diff --git a/src/Composer/Downloader/FileDownloader.php b/src/Composer/Downloader/FileDownloader.php
index 8c8c13bc0456..29e84a9aa64e 100644
--- a/src/Composer/Downloader/FileDownloader.php
+++ b/src/Composer/Downloader/FileDownloader.php
@@ -256,7 +256,7 @@ protected function processUrl(PackageInterface $package, $url)
         return $url;
     }
 
-    private function getCacheKey(PackageInterface $package, $processedUrl)
+    public static function getCacheKey(PackageInterface $package, $processedUrl)
     {
         // we use the complete download url here to avoid conflicting entries
         // from different packages, which would potentially allow a given package
diff --git a/src/Composer/Downloader/Prefetcher/CopyRequest.php b/src/Composer/Downloader/Prefetcher/CopyRequest.php
new file mode 100644
index 000000000000..65ffd059c0a2
--- /dev/null
+++ b/src/Composer/Downloader/Prefetcher/CopyRequest.php
@@ -0,0 +1,341 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Downloader\Prefetcher;
+
+use Composer\Util;
+use Composer\IO;
+use Composer\Config;
+
+class CopyRequest
+{
+    private $scheme;
+    private $user;
+    private $pass;
+    private $host;
+    private $port;
+    private $path;
+    private $query = array();
+
+    /** @var [string => string] */
+    private $headers = array();
+
+    /** @var string */
+    private $destination;
+
+    /** @var resource<stream<plainfile>> */
+    private $fp;
+
+    private $success = false;
+
+    private static $defaultCurlOptions = array(
+        CURLOPT_HTTPGET => true,
+        CURLOPT_FOLLOWLOCATION => true,
+        CURLOPT_MAXREDIRS => 20,
+        CURLOPT_ENCODING => '',
+    );
+
+    private $githubDomains = array();
+    private $gitlabDomains = array();
+
+    private static $NSS_CIPHERS = array(
+        'rsa_3des_sha',
+        'rsa_des_sha',
+        'rsa_null_md5',
+        'rsa_null_sha',
+        'rsa_rc2_40_md5',
+        'rsa_rc4_128_md5',
+        'rsa_rc4_128_sha',
+        'rsa_rc4_40_md5',
+        'fips_des_sha',
+        'fips_3des_sha',
+        'rsa_des_56_sha',
+        'rsa_rc4_56_sha',
+        'rsa_aes_128_sha',
+        'rsa_aes_256_sha',
+        'rsa_aes_128_gcm_sha_256',
+        'dhe_rsa_aes_128_gcm_sha_256',
+        'ecdh_ecdsa_null_sha',
+        'ecdh_ecdsa_rc4_128_sha',
+        'ecdh_ecdsa_3des_sha',
+        'ecdh_ecdsa_aes_128_sha',
+        'ecdh_ecdsa_aes_256_sha',
+        'ecdhe_ecdsa_null_sha',
+        'ecdhe_ecdsa_rc4_128_sha',
+        'ecdhe_ecdsa_3des_sha',
+        'ecdhe_ecdsa_aes_128_sha',
+        'ecdhe_ecdsa_aes_256_sha',
+        'ecdh_rsa_null_sha',
+        'ecdh_rsa_128_sha',
+        'ecdh_rsa_3des_sha',
+        'ecdh_rsa_aes_128_sha',
+        'ecdh_rsa_aes_256_sha',
+        'echde_rsa_null',
+        'ecdhe_rsa_rc4_128_sha',
+        'ecdhe_rsa_3des_sha',
+        'ecdhe_rsa_aes_128_sha',
+        'ecdhe_rsa_aes_256_sha',
+        'ecdhe_ecdsa_aes_128_gcm_sha_256',
+        'ecdhe_rsa_aes_128_gcm_sha_256',
+    );
+
+    /**
+     * @param string $url
+     * @param string $destination
+     * @param bool $useRedirector
+     * @param IO\IOInterface $io
+     * @param Config $config
+     */
+    public function __construct($url, $destination, $useRedirector, IO\IOInterface $io, Config $config)
+    {
+        $this->setURL($url);
+        $this->setDestination($destination);
+        $this->githubDomains = $config->get('github-domains');
+        $this->gitlabDomains = $config->get('gitlab-domains');
+        $this->setupAuthentication($io, $useRedirector);
+    }
+
+    public function __destruct()
+    {
+        if ($this->fp) {
+            fclose($this->fp);
+        }
+
+        if (!$this->success) {
+            if (file_exists($this->destination)) {
+                unlink($this->destination);
+            }
+        }
+    }
+
+    /**
+     * @return string
+     */
+    public function getURL()
+    {
+        $url = self::ifOr($this->scheme, '', '://');
+        if ($this->user) {
+            $user = $this->user;
+            $user .= self::ifOr($this->pass, ':');
+            $url .= $user . '@';
+        }
+        $url .= self::ifOr($this->host);
+        $url .= self::ifOr($this->port, ':');
+        $url .= self::ifOr($this->path);
+        $url .= self::ifOr(http_build_query($this->query), '?');
+        return $url;
+    }
+
+    /**
+     * @return string user/pass/access_token masked url
+     */
+    public function getMaskedURL()
+    {
+        $url = self::ifOr($this->scheme, '', '://');
+        $url .= self::ifOr($this->host);
+        $url .= self::ifOr($this->port, ':');
+        $url .= self::ifOr($this->path);
+        return $url;
+    }
+
+    private static function ifOr($str, $pre = '', $post = '')
+    {
+        if ($str) {
+            return $pre . $str . $post;
