diff --git a/src/Symfony/Component/HttpFoundation/File/File.php b/src/Symfony/Component/HttpFoundation/File/File.php
index b0c2a254cc..a646564ad5 100644
--- a/src/Symfony/Component/HttpFoundation/File/File.php
+++ b/src/Symfony/Component/HttpFoundation/File/File.php
@@ -49,8 +49,9 @@ class File extends \SplFileInfo
     public function guessExtension()
     {
         $type = $this->getMimeType();
+        $guesser = ExtensionGuesser::getInstance();
 
-        return ExtensionGuesser::guessExtension($type);
+        return $guesser->guess($type);
     }
 
     /**
diff --git a/src/Symfony/Component/HttpFoundation/File/MimeType/ExtensionGuesser.php b/src/Symfony/Component/HttpFoundation/File/MimeType/ExtensionGuesser.php
index 4313570d07..b73cd99910 100644
--- a/src/Symfony/Component/HttpFoundation/File/MimeType/ExtensionGuesser.php
+++ b/src/Symfony/Component/HttpFoundation/File/MimeType/ExtensionGuesser.php
@@ -9,441 +9,92 @@
  * file that was distributed with this source code.
  */
 
-namespace Symfony\Component\HttpFoundation\File\Mimetype;
+namespace Symfony\Component\HttpFoundation\File\MimeType;
 
 /**
- * Provides a best-guess mapping of mime-type to file extension.
+ * A singleton mime type to file extension guesser.
+ *
+ * A default guesser is provided.
+ * You can register custom guessers by calling the register()
+ * method on the singleton instance.
+ *
+ * <code>
+ * $guesser = ExtensionGuesser::getInstance();
+ * $guesser->register(new MyCustomExtensionGuesser());
+ * </code>
+ *
+ * The last registered guesser is preferred over previously registered ones.
+ *
  */
-class ExtensionGuesser
+class ExtensionGuesser implements ExtensionGuesserInterface
 {
     /**
-     * A map of mime types and their default extensions.
-     *
-     * @var array
+     * The singleton instance
+     * @var ExtensionGuesser
      */
-    static protected $defaultExtensions = array(
-        'application/andrew-inset' => 'ez',
-        'application/appledouble' => 'base64',
-        'application/applefile' => 'base64',
-        'application/commonground' => 'dp',
-        'application/cprplayer' => 'pqi',
-        'application/dsptype' => 'tsp',
-        'application/excel' => 'xls',
-        'application/font-tdpfr' => 'pfr',
-        'application/futuresplash' => 'spl',
-        'application/hstu' => 'stk',
-        'application/hyperstudio' => 'stk',
-        'application/javascript' => 'js',
-        'application/mac-binhex40' => 'hqx',
-        'application/mac-compactpro' => 'cpt',
-        'application/mbed' => 'mbd',
-        'application/mirage' => 'mfp',
-        'application/msword' => 'doc',
-        'application/ocsp-request' => 'orq',
-        'application/ocsp-response' => 'ors',
-        'application/octet-stream' => 'bin',
-        'application/oda' => 'oda',
-        'application/ogg' => 'ogg',
-        'application/pdf' => 'pdf',
-        'application/x-pdf' => 'pdf',
-        'application/pgp-encrypted' => '7bit',
-        'application/pgp-keys' => '7bit',
-        'application/pgp-signature' => 'sig',
-        'application/pkcs10' => 'p10',
-        'application/pkcs7-mime' => 'p7m',
-        'application/pkcs7-signature' => 'p7s',
-        'application/pkix-cert' => 'cer',
-        'application/pkix-crl' => 'crl',
-        'application/pkix-pkipath' => 'pkipath',
-        'application/pkixcmp' => 'pki',
-        'application/postscript' => 'ps',
-        'application/presentations' => 'shw',
-        'application/prs.cww' => 'cw',
-        'application/prs.nprend' => 'rnd',
-        'application/quest' => 'qrt',
-        'application/rtf' => 'rtf',
-        'application/sgml-open-catalog' => 'soc',
-        'application/sieve' => 'siv',
