The Displaced Guy

Learning To Create a WCF Web Service using PowerBuilder 12.5 .NET

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Continuing through the PowerBuilder wizard for creating the WCF Service… finally we reach the confirmation window where we click finish and let PB get the WCF Service started.

PowerBuilder 12.5 Creating a WCF Service - Confirm

This is how your solution explorer will look after clicking the finish button.  If you have used a recent version of Powerbuilder you’ll recognize the familiar Workspace, Target and PBL’s.   PBL’s sure have changed since the days of PowerBuilder 3.0, they used to consist of one physical file that represented many objects.  Now PBL’s are nothing more than a container for files making things more like the other development languages.

There are two things notable about this screen shot as far as WCF Services go.  The References shown are assemblies that are required to make the WCF Service work, and were added automatically by PowerBuilder because they apply to the WCF Service project type.   The project object is very important because it contains many of the defining parts of the WCF Service.   The project object is where you choose which non visual objects, and functions within them are visible to .NET programs.  You may also change some of the choices made throughout the WCF Service creation wizard in the project object as well.

PowerBuilder 12.5 Training - Solution Tree - WCF Service

This is the step where we (finally) start doing some real work.  I click on File–> New and choose Custom Non-Visual Class.  This class is where I will put functions for accessing the database.  Click the next button and you’ll be prompted for a name.

PowerBuilder 12.5 Training - WCF Service Creating the NVO

Enter the name of your non visual user object here.  I called mine n_datafactory.

PowerBuilder 12.5 Training

This step is one that I was normally confused with.  I didn’t understand the concept of Namespaces until I became comfortable developing .NET applications.  Namespaces are just another way of separating classes and objects, you might have a corporate namespace with classes having the same name as classes in the .NET class library but you refer to your corporate classes by using the corporate namespace.  If you have been around in programming for a while like me you could think of Namespaces as something vaguely resembling link libraries back in the MVS JCL mainframe days.  It allowed you to have the same objects in different libraries and the object that got referenced was the one you specified in the link list.  That was a bad example, but just think of namespaces as a way of organizing and accessing classes.

One thing to note about Namespaces, you can’t reference objects in different namespaces unless you explicitly refer to objects using the namespace, or you add a “using” for the namespace.

PowerBuilder 12.5 Training - Non Visual for WCF Service

Upon clicking finish you will be prompted with a familiar confirmation window.

WCF Service - Creating the NVO

Coding the WCF Data Service Logic – Adding to Non-Visual User Object

Here we will be adding everything from database connectivity, logging,  logic to handle insert, update, delete and exposing functions to the ASP.NET MVC application.  The n_datafactory non-visual user object will contain all the business logic

Step 1: Add Instance Variables for the PowerBuilder WCF Data Service

// Global
integer iiTenantId = 1

// Datastores
n_ds ids_category
n_ds ids_categories

// File Logging
integer ii_log_level = 1 // bitmask 1 = errors, 4 = warnings, 8 = all
long ilFileNum
string isFileName = 'c:\n_data_factory.log'

Step 2: Add DBConnect Function that returns boolean

// this code was written by the last guy, it should never be this way... ok it was me but dont tell
SQLCA.DBMS = "ADO.Net"
SQLCA.LogPass = "yourpasswordhere"
SQLCA.LogId = "sa"
SQLCA.AutoCommit = False
SQLCA.DBParm = "Namespace='System.Data.SqlClient',Database='LinkDBuilder',DataSource='MATRIX\SQLEXPRESS'"

connect USING sqlca;

IF sqlca.SQLCode <> 0 then
    return false
else
    return true
end if

Step 3:  The application will be a multi-tenant application, add function SetTenantId(integer Tenantid) returns None

iiTenantId = TenantId

return

Step 4:  Add function WriteLog(string asMessage) returns None

if ilFileNum <= 0 then
    ilFileNum = FileOpen(isFileName, TextMode!, Write!, Shared!, Append!)
end if

if ilFileNum > 0 then
    FileWriteEx(ilFileNum, asMessage)
end if

FileClose(ilFileNum)
ilFileNum = 0

return

Step 5:  Add a new global structure Category

Step 6: Add dataobject d_get_categories that will be used for retrieving categories

Set dataobject tabular style and set to updateable with primary key of cat_id.