+        }
+        return '';
+    }
+
+    /**
+     * @param string $url
+     */
+    public function setURL($url)
+    {
+        $struct = parse_url($url);
+        foreach ($struct as $key => $val) {
+            if ($key === 'query') {
+                parse_str($val, $this->query);
+            } else {
+                $this->$key = $val;
+            }
+        }
+    }
+
+    public function addParam($key, $val)
+    {
+        $this->query[$key] = $val;
+    }
+
+    public function addHeader($key, $val)
+    {
+        $this->headers[strtolower($key)] = $val;
+    }
+
+    public function makeSuccess()
+    {
+        $this->success = true;
+    }
+
+    /**
+     * @return array
+     */
+    public function getCurlOptions()
+    {
+        $headers = array();
+        foreach ($this->headers as $key => $val) {
+            $headers[] = strtr(ucwords(strtr($key, '-', ' ')), ' ', '-') . ': ' . $val;
+        }
+
+        $url = $this->getURL();
+
+        $curlOpts = array(
+            CURLOPT_URL => $url,
+            CURLOPT_HTTPHEADER => $headers,
+            CURLOPT_USERAGENT => Util\StreamContextFactory::generateUserAgent(),
+            CURLOPT_FILE => $this->fp,
+            //CURLOPT_VERBOSE => true, //for debug
+        );
+        $curlOpts += self::$defaultCurlOptions;
+
+        if ($ciphers = $this->nssCiphers()) {
+            $curlOpts[CURLOPT_SSL_CIPHER_LIST] = $ciphers;
+        }
+        if ($proxy = $this->getProxy($url)) {
+            $curlOpts[CURLOPT_PROXY] = $proxy;
+        }
+
+        return $curlOpts;
+    }
+
+    /**
+     * @param IO\IOInterface $io
+     * @param bool $useRedirector
+     */
+    private function setupAuthentication(IO\IOInterface $io, $useRedirector)
+    {
+        if (preg_match('/\.github\.com$/', $this->host)) {
+            $authKey = 'github.com';
+            if ($useRedirector) {
+                if ($this->host === 'api.github.com' && preg_match('%^/repos(/[^/]+/[^/]+/)zipball(.+)$%', $this->path, $_)) {
+                    $this->host = 'codeload.github.com';
+                    $this->path = $_[1] . 'legacy.zip' . $_[2];
+                }
+            }
+        } else {
+            $authKey = $this->host;
+        }
+        if (!$io->hasAuthentication($authKey)) {
+            if ($this->user || $this->pass) {
+                $io->setAuthentication($authKey, $this->user, $this->pass);
+            } else {
+                return;
+            }
+        }
+
+        $auth = $io->getAuthentication($authKey);
+
+        // is github
+        if (in_array($authKey, $this->githubDomains) && 'x-oauth-basic' === $auth['password']) {
+            $this->addParam('access_token', $auth['username']);
+            $this->user = $this->pass = null;
+            return;
+        }
+        // is gitlab
+        if (in_array($authKey, $this->gitlabDomains) && 'oauth2' === $auth['password']) {
+            $this->addHeader('authorization', 'Bearer ' . $auth['username']);
+            $this->user = $this->pass = null;
+            return;
+        }
+        // others, includes bitbucket
+        $this->user = $auth['username'];
+        $this->pass = $auth['password'];
+    }
+
+    private function getProxy($url)
+    {
+        if (isset($_SERVER['no_proxy'])) {
+            $pattern = new Util\NoProxyPattern($_SERVER['no_proxy']);
+            if ($pattern->test($url)) {
+                return null;
+            }
+        }
+
+        if ($this->scheme === 'https') {
+            if (isset($_SERVER['HTTPS_PROXY'])) {
+                return $_SERVER['HTTPS_PROXY'];
+            }
+            if (isset($_SERVER['https_proxy'])) {
+                return $_SERVER['https_proxy'];
+            }
+        }
+
+        if ($this->scheme === 'http') {
+            if (isset($_SERVER['HTTP_PROXY'])) {
+                return $_SERVER['HTTP_PROXY'];
+            }
+            if (isset($_SERVER['http_proxy'])) {
+                return $_SERVER['http_proxy'];
+            }
+        }
+        return null;
+    }
+
+    /**
+     * enable ECC cipher suites in cURL/NSS
+     */
+    public static function nssCiphers()
+    {
+        static $cache;
+        if (isset($cache)) {
+            return $cache;
+        }
+        $ver = curl_version();
+        if (preg_match('/^NSS.*Basic ECC$/', $ver['ssl_version'])) {
+            return $cache = implode(',', self::$NSS_CIPHERS);
+        }
+        return $cache = false;
+    }
+
+    /**
+     * @param string
+     */
+    public function setDestination($destination)
+    {
+        $this->destination = $destination;
+        if (is_dir($destination)) {
+            throw new FetchException(
+                'The file could not be written to ' . $destination . '. Directory exists.'
