+ +
+

Common Functions

+

CodeIgniter uses a few functions for its operation that are globally +defined, and are available to you at any point. These do not require +loading any libraries or helpers.

+
+
+is_php($version)
+
+++ + + + + + + + +
Parameters:
    +
  • $version (string) – Version number
    • +
+
Returns:

TRUE if the running PHP version is at least the one specified or FALSE if not

+
Return type:

bool

+
+

Determines if the PHP version being used is greater than the +supplied version number.

+

Example:

+
if (is_php('5.3'))
+{
+        $str = quoted_printable_encode($str);
+}
+
+
+

Returns boolean TRUE if the installed version of PHP is equal to or +greater than the supplied version number. Returns FALSE if the installed +version of PHP is lower than the supplied version number.

+
+ +
+
+is_really_writable($file)
+
+++ + + + + + + + +
Parameters:
    +
  • $file (string) – File path
    • +
+
Returns:

TRUE if the path is writable, FALSE if not

+
Return type:

bool

+
+

is_writable() returns TRUE on Windows servers when you really can’t +write to the file as the OS reports to PHP as FALSE only if the +read-only attribute is marked.

+

This function determines if a file is actually writable by attempting +to write to it first. Generally only recommended on platforms where +this information may be unreliable.

+

Example:

+
if (is_really_writable('file.txt'))
+{
+        echo "I could write to this if I wanted to";
+}
+else
+{
+        echo "File is not writable";
+}
+
+
+
+

Note

+

See also PHP bug #54709 for more info.

+
+
+ +
+
+config_item($key)
+
+++ + + + + + + + +
Parameters:
    +
  • $key (string) – Config item key
    • +
+
Returns:

Configuration key value or NULL if not found

+
Return type:

mixed

+
+

The Config Library is the preferred way of +accessing configuration information, however config_item() can be used +to retrieve single keys. See Config Library +documentation for more information.

+
+ +
+
+set_status_header($code[, $text = ''])
+
+++ + + + + + +
Parameters:
    +
  • $code (int) – HTTP Response status code
    • +
  • $text (string) – A custom message to set with the status code
    • +
+
Return type:

void

+
+

Permits you to manually set a server status header. Example:

+
set_status_header(401);
+// Sets the header as:  Unauthorized
+
+
+

See here for +a full list of headers.

+
+ +
+
+remove_invisible_characters($str[, $url_encoded = TRUE])
+
+++ + + + + + + + +
Parameters:
    +
  • $str (string) – Input string
    • +
  • $url_encoded (bool) – Whether to remove URL-encoded characters as well
    • +
+
Returns:

Sanitized string

+
Return type:

string

+
+

This function prevents inserting NULL characters between ASCII +characters, like Java\0script.

+

Example:

+
remove_invisible_characters('Java\\0script');
+// Returns: 'Javascript'
+
+
+
+ +
+
+html_escape($var)
+
+++ + + + + + + + +
Parameters:
    +
  • $var (mixed) – Variable to escape (string or array)
    • +
+
Returns:

HTML escaped string(s)

+
Return type:

mixed

+
+

This function acts as an alias for PHP’s native htmlspecialchars() +function, with the advantage of being able to accept an array of strings.

+

It is useful in preventing Cross Site Scripting (XSS).

+
+ +
+
+get_mimes()
+
+++ + + + + + +
Returns:An associative array of file types
Return type:array
+

This function returns a reference to the MIMEs array from +application/config/mimes.php.

+
+ +
+
+is_https()
+
+++ + + + + + +
Returns:TRUE if currently using HTTP-over-SSL, FALSE if not
Return type:bool
+

Returns TRUE if a secure (HTTPS) connection is used and FALSE +in any other case (including non-HTTP requests).

+
+ +
+
+is_cli()
+
+++ + + + + + +
Returns:TRUE if currently running under CLI, FALSE otherwise
Return type:bool
+

Returns TRUE if the application is run through the command line +and FALSE if not.

+
+

Note

+

This function checks both if the PHP_SAPI value is ‘cli’ +or if the STDIN constant is defined.

+
+
+ +
+
+function_usable($function_name)
+
+++ + + + + + + + +
Parameters:
    +
  • $function_name (string) – Function name
    • +
+
Returns:

TRUE if the function can be used, FALSE if not

+
Return type:

bool

+
+

Returns TRUE if a function exists and is usable, FALSE otherwise.

+

This function runs a function_exists() check and if the +Suhosin extension <http://www.hardened-php.net/suhosin/> is loaded, +checks if it doesn’t disable the function being checked.

+

It is useful if you want to check for the availability of functions +such as eval() and exec(), which are dangerous and might be +disabled on servers with highly restrictive security policies.

+
+

Note

+

This function was introduced because Suhosin terminated +script execution, but this turned out to be a bug. A fix +has been available for some time (version 0.9.34), but is +unfortunately not released yet.

+
+
+ +
+ + +