shinyseo

shinyseo is a small helper package for Shiny apps that need social, search, and PWA metadata.

It builds one shiny::tags$head() fragment containing:

• canonical URL and description
• Open Graph tags for Facebook, LinkedIn, Slack, and similar previews
• Twitter Card tags
• favicon, apple-touch-icon, theme-color, and web app manifest links
• optional schema.org JSON-LD
• optional Bing, Google, Yandex, Baidu, Naver, Facebook, and Pinterest verification
• arbitrary custom meta tags

The package accepts either a YAML file path or a named list.

Six exported functions:

• init_meta(path) — interactively answer a few questions at the console and write the result to a YAML file, so you can get started without reading the field reference below
• social_meta(meta) — inject metadata into the UI at startup
• update_meta(session, ...) — update title, description, url, or image reactively from the server
• write_manifest(meta, ...) — generate www/manifest.json for PWA support
• generate_assets(meta, generator, ...) — fill in a missing favicon, Apple touch icon, or share image by calling your own LLM/image-generation function, or one of the built-in generators below
• openai_image_generator(api_key, model) — a ready-made generator for generate_assets() that calls OpenAI’s image API

Getting started

Run shinyseo::init_meta() in the console. It will ask for your title, description, URL, image, and a handful of optional fields (favicon, theme colour, home screen shortcut support, and so on), then write the answers to meta.yml. Pass that file straight to social_meta():

shinyseo::social_meta("meta.yml")

What it does

When you call social_meta(), the package:

1. Reads metadata from YAML or uses the list you pass in.
2. Fills in safe defaults for common fields like locale, robots, and Twitter card type.
3. Checks that the required fields exist.
4. Builds HTML tags for Shiny UI.
5. Adds JSON-LD unless you turn schema off.
6. Registers a JavaScript handler so update_meta() can update tags at runtime.

API in short

social_meta(meta):

• meta may be a YAML path or a named list
• title, description, url, and image are required
• if meta is a character string, it is read as a UTF-8 YAML file path
• missing keys use package defaults where provided
• schema = FALSE disables JSON-LD output
• any other value of schema keeps JSON-LD enabled

update_meta(session, title, description, url, image):

• call from the server to update metadata without a page reload
• only the fields you supply are changed
• requires social_meta() to be present in the UI

write_manifest(meta, path, display, start_url, background_color):

• generates www/manifest.json for PWA support
• call once in global.R before the app starts
• reference the result with manifest = "/manifest.json" in social_meta()

generate_assets(meta, generator, path, assets):

• fills in a missing favicon, apple_touch_icon, or image by calling a generator function — either one you write yourself, or a built-in one such as openai_image_generator()
• generator is function(prompt, kind); it talks to whatever LLM/image API it’s written against, and returns either raw image bytes or a path to a file on disk
• only missing fields are generated; existing values are left untouched
• run it once at setup time (e.g. from the console), then persist the updated meta with yaml::write_yaml()

meta <- shinyseo::generate_assets(meta,
  generator = shinyseo::openai_image_generator()
)
yaml::write_yaml(meta, "meta.yml")

Or supply your own, against whatever service you already have access to:

meta <- shinyseo::generate_assets(meta, generator = function(prompt, kind) {
  # your own call to Adobe Firefly, a local model, ...
})
yaml::write_yaml(meta, "meta.yml")

openai_image_generator(api_key, model):

• builds a ready-made generator for generate_assets() that calls OpenAI’s image API (gpt-image-1 by default) and returns the generated image bytes
• api_key defaults to the OPENAI_API_KEY environment variable
• requires the httr package, but only loads it (via requireNamespace()) when you call this constructor — it costs nothing if you never use it
• shinyseo ships only this one built-in generator. OpenAI’s image API is a straightforward fit for the job; most other LLM vendors either don’t generate images at all (e.g. Claude/Anthropic, which can see images but not generate them) or need enough vendor-specific glue that they’re better suited to a community-contributed generator — see LLM.md for the shape a contribution should take

meta <- shinyseo::generate_assets(meta,
  generator = shinyseo::openai_image_generator(api_key = "sk-...")
)

Config cheat sheet

Minimal configuration:

title: "Example app"
description: "A short app description."
url: "https://example.no"
image: "https://example.no/share.png"

Common extras:

If you want shared defaults across several apps, you can set these in .Renviron and let app-level YAML override them when needed:

• SHINYSEO_BING_SITE_VERIFICATION
• SHINYSEO_TWITTER_SITE
• SHINYSEO_TWITTER_CREATOR

What belongs where

Use .Renviron for values that are shared across many apps on the same machine or deployment:

• SHINYSEO_BING_SITE_VERIFICATION
• SHINYSEO_TWITTER_SITE
• SHINYSEO_TWITTER_CREATOR

Keep per-app values in each app’s meta.yml:

• title
• description
• url
• image
• locale if one app differs from the shared default
• site_name if one app needs a different display name
• twitter_site or twitter_creator if one app should override the shared default
• bing_site_verification if one app needs a different Bing token

SHINYSEO_GOOGLE_ANALYTICS_MEASUREMENT_ID is not used by shinyseo itself. If you use GA4, keep that in your server or deployment config instead of in meta.yml.

Quick use

# global.R — generate manifest once at startup
shinyseo::write_manifest("meta.yml")

# ui.R
ui <- fluidPage(
  shinyseo::social_meta("meta.yml"),
  h1("My app")
)

# server.R — update metadata when the user navigates
server <- function(input, output, session) {
  observeEvent(input$tabs, {
    shinyseo::update_meta(session, title = paste(input$tabs, "– My App"))
  })
}

You can also pass a list directly instead of a YAML file:

shinyseo::social_meta(list(
  title       = "Example app",
  description = "A short app description.",
  url         = "https://example.no",
  image       = "https://example.no/share.png",
  favicon     = "/favicon.png",
  theme_color = "#1a73e8"
))

Vignettes

The long-form package docs live in vignettes:

• API contract
• Reference guide

If the package is installed, you can also open them with browseVignettes("shinyseo").

For LLM use, see LLM.md.

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