WebRainbow provides 3 functions to handle HTML FORM:
(click on link to display detailed explanation)

1. GetFormData
2. CountFormData
3. SetRequestMethod

and 4 functions to deal with Cookie:

1. GetCookie
2. CountCookie
3. SetCookie
4. GetCookieVersion

As well as 2 functions to process URL ("%XX") encoding/decoding, which can be used for special character in cookie or other place:

1. Chr2Hex
2. Hex2Chr

We'll demonstrate how to use these functions in the Visual Basic by a simple Visual Basic Web application which handles HTML FORM and Cookie:

• HtmlForm.bas (source code for Visual Basic 5 & 6)
• HtmlForm4.bas (source code for Visual Basic 4 32-bit)

This Web Application, HtmlForm, contains three pages:

• login page
• survey form
• result page

It processes almost all of the FORM elements, so you will get enough information to handle FORM for the real application.

Let's step into the code for details.

• Sub Main() is used to set and retrieve cookies, which should always be processed before return page to browser due to the HTTP protocol and cookie specification, followed by the logic to determine which page should be displayed based on the received FORM data.

• Sub ShowLogon() is the first page to let user type in NAME.

• Sub ShowSurvey() presents almost all of FORM elements: 7 TEXT elements, 1 SELECT element, 5 RADIO elements, 5 CHECK elements. To line up all of these FORM elements, the TABLE is used.

• Sub ShowSurveyResult() shows how the CountFormData and GetFormData can be used to handle various FORM elements.

To process cookie, you need to call GetCookie to retrieve cookie, and SetCookie to send cookie. Some time, the Chr2Hex and Hex2Chr are needed to deal with URL encoding/decoding for some special character(s) in the value of cookie. WebRainbow gives a special string constant, ceEncodeChar, containing some commonly used special characters for cookie: TAB, SPACE, Double Quote, Comma, Semicolon. Cookie is widely used for shopping cart, and session control.

To deal with multi-valued FORM element, such as CHECK element, the CountFormData can be used to find how many pairs of name/value associated with same specified name, and then call GetFormData with both sName and sID specified to retrieve proper FORM data.

Note: The source code for VB 4 and VB 5 / 6, is almost identical, except vbNullString is used for optional argument in VB 4 code. This is due to the 32-bit version of VB 4, which we used to test WebRainbow, does not really support optional argument for exposed function of WebRainbow.

To try this demo, follow the steps list bellow:

1. Start Visual Basic

2. Select Standard EXE as project type

3. Select Sub Main as Startup Object

4. Give HtmlForm as project name

5. Set reference to WRHttpB.tlb, WRMimeB.tlb, and WRnbwB.tlb

6. Remove Form1, which is the default form for new VB project

7. Add HtmlForm.bas (source code for Visual Basic 5 & 6) or HtmlForm4.bas (source code for Visual Basic 4 32-bit), corresponding to the version of Visual Basic you used, into the Project HtmlForm. These two files are normally in the folder C:\Program Files\WebRainbow\demo\htmlform\ if you did not change the installation directory for WebRainbow.

8. Compile it to HtmlForm.exe.

9. Click on Debug in VB IDE for detailed debug instruction.

10. Click following link to
    • run this demo on IIS
    • run this demo on Apache

Good luck!