xmlwriter
is an R package that provides a simple interface for creating XML documents
and fragments from R. It provides a simple elegant syntax for creating xml_fragment
s and furthermore
contains a feed-forward API that allows you to write xml.
Details
xmlwriter
's xml generation from R lists is fast, implemented in C++ using Rcpp
.
xmlwriter
provides two different ways to create xml documents:
a light weight R syntax using
xml_doc()
,xml_fragment()
andfrag()
, creating an xml fragment that can be easily translated into a xml string orxml2::xml_document
objecta feed-forward API using
xmlbuilder()
that allows you to create xml documents in a feed-forward manner.
It implements several xml2
methods:
as_xml_document.xml_fragment()
as_list.xml_fragment()
write_xml.xml_fragment()
Author
Maintainer: Edwin de Jonge edwindjonge@gmail.com (ORCID)
Examples
doc <- xml_fragment(
study = frag(
.attr = c(id="1"),
person = frag(
.attr = c(id = "p1"),
name = "John Doe",
age = 30
),
person = frag(
name = "Jane Doe",
age = 25,
address = frag(street = "123 Main St", city = "Springfield"),
"This is a text node"
)
)
)
print(doc)
#> {xml_fragment}
#> <study id="1">
#> <person id="p1">
#> <name>John Doe</name>
#> <age>30</age>
#> ...
if (require("xml2")){
as_xml_document(doc)
}
#> {xml_document}
#> <study id="1">
#> [1] <person id="p1">\n <name>John Doe</name>\n <age>30</age>\n</person>
#> [2] <person><name>Jane Doe</name><age>25</age><address><street>123 Main St</s ...
# you can create a function to generate an xml fragment:
person_frag <- function(name, age, id){
tag("person", id = id) / frag(
name = name,
age = age,
address = frag(
street = "123 Main St",
city = "Springfield"
)
)
}
# xml_doc is a xml_fragment with the restriction of having one root element
doc2 <- xml_doc("study") / (
person_frag("John Doe", 30, "p1") +
person_frag("Jane Doe", 25, "p2")
)
print(doc2)
#> {xml_doc,xml_fragment}
#> <?xml version='1.0' encoding='UTF-8'?>
#> <study>
#> <person id="p1">
#> <name>Joh...
if (require("xml2")){
as_xml_document(doc2)
}
#> {xml_document}
#> <study>
#> [1] <person id="p1">\n <name>John Doe</name>\n <age>30</age>\n <address>\n ...
#> [2] <person id="p2">\n <name>Jane Doe</name>\n <age>25</age>\n <address>\n ...
# a fragment can have multiple root elements
fgmt <- person_frag("John Doe", 30, id = "p1") +
person_frag("Jane Doe", 25, id = "p2")
print(fgmt)
#> {xml_fragment (2)}
#> [1]<person id="p1">
#> <name>John Doe</name>
#> <age>30</age>
#> <address>
#> <street...
#> [2]<person id="p2">
#> <name>Jane Doe</name>
#> <age>25</age>
#> <address>
#> <street...
#> ...
if (require("xml2")){
# as_xml_document won't work because it expects a single root element,
# so we retrieve a nodeset instead
as_xml_nodeset(fgmt)
}
#> {xml_nodeset (2)}
#> [1] <person id="p1">\n <name>John Doe</name>\n <age>30</age>\n <address>\n ...
#> [2] <person id="p2">\n <name>Jane Doe</name>\n <age>25</age>\n <address>\n ...
iris_xml <- xml_doc("fieldstudy", id = "iris", doi ="10.1111/j.1469-1809.1936.tb02137.x") /
frag(
source = "Fisher, R. A. (1936) The use of multiple measurements in
taxonomic problems. Annals of Eugenics, 7, Part II, 179–188.",
data = data_frag(iris, row_tag = "obs")
)
print(iris_xml, max_characters = 300)
#> {xml_doc,xml_fragment}
#> <?xml version='1.0' encoding='UTF-8'?>
#> <fieldstudy id="iris" doi="10.1111/j.1469-1809.1936.tb02137.x">
#> <source>Fisher, R. A. (1936) The use of multiple measurements in
#> taxonomic problems. Annals of Eugenics, 7, Part II, 179–188.</source>
#> <data>
#> <obs>
#> <Sepal.Length>5.1</Sepal.Length>
#> ...
if (require("xml2")){
as_xml_document(iris_xml)
}
#> {xml_document}
#> <fieldstudy id="iris" doi="10.1111/j.1469-1809.1936.tb02137.x">
#> [1] <source>Fisher, R. A. (1936) The use of multiple measurements in\ntaxonom ...
#> [2] <data>\n <obs>\n <Sepal.Length>5.1</Sepal.Length>\n <Sepal.Width>3 ...