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R API Reference v2.25.2

Package: htmltomarkdown | Version: 2.28.1 | R: 4.3+

Installation

install.packages("htmltomarkdown", repos = "https://kreuzberg-dev.r-universe.dev")

The package uses extendr to bind to the Rust core library.

Functions

convert

Convert HTML to Markdown.

convert(html)

Arguments:

Parameter Type Description
html character A character string of HTML content

Returns: character -- the converted Markdown string.

Example:

library(htmltomarkdown)

html <- "<h1>Hello</h1><p>World</p>"
markdown <- convert(html)
cat(markdown)

convert_with_options

Convert HTML to Markdown with options provided as a named list.

convert_with_options(html, options)

Arguments:

Parameter Type Description
html character HTML content
options list Named list of conversion options

Returns: character -- the converted Markdown string.

Example:

options <- list(
  heading_style = "atx",
  wrap = TRUE,
  wrap_width = 80
)
markdown <- convert_with_options(html, options)

convert_with_metadata

Convert HTML to Markdown and extract document metadata.

convert_with_metadata(html, options = NULL, config = NULL)

Arguments:

Parameter Type Description
html character HTML content
options list or NULL Optional conversion options
config list or NULL Optional metadata extraction configuration

Returns: list with markdown and metadata elements.

Example:

html <- '<html lang="en"><head><title>Article</title></head>
         <body><h1>Title</h1><a href="https://example.com">Link</a></body></html>'

result <- convert_with_metadata(html)
cat(result$markdown)
print(result$metadata$document$title)    # "Article"
print(length(result$metadata$headers))   # 1
print(length(result$metadata$links))     # 1

# Selective extraction
config <- list(
  extract_headers = TRUE,
  extract_links = TRUE,
  extract_images = FALSE
)
result <- convert_with_metadata(html, config = config)

convert_with_inline_images

Convert HTML and extract inline images.

convert_with_inline_images(html, options = NULL, config = NULL)

Returns: list with markdown, images, and warnings elements.

convert_with_visitor

Convert HTML with a visitor object (reserved for future use).

convert_with_visitor(html, visitor = NULL, options = NULL)

create_options_handle

Create a reusable options handle for repeated conversions.

create_options_handle(options)

convert_with_options_handle

Convert using a pre-created options handle.

convert_with_options_handle(html, handle)

Example:

handle <- create_options_handle(list(heading_style = "atx"))

for (html in html_documents) {
  markdown <- convert_with_options_handle(html, handle)
}

version

Get the version of the html-to-markdown Rust core.

version()

Options List

Options are passed as named R lists. All fields are optional.

options <- list(
  heading_style = "atx",           # "underlined", "atx", "atx_closed"
  list_indent_type = "spaces",     # "spaces", "tabs"
  list_indent_width = 2,
  bullets = "-",
  code_block_style = "indented",   # "indented", "backticks", "tildes"
  whitespace_mode = "normalized",  # "normalized", "strict"
  wrap = FALSE,
  wrap_width = 80,
  newline_style = "spaces",        # "spaces", "backslash"
  preserve_tags = c(),
  strip_tags = c(),
  skip_images = FALSE,
  output_format = "markdown"       # "markdown", "djot", "plain"
)

See the Configuration Reference for detailed descriptions.

Metadata Config List

config <- list(
  extract_document = TRUE,
  extract_headers = TRUE,
  extract_links = TRUE,
  extract_images = TRUE,
  extract_structured_data = TRUE,
  max_structured_data_size = 1000000
)

Extendr Details

The R binding uses extendr to compile Rust code into a shared library loaded by R:

  • Rust source in packages/r/src/rust/
  • Compiled during package installation
  • R wrappers auto-generated in R/extendr-wrappers.R
  • All errors surfaced as R conditions

See Also