-        'application/smil' => 'smi',
-        'application/toolbook' => 'tbk',
-        'application/vnd.3gpp.pic-bw-large' => 'plb',
-        'application/vnd.3gpp.pic-bw-small' => 'psb',
-        'application/vnd.3gpp.pic-bw-var' => 'pvb',
-        'application/vnd.3gpp.sms' => 'sms',
-        'application/vnd.acucorp' => 'atc',
-        'application/vnd.adobe.xfdf' => 'xfdf',
-        'application/vnd.amiga.amu' => 'ami',
-        'application/vnd.blueice.multipass' => 'mpm',
-        'application/vnd.cinderella' => 'cdy',
-        'application/vnd.cosmocaller' => 'cmc',
-        'application/vnd.criticaltools.wbs+xml' => 'wbs',
-        'application/vnd.curl' => 'curl',
-        'application/vnd.data-vision.rdz' => 'rdz',
-        'application/vnd.dreamfactory' => 'dfac',
-        'application/vnd.fsc.weblaunch' => 'fsc',
-        'application/vnd.genomatix.tuxedo' => 'txd',
-        'application/vnd.hbci' => 'hbci',
-        'application/vnd.hhe.lesson-player' => 'les',
-        'application/vnd.hp-hpgl' => 'plt',
-        'application/vnd.ibm.electronic-media' => 'emm',
-        'application/vnd.ibm.rights-management' => 'irm',
-        'application/vnd.ibm.secure-container' => 'sc',
-        'application/vnd.ipunplugged.rcprofile' => 'rcprofile',
-        'application/vnd.irepository.package+xml' => 'irp',
-        'application/vnd.jisp' => 'jisp',
-        'application/vnd.kde.karbon' => 'karbon',
-        'application/vnd.kde.kchart' => 'chrt',
-        'application/vnd.kde.kformula' => 'kfo',
-        'application/vnd.kde.kivio' => 'flw',
-        'application/vnd.kde.kontour' => 'kon',
-        'application/vnd.kde.kpresenter' => 'kpr',
-        'application/vnd.kde.kspread' => 'ksp',
-        'application/vnd.kde.kword' => 'kwd',
-        'application/vnd.kenameapp' => 'htke',
-        'application/vnd.kidspiration' => 'kia',
-        'application/vnd.kinar' => 'kne',
-        'application/vnd.llamagraphics.life-balance.desktop' => 'lbd',
-        'application/vnd.llamagraphics.life-balance.exchange+xml' => 'lbe',
-        'application/vnd.lotus-1-2-3' => 'wks',
-        'application/vnd.mcd' => 'mcd',
-        'application/vnd.mfmp' => 'mfm',
-        'application/vnd.micrografx.flo' => 'flo',
-        'application/vnd.micrografx.igx' => 'igx',
-        'application/vnd.mif' => 'mif',
-        'application/vnd.mophun.application' => 'mpn',
-        'application/vnd.mophun.certificate' => 'mpc',
-        'application/vnd.mozilla.xul+xml' => 'xul',
-        'application/vnd.ms-artgalry' => 'cil',
-        'application/vnd.ms-asf' => 'asf',
-        'application/vnd.ms-excel' => 'xls',
-        'application/vnd.ms-excel.sheet.macroenabled.12' => 'xlsm',
-        'application/vnd.ms-lrm' => 'lrm',
-        'application/vnd.ms-powerpoint' => 'ppt',
-        'application/vnd.ms-project' => 'mpp',
-        'application/vnd.ms-tnef' => 'base64',
-        'application/vnd.ms-works' => 'base64',
-        'application/vnd.ms-wpl' => 'wpl',
-        'application/vnd.mseq' => 'mseq',
-        'application/vnd.nervana' => 'ent',
-        'application/vnd.nokia.radio-preset' => 'rpst',
-        'application/vnd.nokia.radio-presets' => 'rpss',
-        'application/vnd.oasis.opendocument.text' => 'odt',
-        'application/vnd.oasis.opendocument.text-template' => 'ott',
-        'application/vnd.oasis.opendocument.text-web' => 'oth',
-        'application/vnd.oasis.opendocument.text-master' => 'odm',
-        'application/vnd.oasis.opendocument.graphics' => 'odg',
-        'application/vnd.oasis.opendocument.graphics-template' => 'otg',
-        'application/vnd.oasis.opendocument.presentation' => 'odp',
-        'application/vnd.oasis.opendocument.presentation-template' => 'otp',
