ExpressionEngine Docs

Common Functions

ExpressionEngine 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.


Parameter Type Description
$version String Version number
Returns Bool TRUE if the running PHP version is at least the one specified or FALSE if not


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.


Parameter Type Description
$file String File path
Returns Bool TRUE if the path is writable, FALSE if not

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.


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

Note: See also PHP bug #54709 for more info.


Parameter Type Description
$key String Config item key
Returns Mixed Configuration key value or NULL if not found

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.

show_error($message, $status_code[, $heading = 'An Error Was Encountered'])

Parameter Type Description
$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().

show_404([$page = ''[, $log_error = TRUE]])

Parameter Type Description
$page String URI string
$log_error Bool Whether to log the error
Returns Void

This function calls CI_Exception::show_404().

log_message($level, $message)

Parameter Type Description
$level String Log level: ‘error’, ‘debug’ or ‘info’
$message String Message to log
Returns Void

This function is an alias for CI_Log::write_log().

set_status_header($code[, $text = ''])

Parameter Type Description
$code Int HTTP Response 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:

// Sets the header as:  Unauthorized

See here for a full list of headers.

remove_invisible_characters($str[, $url_encoded = TRUE])

Parameter Type Description
$str String Input string
$url_encoded Bool Whether to remove URL-encoded characters as well
Returns String Sanitized string

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


// Returns: 'Javascript'


Parameter Type Description
$var Mixed Variable to escape (string or array)
Returns Mixed HTML escaped string(s)

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).


Parameter Type Description
Returns Array An associative array of file types

This function returns a reference to the MIMEs array from system/ee/legacy/config/mimes.php.


Parameter Type Description
Returns Bool TRUE if currently using HTTP-over-SSL, FALSE if not

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