ExpressionEngine Docs

# Constants Reference

- Path Constants
- Version Constants
- URL Constants
- HTML Constants
- Request Constants
- Filesystem Mode Constants
- Others

The ExpressionEngine core defines a variety of constants to ensure consistency in several aspects. Please be aware that some of the constants may not be defined, or have different meaning, in the context of the ExpressionEngine installer.

## Path Constants

- `SELF` - Name of the bootstrap file
- `FCPATH` - Path to the bootstrap file
- `SYSDIR` - Name of the system directory
- `SYSPATH` - Path of the system directory
- `APPPATH` and `BASEPATH` - Path to the `system/ee/legacy` directory
- `PATH_ADDONS` - Path to the first-party addons directory
- `PATH_THEMES` - Path to the themes directory
- `PATH_RTE` - Path to the first party RTE tools directory
- `PATH_MBR_THEMES` - Path to the member themes directory
- `PATH_CP_GBL_IMG` - Path to the global image directory
- `PATH_JAVASCRIPT` - Path to the javascript directory
- `PATH_JQUERY` - Path to the jQuery directory
- `PATH_THIRD` - Path to third-party addons directory
- `PATH_THIRD_THEMES` - Path to the third-party themes directory

## Version Constants

- `APP_NAME` - Application Name
- `APP_VER` - Version number
- `APP_BUILD` - Build number

## URL Constants

- `BASE` - Base URL to the control panel
- `AMP` - `&amp;`
- `QUERY_MARKER` - Question mark if forcing query strings, blank otherwise
- `URL_THEMES` - URL to the theme folder
- `URL_THIRD_THEMES` - URL to the third-party theme folder

## HTML Constants

- `NBS` - `&nbsp;`
- `BR` - `<br />`
- `NL` - `\\n`

## Request Constants

- `REQ` - One of: `'PAGE'`, `'CP'`, `'ACT'`
- `AJAX_REQUEST` - (`bool`) `TRUE` if request came from one of jQuery’s ajax functions

## Filesystem Mode Constants

These constants are located in `expressionengine/config/constants.php`, and are user configurable to their hosts’ requirements. You should always use these constants for creating and writing to files so that you do not have to worry about which permissions to use. Listed alongside each is their default equivalency.

- `FILE_READ_MODE` - Equivalent to `0644`
- `FILE_WRITE_MODE` - Equivalent to `0666`
- `DIR_READ_MODE` - Equivalent to `0755`
- `DIR_WRITE_MODE` - Equivalent to `0777`
- `FOPEN_READ` - Equivalent to `rb`
- `FOPEN_READ_WRITE` - Equivalent to `r+b`
- `FOPEN_WRITE_CREATE_DESTRUCTIVE` - Equivalent to `wb`
- `FOPEN_READ_WRITE_CREATE_DESTRUCTIVE` - Equivalent to `w+b`
- `FOPEN_WRITE_CREATE` - Equivalent to `ab`
- `FOPEN_READ_WRITE_CREATE` - Equivalent to `a+b`
- `FOPEN_WRITE_CREATE_STRICT` - Equivalent to `xb`
- `FOPEN_READ_WRITE_CREATE_STRICT` - Equivalent to `x+b`

## Others

- `LD` - Left template tag delimiter (usually `{`)
- `RD` - Right template tag delimiter (usually `}`)
- `DEBUG` - (`bool`) `TRUE` if `$debug` is set to 1
- `CSRF_TOKEN` - CSRF token, blank if csrf protection is disabled.
- `XID_SECURE_HASH` - previous name of `CSRF_TOKEN`
- `MASKED_CP` - (`bool`) `TRUE` if the CP is masked for this request
- `EXT` - File extension (`.php`)
- `UTF8_ENABLED` - Server has proper UTF-8 support
- `MB_ENABLED` - Server has multibyte function support
- `PASSWORD_MAX_LENGTH` - Maximum number of characters for a password.