Exercise 3.4: Passing data to the server with the WebService class

In this exercise, you will use the WebService component to send data to a server to insert it into the database. You will also handle the confirmation message from the server to display in an alert dialog box (see Figure 1).

Remember that, in a previous exercise, you consolidated the form data in a value object and dispatched it from a custom component using a custom event.

In this exercise, you will learn how to:

• Create the WebService instance
• Initialize the data transfer
• Use the Network Monitor to view the result data
• Handling the result event

In this section you will create a WebService instance that will be used to send information to the server.

1. Download the ex3_04_web_starter.zip file if you haven't already and extract the ex3_04_ web_starter.fxp to your computer.
2. Open Flash Builder.
3. Import the ex3_04_ web_starter.fxp project file.
4. From the Package Explorer view, open the ex3_04_web_starter.mxml file.
5. Within the Declarations block, below the WebService instance, type Web and press Ctrl+Space to show the code templates with the content assist tool and create another WebService instance.    

6. Modify the inserted code so that the WebService instance is one tag and not a tag block.
7. To the new WebService object, modify the id property so it has a value of vehicleService and the wsdl property so it has a value of http://www.adobetes.com/f45iaw100/remoteData/vehicleRequestData.cfc?wsdl.
8. Remove the useProxy, showBusyCursor, result, and fault properties from the WebService instance.

Note: This example generates the XML using an Adobe ColdFusion server, but you can use any server to generate the XML file. Refer to the Flex and ColdFusion, PHP, Java, or .NET integration pages for more information.

9. Save the file.

In this section you will add the code to make the WebService request and transfer the Form container data, as a value object dispatched from a custom component using a custom event, to the server.

1. Locate the component:VehicleRequestForm instance below the Declarations block.
2. Note the vehicleRequestEvent property with a value of vehiclerequestform1_vehicleRequestEventHandler(event).

   The vehiclerequestform1_vehicleRequestEventHandler() function was created in Exercise 3.3 (Dispatching a value object from the custom component) to handle the vehicleRequestEvent custom event in the main application.

3. Within the Script block, locate the vehiclerequestform1_vehicleRequestEventHandler() function.
4. Within the function, delete the Alert.show() method.
5. Use the vehicleService.addVehicleRequest() method to pass the event.vehicleRequestData value cast to the VehicleRequest class, to the server.

6. Save the file.

Note: In order to complete this part of the exercise, you must have Flash Builder Premium Edition installed. If you have Flash Builder Standard Edition installed, skip this section and continue with the next section. If you want to download and install a trial version of Flash Builder Premium Edition, be sure to: 1) back up your existing workspace and projects; 2) uninstall Flash Builder Standard Edition; and then 3) install the trial version of Flash Builder Premium Edition. To compare the Standard Edition with the Premium Edition, check out the Upgrade Details page.

In this section you will use the Flash Builder Network Monitor to analyze the result of the vehicleService WebService object.

1. For the vehicleService WebService object, use the content assist tool to generate the result event (see Figure 2).

2. Use the content assist tool to generate a handler function for the result event (see Figure 3).

3. Within the Script block, locate the vehicleService_resultHandler() function and delete the generated code stub.
4. Save the file.
5. Open the Network Monitor.
6. Click the Enable Monitor button.
7. Run the application.
8. Select an employee, a pickup date and a return date, leave the Mobile Phone field empty and click Submit Request.

   You should see an error (see Figure 4).

9. Return to Flash Builder.
10. Double-click the Network Monitor tab to maximize it.
11. Select the POST operation (see Figure 5).

    Note the red circle with an X in it, signifying an error has occurred.

    Note: If the workspace you are using has multiple projects open, you may not see the recording in the Network Monitor. Close all other projects and enable the monitor again for your current project and make sure the message in the Network Monitor view reads, "Enabled for project 'ex3_04_web_starter.'"

12. Open the Response tab and switch to Raw View (see Figure 6).
    

You should see the Response data. Notice the first line tells you that you have experienced the 500 Internal Server Error.

13. Locate the message that reads: Field 'VEHICLEREQUESTS.MOBILEPHONE' cannot be a zero-length string (see Figure 7).

Next, you will add a fault handler to show an Alert message when the Mobile Phone field is left blank.

14. Double-click the Network Monitor tab to minimize the view.
15. To the vehicleService WebService object, add a fault property and, using the content assist tool, generate the fault handler.
16. Locate the vehicleService_faultHandler() method in the Script block and delete the generated code stub.
17. Within the function add the Alert.show() method to display the event.fault.faultString value as the text in the Alert pop-up.
18. Make the title of the alert message Fault Information.

19. Save the file.
20. Run the application.
21. Fill out everything except the Mobile Phone field in the form and click Submit Request.
22. You should see the alert message displayed (see Figure 8).

In this section you will use the WebService object's result event and the server to validate if the value object has been successfully written to the data table.

1. Locate the vehicleService_resultHandler() function.
2. Within the function, remove the generated code and use content assist to insert a code template for an if statement.
   
3. Set the if statement to evaluate if the event.result.id value.

4. Within the if statement, use the Alert.show() method to display the text: The request was submitted. The record id is and add the event.result.id value.

5. Save the file.
6. Run the application.
7. From the DropDownList control, choose an employee.
8. In the Mobile Phone field, type 555-555-5555.
9. Choose a Pickup Date and a Return Date, then click the Submit Request button.

You should see the Alert window displaying the message, You should see the Alert window display the message that your request was submitted successfully and you should also see the record id (see Figure 9).

In this exercise you learned how to use the daily project files and exercise files for Flex in a week. You also learned how to create a new Flex project and switch workspaces.