Common system constants and system variables in thinkphp

-------------------------------------- System variables and constants used in the template ----------------------------------------
(1) System Variables: Output System variables in the template, including server, env, session, post, get, request, and cookie.
{$ Think. server. script_name} // output the $ _ SERVER variable.
{$ Think. session. session_id | md5} // output the $ _ SESSION variable.
{$ Think. get. pageNumber} // output the $ _ GET variable.
{$ Think. cookie. name} // output $ _ COOKIE variable

The preceding method can also be written as follows:
{$ _ SERVER. script_name} // output $ _ SERVER variable
{$ _ SESSION. session_id | md5} // output the $ _ SESSION variable.
{$ _ GET. pageNumber} // output the $ _ GET variable.
{$ _ COOKIE. name} // output $ _ COOKIE variable

System constant:Output with $ Think. const
Note: server, cookie, and config are case-insensitive, but variables are case-sensitive. For example:
{$ Think. server. script_name} is equivalent to {$ Think. SERVER. script_name }.
SESSION and COOKIE support two-dimensional array output

For example:
{$ Think. CONFIG. user. user_name}
{$ Think. session. user. user_name}
The system does not support array output of more than three dimensions.

(2) Language variables:Current language definition value of the output project

{$ Think. lang. page_error}
{$ Think. const. MODULE_NAME}

Or directly use
{$ Think. MODULE_NAME}

(3) special variables:Constants defined internally by the ThinkPHP System

{$ Think. version} // version
{$ Think. now} // current time
{$ Think. template | basename} // template page
{$ Think. LDELIM} // template tag start symbol
{$ Think. RDELIM} // template tag end symbol
(4) configuration parameters: Configuration Parameter Values of the output project

{$ Think. config. db_charset}

The output value is the same as that of C ('db _ charset.

---------------------------------------- System constant used in Action ----------------------------------------
THINK_PATH // ThinkPHP system directory
APP_PATH // current project directory
APP_NAME // current project name
MODULE_NAME // name of the current Module
ACTION_NAME // current operation name
TMPL_PATH // Project template directory
LIB_PATH // directory of the Project class library
CACHE_PATH // Project template cache directory
CONFIG_PATH // project configuration file directory
LOG_PATH // project log file directory
LANG_PATH // project language file directory
TEMP_PATH // temporary project file directory
PLUGIN_PATH // directory of the Project plug-in file
VENDOR_PATH // third-party class library directory
DATA_PATH // project data file directory
IS_APACHE // whether it belongs to Apache
IS_IIS // whether it belongs to IIS
IS_WIN // whether it belongs to the Windows Environment
IS_LINUX // whether it belongs to the Linux environment
IS_FREEBSD // whether it belongs to the FreeBsd Environment
NOW_TIME // current Timestamp
MEMORY_LIMIT_ON // whether the memory usage limit exists
OUTPUT_GZIP_ON // whether to enable output Compression
MAGIC_QUOTES_GPC // MAGIC_QUOTES_GPC
THINK_VERSION // ThinkPHP version
LANG_SET // browser Language
TEMPLATE_NAME // name of the current template
TEMPLATE_PATH // current template path
_ ROOT _ // website ROOT directory address
_ APP _ // current project (entry file) Address
_ URL _ // address of the current Module
_ ACTION _ // current operation address
_ SELF _ // current URL
TMPL_FILE_NAME // default Template Name (including path) for the current operation)
WEB_PUBLIC_URL // public website directory
APP_PUBLIC_URL // Project Public template directory
---------------------------------------- System constant used in the template ----------------------------------------
_ ROOT _ // website ROOT directory address
_ APP _ // current project (entry file) Address
_ URL _ // address of the current Module
_ ACTION _ // current operation address
_ SELF _ // current URL
_ PUBLIC _ // PUBLIC website directory
../Public (Case Insensitive) // Project Public template directory
Note: When we use constants, we can view the source code in the browser after the template is loaded. We can observe some URLs that use constants and we will find a phenomenon that we cannot see the IP address of the server, the URL is from
Why can I access the corresponding Controller correctly? In fact, this is a joke from the browser. When we move the mouse over the URL, right-click and copy
URL, paste it to another place, and the server's ip address will be displayed. It can be seen that the server ip address is included in the constant used in the URL.
---------------------------------------- Custom constant ----------------------------------------
Create Common. php under the common folder in the project folder (for example, Home)
Add the following statement:
Define ('xxx', XXX); // The first parameter is the constant name, and the second parameter is the constant value.