peeky

The peeky package helps you extract, examine, and run the source code from Shiny applications that have been converted to run in the browser using Shinylive. It works with both standalone applications and Quarto documents containing Shinylive components through the quarto-shinylive extension, supporting both R and Python Shiny applications.

About Shinylive

Shinylive converts existing Shiny applications to run entirely in the web browser using WebAssembly versions of R (webR) and Python (Pyodide), eliminating the need for a computational server. This means all application files are accessible to users by design as they are downloaded to the user’s browser when the application is loaded.

The Shinylive ecosystem consists of four main components:

• Shinylive Web Assets: posit-dev/shinylive
• R Shiny App Converter Package: posit-dev/r-shinylive
• Python Shiny App Convert Package: posit-dev/py-shinylive
• Shinylive Quarto Extension: quarto-ext/shinylive

There Are No Secrets in Shinylive

The peeky package was developed to demonstrate a fundamental truth about Shinylive applications stressed by its developers: “There are no secrets.”

Unlike traditional Shiny applications where server-side code remains private, Shinylive apps run entirely in the web browser, making all associated files accessible to users. This includes the source code, data, and any other files used by the application. As a result, Shinylive applications are transparent by design.

This package was developed as part of ongoing discussions in STATS 290 about Shiny application security, transparency, and deployment options. It serves as a practical demonstration of the differences between traditional server-side applications and modern browser-based alternatives.

Installation

You can install the development version of peeky from GitHub with:

# install.packages("remotes")
remotes::install_github("coatless-rpkg/peeky")

Usage

To use the package, load it into your R session:

library(peeky)

Inside the package, there are three main functions:

Extracting Shinylive Applications

We suggest using the peek_shinylive_app() function as it can handle both standalone Shinylive applications and Quarto documents with Shinylive components. For instance, if we take the main Shinylive extension website, we get:

# Choose where the files are written (here, a temporary directory)
out_dir <- file.path(tempdir(), "shinylive-apps")
peeky::peek_shinylive_app("https://quarto-ext.github.io/shinylive/", output_dir = out_dir)
#> 
#> ── Shinylive Applications ──────────────────────────────────────────────────────
#> 
#> ── Shiny for Python Applications ──
#> 
#> Run in Terminal:
#> shiny run --reload --launch-browser "/tmp/RtmpXXXXXX/shinylive-apps/app_1/app.py"
#> shiny run --reload --launch-browser "/tmp/RtmpXXXXXX/shinylive-apps/app_2/app.py"
#> shiny run --reload --launch-browser "/tmp/RtmpXXXXXX/shinylive-apps/app_3/app.py"
#> shiny run --reload --launch-browser "/tmp/RtmpXXXXXX/shinylive-apps/app_4/app.py"

This would be equivalent to if we ran the following:

peeky::peek_quarto_shinylive_app(
  "https://quarto-ext.github.io/shinylive/",
  output_path = out_dir
)

The output location is a required argument, so the package never writes to your working directory unless you ask it to: a relative path such as "my-apps" is created under the current working directory, while an absolute path is used as-is. Each application is placed in a subdirectory named app_1, app_2, etc. We can also set the output format to quarto to extract the files into a single Quarto document.

# Extract the applications into a single Quarto document
peeky::peek_quarto_shinylive_app(
  "https://quarto-ext.github.io/shinylive/",
  output_format = "quarto",
  output_path = file.path(tempdir(), "shinylive-apps.qmd")
)
#> 
#> ── Quarto Document with Shinylive Applications ─────────────────────────────────
#> 
#> ── Setup and Preview Steps ──
#> 
#> Step 1: Change to the document directory:
#> cd "/tmp/RtmpXXXXXX"
#> 
#> Step 2: Install the Shinylive extension:
#> quarto add quarto-ext/shinylive
#> 
#> Step 3: Preview the document:
#> quarto preview "shinylive-apps.qmd"
#> 
#> ── Contents ──
#> 
#> • R applications: 0
#> • Python applications: 4

We can switch to the peek_standalone_shinylive_app() function if we know that the URL is a standalone Shinylive application. For example, if we take the example application used in the conversion tutorial from an app.R to an R Shinylive app on GitHub, we get:

peeky::peek_standalone_shinylive_app(
  "https://tutorials.thecoatlessprofessor.com/convert-shiny-app-r-shinylive/",
  output_dir = file.path(tempdir(), "standalone-app")
)
#> 
#> ── Standalone Shinylive Application ────────────────────────────────────────────
#> Type: R Shiny
#> Run in R:
#> shiny::runApp("/tmp/RtmpXXXXXX/standalone-app")
#> 
#> ── Contents ──
#> 
#> .md files:
#> • README.md
#> .R files:
#> • app.R
#> 
#> Total files: 2
#> 
#> Location: '/tmp/RtmpXXXXXX/standalone-app'

License

AGPL (>= 3)

Evolution

This package represents a more refined and comprehensive approach compared to our earlier tutorial that focused solely on standalone R Shinylive applications.

Ethical Considerations

This package is for educational purposes. Users should:

• Use responsibly
• Respect intellectual property rights
• Understand that viewable code doesn’t imply permission to reuse
• Consider this when designing their own applications

Acknowledgements

Thanks to the Shinylive, webR and Pyodide teams for enabling browser-based data science.