Given an XML Schema how do I use it to schema-validate an instance XML document?
Answer: to do this you need to read and parse both documents, compile the schema and then use the compiled schema to validate the instance document.
package require xml ;# you need to install TclXML/libxml2 v3.2 or better
First read and parse the schema document
set ch open "schema.xsd" set schemaxml read $ch close $ch set schemadoc dom::parse $schemaxml
Next compile the schema so that it is ready to perform schema-validations. There might be something wrong with the schema document, so use the catch command to handle that.
`if {catch {$schemadoc schema compile} msg} {
puts stderr "something is wrong with the XSD schema: $msg"
exit}`
Now read and parse the instance (data) document. This is the document that you are trying to test is schema-valid against the XSD schema.
set ch open "document.xml" set xml read $ch close $ch set doc dom::parse $xml
Everything is now ready to perform the schema-validation. If validation succeeds, the command will return a success code. If the document is invalid, the command will return an error code and the result will contain a description of why the document is invalid.
`if {catch {$schemadoc schema validate $doc} msg} {
puts "document is invalid"
} else {
puts "document is valid"
}`