saveXML {XML}R Documentation

Output internal XML Tree

Description

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 and XMLOutputStream objects allow it to be generic for different representations of the XML tree.

Usage

saveXML(doc, file=NULL, compression=0, indent=TRUE, prefix = '<?xml version="1.0"?>\n',
        doctype = NULL, encoding = "")
saveXML.XMLInternalDocument(doc, file=NULL, compression=0, indent=TRUE, prefix = '<?xml version="1.0"?>\n',
                            doctype = NULL, encoding = "")
saveXML.XMLInternalDOM(doc, file=NULL, compression=0, indent=TRUE, prefix = '<?xml version="1.0"?>\n',
                       doctype = NULL, encoding = "")
saveXML.XMLNode(doc, file=NULL, compression=0, indent=TRUE, prefix = '<?xml version="1.0"?>\n',
                 doctype = NULL, encoding = "")
saveXML.XMLOutputStream(doc, file=NULL, compression=0, indent=TRUE, prefix = '<?xml version="1.0"?>\n',
                         doctype = NULL, encoding = "")

Arguments

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 Doctype.
encoding a string indicating which encoding style to use. This is currently ignored except in the method in Sxslt for saving a document generated by applying an XSL style sheet to an XML document.

Details

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.

Value

Author(s)

Duncan Temple Lang

References

http://www.w3.org/XML, http://www.omegahat.org/RSXML

See Also

newXMLDoc newXMLNode xmlOutputBuffer xmlOutputDOM

Examples

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="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)
[Package XML version 1.6-3 Index]