+            );
+        }
+
+        $this->createDir($destination);
+
+        $this->fp = fopen($destination, 'wb');
+        if (!$this->fp) {
+            throw new FetchException(
+                'The file could not be written to ' . $destination
+            );
+        }
+    }
+
+    private function createDir($fileName)
+    {
+        $targetdir = dirname($fileName);
+        if (!file_exists($targetdir)) {
+            if (!mkdir($targetdir, 0766, true)) {
+                throw new FetchException(
+                    'The file could not be written to ' . $fileName
+                );
+            }
+        }
+    }
+}
diff --git a/src/Composer/Downloader/Prefetcher/CurlMulti.php b/src/Composer/Downloader/Prefetcher/CurlMulti.php
new file mode 100644
index 000000000000..e182ca01d759
--- /dev/null
+++ b/src/Composer/Downloader/Prefetcher/CurlMulti.php
@@ -0,0 +1,179 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Downloader\Prefetcher;
+
+class CurlMulti
+{
+    const MAX_CONNECTIONS = 6;
+
+    /** @var resource<curl_multi> */
+    private $mh;
+
+    /** @var resource<curl_share> */
+    private $sh;
+
+    /** @var resource<curl>[] */
+    private $unused = array();
+
+    /** @var resource<curl>[] */
+    private $using = array();
+
+    /** @var CopyRequest[] */
+    private $requests;
+
+    /** @var CopyRequest[] */
+    private $runningRequests;
+
+    /** @var bool */
+    private $permanent = true;
+
+    private $blackhole;
+
+    /**
+     * @param bool $permanent
+     */
+    public function __construct($permanent = true)
+    {
+        static $mh_cache, $sh_cache, $ch_cache;
+
+        if (!$permanent || !$mh_cache) {
+            $mh_cache = curl_multi_init();
+
+            $ch_cache = array();
+            for ($i = 0; $i < self::MAX_CONNECTIONS; ++$i) {
+                $ch_cache[] = curl_init();
+            }
+            // @codeCoverageIgnoreStart
+            if (function_exists('curl_share_init')) {
+                $sh_cache = curl_share_init();
+                curl_share_setopt($sh_cache, CURLSHOPT_SHARE, CURL_LOCK_DATA_SSL_SESSION);
+
+                foreach ($ch_cache as $ch) {
+                    curl_setopt($ch, CURLOPT_SHARE, $sh_cache);
+                }
+            }
+            // @codeCoverageIgnoreEnd
+        }
+
+        $this->mh = $mh_cache;
+        $this->sh = $sh_cache;
+        $this->unused = $ch_cache;
+        $this->permanent = $permanent;
+
+        // for PHP<5.5 @see getFinishedResults()
+        $this->blackhole = fopen('php://temp', 'wb');
+    }
+
+    /**
+     * @codeCoverageIgnore
+     */
+    public function __destruct()
+    {
+        foreach ($this->using as $ch) {
+            curl_multi_remove_handle($this->mh, $ch);
+            $this->unused[] = $ch;
+        }
+
+        if ($this->permanent) {
+            return; //don't close connection
+        }
+
+        foreach ($this->unused as $ch) {
+            curl_close($ch);
+        }
+
+        curl_multi_close($this->mh);
+    }
+
+    /**
+     * @param CopyRequest[] $requests
+     */
+    public function setRequests(array $requests)
+    {
+        $this->requests = $requests;
+    }
+
+    public function setupEventLoop()
+    {
+        while (count($this->unused) > 0 && count($this->requests) > 0) {
+            $request = array_pop($this->requests);
+            $ch = array_pop($this->unused);
+            $index = (int)$ch;
+
+            $this->using[$index] = $ch;
+            $this->runningRequests[$index] = $request;
+
+            curl_setopt_array($ch, $request->getCurlOptions());
+            curl_multi_add_handle($this->mh, $ch);
+        }
+    }
+
+    public function wait()
+    {
+        $expectRunning = count($this->using);
+        $running = 0;
+        $retryCnt = 0;
+
+        do {
+            do {
+                $stat = curl_multi_exec($this->mh, $running);
+            } while ($stat === CURLM_CALL_MULTI_PERFORM);
+            if (-1 === curl_multi_select($this->mh)) {
+                // @codeCoverageIgnoreStart
+                if ($retryCnt++ > 100) {
+                    throw new FetchException('curl_multi_select failure');
+                }
+                // @codeCoverageIgnoreEnd
+                usleep(100000);
+            }
+        } while ($running > 0 && $running >= $expectRunning);
