OpenEuphoria

Debugging CGI

• Posted by jmduro Oct 05, 2018
• 2166 views

Here is my method for debugging OpenEuphoria CGI scripts with Apache2. To be used for development not for production because of weak safety rules.

Configure Apache2 to compile OpenEuphoria CGI scripts

cd /etc/apache2/ 
sudo nano conf-available/serve-cgi-bin.conf 
add: 
                AddHandler exu-file .exu .ex 
                Action exu-file /cgi-bin/runexu.cgi 
under: 
                ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/ 
 
cd mods-enabled/ 
sudo ln -s ../mods-available/cgi.load 
sudo ln -s ../mods-available/actions.load 
sudo ln -s ../mods-available/actions.conf 
 
sudo a2enmod ssl 
sudo a2ensite default-ssl 
sudo service apache2 reload 
 
sudo chmod 777 /usr/lib/cgi-bin/ 
 
sudo vi /usr/lib/cgi-bin/runexu.cgi  # adapt to your OEU path !!! 
#!/bin/sh 
#runexu.cgi - wrapper to run a euphoria program without the need for #! 
 
debug="log/debug_$(date +"%Y-%m-%d_%H-%M-%S")_runexu.log" 
echo "-----------------------------------" >> $debug 
date --rfc-3339='ns' >> $debug 
echo "-----------------------------------" >> $debug 
/usr/local/euphoria-4.1.0-ARMv6-hardfloat/bin/eui $PATH_TRANSLATED | tee -a $debug 
# END of runexu.cgi 
 
sudo chmod +x /usr/lib/cgi-bin/runexu.cgi 
 
sudo /etc/init.d/apache2 restart 
 
sudo chown -R $(id -un):www-data /var/www/html 
sudo chmod 777 /var/www/html 

Create a sub-directory for debug logs under /var/www/html

sudo mkdir /var/www/html/log 
sudo chmod 777 /var/www/html/log 

Link /var/www/html/log and /usr/lib/cgi-bin/log

sudo ln -s /var/www/html/log /usr/lib/cgi-bin/log 

Create following shell scripts to clean logs before run and to see logs after run:

error.log is built by EU4 Standard library (you may forget it if you don't use it)

vi /var/www/html/clean 
#!/bin/bash 
rm -f log/* 
rm -f /usr/lib/cgi-bin/ex.err 
rm -f /usr/lib/cgi-bin/error.log 

vi /var/www/html/debug 
#!/bin/bash 
echo "--------------------------------------------------------------------------------" 
echo "Debug starts at $(date +"%Y-%m-%d %H:%M:%S")" 
echo "--------------------------------------------------------------------------------" 
echo -e "\n/usr/lib/cgi-bin/ex.err" 
[ -f /usr/lib/cgi-bin/ex.err ] && head -20 /usr/lib/cgi-bin/ex.err || echo "Not found" 
echo -e "\n/usr/lib/cgi-bin/error.log" 
[ -f /usr/lib/cgi-bin/error.log ] && cat /usr/lib/cgi-bin/error.log || echo "Not found" 
for i in $(ls -1tr log/*) 
do 
 echo -e "\n$i" 
 cat $i 
done 

My CGI scripts include following lines:

sequence dt = date() 
sequence path = test_val("PATH_TRANSLATED") 
sequence webDir = dirname(path) 
sequence script = filename(path) 
f_debug = open(webDir & SLASH & "log" & SLASH & 
               sprintf("debug_%d-%02d-%02d_%02d-%02d-%02d_%s.log", 
                       {dt[1]+1900, dt[2], dt[3], dt[4], dt[5], dt[6], script}), "w") 

Here is an exemple:

:/var/www/html$ ./clean 
 
# Access your CGI script with your browser 
 
:/var/www/html$ ./debug 
-------------------------------------------------------------------------------- 
Debug starts at 2018-10-05 15:48:05 
-------------------------------------------------------------------------------- 
 
/usr/lib/cgi-bin/ex.err 
/var/www/html/test.ex:39 
<0074>:: Errors resolving the following references: 
        'f_debug' (/var/www/html/test.ex:31) has not been declared. 
        'f_debug' (/var/www/html/test.ex:39) has not been declared. 
        'InitialDir' (/var/www/html/test.ex:39) has not been declared. 
        'SLASH' (/var/www/html/test.ex:39) has not been declared. 
        'with_debug' (/var/www/html/test.ex:42) has not been declared. 
        'with_debug' (/var/www/html/test.ex:39) has not been declared. 
 
  f_debug = open(InitialDir & SLASH & "log" & SLASH & 
                                                    ^ 
 
 
--- Defined Words --- 
EU4 
EU4_1 
EU4_1_0 
CONSOLE 
UNIX 
LINUX 
 
/usr/lib/cgi-bin/error.log 
Not found 
 
log/debug_2018-10-05_15-47-53_runexu.log 
----------------------------------- 
2018-10-05 15:47:53.246376036+00:00 
----------------------------------- 
:/var/www/html$ 

Jean-Marc