Add temporary metadata for download size tracking

src/Composer/Downloader/FileDownloader.php

@@ -57,6 +57,13 @@ class FileDownloader implements DownloaderInterface, ChangeReportInterface
     protected $eventDispatcher;
     /** @var ProcessExecutor */
     protected $process;
+    /**
+     * @var array<string, int|string>
+     * @private
+     * @internal
+     */
+    public static $downloadMetadata = array();
+
     /**
      * @private this is only public for php 5.3 support in closures
      *
@@ -218,6 +225,7 @@ class FileDownloader implements DownloaderInterface, ChangeReportInterface
         $accept = function ($response) use ($cache, $package, $fileName, $self, &$urls) {
             $url = reset($urls);
             $cacheKey = $url['cacheKey'];
+            FileDownloader::$downloadMetadata[$package->getName()] = @filesize($fileName) ?: $response->getHeader('Content-Length') ?: '?';
 
             if ($cache && !$cache->isReadOnly()) {
                 $self->lastCacheWrites[$package->getName()] = $cacheKey;

src/Composer/Installer/InstallationManager.php

@@ -23,6 +23,7 @@ use Composer\DependencyResolver\Operation\UpdateOperation;
 use Composer\DependencyResolver\Operation\UninstallOperation;
 use Composer\DependencyResolver\Operation\MarkAliasInstalledOperation;
 use Composer\DependencyResolver\Operation\MarkAliasUninstalledOperation;
+use Composer\Downloader\FileDownloader;
 use Composer\EventDispatcher\EventDispatcher;
 use Composer\Util\Loop;
 use Composer\Util\Platform;
@@ -65,6 +66,7 @@ class InstallationManager
     public function reset()
     {
         $this->notifiablePackages = array();
+        FileDownloader::$downloadMetadata = array();
     }
 
     /**
@@ -662,10 +664,18 @@ class InstallationManager
 
                 $postData = array('downloads' => array());
                 foreach ($packages as $package) {
-                    $postData['downloads'][] = array(
+                    $packageNotification = array(
                         'name' => $package->getPrettyName(),
                         'version' => $package->getVersion(),
                     );
+                    if (strpos($repoUrl, 'packagist.org/') !== false) {
+                        if (isset(FileDownloader::$downloadMetadata[$package->getName()])) {
+                            $packageNotification['downloaded'] = FileDownloader::$downloadMetadata[$package->getName()];
+                        } else {
+                            $packageNotification['downloaded'] = false;
+                        }
+                    }
+                    $postData['downloads'][] = $packageNotification;
                 }
 
                 $opts = array(