+    }
+
+    public function getFinishedResults()
+    {
+        $urls = array();
+        $successCnt = $failureCnt = 0;
+        do {
+            if ($raised = curl_multi_info_read($this->mh, $remains)) {
+                $ch = $raised['handle'];
+                $errno = curl_errno($ch);
+                $error = curl_error($ch);
+                $info = curl_getinfo($ch);
+                curl_setopt($ch, CURLOPT_FILE, $this->blackhole); //release file pointer
+                $index = (int)$ch;
+                $request = $this->runningRequests[$index];
+                if (CURLE_OK === $errno && !$error && ('http' !== substr($info['url'], 0, 4) || 200 === $info['http_code'])) {
+                    ++$successCnt;
+                    $request->makeSuccess();
+                    $urls[] = $request->getMaskedURL();
+                } else {
+                    ++$failureCnt;
+                }
+                unset($this->using[$index], $this->runningRequests[$index], $request);
+                curl_multi_remove_handle($this->mh, $ch);
+                $this->unused[] = $ch;
+            }
+        } while ($remains > 0);
+
+        return array(
+            'successCnt' => $successCnt,
+            'failureCnt' => $failureCnt,
+            'urls' => $urls,
+        );
+    }
+
+    public function remain()
+    {
+        return count($this->runningRequests) > 0;
+    }
+}
diff --git a/src/Composer/Downloader/Prefetcher/FetchException.php b/src/Composer/Downloader/Prefetcher/FetchException.php
new file mode 100644
index 000000000000..4075bead935b
--- /dev/null
+++ b/src/Composer/Downloader/Prefetcher/FetchException.php
@@ -0,0 +1,17 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Downloader\Prefetcher;
+
+class FetchException extends \RuntimeException
+{
+}
diff --git a/src/Composer/Downloader/Prefetcher/Prefetcher.php b/src/Composer/Downloader/Prefetcher/Prefetcher.php
new file mode 100644
index 000000000000..f6cbd6e201e9
--- /dev/null
+++ b/src/Composer/Downloader/Prefetcher/Prefetcher.php
@@ -0,0 +1,113 @@
+<?php
+
+/*
+ * This file is part of Composer.
+ *
+ * (c) Nils Adermann <naderman@naderman.de>
+ *     Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Composer\Downloader\Prefetcher;
+
+use Composer\Downloader\FileDownloader;
+use Composer\IO;
+use Composer\Config;
+use Composer\Package;
+use Composer\DependencyResolver\Operation;
+
+class Prefetcher
+{
+    /**
+     * @param IO\IOInterface $io
+     * @param CopyRequest[] $requests
+     */
+    public function fetchAll(IO\IOInterface $io, array $requests)
+    {
+        $successCnt = $failureCnt = 0;
+        $totalCnt = count($requests);
+
+        $multi = new CurlMulti;
+        $multi->setRequests($requests);
+        try {
+            do {
+                $multi->setupEventLoop();
+                $multi->wait();
+
+                $result = $multi->getFinishedResults();
+                $successCnt += $result['successCnt'];
+                $failureCnt += $result['failureCnt'];
+                foreach ($result['urls'] as $url) {
+                    $io->writeError("    <comment>$successCnt/$totalCnt</comment>:\t$url");
+                }
+            } while ($multi->remain());
+        } catch (FetchException $e) {
+            // do nothing
+        }
+
+        $skippedCnt = $totalCnt - $successCnt - $failureCnt;
+        $io->writeError("    Finished: <comment>success:$successCnt, skipped:$skippedCnt, failure:$failureCnt, total: $totalCnt</comment>");
+    }
+
+    /**
+     * @param IO\IOInterface $io
+     * @param Config $config
+     * @param Operation\OperationInterface[] $ops
+     */
+    public function fetchAllFromOperations(IO\IOInterface $io, Config $config, array $ops)
+    {
+        $cachedir = rtrim($config->get('cache-files-dir'), '\/');
+        $requests = array();
+        foreach ($ops as $op) {
+            switch ($op->getJobType()) {
+                case 'install':
+                    $p = $op->getPackage();
+                    break;
+                case 'update':
+                    $p = $op->getTargetPackage();
+                    break;
+                default:
+                    continue 2;
+            }
+
+            $url = $this->getUrlFromPackage($p);
+            if (!$url) {
+                continue;
+            }
