# Repositories This chapter will explain the concept of packages and repositories, what kinds of repositories are available, and how they work. ## Concepts Before we look at the different types of repositories that exist, we need to understand some of the basic concepts that composer is built on. ### Package Composer is a dependency manager. It installs packages locally. A package is essentially just a directory containing something. In this case it is PHP code, but in theory it could be anything. And it contains a package description which has a name and a version. The name and the version are used to identify the package. In fact, internally composer sees every version as a separate package. While this distinction does not matter when you are using composer, it's quite important when you want to change it. In addition to the name and the version, there is useful metadata. The information most relevant for installation is the source definition, which describes where to get the package contents. The package data points to the contents of the package. And there are two options here: dist and source. **Dist:** The dist is a packaged version of the package data. Usually a released version, usually a stable release. **Source:** The source is used for development. This will usually originate from a source code repository, such as git. You can fetch this when you want to modify the downloaded package. Packages can supply either of these, or even both. Depending on certain factors, such as user-supplied options and stability of the package, one will be preferred. ### Repository A repository is a package source. It's a list of packages/versions. Composer will look in all your repositories to find the packages your project requires. By default only the Packagist repository is registered in Composer. You can add more repositories to your project by declaring them in `composer.json`. Repositories are only available to the root package and the repositories defined in your dependencies will not be loaded. Read the [FAQ entry](faqs/why-can't-composer-load-repositories-recursively.md) if you want to learn why. ## Types ### Composer The main repository type is the `composer` repository. It uses a single `packages.json` file that contains all of the package metadata. This is also the repository type that packagist uses. To reference a `composer` repository, just supply the path before the `packages.json` file. In case of packagist, that file is located at `/packages.json`, so the URL of the repository would be `packagist.org`. For `example.org/packages.json` the repository URL would be `example.org`. #### packages The only required field is `packages`. The JSON structure is as follows: { "packages": { "vendor/package-name": { "dev-master": { @composer.json }, "1.0.x-dev": { @composer.json }, "0.0.1": { @composer.json }, "1.0.0": { @composer.json } } } } The `@composer.json` marker would be the contents of the `composer.json` from that package version including as a minimum: * name * version * dist or source Here is a minimal package definition: { "name": "smarty/smarty", "version": "3.1.7", "dist": { "url": "http://www.smarty.net/files/Smarty-3.1.7.zip", "type": "zip" } } It may include any of the other fields specified in the [schema](04-schema.md). #### notify_batch The `notify_batch` field allows you to specify an URL that will be called every time a user installs a package. The URL can be either an absolute path (that will use the same domain as the repository) or a fully qualified URL. An example value: { "notify_batch": "/downloads/" } For `example.org/packages.json` containing a `monolog/monolog` package, this would send a `POST` request to `example.org/downloads/` with following JSON request body: { "downloads": [ {"name": "monolog/monolog", "version": "1.2.1.0"}, ] } The version field will contain the normalized representation of the version number. This field is optional. #### includes For large repositories it is possible to split the `packages.json` into multiple files. The `includes` field allows you to reference these additional files. An example: { "includes": { "packages-2011.json": { "sha1": "525a85fb37edd1ad71040d429928c2c0edec9d17" }, "packages-2012-01.json": { "sha1": "897cde726f8a3918faf27c803b336da223d400dd" }, "packages-2012-02.json": { "sha1": "26f911ad717da26bbcac3f8f435280d13917efa5" } } } The SHA-1 sum of the file allows it to be cached and only re-requested if the hash changed. This field is optional. You probably don't need it for your own custom repository. #### stream options The `packages.json` file is loaded using a PHP stream. You can set extra options on that stream using the `options` parameter. You can set any valid PHP stream context option. See [Context options and parameters](http://php.net/manual/en/context.php) for more information. ### VCS VCS stands for version control system. This includes versioning systems like git, svn or hg. Composer has a repository type for installing packages from these systems. #### Loading a package from a VCS repository There are a few use cases for this. The most common one is maintaining your own fork of a third party library. If you are using a certain library for your project and you decide to change something in the library, you will want your project to use the patched version. If the library is on GitHub (this is the case most of the time), you can simply fork it there and push your changes to your fork. After that you update the project's `composer.json`. All you have to do is add your fork as a repository and update the version constraint to point to your custom branch. For version constraint naming conventions see [Libraries](02-libraries.md) for more information. Example assuming you patched monolog to fix a bug in the `bugfix` branch: { "repositories": [ { "type": "vcs", "url": "http://github.com/igorw/monolog" } ], "require": { "monolog/monolog": "dev-bugfix" } } When you run `php composer.phar update`, you should get your modified version of `monolog/monolog` instead of the one from packagist. It is possible to inline-alias a package constraint so that it matches a constraint that it otherwise would not. For more information [see the aliases article](articles/aliases.md). #### Using private repositories Exactly the same solution allows you to work with your private repositories at GitHub and BitBucket: { "require": { "vendor/my-private-repo": "dev-master" }, "repositories": [ { "type": "vcs", "url": "git@bitbucket.org:vendor/my-private-repo.git" } ] } The only requirement is the installation of SSH keys for a git client. #### Git alternatives Git is not the only version control system supported by the VCS repository. The following are supported: * **Git:** [git-scm.com](http://git-scm.com) * **Subversion:** [subversion.apache.org](http://subversion.apache.org) * **Mercurial:** [mercurial.selenic.com](http://mercurial.selenic.com) To