        block_title("This is a Title in the **Body**"),
        block_text("This is text in the **Body**.")
      ),
    footer =
      blocks(
        block_title("This is a Title in the **Footer**"),
        block_text("This is text in the **Footer**.")
      )
  )

if (interactive()) email

Create the email message body

Description

The compose_email() function allows us to easily create an email message. We can incorporate character vectors into the message body, the header, or the footer.

Usage

compose_email(
  body = NULL,
  header = NULL,
  footer = NULL,
  title = NULL,
  ...,
  template = blastula_template
)

Arguments

header, body, footer

The three layout sections for an email message (ordered from top to bottom). Markdown text can be supplied to each of these by using the md() text helper function. Alternatively, we can supply a set of ⁠block_*()⁠ calls enclosed within the blocks() function to take advantage of precomposed HTML blocks.

title

The title of the email message. This is not the subject but the HTML title text which may appear in limited circumstances.

...

Additional arguments to pass to the template function. If you're using the default template, you can use font_family to control the base font, and content_width to control the width of the main content; see blastula_template(). By default, the content_width is set to ⁠1000px⁠. Using widths less than ⁠600px⁠ is generally not advised but, if necessary, be sure to test such HTML emails with a wide range of email clients before sending to the intended recipients. The Outlook mail client (Windows, Desktop) does not respect content_width.

template

An email template function to use. The default is blastula_template().

Value

An email_message object.

Examples

# Create a simple email message using
# Markdown-formatted text in the `body`
# and `footer` sections with the `md()`
# text helper function
email <-
  compose_email(
    body = md(
"
## Hello!

This is an email message that was generated by the blastula package.

We can use **Markdown** formatting with the `md()` function.

Cheers,

The blastula team
"),
  footer = md(
"
sent via the [blastula](https://rstudio.github.io/blastula) R package
")
)

# The email message can always be
# previewed by calling the object
if (interactive()) email

Store SMTP credentials in a file

Description

We can create a file with SMTP configuration and access credentials for the purpose of more easily sending email messages through smtp_send(). With this file produced, the credentials helper creds_file() can be used in the credentials argument of smtp_send().

Usage

create_smtp_creds_file(
  file,
  user = NULL,
  provider = NULL,
  host = NULL,
  port = NULL,
  use_ssl = NULL
)

Arguments

file

The output filename for the credentials file.

user

The username for the email account. Typically, this is the email address associated with the account.

provider

An optional email provider shortname for autocompleting SMTP configuration details (the host, port, use_ssl options). Options currently include gmail, outlook, and office365. If nothing is provided then values for host, port, and use_ssl are expected.

host, port, use_ssl

Configuration info for the SMTP server. The host and port parameters are the address and port for the SMTP server. use_ssl is an option as to whether to allow the use of STARTTLS, if available: it should be TRUE unless you have a specific reason to set it to FALSE.

Examples

# Create a credentials file to make it
# much easier to send email out through
# Gmail with `smtp_send()`; name the
# file "gmail_creds"

# create_smtp_creds_file(
#   file = "gmail_creds",
#   user = "[email protected]",
#   provider = "gmail"
# )

Store SMTP credentials in the system's key-value store

Description

We can set SMTP access credentials in the system-wide key-value store for the purpose of more easily sending email messages through smtp_send(). With this key added, the credentials helper creds_key() can be used in the credentials argument of smtp_send() (the id value is used to unambiguously refer to each key).

Usage

create_smtp_creds_key(
  id,
  user = NULL,
  provider = NULL,
  host = NULL,
  port = NULL,
  use_ssl = NULL,
  overwrite = FALSE
)

Arguments

id

An identifying label for the keyname. The full key name is constructed in the following way: ⁠blastula-v1-<id>⁠. This id value is what's needed later to either use the key with creds_key(), or, delete the key with delete_credential_key(). A single, non-NA character, numeric, or integer value can be supplied here; the id will be coerced to a character value. If the id is supplied as a single character value, it cannot be an empty string and it cannot include hyphen characters.

user

The username for the email account. Typically, this is the email address associated with the account.

provider

An optional email provider shortname for autocompleting SMTP configuration details (the host, port, use_ssl options). Options currently include gmail, outlook, and office365. If nothing is provided then values for host, port, and use_ssl are expected.

host, port, use_ssl

Configuration info for the SMTP server. The host and port parameters are the address and port for the SMTP server. use_ssl is an option as to whether to allow the use of STARTTLS, if available: it should be TRUE unless you have a specific reason to set it to FALSE.

overwrite

An option that controls the overwriting of existing keys with the same id value. By default, this is FALSE (where overwriting is prohibited).

