Python CGI checklist: Difference between revisions
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"Internal server error" got you down... | |||
== Save the file with the extension ".cgi" == | |||
== Seeing the source code? == | |||
Make sure you are viewing the script via a webserver (not as a file). In other words, the URL should start with "http:" not "file:". | |||
http://localhost/cgi-bin/script.cgi | |||
http://pzwart3.wdka.hro.nl/~YOU/cgi-bin/script.cgi | |||
not | |||
file://Users/YOURUSERNAME/Sites/script.cgi | |||
: | And if this doesn't work, make sure your webserver is running (Mac OS X: System Preferences, Sharing, Personal Web Sharing should be switched on). | ||
== She-Bang! == | |||
First line of the file should be the "shebang" telling the system (Apache) how to run the script (in other words which language it is). | |||
#!/usr/bin/python | |||
Alternatively you could use the "env" trick + specify a text encoding (in case your code has special characters in it) | |||
: | #!/usr/bin/env python | ||
#-*- coding:utf-8 -*- | |||
== Permissions must be set to "world-executable" == | |||
chmod +x myscript.cgi | |||
or | |||
chmod 755 myscript.cgi | |||
< | == See python errors in the browser == | ||
Once the script is actually running, there might of course be something wrong in the code of the program itself. By default, if a python exception occurs, you will see either an Internal Server Error or (worse) a blank page. The ''cgitb'' module (CGI Trackback) will make python errors appear, and even format them for a browser. | |||
<source lang="python"> | |||
import cgitb; cgitb.enable() | import cgitb; cgitb.enable() | ||
</ | </source> | ||
== Print the Content-type first! == | |||
The very first output of your script must be the "HTTP headers", which at the very least should be a Content-type (with optional character set) ''followed by a blank line''. | |||
< | <source lang="python"> | ||
print "Content-type: text/html" | print "Content-type: text/html;charset=utf-8" | ||
print | print | ||
</ | </source> | ||
== Check the webserver's error log == | |||
tail /var/log/apache2/error_log | |||
tail /var/log/ | |||
or | or maybe.. | ||
tail /var/log/httpd/error_log | |||
tail /var/log/ | |||
Revision as of 11:19, 13 May 2013
"Internal server error" got you down...
Save the file with the extension ".cgi"
Seeing the source code?
Make sure you are viewing the script via a webserver (not as a file). In other words, the URL should start with "http:" not "file:".
http://localhost/cgi-bin/script.cgi http://pzwart3.wdka.hro.nl/~YOU/cgi-bin/script.cgi
not
file://Users/YOURUSERNAME/Sites/script.cgi
And if this doesn't work, make sure your webserver is running (Mac OS X: System Preferences, Sharing, Personal Web Sharing should be switched on).
She-Bang!
First line of the file should be the "shebang" telling the system (Apache) how to run the script (in other words which language it is).
#!/usr/bin/python
Alternatively you could use the "env" trick + specify a text encoding (in case your code has special characters in it)
#!/usr/bin/env python #-*- coding:utf-8 -*-
Permissions must be set to "world-executable"
chmod +x myscript.cgi
or
chmod 755 myscript.cgi
See python errors in the browser
Once the script is actually running, there might of course be something wrong in the code of the program itself. By default, if a python exception occurs, you will see either an Internal Server Error or (worse) a blank page. The cgitb module (CGI Trackback) will make python errors appear, and even format them for a browser.
import cgitb; cgitb.enable()
Print the Content-type first!
The very first output of your script must be the "HTTP headers", which at the very least should be a Content-type (with optional character set) followed by a blank line.
print "Content-type: text/html;charset=utf-8"
print
Check the webserver's error log
tail /var/log/apache2/error_log
or maybe..
tail /var/log/httpd/error_log