Apache

References

• Apache Documentation (a bit fuzzy...)
  • mod_rewrite
• Apache HTTP Server Wiki (much clearer but incomplete)

Enabling .htaccess files

In case the .htaccess files are ignored (see [1]):

Stop! Don't use htaccess files for mod_rewrite unless you have no other choice. Doing so is slow and confusing.

1. Put a nonsense line (such as Wooga) in your htaccess file and try the request again. If you don't see a 500 Internal Server Error message, your htaccess file is being ignored altogether. The solution is to set both AllowOverride FileInfo and Options FollowSymlinks in httpd.conf (on Ubuntu, check apache2/sites-enabled/000-default, or add your own config file in apache2/conf.d) for the directory in question.

DocumentRoot /var/www
<Directory />
    Options FollowSymLinks
    AllowOverride FileInfo          # Must *NOT* be ''none''
</Directory>

2. If you think your rules look ok but you still see a 500 Internal Server Error message, make sure mod_rewrite is loaded in the server.
3. If you have ensured that mod_rewrite is loaded, and that RewriteRule is enabled for htaccess files, it could be that your rules are looping.
4. If none of the above steps help, try a very simple rewrite to check if the module is enabled. For example:

RewriteEngine On
# Redirect all requests to example.com
RewriteRule ^ http://example.com/

Basic Rewrite Rules

• References: [2], [3]
• Rewrite rules are either defined in virtual host configuration (i.e. httpd.conf or similar) or in the .htaccess file, per directory ({{{1}}}discouragedTemplate:/red — I don't

know why exactly; slower...}}

Frequent errors

• Make sure that all files in your /var/www (or any other relevant directory) are owned by www:www-data (if not, rule conditions like RewriteCond %{REQUEST_FILENAME} -f may fail!)

sudo chown -R www:www-data /var/www

• If you changed apache config, make sure that you restarted the server

sudo /etc/init.d/apache2 restart

• If you use mod_rewrite in .htaccess files, make sure that these files are indeed read by Apache (see section above).
• Enable rewrite log to ease debugging. Add a file /etc/apache2/conf.d/rewritelog.conf:

RewriteLog "/var/log/apache2/rewrite.log"
RewriteLogLevel 8                              # Max 9

Some example of rewrite rules

See [4] for more examples, and what-not.

Rewrite URL for missing resource

From [5], rewrite URL for missing resource.

# For each web request (file or directory) that doesn't start with /en-US/, 
# serve up the original resource if it exists, otherwise serve up the /en-US/ version.
RewriteCond $0 !^en-US/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule .+ en-US/$0 [L]

Rewrite URL for missing resources (advanced)

# Try to replace query for non-existing images to white/black images
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} -f       # true if file exists
RewriteRule (.*) - [L]                   # Applied if condition above is true, [L] means LAST rule

# 10-0- up to 10-511-
RewriteCond %{REQUEST_URI} /10-[0-9]+-([0-9]|[1-9][0-9]|[1-4][0-9][0-9]|50[0-9]|51[0-1])\.png
RewriteRule (.*) white.png [L]

# 9-0- up to 9-255-
RewriteCond %{REQUEST_URI} /9-[0-9]+-([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])\.png
RewriteRule (.*) white.png [L]

# 8-0- up to 8-127-
RewriteCond %{REQUEST_URI} /8-[0-9]+-([0-9]|[1-9][0-9]|1[01][0-9]|12[0-7])\.png
RewriteRule (.*) white.png [L]

# 7-0- up to 7-63-
RewriteCond %{REQUEST_URI} /7-[0-9]+-([0-9]|[0-5][0-9]|6[0123])\.png
RewriteRule (.*) white.png [L]

# 6-0- up to 6-31-
RewriteCond %{REQUEST_URI} /6-[0-9]+-([0-9]|[0-2][0-9]|3[01])\.png
RewriteRule (.*) white.png [L]

# 5-0- up to 5-15-
RewriteCond %{REQUEST_URI} /5-[0-9]+-([0-9]|1[0-5])\.png
RewriteRule (.*) white.png [L]

# 4-0- up to 4-7-
RewriteCond %{REQUEST_URI} /4-[0-9]+-([0-7])\.png
RewriteRule (.*) white.png [L]

# 3-0- up to 3-3-
RewriteCond %{REQUEST_URI} /3-[0-9]+-([0-3])\.png
RewriteRule (.*) white.png [L]

# 2-0- up to 2-1-
RewriteCond %{REQUEST_URI} /2-[0-9]+-([0-1])\.png
RewriteRule (.*) white.png [L]

# 1-0- up to 1-1-
RewriteCond %{REQUEST_URI} /1-[0-9]+-0\.png
RewriteRule (.*) white.png [L]

RewriteRule (.*) black.png [L]

Tags

DirectoryIndex

• Use DirectoryIndex to change list of default name of index file while browsing directory

DirectoryIndex index.php index.html         # Will serve php version first
DirectoryIndex mycustomindex.html           # To point to specific file when browsing directory (no directory listing)

HTTPS

From [6]. Assumptions:

• Already a website present at /var/www
• Package ssl-cert installed (that create snakeoil (i.e. self-signed) certificates in /etc/ssl)

# Load and enable SSL module
sudo a2enmod ssl
sudo /etc/init.d/apache2 force-reload

# Edit file
sudo vim /etc/apache2/sites-available/default-ssl
# ... and change lines as follows (for key/cert we use the snakeoil ones):
#  SSLEngine on
#  SSLOptions +FakeBasicAuth +ExportCertData +StrictRequire

#Enable the default SSL site:
sudo a2ensite default-ssl

# Tell Apache to reload its configuration:
sudo /etc/init.d/apache2 reload

To also add user authentication, add the following lines to either

• File .htaccess in website directory
• Section <Directory /> in /etc/apache2/sites-available/default-ssl:

AuthType Basic
AuthName "default"
AuthUserFile /var/www/nxl67002ux.ssl.passwd
Require valid-user

Then create the password file with the command htpasswd -c filename.passwd username

Finally, reload apache2:

sudo /etc/init.d/apache2 reload