readSchema: Read the given XML schema and process the contents

In omegahat/XMLSchema: R facilities to read XML schema

Read the given XML schema and process the contents

Description

This is the top-level function for reading an XML schema. It takes the name of the file to read or an already parsed XML document (e.g. via xmlParse or xmlTreeParse) and processes the nodes in the document to create R-level descriptions of the schema's contents.

The function can be given a WSDL document (Web Service Language Description) used for describing SOAP servers. It then extracts the types node and uses that.

Usage

readSchema(filename, createConverters = FALSE, verbose = FALSE,
            namespaces = c(ws = "http://schemas.xmlsoap.org/wsdl/",
                           xs = "http://www.w3.org/2001/XMLSchema"),
           followImports = TRUE, followIncludes = followImports,
           asNode = is(filename, "XMLInternalNode") &&
                     (is(filename, "AsIs") || xmlName(filename) == "schema"), 
            checkCircularTypes = TRUE, ...)

Arguments

filename	the name of the XML document containing the schema or a previously parsed XML document. If this is a character string, it is passed to parseSchemaDoc and on to xmlParse. This allows the value to be the name of a file, the contents of a file, a compressed file or a URL, including a "GET" URL, i.e. a URL with parameters specified via ? and separated by &.
createConverters	a logical value indicating whether, for each type in the schema, to create the functions that convert an XML node to a corresponding R object.
verbose	a logical value indicating whether to emit information about the element currently being processed. This is passed to processSchemaTypes.
namespaces	a character vector giving the prefix = URI pairs for namespaces to be used in searching the XML document for a schema types node.
followImports,followIncludes	see parseSchemaDoc.
asNode	a logical value that specifies whether the filename argument is an XML node or external content in a file or is an in memory string or is a schema XML node.
...	additional parameters that are passed on to
checkCircularTypes	a logical value that controls whether we check for circular references in the defitions of data types, e.g. where type B has a field of type A and type A has a field of type B or perhaps more indirectly via a separate type C.

Value

A list containing the elements. If the schema contains other schema, the result is a SchemaCollection.

Author(s)

Duncan Temple Lang

References

The XML schema specification at http://www.w3.org/XML/Schema. A tutorial at http://www.w3schools.com/Schema/default.asp. Book “The definitive XML Schema”, Priscilla Walmsley, Prentice Hall.

See Also

processSchemaTypes xmlParse

Examples

 f = system.file("samples", "egquery.xsd", package = "XMLSchema")
 x = readSchema(f, createConverters = FALSE)
 names(x)

 sapply(x, class)

 dir = system.file("samples", package = "XMLSchema")
 files = list.files(dir, pattern = "\\.xsd$", full.names = TRUE)
 els = lapply(files, function(x) {
                        print(x)
                        readSchema(x, createConverters = FALSE, verbose = TRUE)
                      })
 sapply(els, length)
 sapply(els, names)

 library(RCurl)
 if(url.exists("http://www.weather.gov/forecasts/xml/SOAP_server/ndfdXMLserver.php?wsdl"))
    z = readSchema("http://www.weather.gov/forecasts/xml/SOAP_server/ndfdXMLserver.php?wsdl")

omegahat/XMLSchema documentation built on Jan. 17, 2024, 7:08 p.m.