Merge remote-tracking branch 'mvriel/custom-installer-doc'
Jordi Boggiano
commit
c9ea542ccc
|
|
@ -0,0 +1,156 @@
|
|||
# Custom installers
|
||||
|
||||
## Synopsis
|
||||
|
||||
At times it may be necessary for a package to require additional actions during
|
||||
installation, such as installing packages outside of the default `vendor`
|
||||
library.
|
||||
|
||||
In these cases you could consider creating a Custom Installer to handle your
|
||||
specific logic.
|
||||
|
||||
## Calling a Custom Installer
|
||||
|
||||
Suppose that your project already has a Custom Installer for specific modules
|
||||
then invoking that installer is a matter of defining the correct [type][1] in
|
||||
your package file.
|
||||
|
||||
> _See the next chapter for an instruction how to create Custom Installers._
|
||||
|
||||
Every Custom Installer defines which [type][1] string it will recognize. Once
|
||||
recognized it will completely override the default installer and only apply its
|
||||
own logic.
|
||||
|
||||
An example use-case would be:
|
||||
|
||||
> phpDocumentor features Templates that need to be installed outside of the
|
||||
> default /vendor folder structure. As such they have chosen to adopt the
|
||||
> `phpdocumentor-template` [type][1] and create a Custom Installer to send
|
||||
> these templates to the correct folder.
|
||||
|
||||
An example composer.json of such a template would be:
|
||||
|
||||
{
|
||||
"name": "phpdocumentor/template-responsive",
|
||||
"type": "phpdocumentor-template"
|
||||
}
|
||||
|
||||
With the package definition shown in the example will any project that includes
|
||||
this package try to find an appropriate installer and use that to execute this
|
||||
[type][1].
|
||||
|
||||
> **IMPORTANT**: the host project will not recognize the [type][1] if the
|
||||
> installer's package is not included. Thus a composer.json consuming a template
|
||||
> package will always need to _require_ the template's installer as well.
|
||||
|
||||
## Creating an Installer
|
||||
|
||||
A Custom Installer is a defined as a class that implements the
|
||||
[\Composer\Installer\InstallerInterface][3] and is contained in a Composer
|
||||
package that has the [type][1] `composer-installer`.
|
||||
|
||||
A basic Installer would thus compose of two files:
|
||||
|
||||
1. the package file: composer.json
|
||||
2. The Installer class, i.e.: \Composer\Installer\MyInstaller.php
|
||||
|
||||
> **NOTE**: _The namespace does not need to be \Composer\Installer, it may be
|
||||
> anything that you would want._
|
||||
|
||||
### composer.json
|
||||
|
||||
The package file is the same as any other package file but with the following
|
||||
requirements:
|
||||
|
||||
1. the [type][1] attribute must be `composer-installer`.
|
||||
2. the [extra][2] attribute must contain an element `class` defining the
|
||||
class name of the installer (including namespace).
|
||||
|
||||
Example:
|
||||
|
||||
{
|
||||
"name": "phpdocumentor/template-installer",
|
||||
"type": "composer-installer",
|
||||
"license": "MIT",
|
||||
"autoload": {
|
||||
"psr-0": {"phpDocumentor\\Composer": "src/"}
|
||||
},
|
||||
"extra": {"class": "\\phpDocumentor\\Composer\\TemplateInstaller"}
|
||||
}
|
||||
|
||||
### The Custom Installer class
|
||||
|
||||
The class that executes the custom installation should implement the
|
||||
[\Composer\Installer\InstallerInterface][3] (or extend another installer that
|
||||
implements that interface).
|
||||
|
||||
The class may be placed in any location and have any name, as long as it
|
||||
matches the `extra.class` element in the package definition.
|
||||
It will also define the [type][1] string as it will be recognized by packages
|
||||
that will use this installer in the `supports()` method.
|
||||
|
||||
> **NOTE**: _choose your [type][1] name carefully, it is recommended to follow
|
||||
> the format: `vendor-type`_. For example: `phpdocumentor-template`.
|
||||
|
||||
The InstallerInterface class defines the following methods (please see the
|
||||
source for the exact signature):
|
||||
|
||||
* **supports()**, here you test whether the passed [type][1] matches the name
|
||||
that you declared for this installer (see the example).
|
||||
* **isInstalled()**, determines whether a supported package is installed or not.
|
||||
* **install()**, here you can determine the actions that need to be executed
|
||||
upon installation.
|
||||
* **update()**, here you define the behavior that is required when Composer is
|
||||
invoked with the update argument.
|
||||
* **uninstall()**, here you can determine the actions that need to be executed
|
||||
when the package needs to be removed.
|
||||
* **getInstallPath()**, this method should return the location where the
|
||||
package is to be installed, _relative from the location of composer.json._
|
||||
|
||||
Example:
|
||||
|
||||
namespace phpDocumentor\Composer;
|
||||
|
||||
use Composer\Package\PackageInterface;
|
||||
use Composer\Installer\LibraryInstaller;
|
||||
|
||||
class TemplateInstaller extends LibraryInstaller
|
||||
{
|
||||
/**
|
||||
* {@inheritDoc}
|
||||
*/
|
||||
public function getInstallPath(PackageInterface $package)
|
||||
{
|
||||
$prefix = substr($package->getPrettyName(), 0, 23);
|
||||
if ('phpdocumentor/template-' != $prefix) {
|
||||
throw new \InvalidArgumentException(
|
||||
'Unable to install template, phpdocumentor templates '
|
||||
.'should always start their package name with '
|
||||
.'"phpdocumentor/template-"'
|
||||
);
|
||||
}
|
||||
|
||||
return 'data/templates/'.substr($package->getPrettyName(), 23);
|
||||
}
|
||||
|
||||
/**
|
||||
* {@inheritDoc}
|
||||
*/
|
||||
public function supports($packageType)
|
||||
{
|
||||
return ('phpdocumentor-template' === $packageType);
|
||||
}
|
||||
}
|
||||
|
||||
The example demonstrates that it is quite simple to extend the
|
||||
[\Composer\Installer\LibraryInstaller][4] class to strip a prefix
|
||||
(`phpdocumentor/template-`) and use the remaining part to assemble a completely
|
||||
different installation path.
|
||||
|
||||
> _Instead of installing to `/vendor` will any package installed using this
|
||||
> Installer be put in the `/data/templates/<stripped name>` folder._
|
||||
|
||||
[1]: http://getcomposer.org/doc/04-schema.md#type
|
||||
[2]: http://getcomposer.org/doc/04-schema.md#extra
|
||||
[3]: https://github.com/composer/composer/blob/master/src/Composer/Installer/InstallerInterface.php
|
||||
[4]: https://github.com/composer/composer/blob/master/src/Composer/Installer/LibraryInstaller.php
|
||||
Loading…
Reference in New Issue