Global variables

index.php sets up these globals before it runs a controller. Declare the ones a module needs:

global $mysqli, $redis, $session, $settings;

See Modules/input/input_controller.php for a typical list.

$settings

Settings array. process_settings.php merges settings.ini (or settings.php) over default-settings.php. See example.settings.ini for the sections.

$path

Base URL of the Emoncms install, for example http://localhost/emoncms/. view() also passes it to every view.

$mysqli

A mysqli connection to the Emoncms database, from $settings['sql']. Use prepared statements.

$redis

A Redis instance when $settings['redis']['enabled'] is true, otherwise false. Emoncms uses Redis to cache input and feed metadata and API keys, and to buffer feed writes on low-write systems. Code that uses Redis must work when $redis is false.

If Redis is enabled but the connection fails, index.php stops with an error. prefix, auth and dbnum in $settings['redis'] set the key prefix, password and database number.

$route

A Route object, defined in route.php. For the URL:

http://server/controller/action/subaction/subaction2.format?name=value

the properties are:

$route->controller   // controller
$route->action       // action
$route->subaction    // subaction
$route->subaction2   // subaction2
$route->format       // format: html (default), json, text, md or csv
$route->method       // GET, POST, ...

$session

Array describing the current session. Set by User::emon_session_start() for a web login, or by User::apikey_session() for an API key.

Key	Meaning
`userid`	User id
`username`	Username. `API` for an API key session
`read`	1 if the session can read
`write`	1 if the session can write
`admin`	1 for an admin session
`lang`	Language. `en` for API key sessions
`timezone`	User timezone
`startingpage`	Page to open after login
`gravatar`	Gravatar address
`cookielogin`	1 if logged in with the remember me cookie
`emailverified`	Email verification state, when email verification is on
`apikey`	1 for an API key session
`public_userid`, `public_username`	Set when a page is viewed through a public username URL, such as `username/dashboard/view`

$user

A User object from Modules/user/user_model.php. Use it for login, API keys and user details such as username, email, language and timezone.

$log

An EmonLogger. Create one per file with new EmonLogger(__FILE__). Logs go to emoncms.log in $settings['log']['location'].

$param

A Param object from param.php. Reads request parameters, including decrypted parameters from an encrypted input request.

Translations

tr() and ctx_tr() read $GLOBALS['language'] and $GLOBALS['translations']. See Developing a new module.