CGI: VBScript CGI
VBScript and JavaScript CGI
VBScript CGI
This page covers running VBScripts as CGI scripts and introduces the CGI shebang. It assumes the Apache server has been configured to permit the running of CGI scripts, and test folder vbs_test and .htaccess have been created as explained on the previous page.
Test Script 1
Inside folder vbs_test, create a new file test1.vbs with the following content:
Wscript.Echo "<h1>VBScript CGI Test</h1>" Wscript.Quit 0
This script writes (echoes) the string "<h1>VBScript CGI Test</h1>" to the standard output stream followed by exit code 0 (Wscript.Quit 0).
Run Script on server
Run the script as follows:
- Start the Apache server (double click on server_start.bat)
- In your browser type: http://localhost:8081/vbs_test/test1.vbs
Note: If you are using The Uniform Server, the port is not required. Instead type the following into your browser: http://localhost/vbs_test/test1.vbs
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The script fails Browser message and entry in Apache log file are shown on the right. Reason script fails; Apache does not know how to locate the program that will run this script! Windows uses file association to appropriately run programs; it checks the file extension and runs the appropriate program that has been assigned to that extension. Apache does not use this mechanism, CGI scripts can have any file extension for example a script written in VBScript has the extension .vbs one written in Vfred may have the extension .fred ; all Apache knows is that the extension is associated with a CGI script. In reality, Apache does know where to find the executable program! Every CGI script must contain a line pointing to the program that will be used to run the script. This line is referred to as the shebang. |
### Browser ### 500 Internal Server Error: The server encountered an internal error or misconfiguration and was unable to complete your request. Please contact the server administrator, admin@localhost and inform them of the time the error occurred, and anything you might have done that may have caused the error. More information about this error may be available in the server error log. ### Apache Log file ### [Mon Aug 29 13:25:00 2011] [error] [client 127.0.0.1] (9)Bad file descriptor: don't know how to spawn child process: C:UniServer/www/vbs_test/test1.vbs |
Add a shebang
A CGI VBScript requires a shebang to inform Apache what program is required to run the script. It has the following format:
'!c:/windows/system32/cscript //nologo
Note:
The shebang is '! followed by the path to the executable that will run the script, which in this case is the Windows Script Host cscript.exe
The //nologo prevents cscript from displaying a banner, otherwise a malformed header error would be produced.
Content-type
Following the shebang, a content type header is required. This also is obligatory, otherwise a malformed header error would be produced.
Wscript.Echo "Content-type: text/html" & vbLF & vbLF
Note:
The second vbLF produces a blank line. This is required before any content is output.
Complete test script
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'!c:/windows/system32/cscript //nologo Wscript.Echo "Content-type: text/html" & vbLF & vbLF Wscript.Echo "<h1>VBScript CGI Test 1</h1>" Wscript.Quit 0 |
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The script produces output as shown on right. |
VBScript CGI Test 1 |
Test Script 2
The above example, although functional, produces only static content and you would be better off using a standard html page. The real reason for writing CGI scripts is to produce dynamic content. The following script expands on the above template (test1.vbs) to display the current date and time.
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'!c:/windows/system32/cscript //nologo Wscript.Echo "Content-type: text/html" & vbLF & vbLF Wscript.Echo "<h1>VBScript CGI Test 2</h1>" WScript.Echo "<p>Today's date is: " & Date & "</p>" WScript.Echo "<p>The current time is: " & Time & "</p>" Wscript.Quit 0 |
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The script produces output as shown on right. |
VBScript CGI Test 2 Today's date is: 21/09/2011 The current time is: 18:05:12 |
Test Script 3
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Although the majority of html tags are optional you do need to
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'!c:/windows/system32/cscript //nologo Wscript.Echo "Content-type: text/html" & vbLF & vbLF WScript.Echo "<html>" WScript.Echo "<title>Test 3</title>" WScript.Echo "<body>" Wscript.Echo "<h1>VBScript CGI Test 3</h1>" WScript.Echo "<p>Today's date is: " & Date & "</p>" WScript.Echo "<p>The current time is: " & Time & "</p>" WScript.Echo "</body>" WScript.Echo "</html>" Wscript.Quit 0 |
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The script produces output as shown on right. Note:
The page title is now displayed on the browser tab and in |
VBScript CGI Test 3 Today's date is: 21/09/2011 The current time is: 18:05:12 |
Summary
Every CGI script must contain a shebang as the first line of any script. This informs Apache what scripting engine to use. The Content-type header for the page must follow this line.
The page template is shown below:
'!c:/windows/system32/cscript //nologo Wscript.Echo "Content-type: text/html" & vbLF & vbLF
Running VBScripts on The Uniform Server and Coral-Mini requires an .htaccess file be placed in the directory containing the scripts. This file enables CGI script execution and has the following content:
AddHandler cgi-script .vbs Options +ExecCGI Options +FollowSymlinks
Where to next
The next page covers adding a banner and footer using include files.