XML

1
XML

• XML Support in Cache 5
• XML Export
• XML Import
• Xerxes 2.0 SAX Parser

2
XML Export

• Add XML.Adapter to any class to enable support
  for XML.
• Basically this adds a few methods and parameters
  to each class and properties of that class
• It also allows you to generate a DTD or XMLSchema
  for the class for export

3
..XMLExport(format)

• XMLExport() outputs the contents of the class in
  either Literal or Encoded formats
• Its an instance method so to use it you must open
  the object then call ref.XMLExport()

4
Export Methods

• ..XMLExport()
• Outputs to the principal device
• ..XMLExportToString(.str)
• Outputs to the variable str. This is limited to
  32k
• ..XMLExportToStream(.stream)
• Outputs to a Stream object. You would need to
  instantiate the stream variable as a reference to
  a character stream first.

5
XML Projection

• XMLPROJECTION Element, Attribute, None
• XMLNAME Override the name of the property
• XMLIO IO conversion done
• IN, INOUT, OUT
• XSDTYPE generated based on the datatype
• XMLKEYNAME Array Key names
• XMLITEMNAME List collection name
• XMLREFERENCE Dictates how references are
  projected in XML
• ID, OID,Complete,Summary

6
XML Descriptors

• Do class(XMLEnabled).XMLSchema()
• Do class(XMLEnabled).XMLDTD()
• Class Methods that export either schemas or dtds.

7
Important Notes

• There are some limitations at the moment. I have
  a class that throws a ltFRAMESTACKgt error due to
  many sub class references we will fix this.
• Each class can have one Projection associated
  with it. If you needed to place a property in an
  Element in one XML Export but an attribute in
  another you would need to subclass the real
  object and implement the different projections.

8
XML Import

• Implemented in XML.Reader class
• Can read files, streams or line by line
• Takes the XML and correlates it with an XML
  Enabled object.
• Can make use of a DTD or XMLSchema to validate
  the data being imported.

9
Sample Reader
Set reader class(XML.Reader).New() Set
screader.OpenString(xml) Do
reader.Correlate("org","isis.org") While
reader.Next(.org,.sc) do stuff
10
Web Services

• What is a Web Service?
• SOAP Protocol
• Uses XML as the transport layer
• Cache 5 implements full support as a SOAP Server
  and limited support as a SOAP Client.

11
Creating a Web Service

• Add SOAP.WebService to your class. Any class can
  contain methods implemented as Web Services
• Web Services must be ClassMethods
• These methods must include the keyword
  webmethod
• Service Parameters
• LOCATION the URL for accessing the service
• http//localhost/csp/user/package.class.cls
• NAMESPACE Essentially a domain name
• http//isc.org
• SERVICENAME The name of the Service
  implementing this collection of Web Services.
• The Signature of the Method matters! Any object
  referenced in the signature must be XML Enabled.
  Our Datatype classes are handled internally.

12
Web Service Sample

• Here is a sample service returning an XML Enabled
  object.
• ClassMethod GetPatient(pid As Integer) As
  Webdev.Patient WebMethod
• set existsclass(Webdev.Patient).ExistsId(pid)
  
• if 'exists quit ERR("Invalid Patient ID")
• set refclass(Webdev.Patient).OpenId(pid)
• quit ref

13
Web Services and Collections

• You can return a collection of objects via a
  Service as well. To Implement this we need to
  return a List of Objects. Here is a sample class
  definition. On the following slide will appear
  the Method.
• Class Webdev.PatientList Extends
  Library.ListOfObjects ClassType serial,
  ProcedureBlock
• /// The type (class name) of the elements stored
  in the collection.
• Parameter ELEMENTTYPE "Webdev.PatHolder"

14
The Method

• ClassMethod SearchPatients(str As String) As
  Webdev.PatientList WebMethod
• set lnP(str,","),fnP(str,",",2)
• set rsclass(ResultSet).New("DynamicQuerySQ
  L")
• set query"Select ID from Webdev.Patient where
  LName STARTSWITH ? and FName STARTSWITH ?"
• do rs.Prepare(query)
• do rs.Execute(ln,fn)
• set listclass(Webdev.PatientList).New()
• while rs.Next()
• set refclass(Webdev.Patient).OpenId(rs.GetDa
  ta(1))
• do list.Insert(ref)
• quit list

15
Soap Client

• Cache 5 has limited support as a consumer of SOAP
  Services
• Implementing these allow Cache to access Web
  Services whether they are implemented via public
  web sites/.NET/or other Cache Systems

16
Implementation

• Your classes must inherit from SOAP.WebClient
• Parameters again these match the service
• LOCATION
• SERVICENAME
• NAMESPACE
• You can literally cut and paste with Cache
  Services.
• Once again your methods must be class methods and
  should have to include the webmethod keyword
• The signatures of the client and the service MUST
  be identical.
• The method should just quit the invocation of the
  service call do the application logic elsewhere.

17
Sample Client Class Returns an Object

• Class Webdev.WebClient Extends SOAP.WebClient
  ProcedureBlock
• Parameter LOCATION "http//localhost/webdev/Webd
  ev.WebServices.cls"
• Parameter NAMESPACE "http//isc.org"
• Parameter SERVICENAME "WebServices"
• ClassMethod GetPatient(pid As Integer) As
  Webdev.Patient WebMethod
• Quit ..WebMethod("GetPatient").Invoke("http//isc
  .org/Webdev.WebServices.GetPatient",pid)

18
Sample Method for passing an object
ClassMethod SetPatient(pid As Webdev.Patient) As
Status WebMethod Quit ..WebMethod("SetPati
ent").Invoke("http//isc.org/Webdev.WebServices.Se
tPatient",pid)
19
Wrapping a SOAP Client call

• All Soap requests throw a generic ltZSOAPgt error.
  Any real Error information is in the
  objlasterror variable.
• As the internet is not a stable place it is a
  good idea to always error trap any soap requests.
  

20
Sample SOAP Wrapper

• Class Webdev.SoapCalls Extends RegisteredObject
  ProcedureBlock
• ClassMethod SearchPatients(str As String) As
  PatientList
• set zt"SoapErrSearch"
• set xmlclass(Webdev.WebClient).SearchPatients(
  str)
• quit xml
• SoapErrSearch
• instantiate my Error object, save and quit.
• set refclass(Webdev.Error).New(objlasterror)
  
• set saveref.Save()
• quit NULLOREF

21
Gotchas

• C(0) Null String handling
• Null properties are not exported by default in
  XML Export
• IDs are not exported