CGI Setup and Troubleshooting
CGI, and Perl Troubleshooting
With any CGI program, there are several
common elements that can be checked to determine why a CGI script is
failing. You may wish to print this list. If you have any additional
suggestions, please let us know.
1. Did
you upload the script(s) with minimal changes?
2. Did you save the files
with a true text editor (possibly with Unix save mode)?
3. Did
you upload the script(s) in ASCII mode?
4. Did you set the correct
permissions?
(chmod correct?)
5. Did you store the CGI Script in
cgi-bin?
6. Is the first line in the script
#!/usr/bin/perl ?
7. Perl is case sensitive, are you
calling everything correctly?
8. Did you escape \ the @ in
any email addresses?
9. Are you using the correct server
root path?
10. Is your CGI Script located in the
cgi-bin folder?
11. Have you used
SSH Telnet in order to
discover error messages?
12. Is your sendmail path correct?
13. Be careful deleting
server files that preexist on your web account.
14. Are you using SHTML and
SSI correctly?
15. Are none of your
images displaying?
1. Our number one
suggestion with all cgi scripts is to first set them up without
making any modifications except which is absolute necessary (like
don't bother with changing the admin email, don't make any customizations to
the HTML, etc.). Then once it is running, after each change, re-upload
and recheck the script for any possible problems.
2. DO: Make sure to only
use a text editor program to edit your cgi programs. You may wish
to use Editeur located at
http://www.studioware.com
as it can save Unix files (this is the program we use), feel free to
search for more at
http://www.download.com or
http://www.shareware.com. Just make sure the text editor that
you use can save as a Unix file.
DON'T: Use WordPad, Microsoft Word, or some other word
processing program to edit your CGI scripts. These programs may
corrupt your CGI programs. Most word processing programs have a
"save as ASCII or TEXT" but even though the word processing program
appears to save in ASCII or text format, it still may corrupt the CGI
program.
DON'T: Use Microsoft
FrontPage to upload your CGI files. However, it is possible, but
if you wish to do so, you will have to customize your FrontPage setup files
located on your computer for each web site in order to do so.
Again, we recommend against it.
3. Make sure your FTP
software uploads the CGI scripts in ASCII mode, binary mode will corrupt the
CGI files.
Some FTP software may have an Auto detect
mode. The Auto Detect mode may not see .cfg, .dat, .database, .db,
.pl, etc. as needing ASCII mode, but typically files such as this do need to
be transferred in ASCII mode. FTP
software can be found here.
4. Make sure to double
check all permissions (for both files and folders). You can change
permission by SSH Telnet or by using your FTP software (the recommending
method). Changing permissions is also referred to as chmod.
5. Make sure that
any CGI Script or PL script is stored inside the cgi-bin folder.
You can create additional folders inside the cgi-bin to maintain
organization.
6. Make sure the first
line of the cgi program points to the location of Perl.
The location of Perl at ActiveWebHost.com is
#!/usr/bin/perl
7. Unix/Linux is case
sensitive.
8. In most cases an
email address that resides in a CGI script must have the @ symbol
escaped such as yourname\@yourdomain.com. Not escaping the @
symbol will cause the CGI program to fail to run.
9. Make sure you have
checked your root path (if your CGI script needs this information) as
inaccurate information will certainly cause a CGI script to fail.
The root path at ActiveWebHost.com is
/home/your_ftp_name/public_html
For example, if your script is located at...
http://www.yourdomain.com/cgi-bin/web_store/web_store.cgi
then the root path to web_store.cgi would be...
/home/your_ftp_name/public_html/cgi-bin/web_store/web_store.cgi.
10. Is your script
located in the cgi-bin? All scripts at ActiveWebHost.com must be
located in the cgi-bin in order to run.
11. If your script
continues to fail, you can also log in to your account via SSH Telnet.
Then locate your script and then run:
perl yourscriptname.cgi
or
perl yourscriptname.pl
Based upon the error messages, edit the
script and re-upload.
12. If you are
experiencing email problems with your CGI script, make sure you have set the
correct path to sendmail in your cgi script.
The location of sendmail at ActiveWebHost.com
is /usr/sbin/sendmail
13. If you see files
like .bash_logout, .screenrc, etc. don't delete them as they will affect
your entire web account. They are there for a reason.
Folders that begin with _vti are
related to Microsoft Front Page and should also be left alone. Though
they won't affect your CGI scripts whether you delete them or not.
14. If you call or run a CGI
or PL program from an HTML document in a statement such as...
<!--#exec
cgi="/cgi-bin/counter/counter.cgi"-->
...visit the
SSI / SHTML page which may help you discover solutions and find
answers to common questions regarding SSI and SHTML.
15. If none of your images are
displaying in your online program, it is due to one of the following
reasons...
Have you FTP/Uploaded your images to the
correct location on the server? While running the program via your
browser, view the HTML source code, and look at the full path of an
image. Is this where you stored your image? If not, move
your image(s) to the correct location.
Most Unix/Linux hosts (including
ActiveWebHost.com) don't allow images to display if they are located in
the cgi-bin folder. Typically your images must reside OUTSIDE the
cgi-bin folder. This is done because many online programs require
setup files, store sensitive data, etc. inside the cgi-bin folder.
To minimize the risk of a visitor to your web site from intentionally or
unintentionally displaying things they shouldn't see that is located in
the cgi-bin folder, hosting companies typically only allow your visitors
to run programs located in the cgi-bin, but are not allowed to view any
other files (which includes images, text files, etc.).
Please note that scripts can enter infinite
loops and cause problems for any server. Please edit scripts with
care!
For additional assistance visit our
CGI-bin Applications Page. |