+
+            $destination = $cachedir . DIRECTORY_SEPARATOR . FileDownloader::getCacheKey($p, $url);
+            if (file_exists($destination)) {
+                continue;
+            }
+            $useRedirector = (bool)preg_match('%^(?:https|git)://github\.com%', $p->getSourceUrl());
+            try {
+                $request = new CopyRequest($url, $destination, $useRedirector, $io, $config);
+                $requests[] = $request;
+            } catch (FetchException $e) {
+                // do nothing
+            }
+        }
+
+        if (count($requests) > 0) {
+            $this->fetchAll($io, $requests);
+        }
+    }
+
+    private static function getUrlFromPackage(Package\PackageInterface $package)
+    {
+        $url = $package->getDistUrl();
+        if (!$url) {
+            return false;
+        }
+        if ($package->getDistMirrors()) {
+            $url = current($package->getDistUrls());
+        }
+        if (!parse_url($url, PHP_URL_HOST)) {
+            return false;
+        }
+        return $url;
+    }
+
+}
diff --git a/src/Composer/Installer.php b/src/Composer/Installer.php
index ec815745605e..9231d98a2be3 100644
--- a/src/Composer/Installer.php
+++ b/src/Composer/Installer.php
@@ -25,6 +25,7 @@
 use Composer\DependencyResolver\Solver;
 use Composer\DependencyResolver\SolverProblemsException;
 use Composer\Downloader\DownloadManager;
+use Composer\Downloader\Prefetcher;
 use Composer\EventDispatcher\EventDispatcher;
 use Composer\Installer\InstallationManager;
 use Composer\Installer\InstallerEvents;
@@ -504,6 +505,11 @@ protected function doInstall($localRepo, $installedRepo, $platformRepo, $aliases
             $devPackages = null;
         }
 
+        if (extension_loaded('curl')) {
+            $prefetcher = new Prefetcher\Prefetcher;
+            $prefetcher->fetchAllFromOperations($this->io, $this->config, $operations);
+        }
+
         if ($operations) {
             $installs = $updates = $uninstalls = array();
             foreach ($operations as $operation) {
diff --git a/src/Composer/Util/StreamContextFactory.php b/src/Composer/Util/StreamContextFactory.php
index 9fd28388dacb..5f6f85f19986 100644
--- a/src/Composer/Util/StreamContextFactory.php
+++ b/src/Composer/Util/StreamContextFactory.php
@@ -133,24 +133,29 @@ public static function getContext($url, array $defaultOptions = array(), array $
             $options['http']['header'] = self::fixHttpHeaderField($options['http']['header']);
         }
 
+        if (!isset($options['http']['header']) || false === strpos(strtolower(implode('', $options['http']['header'])), 'user-agent')) {
+            $options['http']['header'][] = 'User-Agent: ' . self::generateUserAgent();
+        }
+
+        return stream_context_create($options, $defaultParams);
+    }
+
+    public static function generateUserAgent()
+    {
         if (defined('HHVM_VERSION')) {
             $phpVersion = 'HHVM ' . HHVM_VERSION;
         } else {
             $phpVersion = 'PHP ' . PHP_MAJOR_VERSION . '.' . PHP_MINOR_VERSION . '.' . PHP_RELEASE_VERSION;
         }
 
-        if (!isset($options['http']['header']) || false === strpos(strtolower(implode('', $options['http']['header'])), 'user-agent')) {
-            $options['http']['header'][] = sprintf(
-                'User-Agent: Composer/%s (%s; %s; %s%s)',
-                Composer::VERSION === '@package_version@' ? 'source' : Composer::VERSION,
-                php_uname('s'),
-                php_uname('r'),
-                $phpVersion,
-                getenv('CI') ? '; CI' : ''
-            );
-        }
-
-        return stream_context_create($options, $defaultParams);
+        return sprintf(
+            'Composer/%s (%s; %s; %s%s)',
+            Composer::VERSION === '@package_version@' ? 'source' : Composer::VERSION,
+            php_uname('s'),
+            php_uname('r'),
+            $phpVersion,
+            getenv('CI') ? '; CI' : ''
+        );
     }
 
     /**
diff --git a/tests/Composer/Test/Downloader/Prefetcher/CopyRequestTest.php b/tests/Composer/Test/Downloader/Prefetcher/CopyRequestTest.php
new file mode 100644
index 000000000000..23d5a2e1875a
--- /dev/null
+++ b/tests/Composer/Test/Downloader/Prefetcher/CopyRequestTest.php
@@ -0,0 +1,136 @@
+<?php
+namespace Composer\Test\Downloader\Prefetcher;
