Global Functions and Constants

CodeIgniter provides a few functions and variables that are globally defined, and are available to you at any point. These do not require loading any additional libraries or helpers.

Global Functions

Service Accessors

  • $key (string) – The cache name of the item to retrieve from cache (Optional)

Either the cache object, or the item retrieved from the cache

Return type:


If no $key is provided, will return the Cache engine instance. If a $key is provided, will return the value of $key as stored in the cache currently, or null if no value is found.


$foo = cache('foo');
$cache = cache();
  • $name (string) – Cookie name
  • $value (string) – Cookie value
  • $options (array) – Cookie options
Return type:



Cookie instance



Simpler way to create a new Cookie instance.

cookies([array $cookies = [][, bool $getGlobal = true]])
  • $cookies (array) – If getGlobal is false, this is passed to CookieStore’s constructor.
  • $getGlobal (bool) – If false, creates a new instance of CookieStore.
Return type:



Instance of CookieStore saved in the current Response, or a new CookieStore instance.

Fetches the global CookieStore instance held by Response.

env($key[, $default = null])
  • $key (string) – The name of the environment variable to retrieve
  • $default (mixed) – The default value to return if no value is found.

The environment variable, the default value, or null.

Return type:


Used to retrieve values that have previously been set to the environment, or return a default value if it is not found. Will format boolean values to actual booleans instead of string representations.

Especially useful when used in conjunction with .env files for setting values that are specific to the environment itself, like database settings, API keys, etc.

esc($data[, $context = 'html'[, $encoding]])
  • $data (string|array) – The information to be escaped.
  • $context (string) – The escaping context. Default is ‘html’.
  • $encoding (string) – The character encoding of the string.

The escaped data.

Return type:


Escapes data for inclusion in web pages, to help prevent XSS attacks. This uses the Laminas Escaper library to handle the actual filtering of the data.

If $data is a string, then it simply escapes and returns it. If $data is an array, then it loops over it, escaping each ‘value’ of the key/value pairs.

Valid context values: html, js, css, url, attr, raw

  • $filename (string|array) – The name of the helper file to load, or an array of names.

Loads a helper file.

For full details, see the Helper Functions page.

lang($line[, $args[, $locale]])
  • $line (string) – The line of text to retrieve
  • $args (array) – An array of data to substitute for placeholders.
  • $locale (string) – Specify a different locale to be used instead of default one.

Retrieves a locale-specific file based on an alias string.

For more information, see the Localization page.

model($name[, $getShared = true[, &$conn = null]])
  • $name (string) –
  • $getShared (boolean) –
  • $conn (ConnectionInterface|null) –

More simple way of getting model instances

Return type:


old($key[, $default = null[, $escape = 'html']])
  • $key (string) – The name of the old form data to check for.
  • $default (mixed) – The default value to return if $key doesn’t exist.
  • $escape (mixed) – An escape context or false to disable it.

The value of the defined key, or the default value.

Return type:


Provides a simple way to access “old input data” from submitting a form.


// in controller, checking form submittal
if (! $model->save($user))
    // 'withInput' is what specifies "old data"
    // should be saved.
    return redirect()->back()->withInput();

// In the view
<input type="email" name="email" value="<?= old('email') ?>">
// Or with arrays
<input type="email" name="user[email]" value="<?= old('') ?>">


If you are using the form helper, this feature is built-in. You only need to use this function when not using the form helper.

  • $key (string) – The name of the session item to check for.

An instance of the Session object if no $key, the value found in the session for $key, or null.

Return type:


Provides a convenient way to access the session class and to retrieve a stored value. For more information, see the Sessions page.

  • $name (string) – The name of the benchmark point.

The Timer instance

Return type:


A convenience method that provides quick access to the Timer class. You can pass in the name of a benchmark point as the only parameter. This will start timing from this point, or stop timing if a timer with this name is already running.


// Get an instance
$timer = timer();

// Set timer start and stop points
timer('controller_loading');    // Will start the timer
. . .
timer('controller_loading');    // Will stop the running timer
view($name[, $data[, $options]])
  • $name (string) – The name of the file to load
  • $data (array) – An array of key/value pairs to make available within the view.
  • $options (array) – An array of options that will be passed to the rendering class.

The output from the view.

Return type:


Grabs the current RendererInterface-compatible class and tells it to render the specified view. Simply provides a convenience method that can be used in Controllers, libraries, and routed closures.

Currently, these options are available for use within the $options array:

  • saveData specifies that data will persistent between multiple calls to view() within the same request. If you do not want the data to be persisted, specify false.
  • cache specifies the number of seconds to cache the view for. See Caching Views for the details.
  • debug can be set to false to disable the addition of debug code for Debug Toolbar.

The $option array is provided primarily to facilitate third-party integrations with libraries like Twig.


$data = ['user' => $user];

echo view('user_profile', $data);

For more details, see the Views page.

view_cell($library[, $params = null[, $ttl = 0[, $cacheName = null]]])
  • $library (string) –
  • $params (null) –
  • $ttl (integer) –
  • $cacheName (string|null) –

View cells are used within views to insert HTML chunks that are managed by other classes.

Return type:


For more details, see the View Cells page.

