A web service project Change was
created with the folder structure as shown in Figure 3.
Figure 3
Listing 1 describes the method(s) provided by the service as
coded in the code-behind of the Service.asmx file. The
function, change, defines the method. It takes a
string (testStrg) as an argument and returns the encoded string (StrChange).
This is a pretty simple web service.
Listing 1: Service.vb file
Imports System.Web
Imports System.Web.Services
Imports System.Web.Services.Protocols
<WebService (Namespace:="http://tempuri.org/")> _
<WebServiceBinding (ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated ()> _
Public Class Service
Inherits System.Web.Services.WebService
<WebMethod ()> _
Public Function <span class=Bold>change</span> (ByVal testStrg As String) As String
Dim Strchange As String = Convert.ToBase64String (System.Text. _
ASCIIEncoding.ASCII.GetBytes (testStrg))
Return Strchange
End Function
End Class
In Visual Studio 2005 this service can be tested in-situ
just by displaying the Service.asmx file which is
rendered as shown in Figure 4 (only part of it shown).
Figure 4
The hyperlink change can be used
to test the service. Clicking on the hyperlink reveals the page shown in Figure
5 (again only relevant portion is shown).
Figure 5
This service may be tested by inserting a text ("This
is a test string") such as shown in Figure 5 and clicking on the button
marked, Invoke. Figure 6 shows the result returned
by the web service.
Figure 6
The Service Description hyperlink in
Figure 4, when clicked, reveals what is called the WSDL
file, which contains the complete description of this service in XML as shown
in Figure 7. The various nodes can be expanded to drill into more details.
Figure 7
The URL that is displayed in the browser when the Service Description hyperlink is clicked provides the web
reference to this service. For this particular service the URL reference is
shown in the next paragraph.
http://localhost/Change/Service.asmx?WSDL
This is just the URL of the project with Service.asmx?
WSDL appended to it.
Creating a Web Service Task in the Visual Studio IDE
An Integration Services Project can be created by following
the trail, FileàNew Project…. This would open up a
New Project window where the Integration
Services Project can be chosen from the Visual Studio
installed templates. A project created this way can contain a number of
packages created by the user/developer as shown in Figure 8. The description of
creating a SSIS project is described in minute detail in an earlier article, Building
a SQL Server 2005 Integration Services Package Using Visual Studio 2005.
Figure 8
In the above figure a Package2.dtsx was added for this
tutorial. This provides an empty canvas with four tabs, Control
Flow; Data Flow; Event
Handlers; and Package Explorer.
Figure 9
Adding a Web Service Task
The Web Service Task is a new task
item added to the data transformation software, SSIS, formerly called Data Transformation Services. This task can be found in the
Toolbox.
Figure 10
This can be dragged from the Toolbox and dropped on the
design pane of the Control Flow.
Figure 11
In the Control Flow design pane,
the Web Service Task control is shown. On the right
of this figure the Properties window of this control is shown. Additionally,
two hyperlinks at the bottom, Show Editor and Edit Breakpoints, are also shown. The bulk of the package design
consists of editing this control.
Configuring the Web Service Task Control
The editor for this control, Web Service
Task Editor, can be invoked either by clicking the hyperlink mentioned
previously (Show Editor) or by right clicking the
control in the design area and choosing the Edit...
option. This brings up the Web Service Task Editor
window as shown in Figure 12.
Figure 12
The Editor wizard comes up with its initial page set to the
tab, General. Here in the Connection
information and some General Information
consisting of Name and Description
may be supplied. As discussed earlier, the HttpConnection
and the WSDLFile are sufficient for the package
design. In the above window a Name (Encoder Service)
and Description (Method to return a base64 encoded string)
have been inserted.
Clicking on an empty area (shown with a red dot) in the HTTPConnection box results in a drop-down control. This
will show connection information, if it exists or a hyperlink, to make a new
connection. Clicking on the <New Connection…>
link in the drop-down, results in opening up the HTTP
Connection Manager Editor window shown in Figure 13.
