1. LING 408/508: Computational Techniques for Linguists
Lecture 20

2. Today's Topic
Did everyone get their webserver (OS X or Ubuntu or both) up and running?
Apache2
Last time: we configured the root site and a user site
Those are static webpages (but could contain Javascript which runs on the client):
Today we will start running programs on the webserver itself.

3. Today's Topics Quick Homework 8: do before next time! Warning message:
"Could not reliably determine the server’s fully qualified domain name"
Solution: define in /etc/apache2.conf (or httpd.conf):
ServerName localhost
Quick Homework 8: do before next time!

4. Apache Webserver on OSX
Storage locations:
cgi-bin directory:
/Library/WebServer/CGI-Executables/
usage:
permissions for *.cgi should be readable and executable
ls -l /Library/WebServer/CGI-Executables/
-rwxr-xr-x 1 root wheel Oct get.cgi
-rwxr-xr-x 1 root wheel Oct post.cgi
-rw-r--r-- 1 root wheel Oct 27 16:06 test.cgi
to change permissions
sudo chmod 755 test.cgi
html pages:
/Library/WebServer/Documents/

5. Apache Webserver on OSX
By default, Apple ships Apache2 with the cgi module turned off. Assuming the webserver is running, possible symptoms:
prints program.cgi as plain text instead of executing it
get.cgi doesn't exist!

6. Apache Webserver on OSX
Enabling cgi-bin:
uncomment cgi_module line in file /etc/apache2/httpd.conf
sudo nano /etc/apache2/httpd.conf
restart apache2

7. Apache Webserver on OSX
Boilerplate browser expects:
Content-Type: text/plain
<blank line>
Simple bash script, let's call it test:
#!/bin/bash
echo "Content-Type: text/plain"
echo
echo "Running Bash script from cgi-bin successfully!"
echo -n "Now: "
date
echo -n "User: "
whoami
exit 0
755
rwx
100 = 4
010 = 2
001 = 1

8. Apache Webserver on OSX
Boilerplate browser expects:
Content-Type: text/plain
<blank line>
Simple bash script, let's call it test:
#!/bin/bash
echo "Content-Type: text/plain"
echo
echo "Running Bash script from cgi-bin successfully!"
echo -n "Now: "
date
echo -n "User: "
whoami
exit 0
CGI-Executables$ ./test.cgi
Content-Type: text/plain
Running Bash script from cgi-bin successfully!
Now: Tue Oct 30 11:10:12 MST 2018
User: sandiway
make sure our
bash script runs
on the server…

9. Apache Webserver on OSX
Compare:
CGI-Executables$ ./test.cgi Content-Type: text/plain Running Bash script from cgi-bin successfully! Now: Tue Oct 30 11:10:12 MST 2018 User: sandiway
User:
Preamble: content-type and blank line

10. Apache Webserver on Ubuntu
cgi-bin/
CGI binaries directory: /usr/lib/cgi-bin/
files must be made executable!
create same test script
executable permissions needed

11. Apache Webserver on Ubuntu
Enabling cgi-bin:
sudo a2enmod cgi (enables cgid instead of cgi)
directory /etc/apache2/mods-enabled/

12. Apache Webserver on Ubuntu
Compare running test directly:
http//localhost/cgi-bin/test:
User: www-data
On OS X: _www

13. Running cgi-bin for users

14. Apache Webserver on OSX
To run programs in ~sandiway/Sites, i.e. outside of
/Library/WebServer/CGI-Executables
modify the Apache httpd configuration file:
sudo nano /etc/apache2/httpd.conf
uncomment
invokes the cgi-script handler for all files of type .cgi

15. Apache Webserver on OSX
Also modify /etc/apache2/users/sandiway.conf (created last lecture) to add the ExecCGI option as follows:
<Directory "/Users/sandiway/Sites/">
AllowOverride All
Options Indexes Multiviews FollowSymLinks ExecCGI
Require all granted
</Directory>
#!/bin/bash
echo "Content-Type: text/plain"
echo
echo "Running Bash script from ~sandiway/Sites successfully!"
echo -n "Now: "
date
echo -n "User: "
whoami
echo -n "Directory: "
ls -l
exit 0
File ~/Sites/test.cgi

16. Apache Webserver on OSX
Dangerous! Why?

17. Apache Webserver on Ubuntu
By default cgi-bin is not enabled for ~/public_html
just displays program instead of running it

18. Apache Webserver on Ubuntu
From
add these lines to /etc/apache2/apache.conf
<Directory "/home/*/public_html">
Options +ExecCGI
AddHandler cgi-script .cgi
</Directory>
and restart apache2

19. Apache Webserver on Ubuntu
/etc/apache2/apache2.conf
I put the declarations here
(I'm not sure it's the best place though…)

20. Apache Webserver on Ubuntu
/etc/apache2/mods-available/userdir.conf

21. Apache Webserver on Ubuntu

22. Documentation

23. Quick Homework 8
Make up two different bash shell scripts, one for the root server and one for the user.
[Refresh your knowledge of bash scripting from the first few lectures.]
Show them running using localhost/cgi-bin/example.cgi and localhost/~user/example.cgi
Send me screen snapshots.
Be adventurous!