This will be used in datastores so do not worry about visual aspects.

The data source…

Step 7:  Add a function GetCategoriesAll()  returns Category[]

Notice this function returns an array of Cagegory structure, this is how you return a multi-row result set to ASP.NET MVC

integer liRowCount, liRtn, liRow, liNew
Category newCat, emptyCat
Category newCategories[]

TRY 

   // connect if needed
   if sqlca.DBHandle() <= 0 then
    DBConnect()
  end if

    // create datastore
    if not IsValid(ids_categories) then
      ids_categories = create n_ds
    end if

  // initialize datastore
  ids_categories.DataObject = 'd_get_categories'
  ids_categories.SetTransObject(sqlca)

  // retrieve data
  liRowCount = ids_categories.Retrieve(iiTenantId)

  // populate structure
  for liRow = 1 to liRowCount

    // create new category
    newCat = emptyCat

   // set variables
   newCat.CatId = ids_categories.GetItemNumber(liRow, 'cat_id')
   newCat.CatName = ids_categories.GetItemString(liRow,'category_name')
   newCat.StatusCd = ids_categories.GetItemString(liRow,'status_cd')
   newCat.CreateDate = ids_categories.GetItemDateTime(liRow,'date_added')

   // add category to the list
   liNew ++
   newCategories[liNew] = newCat

  next

  if liRowCount = 0 then
    newCategories[1].CatId = -1
    newCategories[1].CatName = 'No Data Found'
  end if

  return newCategories

catch ( runtimeerror er)
  WriteLog(string(Today(),'mm/dd/yy') + " " + string(Now(), 'hh:mm:ss') + " Exception in GetCategory")
  newCategories[1].CatId = -1
  newCategories[1].CatName = 'Runtime Error'
  return newCategories

end try

Step 8: Add dataobject d_get_category for single row selection

Freeform type..

Not updateable

Design Source…

Step 8: Add function GetCategory(integer CatId) return Category

This function returns single row for the WCF Web Service, using the Category structure.

integer liRowCount, liRtn
Category newCat

TRY
  // create new category
  newCat = create Category

  // connect if needed
  if sqlca.DBHandle() <= 0 then
    DBConnect()
  end if

  // create datastore
  if not IsValid(ids_category) then
    ids_category = create n_ds
  end if

  // initialize datastore
  ids_category.DataObject = 'd_get_category'
  ids_category.SetTransObject(sqlca)

  // retrieve data
  liRowCount = ids_category.Retrieve(iiTenantId, CatId)

  // populate structure
  if liRowCount >= 1 then
     newCat.CatId = CatId
     newCat.CatName = ids_category.GetItemString(1,'category_name')
     newCat.StatusCd = ids_category.GetItemString(1,'status_cd')
     newCat.CreateDate = ids_category.GetItemDateTime(1,'date_added') 
  else
    newCat.CatId = -1
  end if

  return newCat

catch ( runtimeerror er)   
  WriteLog(string(Today(),'mm/dd/yy') + " " + string(Now(), 'hh:mm:ss') + " Exception in GetCategory")
  newCat.CatId = -1
  return newCat

end try

Step 9:  Add function UpdateCategory(integer aiCatId, string asCatName, string asCatStatus) returns integer

integer liRowCount, liRtn, liRow, liNew, liCatId
Category newCat, emptyCat
Category newCategories[]
datetime ldtToday
string lsCatStatus, lsCatName