-        'application/vnd.oasis.opendocument.spreadsheet' => 'ods',
-        'application/vnd.oasis.opendocument.spreadsheet-template' => 'ots',
-        'application/vnd.oasis.opendocument.chart' => 'odc',
-        'application/vnd.oasis.opendocument.formula' => 'odf',
-        'application/vnd.oasis.opendocument.database' => 'odb',
-        'application/vnd.oasis.opendocument.image' => 'odi',
-        'application/vnd.openxmlformats-officedocument.wordprocessingml.document' => 'docx',
-        'application/vnd.openxmlformats-officedocument.wordprocessingml.template' => 'dotx',
-        'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' => 'xlsx',
-        'application/vnd.openxmlformats-officedocument.presentationml.presentation' => 'pptx',
-        'application/vnd.palm' => 'prc',
-        'application/vnd.picsel' => 'efif',
-        'application/vnd.pvi.ptid1' => 'pti',
-        'application/vnd.quark.quarkxpress' => 'qxd',
-        'application/vnd.sealed.doc' => 'sdoc',
-        'application/vnd.sealed.eml' => 'seml',
-        'application/vnd.sealed.mht' => 'smht',
-        'application/vnd.sealed.ppt' => 'sppt',
-        'application/vnd.sealed.xls' => 'sxls',
-        'application/vnd.sealedmedia.softseal.html' => 'stml',
-        'application/vnd.sealedmedia.softseal.pdf' => 'spdf',
-        'application/vnd.seemail' => 'see',
-        'application/vnd.smaf' => 'mmf',
-        'application/vnd.sun.xml.calc' => 'sxc',
-        'application/vnd.sun.xml.calc.template' => 'stc',
-        'application/vnd.sun.xml.draw' => 'sxd',
-        'application/vnd.sun.xml.draw.template' => 'std',
-        'application/vnd.sun.xml.impress' => 'sxi',
-        'application/vnd.sun.xml.impress.template' => 'sti',
-        'application/vnd.sun.xml.math' => 'sxm',
-        'application/vnd.sun.xml.writer' => 'sxw',
-        'application/vnd.sun.xml.writer.global' => 'sxg',
-        'application/vnd.sun.xml.writer.template' => 'stw',
-        'application/vnd.sus-calendar' => 'sus',
-        'application/vnd.vidsoft.vidconference' => 'vsc',
-        'application/vnd.visio' => 'vsd',
-        'application/vnd.visionary' => 'vis',
-        'application/vnd.wap.sic' => 'sic',
-        'application/vnd.wap.slc' => 'slc',
-        'application/vnd.wap.wbxml' => 'wbxml',
-        'application/vnd.wap.wmlc' => 'wmlc',
-        'application/vnd.wap.wmlscriptc' => 'wmlsc',
-        'application/vnd.webturbo' => 'wtb',
-        'application/vnd.wordperfect' => 'wpd',
-        'application/vnd.wqd' => 'wqd',
-        'application/vnd.wv.csp+wbxml' => 'wv',
-        'application/vnd.wv.csp+xml' => '8bit',
-        'application/vnd.wv.ssp+xml' => '8bit',
-        'application/vnd.yamaha.hv-dic' => 'hvd',
-        'application/vnd.yamaha.hv-script' => 'hvs',
-        'application/vnd.yamaha.hv-voice' => 'hvp',
-        'application/vnd.yamaha.smaf-audio' => 'saf',
-        'application/vnd.yamaha.smaf-phrase' => 'spf',
-        'application/vocaltec-media-desc' => 'vmd',
-        'application/vocaltec-media-file' => 'vmf',
-        'application/vocaltec-talker' => 'vtk',
-        'application/watcherinfo+xml' => 'wif',
-        'application/wordperfect5.1' => 'wp5',
-        'application/x-123' => 'wk',
-        'application/x-7th_level_event' => '7ls',
-        'application/x-authorware-bin' => 'aab',
-        'application/x-authorware-map' => 'aam',
-        'application/x-authorware-seg' => 'aas',
-        'application/x-bcpio' => 'bcpio',
-        'application/x-bleeper' => 'bleep',
-        'application/x-bzip2' => 'bz2',
-        'application/x-cdlink' => 'vcd',
-        'application/x-chat' => 'chat',
-        'application/x-chess-pgn' => 'pgn',