Details

Support for setting keys through create_smtp_creds_key() is provided through the keyring package. This function cannot be used without that package being available on the system. We can use install.packages("keyring") to install keyring.

Examples

# Store SMTP credentials using the
# system's secure key-value store to
# make it much easier to send email
# out through Gmail with `smtp_send()`;
# provide the `id` of "gmail_creds"

# create_smtp_creds_key(
#   id = "gmail_creds",
#   provider = "gmail",
#   user = "[email protected]",
#   )

Helpers for supplying SMTP credentials

Description

These helper functions, the credential helpers, are used to supply SMTP configuration and authorization information for the smtp_send() function. The creds_file(), creds_anonymous(), creds_key(), and creds() functions are to be used expressly with the credentials argument of smtp_send().

Usage

creds(user = NULL, provider = NULL, host = NULL, port = NULL, use_ssl = TRUE)

creds_anonymous(provider = NULL, host = NULL, port = NULL, use_ssl = TRUE)

creds_envvar(
  user = NULL,
  pass_envvar = "SMTP_PASSWORD",
  provider = NULL,
  host = NULL,
  port = NULL,
  use_ssl = TRUE
)

creds_key(id)

creds_file(file)

Arguments

user

The username for the email account. Typically, this is the email address associated with the account.

provider

An optional email provider shortname for autocompleting SMTP configuration details (the host, port, use_ssl options). Options currently include gmail, outlook, and office365. If nothing is provided then values for host, port, and use_ssl are expected.

host, port, use_ssl

Configuration info for the SMTP server. The host and port parameters are the address and port for the SMTP server; use_ssl is an option as to whether to use SSL: supply a TRUE or FALSE value.

pass_envvar

The name of the environment variable that holds the value for an email account password. This is only used in the creds_envvar() credential helper function.

id

When using the creds_key() credential helper, the ID value of the key (in the system key-value store) needs to be given here. This was explicitly provided when using the create_smtp_creds_key() function (with its own id argument). To get an information table with all available blastula keys in the key-value store, we can use the view_credential_keys() function.

file

When using the creds_file() credential helper, we need to specify the location of the credential file, and, this is where that is done. The credential file was ideally generated by the create_smtp_creds_file() function.

Details

The creds() credential helper allows for manual specification of SMTP configuration and authentication.

The creds_anonymous() credential helper is similar to creds() but provides convenient defaults for authenticating anonymously with an SMTP server.

The creds_key() credential helper gets credentials stored in the system-wide key-value store. We can set that key and the credentials data using the create_smtp_creds_key() function.

The creds_file() credential helper is used to obtain credentials from a file stored on disk. We can create that file using the create_smtp_creds_file() function.

The creds_envvar() credential helper reads the password from the SMTP_PASSWORD environment variable (or an environment variable name that you specify). If using environment variables for other parameters, call Sys.getenv() manually (e.g. user = Sys.getenv("SMTP_USER")).

Value

A credentials list object.


Delete all blastula credential keys

Description

The delete_all_credential_keys() function deletes all blastula credential keys, giving you a clean slate. Should specific keys need to be deleted, the delete_credential_key() could be used (one call per credential key to delete). Before using delete_all_credential_keys(), it may be useful to see which keys are available in the key-value store. For that, use the view_credential_keys() function.

Usage

delete_all_credential_keys()

Details

Support for using the delete_all_credential_keys() function (and for doing any credential key management) is provided through the keyring package. This function cannot be used without that package being available on the system. We can use install.packages("keyring") to install keyring.

