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6 years ago
#' HTML/XML pretty printer and viewer
#'
#' This uses the \code{vkbeautify} and \code{highlight.js} javascript modules to format and
#' "pretty print" HTML/XML documents, nodes, node sets and plain character
#' HTML/XML in an \code{htmlwidget} pane.
#'
#' @param doc \code{xml2} document/node/nodeset, an \code{HTMLInternalDocument}/
#' \code{XMLInternalDocument} or atomic character vector of HTML/XML content
#' @param style CSS stylesheet to use (see \code{higlight_styles()})
#' @param scroll should the \code{<div>} holding the HTML/XML content scroll
#' (\code{TRUE}) or take up the full viewer/browser window (\code{FALSE}).
#' Default is \code{FALSE} (take up the full viewer/browser window). If
#' this is set to \code{TRUE}, \code{height} should be set to a value
#' other than \code{NULL}.
#' @param add_filter show an XPath input box to enable live filtering?
#' (default: \code{FALSE})
#' @param apply_xpath Add and apply an XPath query string to the view. If
#' \code{add_filter} is \code{TRUE} then this query string will
#' appear in the filter box and be applied to the passed in document.
#' @param elementId element id
#' @param width widget width (best to keep it at 100\%)
#' @param height widget height (kinda only useful for knitting since this is
#' meant to be an interactive tool).
#' @note Large HTML or XML content may take some time to render properly. It is suggested
#' that this function be used on as minimal of a subset of HTML/XML as possible
#' or used in a browser context vs an IDE viewer context.
#' @export
#' @references \href{https://highlightjs.org/}{highlight.js},
#' \href{http://www.eslinstructor.net/vkbeautify/}{vkbeautify}
#' @examples \dontrun{
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#' library(xml2)
#'
#' # plain text
#' txt <- paste0("<note><to>Tove</to><from>Jani</from><heading>Reminder</heading>",
#' "<body>Don't forget me this weekend!</body></note>")
#' xml_view(txt)
#'
#' # xml object
#' doc <- read_xml(txt)
#' xml_view(doc, style="obsidian")
#'
#' # different style
#' xml_view(xml_find_all(doc, ".//to"), style="github-gist")
#'
#' # some more complex daata
#' xml_view(read_xml(system.file("extdata/dwml.xml", package="htmltidy")))
#' xml_view(read_xml(system.file("extdata/getHistory.xml", package="htmltidy")),
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#' "androidstudio")
#' xml_view(read_xml(system.file("extdata/input.xml", package="htmltidy")),
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#' "sunburst")
#'
#' # filter + apply an initial XPath query string
#' xml_view(read_xml(system.file("extdata/dwml.xml", package="xmlview")),
#' add_filter=TRUE, apply_xpath=".//temperature")
#'
#' doc <- read_xml("http://www.npr.org/rss/rss.php?id=1001")
#'
#' str(doc)
#'
#' xml_view(doc, add_filter=TRUE)
#' xml2::xml_find_all(doc, './/dc:creator', ns=xml2::xml_ns(doc))
#'
#' xml_text(xml2::xml_find_all(doc, './/link[contains(., "soccer")]', ns=xml2::xml_ns(doc)))
#' }
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xml_view <- function(doc, style="default", scroll=FALSE, add_filter=FALSE,
apply_xpath=NULL, elementId=NULL,
width="100%", height=NULL) {
xml_doc_name <- "doc"
if (!inherits(doc, "character") &
inherits(substitute(doc), "name")) {
xml_doc_name <- deparse(substitute(doc))
}
style <- trimws(tolower(style))
if (!style %in% highlight_styles()) {
style <- "default"
warning(sprintf("Style '%s' not found, using 'default'", style))
}
if (inherits(doc, "character")) {
doc <- paste0(doc, collapse="")
} else if (inherits(doc, "xml_nodeset")) {
doc <- paste0(as.character(doc), collapse="")
} else if (inherits(doc, "xml_document") | inherits(doc, "xml_node")) {
doc <- as.character(doc)
}
params <- list(
xmlDoc = doc,
styleSheet = style,
addFilter = add_filter,
applyXPath = apply_xpath,
scroll=scroll,
xmlDocName=xml_doc_name
)
htmlwidgets::createWidget(
name = 'xmlview',
params,
width = width,
height = height,
package = 'htmltidy',
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elementId = elementId
)
}
#' @rdname xml_view
#' @export
html_view <- xml_view
#' List available HTML/XML highlight styles
#'
#' Returns a character vector of available style sheets to use when displaying
#' an XML document.
#'
#' @references See \url{https://highlightjs.org/static/demo/} for a demo of all
#' highlight.js styles
#' @export
#' @examples
#' highlight_styles()
highlight_styles <- function() {
gsub("\\.css$", "",
grep("\\.css$",
list.files(system.file("htmlwidgets/lib/highlightjs/styles", package="htmltidy")),
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value=TRUE))
}