-        'application/x-compress' => 'z',
-        'application/x-cpio' => 'cpio',
-        'application/x-cprplayer' => 'pqf',
-        'application/x-csh' => 'csh',
-        'application/x-cu-seeme' => 'csm',
-        'application/x-cult3d-object' => 'co',
-        'application/x-debian-package' => 'deb',
-        'application/x-director' => 'dcr',
-        'application/x-dvi' => 'dvi',
-        'application/x-envoy' => 'evy',
-        'application/x-futuresplash' => 'spl',
-        'application/x-gtar' => 'gtar',
-        'application/x-gzip' => 'gz',
-        'application/x-hdf' => 'hdf',
-        'application/x-hep' => 'hep',
-        'application/x-html+ruby' => 'rhtml',
-        'application/x-httpd-miva' => 'mv',
-        'application/x-httpd-php' => 'phtml',
-        'application/x-ica' => 'ica',
-        'application/x-imagemap' => 'imagemap',
-        'application/x-ipix' => 'ipx',
-        'application/x-ipscript' => 'ips',
-        'application/x-java-archive' => 'jar',
-        'application/x-java-jnlp-file' => 'jnlp',
-        'application/x-java-serialized-object' => 'ser',
-        'application/x-java-vm' => 'class',
-        'application/x-javascript' => 'js',
-        'application/x-koan' => 'skp',
-        'application/x-latex' => 'latex',
-        'application/x-mac-compactpro' => 'cpt',
-        'application/x-maker' => 'frm',
-        'application/x-mathcad' => 'mcd',
-        'application/x-midi' => 'mid',
-        'application/x-mif' => 'mif',
-        'application/x-msaccess' => 'mda',
-        'application/x-msdos-program' => 'com',
-        'application/x-msdownload' => 'base64',
-        'application/x-msexcel' => 'xls',
-        'application/x-msword' => 'doc',
-        'application/x-netcdf' => 'nc',
-        'application/x-ns-proxy-autoconfig' => 'pac',
-        'application/x-pagemaker' => 'pm5',
-        'application/x-perl' => 'pl',
-        'application/x-pn-realmedia' => 'rp',
-        'application/x-python' => 'py',
-        'application/x-quicktimeplayer' => 'qtl',
-        'application/x-rar-compressed' => 'rar',
-        'application/x-ruby' => 'rb',
-        'application/x-sh' => 'sh',
-        'application/x-shar' => 'shar',
-        'application/x-shockwave-flash' => 'swf',
-        'application/x-sprite' => 'spr',
-        'application/x-spss' => 'sav',
-        'application/x-spt' => 'spt',
-        'application/x-stuffit' => 'sit',
-        'application/x-sv4cpio' => 'sv4cpio',
-        'application/x-sv4crc' => 'sv4crc',
-        'application/x-tar' => 'tar',
-        'application/x-tcl' => 'tcl',
-        'application/x-tex' => 'tex',
-        'application/x-texinfo' => 'texinfo',
-        'application/x-troff' => 't',
-        'application/x-troff-man' => 'man',
-        'application/x-troff-me' => 'me',
-        'application/x-troff-ms' => 'ms',
-        'application/x-twinvq' => 'vqf',
-        'application/x-twinvq-plugin' => 'vqe',
-        'application/x-ustar' => 'ustar',
-        'application/x-vmsbackup' => 'bck',
-        'application/x-wais-source' => 'src',
-        'application/x-wingz' => 'wz',
-        'application/x-word' => 'base64',
-        'application/x-wordperfect6.1' => 'wp6',
-        'application/x-x509-ca-cert' => 'crt',
-        'application/x-zip-compressed' => 'zip',
-        'application/xhtml+xml' => 'xhtml',
-        'application/zip' => 'zip',
-        'audio/3gpp' => '3gpp',
-        'audio/amr' => 'amr',
-        'audio/amr-wb' => 'awb',
-        'audio/basic' => 'au',
-        'audio/evrc' => 'evc',
-        'audio/l16' => 'l16',
-        'audio/midi' => 'mid',
-        'audio/mpeg' => 'mp3',
-        'audio/prs.sid' => 'sid',
-        'audio/qcelp' => 'qcp',
-        'audio/smv' => 'smv',
