Note: This section is under development.
Yii2 uses Composer as its dependency management tool. Composer is a PHP utility that can automatically handle the installation of needed libraries and extensions, thereby keeping those third-party resources up to date while absolving you of the need to manually manage the project's dependencies.
In order to install Composer, check the official guide for your operating system:
All of the details can be found in the guide, but you'll either download Composer directly from http://getcomposer.org/, or run the following command:
curl -s http://getcomposer.org/installer | php
We strongly recommend a global composer installation.
The act of installing a Yii application with
composer.phar create-project --stability dev yiisoft/yii2-app-basic
creates a new root directory for your project along with the composer.json
and compoer.lock
file.
While the former lists the packages, which your application requires directly together with a version constraint, while the latter keeps track of all installed packages and their dependencies in a specific revision. Therefore the composer.lock
file should also be committed to your version control system.
These two files are strongly linked to the two composer commands update
and install
.
Usually, when working with your project, such as creating another copy for development or deployment, you will use
composer.phar install
to make sure you get exactly the same packages and versions as specified in composer.lock
.
Only if want to intentionally update the packages in your project you should run
composer.phar update
As an example, packages on dev-master
will constantly get new updates when you run update
, while running install
won't, unless you've pulled an update of the composer.lock
file.
There are several paramaters available to the above commands. Very commonly used ones are --no-dev
, which would skip packages in the require-dev
section and --prefer-dist
, which downloads archives if available, instead of checking out repositories to your vendor
folder.
Composer commands must be executed within your Yii project's directory, where the
composer.json
file can be found. Depending upon your operating system and setup, you may need to provide paths to the PHP executable and to thecomposer.phar
script.
To add two new packages to your project run the follwing command:
composer.phar require "michelf/php-markdown:>=1.3" "ezyang/htmlpurifier:>4.5.0"
This will resolve the dependencies and then update your composer.json
file.
The above example says that a version greater than or equal to 1.3 of Michaelf's PHP-Markdown package is required
and version 4.5.0 or greater of Ezyang's HTMLPurifier.
For details of this syntax, see the official Composer documentation.
The full list of available Composer-supported PHP packages can be found at packagist. You may also search packages interactively just by entering composer.phar require
.
You may also edit the composer.json
file manually. Within the require
section, you specify the name and version of each required package, same as with the command above.
{
"require": {
"michelf/php-markdown": ">=1.4",
"ezyang/htmlpurifier": ">=4.6.0"
}
}
Once you have edited the composer.json
, you can invoke Composer to download the updated dependencies. Run
composer.phar update michelf/php-markdown ezyang/htmlpurifier
afterwards.
Depending on the package additional configuration may be required (eg. you have to register a module in the config), but autoloading of the classes should be handled by composer.
Yii always comes with the latest version of a required library that it is compatible with, but allows you to use an older version if you need to.
A good example for this is jQuery which has dropped old IE browser support in version 2.x. When installing Yii via composer the installed jQuery version will be the latest 2.x release. When you want to use jQuery 1.10 because of IE browser support you can adjust your composer.json by requiring a specific version of jQuery like this:
{
"require": {
...
"yiisoft/jquery": "1.10.*"
}
}
If you're using WAMP check this answer at StackOverflow.
Either install git or try adding --prefer-dist
to the end of install
or update
command.
Short answer: No. Long answer, see here.