Miscellaneous Functions

Returns:The timezone the application has been set to display dates in.
Return type:string

Returns the timezone the application has been set to display dates in.

Returns:The name of the current CSRF token.
Return type:string

Returns the name of the current CSRF token.

Returns:The name of the header for current CSRF token.
Return type:string

The name of the header for current CSRF token.

Returns:The current value of the CSRF hash.
Return type:string

Returns the current CSRF hash value.

Returns:A string with the HTML for hidden input with all required CSRF information.
Return type:string

Returns a hidden input with the CSRF information already inserted:

<input type="hidden" name="{csrf_token}" value="{csrf_hash}">
Returns:A string with the HTML for meta tag with all required CSRF information.
Return type:string

Returns a meta tag with the CSRF information already inserted:

<meta name="{csrf_header}" content="{csrf_hash}">
force_https($duration = 31536000[, $request = null[, $response = null]])
  • $duration (int) – The number of seconds browsers should convert links to this resource to HTTPS.
  • $request (RequestInterface) – An instance of the current Request object.
  • $response (ResponseInterface) – An instance of the current Response object.

Checks to see if the page is currently being accessed via HTTPS. If it is, then nothing happens. If it is not, then the user is redirected back to the current URI but through HTTPS. Will set the HTTP Strict Transport Security header, which instructs modern browsers to automatically modify any HTTP requests to HTTPS requests for the $duration.

  • $function_name (string) – Function to check for

true if the function exists and is safe to call, false otherwise.

Return type:


Returns:true if the script is being executed from the command line or false otherwise.
Return type:bool
  • $file (string) – The filename being checked.

true if you can write to the file, false otherwise.

Return type:


log_message($level, $message[, $context])
  • $level (string) – The level of severity
  • $message (string) – The message that is to be logged.
  • $context (array) – An associative array of tags and their values that should be replaced in $message

true if was logged successfully or false if there was a problem logging it

Return type:


Logs a message using the Log Handlers defined in app/Config/Logger.php.

Level can be one of the following values: emergency, alert, critical, error, warning, notice, info, or debug.

Context can be used to substitute values in the message string. For full details, see the Logging Information page.

redirect(string $route)
  • $route (string) – The reverse-routed or named route to redirect the user to.

Returns a RedirectResponse instance allowing you to easily create redirects:

// Go back to the previous page
return redirect()->back();

// Go to specific URI
return redirect()->to('/admin');

// Go to a named route
return redirect()->route('named_route');

// Keep the old input values upon redirect so they can be used by the `old()` function
return redirect()->back()->withInput();

// Set a flash message
return redirect()->back()->with('foo', 'message');

// Copies all cookies from global response instance
return redirect()->back()->withCookies();

// Copies all headers from the global response instance
return redirect()->back()->withHeaders();

When passing an argument into the function, it is treated as a named/reverse-routed route, not a relative/full URI, treating it the same as using redirect()->route():

// Go to a named/reverse-routed URI
return redirect('named_route');
remove_invisible_characters($str[, $urlEncoded = true])
  • $str (string) – Input string
  • $urlEncoded (bool) – Whether to remove URL-encoded characters as well

Sanitized string

Return type:


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


// Returns: 'Javascript'
route_to($method[, ...$params])
  • $method (string) – The named route alias, or name of the controller/method to match.
  • $params (mixed) – One or more parameters to be passed to be matched in the route.

Generates a URI relative to the domain name (not baseUrl) for you based on either a named route alias, or a controller::method combination. Will take parameters into effect, if provided.

For full details, see the URI Routing page.

service($name[, ...$params])
  • $name (string) – The name of the service to load
  • $params (mixed) – One or more parameters to pass to the service method.

An instance of the service class specified.

Return type:


Provides easy access to any of the Services defined in the system. This will always return a shared instance of the class, so no matter how many times this is called during a single request, only one class instance will be created.


$logger = service('logger');
$renderer = service('renderer', APPPATH.'views/');
single_service($name[, ...$params])
  • $name (string) – The name of the service to load
  • $params (mixed) – One or more parameters to pass to the service method.

An instance of the service class specified.

Return type:


Identical to the service() function described above, except that all calls to this function will return a new instance of the class, where service returns the same instance every time.

  • $item (string) – Config item name

The configuration item or null if the item doesn’t exist

Return type:


Fetch a config file item with slash appended (if not empty)

stringify_attributes($attributes[, $js])
  • $attributes (mixed) – string, array of key value pairs, or object
  • $js (boolean) – true if values do not need quotes (Javascript-style)

String containing the attribute key/value pairs, comma-separated

Return type:


Helper function used to convert a string, array, or object of attributes to a string.

Global Constants

The following constants are always available anywhere within your application.

Core Constants

constant APPPATH

The path to the app directory.

constant ROOTPATH

The path to the project root directory. Just above APPPATH.


The path to the system directory.

constant FCPATH

The path to the directory that holds the front controller.

constant WRITEPATH

The path to the writable directory.

Time Constants

constant SECOND

Equals 1.

constant MINUTE

Equals 60.

constant HOUR

Equals 3600.

constant DAY

Equals 86400.

constant WEEK

Equals 604800.

constant MONTH

Equals 2592000.

constant YEAR

Equals 31536000.

constant DECADE

Equals 315360000.