The config.php filecontains a series of configuration options all of them stored in a PHP array called,
appropriately enough, $config) that CodeIgniter uses to keep track of your application ’ s information
and settings.
The first configuration option you need to set inside config.php is the base URL of your application. You
do that by setting the absolute URL (including the http:// part) for $config[ ‘ base_url ’ ], like so:
$config[‘base_url’] = “http://www.example.com/test/”;
Once you ’ ve set this configuration option, you can recall it whenever you want using the CodeIgniter
base_url()function, which can be a very handy thing to know. This one feature keeps you from
having to rewrite hard - coded URLs in your application, when you migrate from development to test or
from test to production.
The second thing you need to do is set a value for your home page by editing the $config[ ‘ index_
page ’ ]configuration option. CodeIgniter ships with a value of “ index.php ” for this option, which
means that index.php will appear in all of your URLs. Many CodeIgniter developers prefer to keep this
value blank, like so:
$config[‘index_page’] = ‘’;
To make this work, you need to include an .htaccess file to the CodeIgniter root directory, After you ’ ve set this option value, there ’ s very little to do.
For now, leave all the other values at their
default settings:
$config[‘uri_protocol’] = “AUTO”;
$config[‘url_suffix’] = “”;
$config[‘language’] = “english”;
$config[‘charset’] = “UTF-8”;
$config[‘enable_hooks’] = FALSE;
$config[‘subclass_prefix’] = ‘MY_’;
$config[‘permitted_uri_chars’] = ‘a-z 0-9~%.:_-’;
$config[‘enable_query_strings’] = FALSE;
$config[‘controller_trigger’] = ‘c’;
$config[‘function_trigger’] = ‘m’;
$config[‘log_threshold’] = 0;
$config[‘log_path’] = ‘’;
$config[‘log_date_format’] = ‘Y-m-d H:i:s’;
$config[‘cache_path’] = ‘’;
$config[‘encryption_key’] = “enter_a_32_character_string_here”;
$config[‘sess_cookie_name’] = ‘ci_session’;
$config[‘sess_expiration’] = 7200;
$config[‘sess_encrypt_cookie’] = TRUE;
$config[‘sess_use_database’] = FALSE;
$config[‘sess_table_name’] = ‘ci_sessions’;
$config[‘sess_match_ip’] = FALSE;
$config[‘sess_match_useragent’] = TRUE;
$config[‘cookie_prefix’] = “”;
$config[‘cookie_domain’] = “”;
$config[‘cookie_path’] = “/”;
$config[‘global_xss_filtering’] = TRUE;
$config[‘compress_output’] = FALSE;
$config[‘time_reference’] = ‘local’;
$config[‘rewrite_short_tags’] = FALSE
For more details on each of these configuration options, simply read the comments embedded in /
system/application/config/config.php. You will also get more detail on certain settings as you work
through the sections of the book and tweak the configuration as needed. For example, at some point, you
will want to use encryption for security purposes or set your logging threshold for debugging, and they
both require making changes to this file.
CodeIgniter ’ s Global XSS Filtering option is set to FALSE by default. The online User Guide suggests
that setting this to TRUE adds a lot of performance overhead to the system. However, at this point, it is
better to have some global protection put in place. That way you can be assured of some security
precautions while you ’ re in development. Chapter 9 discusses security issues in more depth, but for
now, it ’ s good to have something in place while you ’ re developing.
In the same security vein, notice that sess_encrypt_cookie has been set to TRUE, and that you are to
enter a 32 - character encryption salt in encryption_key. Doing these two things will encrypt any
sessions and provide a salt for any hashing methods you use. Be sure to use a random string of upper -
and lowercase letters and numbers.
One final note before moving on: Make sure that you write down your encryption key and keep it safe
somewhere, or, at least, maintain good backups. You ’ ll need the key to retrieve other information, so if
your site is compromised or erased or if you lose your key any other way, you ’ ll be glad you have a
record of it.
appropriately enough, $config) that CodeIgniter uses to keep track of your application ’ s information
and settings.