Examples

# Delete all blastula credential keys
# in the system's key-value store

# delete_all_credential_keys()

Delete a single blastula credential key

Description

It may be important to delete a credential key and the delete_credential_key() function makes this possible. To understand which keys are available in the key-value store (and to get their id values), use the view_credential_keys() function.

Usage

delete_credential_key(id)

Arguments

id

The identifying label for the credential key. Use the same id that was used to create the key with the create_smtp_creds_key() function.

Details

Support for using the delete_credential_key() function (and for doing any credential key management) is provided through the keyring package. This function cannot be used without that package being available on the system. We can use install.packages("keyring") to install keyring.

Examples

# Delete the credential key with
# the `id` value of "outlook"

# delete_credential_key("outlook")

Get the HTML content of an email message

Description

Get the HTML content string from an email_message object as a single-length character vector.

Usage

get_html_str(message)

Arguments

message

The email message object, as created by the compose_email() function. The object's class is email_message

Value

A character object containing the email message's HTML content.


Interpret input text as Markdown-formatted text

Description

Interpret input text as Markdown-formatted text

Usage

md(text)

Arguments

text

The text that is understood to contain Markdown formatting.

Value

A character object that is tagged for a Markdown-to-HTML transformation.

A rendered HTML object.


Prepare example files for Posit Connect emailing with R Markdown

Description

A set of example files relevant to emailing with R Markdown in RStudio Connect can be spawned in a specified location. There is a set of three files that work together to provide a full report, an emailable version of that report, and a file attachment; these files are:

Usage

prepare_rsc_example_files(path = NULL)

Arguments

path

The location to which the files (in a subdirectory named "connect_examples") will be written. The path needs to exist but the aforementioned subdirectory is not required to be present.

Details

  • "connect-example-main.Rmd": The main R Markdown document. Contains a report template culminating in a final R code chunk that has calls to render_connect_email() and attach_connect_email().

  • "connect-example-email.Rmd": An R Markdown document that contains the email message. It is associated with the main R Markdown document by incorporating some of its content (i.e., by reusing chunk names and extending assigned values). It uses the blastula::blastula_email output type in the YAML front matter.

  • "austin_home_sales.csv": A CSV file that will be included as an attachment by way of the attachments argument in the attach_connect_email() function call within the main R Markdown document.

The main report and associated email can be published by opening "connect-example-main.Rmd" and pressing the Publish button at the top-right of the Editor pane (please ensure beforehand that you are set up work with Posit Connect). If asked "What do you want to publish?", choose the first option where only the "connect-example-main" document is published. All three files should be checked in the final dialog box, press the Publish button to publish to Posit Connect.

There is also the single "connect-example-text-only.Rmd" file that, when published, serves as a mechanism to send a text-only email. The content of the email is specified directly in the single attach_connect_email() function call and all other text in the R Markdown file is disregarded.


Prepare a email test message object

Description

Create an email test message object, which is helpful for sending a test message with the smtp_send() function.

Usage

prepare_test_message(incl_ggplot = FALSE, incl_image = FALSE)

Arguments

incl_ggplot

An option to include a ggplot plot within the body of the test message. This requires that the ggplot2 package is installed. By default, this is FALSE.

incl_image

An option to include a test image within the body of the test message. By default, this is FALSE.

Value

An email_message object.

Examples

# Create a credentials file to send
# a test message via Gmail's SMTP
# (this file is named "gmail_secret")

# create_smtp_creds_file(
#   file = "gmail_secret",
#   user = "[email protected]",
#   provider = "gmail"
# )

# Send oneself a test message to
# test these new SMTP settings and
# to ensure that the message appears
# correctly in the email client

# prepare_test_message() %>%
#   smtp_send(
#     from = "[email protected]",
#     to = "[email protected]",
#     subject = "Test Message",
#     credentials = creds_file(
#       file = "gmail_secret"
#       )
#     )

R Markdown render functions for the blastula_email output format

Description

The render_email() and render_connect_email() functions both allow for rendering an an email message. We can supply an R Markdown document (.Rmd) with the output specified as output: blastula::blastula_email. While the render_email() and render_connect_email() functions have similar arguments, the render_connect_email() is preferred when publishing to the Posit Connect service. It allows for the inclusion of a predefined footer that contains useful links for email recipients.

