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Tutorial 3 - Web Hit Counter Using an Image Tag
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Installation:
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Part I: Server side installation:
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ftp article03.cgi to your cgi-bin/thecgibin directory
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on telnet change directories to cgi-bin/thecgibin and
enter the command 'perl -wc article03.cgi'.
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you should get the response 'article03.cgi syntax ok'
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now that the program's on your server and compiles cleanly,
you need to set up the data file. use the 'data'
subdirectory of thecgibin.
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create a new file on your text editor and type the number 0
on it and save the file as article03.dat
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now ftp article03.dat into cgi-bin/thecgibin/data
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on telnet say 'perl -wT article03.cgi'
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here's what I got back on my server...
cannot open image file: No such file or directory at
article03.cgi line 36.
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now look at the contents of
cgi-bin/thecgibin/data/article03.dat. if you ran
the program once it should equal '1', because even though it
died on line 36 when it couldn't open the image file, it
did so after it updated the count file
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Preparing the Image File on Your Server :
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So now you need an image file for &prtpx to output, and
it's going to be named a.gif on the same directory as the
program. Point your web browser to
http://www.thecgibin.com/download/ and right click on the
file 'a.exe'. Now select 'Save Link As' (Netscape) or 'Save
Target As' (Explorer). Your browser will start to download
and ask you where to put it and what to name it. Put it
in the same directory as your article03.cgi program, and
name it a.gif. If it renders it instead you'll get a blank
screen because after all, it is a 1 pixel transparent gif.
In that case, hit the back button (or press alt+<-) to get
back to the main download directory, and try again.
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Now that you've got the image file downloaded from my
server, you can FTP it to your server. Be sure to put it
in cgi-bin/thecgibin/, the same directory you put the
article03.cgi program into. You'll have to make sure that
the file transfer is done using binary mode, as opposed to
ascii mode which is what we've used for all our other
uploads so far.
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Part II - Installation on the Web:
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First of all, let's get those pesky permissions done right.
You'll need to specify the following chmod's for your files.
| article03.cgi |
755 |
| article03.dat |
666 |
| a.gif |
644 |
Now we have the program, the data file that the program is
updating, and the gif image file that the program is reading
and outputting to our web page. We're just missing... you
guessed it. The web page code. It'll be very similar to
the one we used for tutorial 2, with a couple of slight
differences.
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Here it is :
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<html>
<head><title>Hello Out There</title></head>
<body bgcolor="#FFFFFF">
<img src="article03.cgi" width="1" height="1" alt="">
<h1>Hello Out There (Version Two)</h1>
</body>
</html>
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Installing your Webpage:
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in your text editor copy the html code above into a
file on your local computer and call it article03.html,
we don't need to use the shtml extension anymore because
we're not using a server side include, just a plain old
HTML image tag
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ftp article03.html to your cgi-bin/thecgibin directory
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now get on a browser window and type in the url
http://www.mysitename/cgi-bin/thecgibin/article03.html/
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now go to ftp and look at the data/article03.dat file
if it didn't change double check the chmod's and try
again
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reload the page a few times and verify that the
article03.dat file has changed accordingly, we've used
the pragma: no-cache instruction so that image should
reload each time we refresh the page, and the count file
should be updated with each reload
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and of course the page should say "Hello Out There
(Version Two)" in great big letters
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