-        'audio/vnd.audiokoz' => 'koz',
-        'audio/vnd.digital-winds' => 'eol',
-        'audio/vnd.everad.plj' => 'plj',
-        'audio/vnd.lucent.voice' => 'lvp',
-        'audio/vnd.nokia.mobile-xmf' => 'mxmf',
-        'audio/vnd.nortel.vbk' => 'vbk',
-        'audio/vnd.nuera.ecelp4800' => 'ecelp4800',
-        'audio/vnd.nuera.ecelp7470' => 'ecelp7470',
-        'audio/vnd.nuera.ecelp9600' => 'ecelp9600',
-        'audio/vnd.sealedmedia.softseal.mpeg' => 'smp3',
-        'audio/voxware' => 'vox',
-        'audio/x-aiff' => 'aif',
-        'audio/x-mid' => 'mid',
-        'audio/x-midi' => 'mid',
-        'audio/x-mpeg' => 'mp2',
-        'audio/x-mpegurl' => 'mpu',
-        'audio/x-pn-realaudio' => 'rm',
-        'audio/x-pn-realaudio-plugin' => 'rpm',
-        'audio/x-realaudio' => 'ra',
-        'audio/x-wav' => 'wav',
-        'chemical/x-csml' => 'csm',
-        'chemical/x-embl-dl-nucleotide' => 'emb',
-        'chemical/x-gaussian-cube' => 'cube',
-        'chemical/x-gaussian-input' => 'gau',
-        'chemical/x-jcamp-dx' => 'jdx',
-        'chemical/x-mdl-molfile' => 'mol',
-        'chemical/x-mdl-rxnfile' => 'rxn',
-        'chemical/x-mdl-tgf' => 'tgf',
-        'chemical/x-mopac-input' => 'mop',
-        'chemical/x-pdb' => 'pdb',
-        'chemical/x-rasmol' => 'scr',
-        'chemical/x-xyz' => 'xyz',
-        'drawing/dwf' => 'dwf',
-        'drawing/x-dwf' => 'dwf',
-        'i-world/i-vrml' => 'ivr',
-        'image/bmp' => 'bmp',
-        'image/cewavelet' => 'wif',
-        'image/cis-cod' => 'cod',
-        'image/fif' => 'fif',
-        'image/gif' => 'gif',
-        'image/ief' => 'ief',
-        'image/jp2' => 'jp2',
-        'image/jpeg' => 'jpg',
-        'image/jpm' => 'jpm',
-        'image/jpx' => 'jpf',
-        'image/pict' => 'pic',
-        'image/pjpeg' => 'jpg',
-        'image/png' => 'png',
-        'image/targa' => 'tga',
-        'image/tiff' => 'tif',
-        'image/vn-svf' => 'svf',
-        'image/vnd.dgn' => 'dgn',
-        'image/vnd.djvu' => 'djvu',
-        'image/vnd.dwg' => 'dwg',
-        'image/vnd.glocalgraphics.pgb' => 'pgb',
-        'image/vnd.microsoft.icon' => 'ico',
-        'image/vnd.ms-modi' => 'mdi',
-        'image/vnd.sealed.png' => 'spng',
-        'image/vnd.sealedmedia.softseal.gif' => 'sgif',
-        'image/vnd.sealedmedia.softseal.jpg' => 'sjpg',
-        'image/vnd.wap.wbmp' => 'wbmp',
-        'image/x-bmp' => 'bmp',
-        'image/x-cmu-raster' => 'ras',
-        'image/x-freehand' => 'fh4',
-        'image/x-png' => 'png',
-        'image/x-portable-anymap' => 'pnm',
-        'image/x-portable-bitmap' => 'pbm',
-        'image/x-portable-graymap' => 'pgm',
-        'image/x-portable-pixmap' => 'ppm',
-        'image/x-rgb' => 'rgb',
-        'image/x-xbitmap' => 'xbm',
-        'image/x-xpixmap' => 'xpm',
-        'image/x-xwindowdump' => 'xwd',
-        'message/external-body' => '8bit',
-        'message/news' => '8bit',
-        'message/partial' => '8bit',
-        'message/rfc822' => '8bit',
-        'model/iges' => 'igs',
-        'model/mesh' => 'msh',
-        'model/vnd.parasolid.transmit.binary' => 'x_b',
-        'model/vnd.parasolid.transmit.text' => 'x_t',
-        'model/vrml' => 'wrl',
-        'multipart/alternative' => '8bit',
-        'multipart/appledouble' => '8bit',
-        'multipart/digest' => '8bit',
-        'multipart/mixed' => '8bit',
-        'multipart/parallel' => '8bit',
-        'text/comma-separated-values' => 'csv',
-        'text/css' => 'css',
-        'text/html' => 'html',
-        'text/plain' => 'txt',
-        'text/prs.fallenstein.rst' => 'rst',
-        'text/richtext' => 'rtx',
-        'text/rtf' => 'rtf',