+
+use Composer\Downloader\Prefetcher\CopyRequest;
+use Prophecy\Argument as arg;
+
+class CopyRequestTest extends \PHPUnit_Framework_TestCase
+{
+    private $iop;
+    private $configp;
+
+    protected function setUp()
+    {
+        $this->iop = $this->prophesize('Composer\IO\IOInterface');
+        $this->configp = $configp = $this->prophesize('Composer\Config');
+        $configp->get('github-domains')->willReturn(array('github.com'));
+        $configp->get('gitlab-domains')->willReturn(array('gitlab.com'));
+    }
+
+    public function testConstruct()
+    {
+        $tmpfile = tempnam(sys_get_temp_dir(), 'composer_unit_test_');
+        $example = 'http://user:pass@example.com:80/p/a/t/h?a=b';
+
+        $this->iop->setAuthentication('example.com', 'user', 'pass')
+            ->will(function($args, $iop){
+                $iop->getAuthentication($args[0])
+                    ->willReturn(array('username' => $args[1], 'password' => $args[2]));
+            })
+            ->shouldBeCalled();
+        $this->iop->hasAuthentication(arg::type('string'))
+            ->willReturn(false);
+
+        $req = new CopyRequest($example, $tmpfile, false, $this->iop->reveal(), $this->configp->reveal());
+        $this->assertEquals($example, $req->getURL());
+    }
+
+    public function testDirectoryExists()
+    {
+        $rand = sha1(mt_rand());
+        $tmpbase = sys_get_temp_dir();
+        $tmpdir = $tmpbase . DIRECTORY_SEPARATOR . $rand;
+        mkdir($tmpdir);
+
+        try {
+            // if is_dir(destination) then throws exception
+            $req = new CopyRequest('http://example.com/', $tmpdir, false, $this->iop->reveal(), $this->configp->reveal());
+            rmdir($tmpdir);
+            $this->fail('expectedException: \Composer\Downloader\Prefetcher\FetchException');
+        } catch (\Exception $e) {
+            rmdir($tmpdir);
+            $this->assertInstanceOf('Composer\Downloader\Prefetcher\FetchException', $e);
+            $this->assertContains('Directory exists', $e->getMessage());
+        }
+    }
+
+    public function testDestruct()
+    {
+        $tmpfile = tempnam(sys_get_temp_dir(), 'composer_unit_test_');
+
+        $req = new CopyRequest('http://example.com/', $tmpfile, false, $this->iop->reveal(), $this->configp->reveal());
+        $this->assertFileExists($tmpfile);
+
+        // if $req->success === true ...
+        $req->makeSuccess();
+        unset($req);
+
+        // then tmpfile remain
+        $this->assertFileExists($tmpfile);
+        unlink($tmpfile);
+
+        $req = new CopyRequest('http://example.com/', $tmpfile, false, $this->iop->reveal(), $this->configp->reveal());
+        // if $req->success === false (default) ...
+        // $req->makeSuccess();
+        unset($req);
+
+        // then cleaned tmpfile automatically
+        $this->assertFileNotExists($tmpfile);
+    }
+
+    public function testGetMaskedURL()
+    {
+        $tmpfile = tempnam(sys_get_temp_dir(), 'composer_unit_test_');
+
+        $req = new CopyRequest('http://user:pass@example.com/p/a/t/h?token=opensesame', $tmpfile, false, $this->iop->reveal(), $this->configp->reveal());
+        // user/pass/query masked
+        $this->assertEquals('http://example.com/p/a/t/h', $req->getMaskedURL());
+    }
+
+    public function testGitHubRedirector()
+    {
+        $tmpfile = tempnam(sys_get_temp_dir(), 'composer_unit_test_');
+        $example = 'https://api.github.com/repos/vendor/name/zipball/aaaa?a=b';
+
+        $this->iop->hasAuthentication('github.com')->willReturn(true);
+        $this->iop->getAuthentication('github.com')->willReturn(array('username' => 'at', 'password' => 'x-oauth-basic'));
+
+        // user:pass -> query
+        $req = new CopyRequest($example, $tmpfile, false, $this->iop->reveal(), $this->configp->reveal());
+        $this->assertEquals("$example&access_token=at", $req->getURL());
+
+        // api.github.com -> codeload.github.com
+        $req = new CopyRequest($example, $tmpfile, true, $this->iop->reveal(), $this->configp->reveal());
+        $this->assertEquals('https://codeload.github.com/vendor/name/legacy.zip/aaaa?a=b&access_token=at', $req->getURL());
+    }
+
+    public function testGitLab()
+    {
+        $tmpfile = tempnam(sys_get_temp_dir(), 'composer_unit_test_');
