Output internal XML Tree
Methods for writing the representation of an XML tree to a string or
file.
Originally this was intended to be used only for
DOMs (Document Object Models) stored in internal memory
created via xmlTree, but methods for
XMLNode, XMLInternalNode and XMLOutputStream
objects
(and others)
allow it to be generic for different representations of the
XML tree.
Note that the indentation when writing an internal C-based node (XMLInternalNode) may not be as expected if there are text nodes within the node.
Also, not all the parameters are meaningful for all methods. For example, compressing when writing to a string is not supported.
saveXML(doc, file=NULL, compression=0, indent=TRUE, prefix = '<?xml version="1.0"?>\n',
doctype = NULL, encoding = getEncoding(doc), ...)
## S3 method for class 'XMLInternalDocument'
saveXML(doc, file=NULL, compression=0, indent=TRUE, prefix = '<?xml version="1.0"?>\n',
doctype = NULL, encoding = getEncoding(doc), ...)
## S3 method for class 'XMLInternalDOM'
saveXML(doc, file=NULL, compression=0, indent=TRUE, prefix = '<?xml version="1.0"?>\n',
doctype = NULL, encoding = getEncoding(doc), ...)
## S3 method for class 'XMLNode'
saveXML(doc, file=NULL, compression=0, indent=TRUE, prefix = '<?xml version="1.0"?>\n',
doctype = NULL, encoding = getEncoding(doc), ...)
## S3 method for class 'XMLOutputStream'
saveXML(doc, file=NULL, compression=0, indent=TRUE, prefix = '<?xml version="1.0"?>\n',
doctype = NULL, encoding = getEncoding(doc), ...)doc |
the document object representing the XML document. |
file |
the name of the file to which the contents of the XML nodes will be serialized. |
compression |
an integer value between 0 and 9 indicating the level of compression to use when saving the file. Higher values indicate increased compression and hence smaller files at the expense of computational time to do the compression and decompression. |
indent |
a logical value indicating whether to indent the nested nodes when serializing to the stream. |
prefix |
a string that is written to the stream/connection before the XML is output. If this is NULL, it is ignored. This allows us to put the XML introduction/preamble at the beginning of the document while allowing it to be omitted when we are outputting multiple "documents" within a single stream. |
doctype |
an object identifying the elements for the DOCTYPE in the output.
This can be a string or an object of class |
encoding |
a string indicating which encoding style to use. This
is currently ignored except in the method in |
... |
extra parameters for specific methods |
One can create an internal XML tree (or DOM)
using newXMLDoc and newXMLNode.
saveXML allows one to generate a textual representation of
that DOM in human-readable and reusable XML format.
saveXML is a generic function that allows one to call
the rendering operation with either the top-level node
of the DOM or of the document object (of class XMLInternalDocument
that is used to
accumulate the nodes and with which the developer
adds nodes.
If file is not specified, the result is a character string containing
the resulting XML content.
If file is passed in the call,
Duncan Temple Lang
b = newXMLNode("bob")
saveXML(b)
f = tempfile()
saveXML(b, f)
doc = xmlInternalTreeParse(f)
saveXML(doc)
con <- xmlOutputDOM()
con$addTag("author", "Duncan Temple Lang")
con$addTag("address", close=FALSE)
con$addTag("office", "2C-259")
con$addTag("street", "Mountain Avenue.")
con$addTag("phone", close=FALSE)
con$addTag("area", "908", attrs=c(state="NJ"))
con$addTag("number", "582-3217")
con$closeTag() # phone
con$closeTag() # address
saveXML(con$value(), file=file.path(tempdir(), "out.xml"))
# Work with entities
f = system.file("exampleData", "test1.xml", package = "XML")
doc = xmlRoot(xmlTreeParse(f))
outFile = tempfile()
saveXML(doc, outFile)
alt = xmlRoot(xmlTreeParse(outFile))
if(! identical(doc, alt) )
stop("Problems handling entities!")
con = textConnection("test1.xml", "w")
saveXML(doc, con)
close(con)
alt = get("test1.xml")
identical(doc, alt)
x = newXMLNode("a", "some text", newXMLNode("c", "sub text"), "more text")
cat(saveXML(x), "\n")
cat(as(x, "character"), "\n")
# Showing the prefix parameter
doc = newXMLDoc()
n = newXMLNode("top", doc = doc)
b = newXMLNode("bar", parent = n)
# suppress the <?xml ...?>
saveXML(doc, prefix = character())
# put our own comment in
saveXML(doc, prefix = "<!-- This is an alternative prefix -->")
# or use a comment node.
saveXML(doc, prefix = newXMLCommentNode("This is an alternative prefix"))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.