TRY
  // get arguments
  if IsNull(aiCatId) then
    return -1
  else
     liCatId = aiCatId
  end if
  if IsNull(asCatName) then
     lsCatName = ''
  else
     lsCatName = Trim(asCatName)
  end if
  if IsNull(asCatStatus) then
    lsCatStatus = 'A'
  else
    lsCatStatus = Upper(Trim(asCatStatus))
  end if

 // bail out if no category name
 if Len(Trim(lsCatName)) = 0 then
 return -1
 end if

  // connect if needed
  if sqlca.DBHandle() <= 0 then
   DBConnect()
  end if

  // create datastore
  if not IsValid(ids_categories) then
   // get cateegories
   this.GetCategoriesAll()
  end if

  // see if we have an insert
  if liCatId = 0 then

    ldtToday = datetime(Today(), Now())

    liRow = ids_categories.InsertRow(0)

     // set variables
     ids_categories.SetItem(liRow, 'tenant_id', iiTenantId)
    ids_categories.SetItem(liRow, 'category_name', lsCatName)
    ids_categories.SetItem(liRow, 'status_cd', lsCatStatus)
    ids_categories.SetItem(liRow, 'date_added', ldtToday)

    liRtn = ids_categories.Update()

    if liRtn >= 0 then
      commit;
    end if

    return 0
  end if

  // see if we have categories already
  liRowCount = ids_categories.RowCount()

 if liRowCount = 0 then
  // get cateegories
  this.GetCategoriesAll()
  liRowCount = ids_categories.RowCount()
 end if

  // find category
  liRow = ids_categories.Find("cat_id = " + aiCatId.ToString(), 1, liRowCount)

 if liRow >= 0 then

  // set variables

  ids_categories.SetItem(liRow, 'category_name', lsCatName)
  ids_categories.SetItem(liRow, 'status_cd', lsCatStatus)
  liRtn = ids_categories.Update()
  if liRtn >= 0 then
    commit;
  end if
 end if

 return liRtn

catch ( runtimeerror er)
  WriteLog(string(Today(),'mm/dd/yy') + " " + string(Now(), 'hh:mm:ss') + " Exception in GetCategory")
  return -1

end try

Step 10: add function GetLastDBCode() returns integer

return sqlca.SQLCode

Step 11: Add function Shutdown() returns none

// clean up prior to shutdown
if ilFileNum > 0 then
 FileClose(ilFileNum)
 ilFileNum = 0
end if

if not IsNull(sqlca.DBHandle()) then
 disconnect using sqlca;
end if

if IsValid(ids_categories) then
 destroy ids_categories
end if

if IsValid(ids_category) then
 destroy ids_category
end if

Step 12: Add global variable

n_datafactory gnv_data

Step 13: Add code to the Application Open event of the PowerBuilder program.

integer liRtn

gnv_data = create n_datafactory

gnv_data.DBConnect()

PB WCF Service - Solution Explorer

d_get_categories:  This is a new data object that gets a list of all categories.

d_get_category:  New data object that will select one category by category_id

d_get_category_byname:  not used

Category:  New Structure for the category data.  I found myself mixing my PowerBuilder naming standards with naming standards commonly seen in .NET applications.  I named the structure without the typical s_ or str_ prefix commonly used in PB because it was going to be available in the .NET application and it might be confusing to a .NET developer named str_category.  These are things that we never had to think about…

n_datafactory:  New non-visual class that contains the functions to be available in the .NET application via the WCF Service.  Most of the coding will be in here.

n_ds:  New base class (standard non visual) of type datastore just because I like to inherit from my base objects rather than use dataobject directly especially with datastores.

You need to be cognizant about  how the various data types map between PB and .NET.

PowerBuilder 12.5 .NET WCF Service – Console Hosting Options

PB.NET WCF Service - Project Painter

Project Painter PB 12.5.NET WCF Service

PowerBuilder WCF Service - Console Window

WCF Service WSDL Page - PowerBuilder 12.5

Using SVCUTIL to generate a WCF Service Proxy

Continue to Page 3 of Creating & Using a PowerBuilder 12.5 WCF Service