This is a minimal example of a book based on R Markdown and bookdown (https://github.com/rstudio/bookdown). Please see the page "Get Started" at https://bookdown.org/ for how to compile this example.
Here the rendered book version is password protected through a js script in the docs-folder, together with the landing index.html.
The JS-script translates the password into a SHA215 has-key, this is the folder name within docs/ folder that the book should be rendered into.
In the _bookdown.yml you need to add the extra option output_dir: "docs/GENERATED_SHA_HASH_FROM_PASSWORD".
This means that when you build the book locally (with bookdown::render_book("index.Rmd", "bookdown::gitbook")), the book will be built into that specified folder, which will also be generated by the command.
I recommend having a small script handy to purge this dacs/hash/ directory, rebuild based on new docs, commit and puch to github in a script in the repo (I call mine _deploy.sh), and have the simple R-code above in a script called _build.R.
# clone the repository to the book-output directory
git pull
# Purge the old files to make sure new ones are built
git rm -rf docs/SHA_GENERATED/
Rscript _build.R
git add --all *
git commit -m "Update the book"
git push -q origin master
If github repo has github pages turned on for the docs folder. You will land on the index.html page, which is directly in the docs folder.
Once the correct password it typed in the field, an html iframe will cover the entire view-screen with the rendered book.
If you are having problems setting the correct password, comment out line 24 in docs/pass.html, and uncomment line 26. Re-knit docs/index.Rmd, and type in your desired password. Next to the password field, the corresponding SHA512 key should appear. Copy this string and paste it into your _output.yml as output_dir: "docs/GENERATED_SHA_HASH_FROM_PASSWORD".
For the password to work, the folder "docs/GENERATED_SHA_HASH_FROM_PASSWORD" needs to exist.
Run bookdown::render_book("index.Rmd", "bookdown::gitbook") in your R-console to render to book, which will create all necessary documents into the output_dir specified above.
Typing the password on the landing page should now redirect you to your book. Once this procedure works, make sure to comment out line 26, and uncomment line 24 in docs/pass.html.
You can copy this repo and build further on it to set up your password protected rendered book.
The result can be seen at https://athanasiamo.github.io/bookdown_password/