+        $example = 'https://gitlab.com/p/a/t/h';
+
+        $this->iop->hasAuthentication('gitlab.com')->willReturn(true);
+        $this->iop->getAuthentication('gitlab.com')->willReturn(array('username' => 'at', 'password' => 'oauth2'));
+
+        $req = new CopyRequest($example, $tmpfile, false, $this->iop->reveal(), $this->configp->reveal());
+        $opts = $req->getCurlOptions();
+        $this->assertContains('Authorization: Bearer at', $opts[CURLOPT_HTTPHEADER]);
+    }
+
+    public function testProxy()
+    {
+        $serverBackup = $_SERVER;
+
+        $tmpfile = tempnam(sys_get_temp_dir(), 'composer_unit_test_');
+
+        $_SERVER['no_proxy'] = 'example.com';
+        $_SERVER['HTTP_PROXY'] = 'http://example.com:8080';
+        $req = new CopyRequest('http://localhost', $tmpfile, false, $this->iop->reveal(), $this->configp->reveal());
+        $this->assertArrayHasKey(CURLOPT_PROXY, $req->getCurlOptions());
+
+        $req = new CopyRequest('http://example.com', $tmpfile, false, $this->iop->reveal(), $this->configp->reveal());
+        $this->assertArrayNotHasKey(CURLOPT_PROXY, $req->getCurlOptions());
+
+        $_SERVER = $serverBackup;
+    }
+}
diff --git a/tests/Composer/Test/Downloader/Prefetcher/CurlMultiTest.php b/tests/Composer/Test/Downloader/Prefetcher/CurlMultiTest.php
new file mode 100644
index 000000000000..dacdaa143539
--- /dev/null
+++ b/tests/Composer/Test/Downloader/Prefetcher/CurlMultiTest.php
@@ -0,0 +1,76 @@
+<?php
+namespace Composer\Test\Downloader\Prefetcher;
+
+use Composer\Downloader\Prefetcher\CurlMulti;
+
+class CurlMultiTest extends \PHPUnit_Framework_TestCase
+{
+    private $iop;
+    private $configp;
+
+    protected function setUp()
+    {
+        $this->iop = $this->prophesize('Composer\IO\IOInterface');
+        $this->configp = $configp = $this->prophesize('Composer\Config');
+        $configp->get('github-domains')->willReturn(array('github.com'));
+        $configp->get('gitlab-domains')->willReturn(array('gitlab.com'));
+    }
+
+    public function testRequestSuccess()
+    {
+        $tmpfile = tmpfile();
+        $reqp = $this->prophesize('Composer\Downloader\Prefetcher\CopyRequest');
+        $reqp->getCurlOptions()->willReturn(array(
+            CURLOPT_URL => 'file://' . __DIR__ . '/test.txt',
+            CURLOPT_FILE => $tmpfile,
+        ));
+        $reqp->getMaskedURL()->willReturn('file://' . __DIR__ . '/test.txt');
+        $reqp->makeSuccess()->willReturn(null);
+        $requests = array($reqp->reveal());
+
+        $multi = new CurlMulti;
+        $multi->setRequests($requests);
+
+        do {
+            $multi->setupEventLoop();
+            $multi->wait();
+
+            $result = $multi->getFinishedResults();
+            $this->assertEquals(1, $result['successCnt']);
+            $this->assertEquals(0, $result['failureCnt']);
+        } while ($multi->remain());
+
+        rewind($tmpfile);
+        $content = stream_get_contents($tmpfile);
+        $this->assertEquals(file_get_contents(__DIR__ . '/test.txt'), $content);
+    }
+
+    public function testWait()
+    {
+        $tmpfile = tmpfile();
+        $reqp = $this->prophesize('Composer\Downloader\Prefetcher\CopyRequest');
+        $reqp->getCurlOptions()->willReturn(array(
+            CURLOPT_URL => 'file://uso800.txt',
+            CURLOPT_FILE => $tmpfile,
+        ));
+        $reqp->getMaskedURL()->willReturn('file://uso800.txt');
+        $reqp->makeSuccess()->willReturn(null);
+        $requests = array($reqp->reveal());
+
+        $multi = new CurlMulti;
+        $multi->setRequests($requests);
+
+        do {
+            $multi->setupEventLoop();
+            $multi->wait();
+
+            $result = $multi->getFinishedResults();
+            $this->assertEquals(0, $result['successCnt']);
+            $this->assertEquals(1, $result['failureCnt']);
+        } while ($multi->remain());
+
+        rewind($tmpfile);
+        $content = stream_get_contents($tmpfile);
+        $this->assertEmpty($content);
+    }
+}
diff --git a/tests/Composer/Test/Downloader/Prefetcher/PrefetcherTest.php b/tests/Composer/Test/Downloader/Prefetcher/PrefetcherTest.php
new file mode 100644
index 000000000000..17560afc8a7a
--- /dev/null
+++ b/tests/Composer/Test/Downloader/Prefetcher/PrefetcherTest.php
@@ -0,0 +1,103 @@
+<?php
+namespace Composer\Test\Downloader\Prefetcher;
