Composer Downloads Plugin

The "Downloads" plugin allows you to download extra files (*.zip or *.tar.gz) and extract them within your package.

Example

Suppose you publish a PHP package foo/bar which relies on an external artifact examplelib-0.1.zip. Place this configuration in the composer.json for foo/bar:

{
  "name": "foo/bar",
  "require": {
    "civicrm/composer-downloads-plugin": "~3 || ~4"
  },
  "extra": {
    "downloads": {
      "examplelib": {
        "url": "https://example.com/examplelib-0.1.zip",
        "path": "extern/examplelib",
        "ignore": ["test", "doc", ".*"]
      }
    }
  }
}

When a downstream user of foo/bar runs composer install, it will fetch and extract the zip file, creating vendor/foo/bar/extern/examplelib.

Release History

• v1.x: Original release of lastcall/composer-extra-files
• v2.x: Fork. Add test suite. Rename to composer-downloads-plugin (extra.downloads). Improve tracking/redownload behaviors. Add more download options. Expand docs.
• v3.x: Add support for composer v2.
• v4.x: Improve PHP 8.2+. Swap gitignore parser. Drop composer v1.

Evaluation

The primary strengths of composer-downloads-plugin are:

• Simple: It downloads a URL (ZIP/TAR file) and extracts it. It only needs to know two things: what to download (url) and where to put it (path). It runs as pure-PHP without any external dependencies.
• Fast: The logic does not require scanning, indexing, or mapping any large registries. The download system uses composer's built-in cache.
• Isolated: As the author of a package foo/bar, you define the content under the vendor/foo/bar folder. When others use foo/bar, there is no need for special instructions, no root-level configuration, no interaction with other packages.

The "Downloads" plugin is only a download mechanism. Use it to assimilate an external resource as part of a composer package.

The "Downloads" plugin is not a dependency management system. There is no logic to scan registries, resolve transitive dependencies, identify version-conflicts, etc among diverse external resources. If you need that functionality, then you may want a bridge to integrate composer with an external dependency management tool. A few good bridges to consider:

• Asset Packagist
• Composer Asset Plugin
• Composer Bower Plugin
• Foxy

Configuration: Properties

The extra.downloads section contains a list of files to download. Each extra-file has a symbolic ID (e.g. examplelib above) and some mix of properties:

• url: The URL to fetch the content from.

• path: The releative path where content will be extracted.

• type: (Optional) Determines how the download is handled

  • archive: The url references a zip or tarball which should be extracted at the given path. (Default for URLs involving *.zip, *.tar.gz, or *.tgz.)
  • file: The url should be downloaded to the given path. (Default for all other URLs.)
  • phar: The url references a PHP executable which should be installed at the given path.

• ignore: (Optional) A list of a files that should be omited from the extracted folder. (This supports a subset of .gitignore notation.)

• version: (Optional) A version number for the downloaded artifact. This has no functional impact on the lifecycle of the artifact, but it can affect the console output, and it can be optionally used as a variable when setting url or path.

Values in url and path support the following variables:

• {$id}: The symbolic identifier of the download. (In the introductory example, it would be examplelib.)
• {$version}: The displayed/simulated/pretty version number of the package.

Configuration: Defaults

You may set default properties for all downloads. Place them under *, as in:

{
  "extra": {
    "downloads": {
      "*": {
        "path": "bower_components/{$id}",
        "ignore": ["test", "tests", "doc", "docs"]
      },
      "jquery": {
        "url": "https://github.com/jquery/jquery-dist/archive/1.12.4.zip"
      },
      "jquery-ui": {
        "url": "https://github.com/components/jqueryui/archive/1.12.1.zip"
      }
    }
  }
}

This example will:

• Create bower_components/jquery (based on jQuery 1.12.4), minus any test/doc folders.
• Create bower_components/jquery-ui (based on jQueryUI 1.12.1), minus any test/doc folders.

Tips

• In each downloaded folder, this plugin will create a small metadata folder (.composer-downloads) to track the origin of the current code. If you modify the composer.json to use a different URL, then it will re-download the file.

• Download each extra file to a distinct path. Don't try to download into overlapping paths. (This has not been tested, but I expect downloads are not well-ordered, and you may find that updates require re-downloading.)

• What should you do if you normally download the extra-file as *.tar.gz but sometimes (for local dev) need to grab bleeding edge content from somewhere else? Simply delete the autodownloaded folder and replace it with your own. composer-downloads-plugin will detect that conflict (by virtue of the absent .composer-downloads) and leave your code in place (until you choose to get rid of it). To switch back, you can simply delete the code and run composer install again.

Known Limitations

If you use downloads in a root-project (or in symlinked dev repo), it will create+update downloads, but it will not remove orphaned items automatically. This could be addressed by doing a file-scan for .composer-downloads (and deleting any orphan folders). Since the edge-case is not particularly common right now, and since a file-scan could be time-consuming, it might make sense as a separate subcommand.

I believe the limitation does not affect downstream consumers of a dependency. In that case, the regular composer install/update/removal mechanics should take care of any nested downloads.

Automated Tests

The tests/ folder includes unit-tests and integration-tests written with PHPUnit. Each integration-test generates a new folder/project with a plausible, representative composer.json file and executes composer install. It checks the output has the expected files.

To run the tests, you will need composer and phpunit in the PATH.

[~/src/composer-downloads-plugin] which composer
/Users/myuser/bin/composer

[~/src/composer-downloads-plugin] which phpunit
/Users/myuser/bin/phpunit

[~/src/composer-downloads-plugin] phpunit
PHPUnit 5.7.27 by Sebastian Bergmann and contributors.

.....                                                               5 / 5 (100%)

Time: 40.35 seconds, Memory: 10.00MB

OK (5 tests, 7 assertions)

The integration tests can be a bit large/slow. To monitor the tests more closesly, set the DEBUG variable, as in:

[~/src/composer-downloads-plugin] env DEBUG=2 phpunit

Local Dev Harness

What if you want to produce an environment which uses the current plugin code - one where you can quickly re-run composer commands while iterating on code?

You may use any of the integration-tests to initialize a baseline environment:

env USE_TEST_PROJECT=$HOME/src/myprj DEBUG=2 phpunit tests/SniffTest.php