A

action

Action is a callable, class, or class method that handles a matched route and returns a response. Read more in "Actions".

alias

Alias is a string used by Yii to refer to the class or directory such as @app/vendor. Read more in "Aliases".

application

Application is an object that starts up, handles a request through configured middleware, and shuts down. Read more in "Application".

asset

Asset refers to a resource file. Typically, it contains JavaScript or CSS code but can be any static content accessed via HTTP. Read more in "Assets".

asset bundle

Asset bundle is a PHP class that declares a group of CSS, JavaScript, image, or font files that should be published and registered together. Read more in "Asset Bundles".

authentication

Authentication is the process of determining the identity of the current user. Read more in "Authentication".

authorization

Authorization is the process of checking whether an authenticated or anonymous user is allowed to perform an action. Read more in "Authorization".

autoloading

Autoloading is the process of loading PHP classes automatically when they are first used. Read more in "Class autoloading".

B

bootstrap

Bootstrap is application startup code that prepares services, configuration, and runtime state before request handling. Read more in "Configuration".

C

configuration

Configuration may refer either to the process of setting properties of an object or to a configuration file that stores settings for an object, or a class of objects. Read more in "Configuration".

container

Container is an object that creates services, resolves their dependencies, and returns configured instances. Read more in "DI container".

controller

Controller is a class that groups action methods for related routes. Read more in "Actions".

cookie

Cookie is a small piece of data stored by a browser and sent with later requests to the same site. Read more in "Cookies".

CSRF

CSRF means cross-site request forgery, an attack where another site tries to make a user's browser submit an unwanted request to your application. Read more in "Avoiding CSRF".

D

DI

Dependency injection is a programming technique where an object receives its dependencies from the outside. Read more in "Dependency injection and container".

E

entry script

Entry script is the first PHP script executed for a web or console application. Read more in "Entry scripts".

event

Event is an object that represents something that happened and can be passed to listeners. Read more in "Events".

H

handler

Handler is callable code selected by routing or middleware to process a request and produce a response. Read more in "Routing and URL generation".

I

installation

Installation is a process of preparing something to work either by following a readme file or by executing a specially prepared script. In the case of Yii, it's setting permissions and fulfilling software requirements.

L

layout

Layout is a view template that wraps page-specific content with shared page structure. Read more in "Working with layouts".

M

migration

Migration is a versioned PHP class that applies or reverts a database schema or data change. Read more in "Migrations".

middleware

Middleware is a processor in the request processing stack. Given a request, it may either produce a response or do some action and pass processing to the next middleware. Read more in "Middleware".

model

Model is an object that represents application data and usually contains validation or business rules for that data. Read more in "Working with forms".

module

The module is a namespace that groups some code based on a use-case. It's typically used within the main application and may contain any source code, define additional URL handlers or console commands.

N

namespace

Namespace refers to a PHP language feature to group multiple classes under a certain name.

P

package

A package usually refers to Composer package. It's code ready for reuse and redistribution installable automatically via a package manager.

parameter

Parameter is a configuration value that can be used by application or package config files. Read more in "Parameters".

Q

queue

A queue is a data structure that processes items in first-in, first-out order. Yii has a yiisoft/queue package.

R

request

Request is a PSR-7 object that represents an incoming HTTP message, including method, URI, headers, body, uploaded files, and attributes. Read more in "Request".

response

Response is a PSR-7 object that represents an outgoing HTTP message, including status code, headers, and body. Read more in "Response".

route

Route describes which request method and URL pattern should be handled by which action or middleware. Read more in "Routing and URL generation".

rule

The rule usually refers to a validation rule of the yiisoft/validator package. It holds a set of parameters for checking if a data set is valid. "Rule handler" does the actual processing.

S

service

Service is a focused object that performs application work or provides infrastructure behavior and is usually stored in the DI container. Read more in "Service components".

service provider

Service provider is a class that registers related service definitions for the DI container. Read more in "Service providers".

session

Session is server-side storage associated with a browser across multiple requests. Read more in "Sessions".

T

template

Template is a file used by a view or template engine to produce presentation output such as HTML. Read more in "Views".

V

vendor

A vendor is an organization or individual developer providing code in the form of packages. It also may refer to Composer's vendor directory.

view

View is responsible for presenting data to end users, usually by executing a template with provided data. Read more in "Views".

W

widget

Widget is a reusable view component that renders a piece of user interface. Read more in "Widgets".