The first configuration option you need to set inside config.php is the base URL of your application. You
do that by setting the absolute URL (including the http:// part) for $config[ ‘ base_url ’ ], like so:
$config[‘base_url’] = “http://www.example.com/test/”;
Once you ’ ve set this configuration option, you can recall it whenever you want using the CodeIgniter
base_url()function, which can be a very handy thing to know. This one feature keeps you from
having to rewrite hard - coded URLs in your application, when you migrate from development to test or
from test to production.
The second thing you need to do is set a value for your home page by editing the $config[ ‘ index_
page ’ ]configuration option. CodeIgniter ships with a value of “ index.php ” for this option, which
means that index.php will appear in all of your URLs. Many CodeIgniter developers prefer to keep this
value blank, like so:
$config[‘index_page’] = ‘’;
To make this work, you need to include an .htaccess file to the CodeIgniter root directory, After you ’ ve set this option value, there ’ s very little to do.
For now, leave all the other values at their
default settings:
$config[‘uri_protocol’] = “AUTO”;
$config[‘url_suffix’] = “”;
$config[‘language’] = “english”;
$config[‘charset’] = “UTF-8”;
$config[‘enable_hooks’] = FALSE;
$config[‘subclass_prefix’] = ‘MY_’;
$config[‘permitted_uri_chars’] = ‘a-z 0-9~%.:_-’;
$config[‘enable_query_strings’] = FALSE;
$config[‘controller_trigger’] = ‘c’;
$config[‘function_trigger’] = ‘m’;
$config[‘log_threshold’] = 0;
$config[‘log_path’] = ‘’;
$config[‘log_date_format’] = ‘Y-m-d H:i:s’;
$config[‘cache_path’] = ‘’;
$config[‘encryption_key’] = “enter_a_32_character_string_here”;
$config[‘sess_cookie_name’] = ‘ci_session’;
$config[‘sess_expiration’] = 7200;
$config[‘sess_encrypt_cookie’] = TRUE;
$config[‘sess_use_database’] = FALSE;
$config[‘sess_table_name’] = ‘ci_sessions’;
$config[‘sess_match_ip’] = FALSE;
$config[‘sess_match_useragent’] = TRUE;
$config[‘cookie_prefix’] = “”;
$config[‘cookie_domain’] = “”;
$config[‘cookie_path’] = “/”;
$config[‘global_xss_filtering’] = TRUE;
$config[‘compress_output’] = FALSE;
$config[‘time_reference’] = ‘local’;
$config[‘rewrite_short_tags’] = FALSE
For more details on each of these configuration options, simply read the comments embedded in /
system/application/config/config.php. You will also get more detail on certain settings as you work
through the sections of the book and tweak the configuration as needed. For example, at some point, you
will want to use encryption for security purposes or set your logging threshold for debugging, and they
both require making changes to this file.
CodeIgniter ’ s Global XSS Filtering option is set to FALSE by default. The online User Guide suggests
that setting this to TRUE adds a lot of performance overhead to the system. However, at this point, it is
better to have some global protection put in place. That way you can be assured of some security
precautions while you ’ re in development. Chapter 9 discusses security issues in more depth, but for
now, it ’ s good to have something in place while you ’ re developing.
In the same security vein, notice that sess_encrypt_cookie has been set to TRUE, and that you are to
enter a 32 - character encryption salt in encryption_key. Doing these two things will encrypt any
sessions and provide a salt for any hashing methods you use. Be sure to use a random string of upper -
and lowercase letters and numbers.
One final note before moving on: Make sure that you write down your encryption key and keep it safe
somewhere, or, at least, maintain good backups. You ’ ll need the key to retrieve other information, so if
your site is compromised or erased or if you lose your key any other way, you ’ ll be glad you have a
record of it.