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()¶
- is_php($version = '5.3.0')¶
Parameters: - $version (string) – Version number
Returns: bool
Determines of 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()¶
- is_really_writable($file)¶
Parameters: - $file (string) – File path
Returns: bool
is_writable() returns TRUE on Windows servers when you really can’t write to the file as the OS reports to PHP as FALSE only if the read-only attribute is marked.
This function determines if a file is actually writable by attempting to write to it first. Generally only recommended on platforms where this information may be unreliable.
Example:
if (is_really_writable('file.txt'))
{
echo "I could write to this if I wanted to";
}
else
{
echo "File is not writable";
}
config_item()¶
- config_item($key)¶
Parameters: - $key (string) – Config item key
Returns: mixed
The Config Library is the preferred way of accessing configuration information, however config_item() can be used to retrieve single keys. See Config Library documentation for more information.
Important
This function only returns values set in your configuration files. It does not take into account config values that are dynamically set at runtime.
show_error()¶
- show_error($message, $status_code, $heading = 'An Error Was Encountered')¶
Parameters: - $message (mixed) – Error message
- $status_code (int) – HTTP Response status code
- $heading (string) – Error page heading
Returns: void
This function calls CI_Exception::show_error(). For more info, please see the Error Handling documentation.
show_404()¶
- show_404($page = '', $log_error = TRUE)¶
Parameters: - $page (string) – URI string
- $log_error (bool) – Whether to log the error
Returns: void
This function calls CI_Exception::show_404(). For more info, please see the Error Handling documentation.
log_message()¶
- log_message($level, $message, $php_error = FALSE)¶
Parameters: - $level (string) – Log level: ‘error’, ‘debug’ or ‘info’
- $message (string) – Message to log
- $php_error (bool) – Whether we’re logging a native PHP error message
Returns: void
This function is an alias for CI_Log::write_log(). For more info, please see the Error Handling documentation.
set_status_header()¶
- set_status_header($code, $text = '')¶
Parameters: - $code (int) – HTTP Reponse status code
- $text (string) – A custom message to set with the status code
Returns: void
Permits you to manually set a server status header. Example:
set_status_header(401);
// Sets the header as: Unauthorized
See here for a full list of headers.
remove_invisible_characters()¶
- remove_invisible_characters($str, $url_encoded = TRUE)¶
Parameters: - $str (string) – Input string
- $url_encoded (bool) – Whether to remove URL-encoded characters as well
Returns: string
This function prevents inserting NULL characters between ASCII characters, like Java\0script.
Example:
remove_invisible_characters('Java\\0script');
// Returns: 'Javascript'
html_escape()¶
- html_escape($var)¶
Parameters: - $var (mixed) – Variable to escape (string or array)
Returns: mixed
This function acts as an alias for PHP’s native htmlspecialchars() function, with the advantage of being able to accept an array of strings.
It is useful in preventing Cross Site Scripting (XSS).
get_mimes()¶
- get_mimes()¶
Returns: array
This function returns a reference to the MIMEs array from application/config/mimes.php.
is_https()¶
- is_https()¶
Returns: bool
Returns TRUE if a secure (HTTPS) connection is used and FALSE in any other case (including non-HTTP requests).
function_usable()¶
- function_usable($function_name)¶
Parameters: - $function_name (string) – Function name
Returns: 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.