库

本章将告诉您，如何让您的库可以通过 Composer 进行安装。

每个项目都是一个软件包

只要目录中存在一个 composer.json 文件，该目录就是一个包。 当您通过 require 向您的项目添加依赖时，您就是在制作一个依赖于其他软件包的软件包。 您的项目和一个库唯一的区别是，您的项目是一个没有名字的包。

为了使这个软件包可以安装，您需要给它一个名字。您可以通过在 composer.json 中添加 name 属性来执行此操作：

  1. {
  2.     "name": "acme/hello-world",
  3.     "require": {
  4.         "monolog/monolog": "1.0.*"
  5.     }
  6. }

在这种情况下，项目名称是 acme/hello-world，而 acme 是所有者名称。提供所有者名称是强制性的。

注意： 如果您不知道如何使用所有者名称，那么您的 GitHub 用户名通常是一个不错的选择。 虽然软件包名称不区分大小写，但惯例全部为小写字母并且为了分词而使用中横线。

库的版本控制

在绝大多数情况下，您将使用某种类型的版本控制系统（如 git，svn，hg 或 fossil）来维护您的库。 在这些情况下，Composer 会推断版本控制系统中的版本，并且您不应该在 composer.json 文件中直接指定版本。 （请参阅 版本与约束 一文，以了解 Composer 如何使用版本控制系统中的分支和标签来解析版本限制。）

如果您手动维护软件包（即没有版本控制系统），则需要通过 version 在 composer.json 文件中添加值来明确指定版本：

  1. {
  2.     "version": "1.0.0"
  3. }

注意： 当您添加一个硬性的版本号到版本控制系统中时，版本将与标签名称冲突。Composer 将无法确定版本号。 When you add a hardcoded version to a VCS, the version will conflict with tag names. Composer will not be able to determine the version number.

VCS Versioning

Composer uses your VCS’s branch and tag features to resolve the version constraints you specify in your require field to specific sets of files. When determining valid available versions, Composer looks at all of your tags and branches and translates their names into an internal list of options that it then matches against the version constraint you provided.

For more on how Composer treats tags and branches and how it resolves package version constraints, read the versions article.

Lock file

For your library you may commit the composer.lock file if you want to. This can help your team to always test against the same dependency versions. However, this lock file will not have any effect on other projects that depend on it. It only has an effect on the main project.

If you do not want to commit the lock file and you are using git, add it to the .gitignore.

Publishing to a VCS

Once you have a VCS repository (version control system, e.g. git) containing a composer.json file, your library is already composer-installable. In this example we will publish the acme/hello-world library on GitHub under github.com/username/hello-world.

Now, to test installing the acme/hello-world package, we create a new project locally. We will call it acme/blog. This blog will depend on acme/hello-world, which in turn depends on monolog/monolog. We can accomplish this by creating a new blog directory somewhere, containing a composer.json:

  1. {
  2.     "name": "acme/blog",
  3.     "require": {
  4.         "acme/hello-world": "dev-master"
  5.     }
  6. }

The name is not needed in this case, since we don’t want to publish the blog as a library. It is added here to clarify which composer.json is being described.

Now we need to tell the blog app where to find the hello-world dependency. We do this by adding a package repository specification to the blog’s composer.json:

  1. {
  2.     "name": "acme/blog",
  3.     "repositories": [
  4.         {
  5.             "type": "vcs",
  6.             "url": "https://github.com/username/hello-world"
  7.         }
  8.     ],
  9.     "require": {
  10.         "acme/hello-world": "dev-master"
  11.     }
  12. }

For more details on how package repositories work and what other types are available, see Repositories.

That’s all. You can now install the dependencies by running Composer’s install command!

Recap: Any git/svn/hg/fossil repository containing a composer.json can be added to your project by specifying the package repository and declaring the dependency in the require field.

Publishing to packagist

Alright, so now you can publish packages. But specifying the VCS repository every time is cumbersome. You don’t want to force all your users to do that.

The other thing that you may have noticed is that we did not specify a package repository for monolog/monolog. How did that work? The answer is Packagist.

Packagist is the main package repository for Composer, and it is enabled by default. Anything that is published on Packagist is available automatically through Composer. Since Monolog is on Packagist, we can depend on it without having to specify any additional repositories.

If we wanted to share hello-world with the world, we would publish it on Packagist as well. Doing so is really easy.

You simply visit Packagist and hit the “Submit” button. This will prompt you to sign up if you haven’t already, and then allows you to submit the URL to your VCS repository, at which point Packagist will start crawling it. Once it is done, your package will be available to anyone!

← Basic usage | Command-line interface →