Usage

render_email(
  input,
  envir = parent.frame(),
  quiet = TRUE,
  output_options = list(),
  render_options = list()
)

render_connect_email(
  input,
  connect_footer = TRUE,
  envir = parent.frame(),
  quiet = TRUE,
  output_options = list(),
  render_options = list()
)

Arguments

input

The input file to be rendered. This should be an R Markdown document (.Rmd) with the output specified as output: blastula::blastula_email.

envir

The environment in which the code chunks are to be evaluated during knitting.

quiet

An option to suppress printing of the command line output from Pandoc during rendering. By default, this is set to TRUE.

output_options, render_options

Lists of options can be used to augment the rendering of the email message. The output_options list will be passed as the output_options argument of rmarkdown::render(). The render_options list is for providing additional arguments to rmarkdown::render(). By default, both lists are empty.

connect_footer

Should a prepared footer message with links be included in the rendered email? This argument is only available in the render_connect_email() function and is set to TRUE by default.


Send an email message through the Mailgun API

Description

Send an email message via the Mailgun API. This requires an account with Mailgun.

Usage

send_by_mailgun(message, subject = NULL, from, recipients, url, api_key)

Arguments

message

The email message object, as created by the compose_email() function. The object's class is email_message

subject

The subject of the email.

from

The email address of the sender. This does not have to be the same email that is associated with the account actually sending the message.

recipients

A vector of email addresses.

url

The URL for the sending domain.

api_key

The API key registered to the Mailgun service.

Examples

# Create a simple email message using
# Markdown formatting

# email <-
#   compose_email(
#   body = "
#   Hello!
#
#   ## This a section heading
#
#   We can use Markdown formatting \
#   to **embolden** text or to add \
#   *emphasis*. This is exciting, \
#   right?
#
#   Cheers")

# Generate a vector of recipients

# recipient_list <-
#   c("[email protected]",
#     "[email protected]")

# Send it to multiple people through
# the Mailgun API

# email %>%
#   send_by_mailgun(
#     subject = "Sent through Mailgun",
#     from = "The Sender <[email protected]>",
#     recipients = recipient_list,
#     url = "<..mailgun_sending_domain..>",
#     api = "<..mailgun_api_key..>")

Send an email message through SMTP

Description

Send an email message to one or more recipients via an SMTP server. The email message required as input to smtp_send() has to be created by using the compose_email() function. The email_message object can be previewed by printing the object, where the HTML preview will show how the message should appear in recipients' email clients. File attachments can be added to the email object by using the add_attachment() function (one call per attachment) prior to sending through this function.

Usage

smtp_send(
  email,
  to,
  from,
  subject = NULL,
  cc = NULL,
  bcc = NULL,
  credentials = NULL,
  creds_file = "deprecated",
  verbose = FALSE,
  login_options = NULL,
  ...
)

Arguments

email

The email message object, as created by the compose_email() function. The object's class is email_message.

to

A vector of email addresses serving as primary recipients for the message. For secondary recipients, use the cc and bcc arguments. A named character vector can be used to specify the recipient names along with the their email address (e.g., c("Jane Doe" = "[email protected]")).

from

The email address of the sender. Often this needs to be the same email address that is associated with the account actually sending the message. As with to, cc, and bcc, we can either supply a single email address or use a named character vector with the sender name and email address (e.g., c("John Doe" = "[email protected]")).

subject

The subject of the message, which is usually a brief summary of the topic of the message. If not provided, an empty string will be used (which is handled differently by email clients).

cc, bcc

A vector of email addresses for sending the message as a carbon copy or blind carbon copy. The CC list pertains to recipients that are to receive a copy of a message that is addressed primarily to others. The CC listing of recipients is visible to all other recipients of the message. The BCC list differs in that those recipients will be concealed from all other recipients (including those on the BCC list). A named character vector can be used to specify the recipient names along with the their email address (e.g., c("Joe Public" = "[email protected]")).