+
+use Composer\Downloader\Prefetcher\Prefetcher;
+use Composer\Downloader\FileDownloader;
+use Prophecy\Argument as arg;
+
+class PrefetcherTest extends \PHPUnit_Framework_TestCase
+{
+    private $iop;
+    private $configp;
+
+    protected function setUp()
+    {
+        $this->iop = $this->prophesize('Composer\IO\IOInterface');
+        $this->configp = $configp = $this->prophesize('Composer\Config');
+        $configp->get('github-domains')->willReturn(array('github.com'));
+        $configp->get('gitlab-domains')->willReturn(array('gitlab.com'));
+        $configp->get('cache-files-dir')->willReturn(sys_get_temp_dir());
+    }
+
+    public function testFetchAllOnFailure()
+    {
+        $reqp = $this->prophesize('Composer\Downloader\Prefetcher\CopyRequest');
+        $reqp->getCurlOptions()->willReturn(array(
+            CURLOPT_URL => 'file://uso800.txt',
+            CURLOPT_FILE => tmpfile(),
+        ));
+        $this->iop->writeError("    Finished: <comment>success:0, skipped:0, failure:1, total: 1</comment>")->shouldBeCalledTimes(1);
+
+        $fetcher = new Prefetcher;
+        $fetcher->fetchAll($this->iop->reveal(), array($reqp->reveal()));
+    }
+
+    public function testFetchAllOnSuccess()
+    {
+        $reqp = $this->prophesize('Composer\Downloader\Prefetcher\CopyRequest');
+        $reqp->getCurlOptions()->willReturn(array(
+            CURLOPT_URL => 'file://' . __DIR__ . '/test.txt',
+            CURLOPT_FILE => tmpfile(),
+        ));
+        $reqp->makeSuccess()->willReturn(null);
+        $reqp->getMaskedURL()->willReturn('file://' . __DIR__ . '/test.txt');
+        $this->iop->writeError(arg::type('string'))->shouldBeCalled();
+
+        $fetcher = new Prefetcher;
+        $fetcher->fetchAll($this->iop->reveal(), array($reqp->reveal()));
+    }
+
+    public function testFetchAllFromOperationsWithNoOperations()
+    {
+        $opp = $this->prophesize('Composer\DependencyResolver\Operation\OperationInterface');
+        $opp->getJobType()->willReturn('remove');
+
+        $this->iop->writeError(arg::any())->shouldNotBeCalled();
+
+        $fetcher = new Prefetcher;
+        $fetcher->fetchAllFromOperations($this->iop->reveal(), $this->configp->reveal(), array($opp->reveal()));
+    }
+
+    private function createProphecies()
+    {
+        $opp = $this->prophesize('Composer\DependencyResolver\Operation\InstallOperation');
+        $opp->getJobType()->willReturn('install');
+        $pp = $this->prophesize('Composer\Package\PackageInterface');
+        return array($opp, $pp);
+    }
+
+    public function testFetchAllWithInstallOperation()
+    {
+        list($opp, $pp) = $this->createProphecies();
+        $pp->getName()->willReturn('acme/acme');
+        $pp->getDistType()->willReturn('composer');
+        $pp->getDistUrl()->willReturn('file://' . __DIR__ . '/test.txt');
+        $pp->getDistMirrors()->willReturn(array());
+        $pp->getSourceUrl()->shouldNotBeCalled();
+
+        $opp->getPackage()->willReturn($pp->reveal())->shouldBeCalled();
+
+        $fetcher = new Prefetcher;
+        $fetcher->fetchAllFromOperations($this->iop->reveal(), $this->configp->reveal(), array($opp->reveal()));
+    }
+
+    public function testFetchAllWithInstallButFileExists()
+    {
+        list($opp, $pp) = $this->createProphecies();
+        $pp->getName()->willReturn('');
+        $pp->getDistType()->willReturn('html');
+        $pp->getDistUrl()->willReturn('http://example.com/');
+        $pp->getDistMirrors()->willReturn(array());
+        $pp->getSourceUrl()->willReturn('git://uso800');
+
+        $path = sys_get_temp_dir() . DIRECTORY_SEPARATOR . FileDownloader::getCacheKey($pp->reveal(), 'http://example.com/');
+        $fp = fopen($path, 'wb');
+
+        $opp->getPackage()->willReturn($pp->reveal())->shouldBeCalled();
+
+        $fetcher = new Prefetcher;
+        $fetcher->fetchAllFromOperations($this->iop->reveal(), $this->configp->reveal(), array($opp->reveal()));
+        fclose($fp);
+        unlink($path);
+    }
+}
diff --git a/tests/Composer/Test/Downloader/Prefetcher/test.txt b/tests/Composer/Test/Downloader/Prefetcher/test.txt
new file mode 100644
index 000000000000..6684d285884e
--- /dev/null
+++ b/tests/Composer/Test/Downloader/Prefetcher/test.txt
@@ -0,0 +1 @@
+Composer\Downloader\Prefetcher test