get packages from these systems you need to have their respective clients installed. That can be inconvenient. And for this reason there is special support for GitHub and BitBucket that use the APIs provided by these sites, to fetch the packages without having to install the version control system. The VCS repository provides `dist`s for them that fetch the packages as zips. * **GitHub:** [github.com](https://github.com) (Git) * **BitBucket:** [bitbucket.org](https://bitbucket.org) (Git and Mercurial) The VCS driver to be used is detected automatically based on the URL. However, should you need to specify one for whatever reason, you can use `git`, `svn` or `hg` as the repository type instead of `vcs`. #### Subversion Options Since Subversion has no native concept of branches and tags, Composer assumes by default that code is located in `$url/trunk`, `$url/branches` and `$url/tags`. If your repository has a different layout you can change those values. For example if you used capitalized names you could configure the repository like this: { "repositories": [ { "type": "vcs", "url": "http://svn.example.org/projectA/", "trunk-path": "Trunk", "branches-path": "Branches", "tags-path": "Tags" } ] } ### PEAR It is possible to install packages from any PEAR channel by using the `pear` repository. Composer will prefix all package names with `pear-{channelName}/` to avoid conflicts. All packages are also aliased with prefix `pear-{channelAlias}/` Example using `pear2.php.net`: { "repositories": [ { "type": "pear", "url": "http://pear2.php.net" } ], "require": { "pear-pear2.php.net/PEAR2_Text_Markdown": "*", "pear-pear2/PEAR2_HTTP_Request": "*" } } In this case the short name of the channel is `pear2`, so the `PEAR2_HTTP_Request` package name becomes `pear-pear2/PEAR2_HTTP_Request`. > **Note:** The `pear` repository requires doing quite a few requests per > package, so this may considerably slow down the installation process. #### Custom vendor alias It is possible to alias PEAR channel packages with a custom vendor name. Example: Suppose you have a private PEAR repository and wish to use Composer to incorporate dependencies from a VCS. Your PEAR repository contains the following packages: * `BasePackage` * `IntermediatePackage`, which depends on `BasePackage` * `TopLevelPackage1` and `TopLevelPackage2` which both depend on `IntermediatePackage` Without a vendor alias, Composer will use the PEAR channel name as the vendor portion of the package name: * `pear-pear.foobar.repo/BasePackage` * `pear-pear.foobar.repo/IntermediatePackage` * `pear-pear.foobar.repo/TopLevelPackage1` * `pear-pear.foobar.repo/TopLevelPackage2` Suppose at a later time you wish to migrate your PEAR packages to a Composer repository and naming scheme, and adopt the vendor name of `foobar`. Projects using your PEAR packages would not see the updated packages, since they have a different vendor name (`foobar/IntermediatePackage` vs `pear-pear.foobar.repo/IntermediatePackage`). By specifying `vendor-alias` for the PEAR repository from the start, you can avoid this scenario and future-proof your package names. To illustrate, the following example would get the `BasePackage`, `TopLevelPackage1`, and `TopLevelPackage2` packages from your PEAR repository and `IntermediatePackage` from a Github repository: { "repositories": [ { "type": "git", "url": "https://github.com/foobar/intermediate.git" }, { "type": "pear", "url": "http://pear.foobar.repo", "vendor-alias": "foobar" } ], "require": { "foobar/TopLevelPackage1": "*", "foobar/TopLevelPackage2": "*" } } ### Package If you want to use a project that does not support composer through any of the means above, you still can define the package yourself by using a `package` repository. Basically, you define the same information that is included in the `composer` repository's `packages.json`, but only for a single package. Again, the minimum required fields are `name`, `version`, and either of `dist` or `source`. Here is an example for the smarty template engine: { "repositories": [ { "type": "package", "package": { "name": "smarty/smarty", "version": "3.1.7", "dist": { "url": "http://www.smarty.net/files/Smarty-3.1.7.zip", "type": "zip" }, "source": { "url": "http://smarty-php.googlecode.com/svn/", "type": "svn", "reference": "tags/Smarty_3_1_7/distribution/" }, "autoload": { "classmap": ["libs/"] } } } ], "require": { "smarty/smarty": "3.1.*" } } Typically you would leave the source part off, as you don't really need it. ## Hosting your own While you will probably want to put your packages on packagist most of the time, there are some use cases for hosting your own repository. * **Private company packages:** If you are part of a company that uses composer for their packages internally, you might want to keep those packages private. * **Separate ecosystem:** If you have a project which has its own ecosystem, and the packages aren't really reusable by the greater PHP community, you might want to keep them separate to packagist. An example of this would be wordpress plugins. When hosting your own package repository it is recommended to use a `composer` one. This is type that is native to composer and yields the best performance. There are a few tools that can help you create a `composer` repository. ### Packagist The underlying application used by packagist is open source. This means that you can just install your own copy of packagist, re-brand, and use it. It's really quite straight-forward to do. However due to its size and complexity, for most small and medium sized companies willing to track a few packages will be better off using Satis. Packagist is a Symfony2 application, and it is [available on GitHub](https://github.com/composer/packagist). It uses composer internally and acts as a proxy between VCS repositories and the composer users. It holds a list of all VCS packages, periodically re-crawls them, and exposes them as a composer repository. To set your own copy, simply follow the instructions from the [packagist github repository](https://github.com/composer/packagist). ### Satis Satis is a static `composer` repository generator. It is a bit like an ultra- lightweight, static file-based version of packagist. You give it a `composer.json` containing repositories, typically VCS and package repository definitions. It will fetch all the packages that are `require`d and dump a `packages.json` that is your `composer` repository. Check [the satis GitHub repository](https://github.com/composer/satis) and the [Satis article](articles/handling-private-packages-with-satis.md) for more information. ## Disabling Packagist You can disable the default Packagist repository by adding this to your `composer.json`: { "repositories": [ { "packagist": false } ] } ← [Schema](04-schema.md) | [Community](06-community.md) →