credentials

One of three credential helper functions must be used here: (1) creds(), (2) creds_key(), or (3) creds_file(). The first, creds(), allows for a manual specification of SMTP configuration and credentials within that helper function. This is the most secure method for supplying credentials as they aren't written to disk. The creds_key() function is used if credentials are stored in the system-wide key-value store, through use of the create_smtp_creds_key() function. The creds_file() helper function relies on a credentials file stored on disk. Such a file is created using the create_smtp_creds_file() function.

creds_file

An option to specify a credentials file. As this argument is deprecated, please consider using ⁠credentials = creds_file(<file>)⁠ instead.

verbose

Should verbose output from the internal curl send_mail() call be printed? While the username and password will likely be echoed during the exchange, such information is encoded and won't be stored on the user's system.

login_options

A string representation of login options allowed by CURLOPT_LOGIN_OPTIONS.

...

Extra arguments passed to curl::send_mail()

Details

We can avoid re-entering SMTP configuration and credentials information by retrieving this information either from disk (with the file generated by use of the create_smtp_creds_file() function), or, from the system's key-value store (with the key set by the create_smtp_creds_key() function).

Examples

# Before sending out an email through
# SMTP, we need an `email_message`
# object; for the purpose of a simple
# example, we can use the function
# `prepare_test_message()` to create
# a test version of an email (although
# we'd normally use `compose_email()`)
email <- prepare_test_message()

# The `email` message can be sent
# through the `smtp_send()` function
# so long as we supply the appropriate
# credentials; The following three
# examples provide scenarios for both
# the creation of credentials and their
# retrieval within the `credentials`
# argument of `smtp_send()`

# (1) Providing the credentials info
# directly via the `creds()` helper
# (the most secure means of supplying
# credentials information)

# email %>%
#   smtp_send(
#     from = "[email protected]",
#     to = "[email protected]",
#     credentials = creds(
#       provider = "gmail",
#       user = "[email protected]")
#   )

# (2) Using a credentials key (with
# the `create_smtp_creds_key()` and
# `creds_key()` functions)

# create_smtp_creds_key(
#  id = "gmail",
#  user = "[email protected]",
#  provider = "gmail"
#  )

# email %>%
#   smtp_send(
#     from = "[email protected]",
#     to = "[email protected]",
#     credentials = creds_key(
#       "gmail"
#       )
#   )

# (3) Using a credentials file (with
# the `create_smtp_creds_file()` and
# `creds_file()` functions)

# create_smtp_creds_file(
#  file = "gmail_secret",
#  user = "[email protected]",
#  provider = "gmail"
#  )

# email %>%
#   smtp_send(
#     from = "[email protected]",
#     to = "[email protected]",
#     credentials = creds_file(
#       "gmail_secret")
#   )

Suppress any scheduled emailing in Posit Connect

Description

This function is useful for suppressing the scheduled emailing of a published R Markdown document. It can be invoked anywhere in the R Markdown document and is useful in a conditional statement, where the result of the condition determines whether or not email suppression should occur.

Usage

suppress_scheduled_email(suppress = TRUE)

Arguments

suppress

A logical value for whether email suppression should occur after publication. By default, this is TRUE.

Details

Since this function needs to be invoked within an R Markdown document, the chunk option echo=FALSE is useful here (so that viewers of the rendered document don't have to unnecessarily read code related to email suppression). While the output is invisible, any errors related to the use of this function will be visible to the author.


View all available blastula credential keys

Description

To understand which keys have been set using the create_smtp_creds_key() function (and how they are identified), we can use the view_credential_keys() function. What's provided is a tibble with three columns: id, key_name, and username.

Usage

view_credential_keys()

Details

Support for using the view_credential_keys() function (and for doing any credential key management) is provided through the keyring package. This function cannot be used without that package being available on the system. We can use install.packages("keyring") to install keyring.

Examples

# View the available SMTP credentials
# that are in the system's secure
# key-value store; the `id` values
# in the returned tibble provide what's
# necessary to send email through
# `smtp_send()` and the `creds_key()`
# credential helper function

# view_credential_keys()