Figure 13
When the above window loads, it comes up with empty
information to be filled in. Enter http://localhost in
the Server URL: text box as shown and click on the Test Connection button. The result of a successful
connection comes up as a Microsoft Visual Studio
message alert which is also shown superposed in Figure 13. The text
"HTTPConnection Manager" gets added to the Web
Service Task Editor window's General page.
Additionally, the property window of the Web Service Task
changes as well as a control HTTP Connection manager
is added to the try below the design pane as shown in Figure 14. In the present
tutorial we are not using the proxy tab of this window as we have direct access
to the Server.
Figure 14
In addition to the HttpConnection,
the WSDLFile location (this should be a file with the
wsdl extension on the machine) should also be specified (refer to Figure 12). It
may be noted that the WSDLFile location will not
accept a URL Reference. This is the location of the Service.wsdl
file generated in a consuming client application. When a client consumes the
service it also generates a Service.wsdl file that gets
saved in a Web References folder of the web service consumer
application project. The method to create a client (a windows, web or console
client) is described in numerous tutorials at this link
as well as on the internet. The Project folder of the client which consumes
the service used in this tutorial using the methods discussed from an article
available at the above link.
Figure 15
The properties window of the localhost,
which is the URL used in the Web Service Task Editor's
Server URL (Figure 13), can now use the Service.wsdl associated with this client.
The general page of the task
editor can be completed by browsing to the WSDL file location shown in Figure
15. For this windows client, this location was:
C:\Documents and Settings\Jay\My Documents\Visual Studio
2005\Projects\ChangeConsumer\ChangeConsumer\Web References\localhost\Service.wsdl
The Completed Web Service Task Editor
for the General page is shown in Figure 16.
Figure 16
Now change the navigation to input
which brings you to the Web Service Task Editor's next
window shown in Figure 17.
Figure 17
Clicking on the empty space along the textbox indicated by
the label, Service shows up as a drop-down from which
Service was accepted. Clicking an empty area in the Method textbox converts it to a drop down with a single
method change as shown. When this drop-down choice is
accepted (the web service change had just one method
and it could have been created with more than one method), the Web Service Task Editor window changes to the one shown in
Figure 18.
Figure 18
In this window the Method is more
fully described as to its input parameters. It just accepts a string whose value when it shows
up is empty. For this web service task "Hello Web Service" has been
entered.
Clicking on the Output page link
in the Web Service Task Editor opens the next window
shown in Figure 19.
Figure 19
Accepting the OutputType's default File
Connection, a File has to be defined. This is the file which will contain
the result of running this task. Clicking on an empty area in the textbox
labeled File will bring up a link for creating a new connection,
<New Connection…>. When clicked, this link will open the File Connection Manager Editor window shown in Figure 20.
Figure 20
Using this Editor it is possible to
create a folder or a file. It is also possible to use an existing File or
folder. Here, a new file, ChangeTask, will be created
in a location to be defined next by using the Browse… button,
[C:\Inetpub\wwwroot\Change\ChangeTask] shown in Figure 21. When the task is run,
a file with the results of the task should be created at that location. This
location can be arbitrary, but must be an easily recognizable file location.
Figure 21
This completes the output page which now appears as shown in
Figure 22.
Figure 22
The third page, Expressions is not
relevant for this tutorial and it is skipped.
Clicking on the OK button, the ChangeTask task will be created.
Figure 23
This package has neither Data Flow
components nor any Event Handlers. The Package Explorer window with the essentials expanded is
shown in Figure 24.
Figure 24
The ChangeTask may now be executed
as shown in Figure 25 by right clicking the Encoder Service
control in the Control Flow's design view pane. The
task can be executed by other means as well, as described in an earlier
tutorial on SSIS at this site by the author.
Figure 25
When the Execute Task is clicked,
the screen may go blank for while and when the screen returns to normalcy, it
may show the Encoder Service Control with a yellow
background. When the task succeeds it turns to green as shown in Figure 26. In
case it fails, it will turn red.
Figure 26
Now, if you browse to the root directory of the IIS you will
find the ChangeTask file.
Figure 27
This file was not given an extension in the Web Service Task Editor, but can be opened with a text
editor such as Word or Notepad
which displays the following shown in Figure 28. This is the encoded string
provided by the web service.
Figure 28
