B4J Question Validate XML using a XSD / Json using Schema?

[MathiasM]

Hello

Is it in any way possible to validate data (XML or JSON) via a so-called Schema?
I tried the search function for a lot of different search terms, but got no real results, so my hopes aren't very high!

If someone knows a way how to do this, I'm very open to any insights or ti

 

[Erel]

XmlSax library doesn't support validation.

 

[MathiasM]

Ok no problem, thanks for the fast reply!

 

[Daestrum]

This code module code will validate xml against an xsd file

'Static code module
Sub Process_Globals
 Private SchemaFactory As JavaObject
 Private factory As JavaObject
 Private XMLconstants As JavaObject
 Private Validator As JavaObject
 Private StreamSource As JavaObject
 Private xsd,xml As JavaObject
 Private Schema As JavaObject
End Sub
' returns true for valid and false for invalid or IO error
Sub ValidateFile(xsdFile As String,xmlFile As String) As Boolean
 XMLconstants.InitializeStatic("javax.xml.XMLConstants")
 SchemaFactory.InitializeStatic("javax.xml.validation.SchemaFactory")
 factory = SchemaFactory.RunMethod("newInstance",Array(XMLconstants.GetField("W3C_XML_SCHEMA_NS_URI")))
 xsd.InitializeNewInstance("java.io.File",Array(xsdFile))
 xml.InitializeNewInstance("java.io.File",Array(xmlFile))
 Schema = factory.RunMethod("newSchema",Array(xsd))
 Validator = Schema.RunMethod("newValidator",Null)
 StreamSource.InitializeNewInstance("javax.xml.transform.stream.StreamSource",Array(xml))
 Try
  Validator.RunMethod("validate",Array(StreamSource))
 Catch
  Log(LastException.Message)
  Return False
 End Try
 Return True 
End Sub

call it with (where xsd and xml are the full path names to the files) I called my module XMLValidator

Log(XMLValidator.ValidateFile(xsd,xml))

If there is an error in the xml you get a log message like

org.xml.sax.SAXParseException; systemId: file:/c:/temp/Employee.xml; lineNumber: 13; columnNumber: 31; cvc-datatype-valid.1.2.1: 'A1999' is not a valid value for 'integer'.

which pretty much tells you exactly what is wrong and where.

Hope it helps.

 

[Daestrum]

For completeness (and an example of an xsd file construct) here are the two test files I used records.xsd and records.xml

 

[MathiasM]

Very nice of you to share it with the community man! Cheers

 

[Daestrum]

Slightly improved code module - this one will list out all the errors instead of stopping at the first one it finds.

'Static code module
Sub Process_Globals
 Private SchemaFactory As JavaObject
 Private factory As JavaObject
 Private XMLconstants As JavaObject
 Private Validator As JavaObject
 Private StreamSource As JavaObject
 Private xsd,xml As JavaObject
 Private Schema As JavaObject
 Private ErrorList As List
End Sub
' returns true for valid and false for invalid or IO error
Sub ValidateFile(xsdFile As String,xmlFile As String) As Boolean
 ErrorList.Initialize
 XMLconstants.InitializeStatic("javax.xml.XMLConstants")
 SchemaFactory.InitializeStatic("javax.xml.validation.SchemaFactory")
 factory = SchemaFactory.RunMethod("newInstance",Array(XMLconstants.GetField("W3C_XML_SCHEMA_NS_URI")))
 xsd.InitializeNewInstance("java.io.File",Array(xsdFile))
 xml.InitializeNewInstance("java.io.File",Array(xmlFile))
 Schema = factory.RunMethod("newSchema",Array(xsd))
 Validator = Schema.RunMethod("newValidator",Null)
 StreamSource.InitializeNewInstance("javax.xml.transform.stream.StreamSource",Array(xml))
 Validator.RunMethod("setErrorHandler",Array(Validator.CreateEvent("org.xml.sax.ErrorHandler","xmlerr",Null)))
 Validator.RunMethod("validate",Array(StreamSource))
 
 If ErrorList.Size > 0 Then
  For Each i As Object In ErrorList
   Log("Error "&i)
  Next
  Return False
 End If
 Return True
End Sub
Sub xmlerr_Event(method As String,args() As Object) As Object
 ErrorList.Add(args(0))
 Return True
End Sub

If you don't want the error logged twice then choose either of these code snippets to replace the 'For Each … part

 'Technical error report
 For a = 0 To ErrorList.Size-2 Step 2
  Log(ErrorList.Get(a))
 Next

gives this output

org.xml.sax.SAXParseException; systemId: file:/c:/temp/records.xml; lineNumber: 13; columnNumber: 30; cvc-minInclusive-valid: Value '1945' is not facet-valid with respect to minInclusive '1950' for type '#AnonType_yearrecordType'.

 'Logical error report
 For a = 1 To ErrorList.Size-1 Step 2
  Log(ErrorList.Get(a))
 Next

and this gives

org.xml.sax.SAXParseException; systemId: file:/c:/temp/records.xml; lineNumber: 13; columnNumber: 30; cvc-type.3.1.3: The value '1945' of element 'year' is not valid.

 

[avalle]

Anything available for JSON?

 

[Daestrum]

Anything available for JSON?

The JSON is a bit harder to get working as the json.jar in the built in libraries takes preference but does not have the method toMap(…) on JSONObject so fails with a method not found exception.
Still looking at ways round this.