-        'text/sgml' => 'sgml',
-        'text/tab-separated-values' => 'tsv',
-        'text/vnd.net2phone.commcenter.command' => 'ccc',
-        'text/vnd.sun.j2me.app-descriptor' => 'jad',
-        'text/vnd.wap.si' => 'si',
-        'text/vnd.wap.sl' => 'sl',
-        'text/vnd.wap.wml' => 'wml',
-        'text/vnd.wap.wmlscript' => 'wmls',
-        'text/x-hdml' => 'hdml',
-        'text/x-setext' => 'etx',
-        'text/x-sgml' => 'sgml',
-        'text/x-speech' => 'talk',
-        'text/x-vcalendar' => 'vcs',
-        'text/x-vcard' => 'vcf',
-        'text/xml' => 'xml',
-        'ulead/vrml' => 'uvr',
-        'video/3gpp' => '3gp',
-        'video/dl' => 'dl',
-        'video/gl' => 'gl',
-        'video/mj2' => 'mj2',
-        'video/mpeg' => 'mpeg',
-        'video/quicktime' => 'mov',
-        'video/vdo' => 'vdo',
-        'video/vivo' => 'viv',
-        'video/vnd.fvt' => 'fvt',
-        'video/vnd.mpegurl' => 'mxu',
-        'video/vnd.nokia.interleaved-multimedia' => 'nim',
-        'video/vnd.objectvideo' => 'mp4',
-        'video/vnd.sealed.mpeg1' => 's11',
-        'video/vnd.sealed.mpeg4' => 'smpg',
-        'video/vnd.sealed.swf' => 'sswf',
-        'video/vnd.sealedmedia.softseal.mov' => 'smov',
-        'video/vnd.vivo' => 'vivo',
-        'video/x-fli' => 'fli',
-        'video/x-ms-asf' => 'asf',
-        'video/x-ms-wmv' => 'wmv',
-        'video/x-msvideo' => 'avi',
-        'video/x-sgi-movie' => 'movie',
-        'x-chemical/x-pdb' => 'pdb',
-        'x-chemical/x-xyz' => 'xyz',
-        'x-conference/x-cooltalk' => 'ice',
-        'x-drawing/dwf' => 'dwf',
-        'x-world/x-d96' => 'd',
-        'x-world/x-svr' => 'svr',
-        'x-world/x-vream' => 'vrw',
-        'x-world/x-vrml' => 'wrl',
-    );
+    static private $instance = null;
 
     /**
-     * Returns the extension based on the mime type.
-     *
-     * If the mime type is unknown, returns null.
-     *
-     * @return string|null The guessed extension or null if it cannot be guessed
+     * All registered ExtensionGuesserInterface instances
+     * @var array
      */
-    static function guessExtension($mimeType)
+    protected $guessers = array();
+
+    /**
+     * Returns the singleton instance
+     *
+     * @return ExtensionGuesser
+     */
+    static public function getInstance()
     {
-        return isset(static::$defaultExtensions[$mimeType]) ? static::$defaultExtensions[$mimeType] : null;
+        if (null === self::$instance) {
+            self::$instance = new self();
+        }
+
+        return self::$instance;
     }
 
+    /**
+     * Registers all natively provided extension guessers
+     */
+    private function __construct()
+    {
+        $this->register(new MimeTypeExtensionGuesser());
+    }
+
+    /**
+     * Registers a new extension guesser
+     *
+     * When guessing, this guesser is preferred over previously registered ones.
+     *
+     * @param ExtensionGuesserInterface $guesser
+     */
+    public function register(ExtensionGuesserInterface $guesser)
+    {
+        array_unshift($this->guessers, $guesser);
+    }
+
+    /**
+     * Tries to guess the extension
+     *
+     * The mime type is passed to each registered mime type guesser in reverse order
+     * of their registration (last registered is queried first). Once a guesser
+     * returns a value that is not NULL, this method terminates and returns the
+     * value.
+     *
+     * @param  string $mimeType   The mime type
+     * @return string             The guessed extension or NULL, if none could be guessed
+     */
+    public function guess($mimeType)
+    {
+        foreach ($this->guessers as $guesser) {
+            $extension = $guesser->guess($mimeType);
+
+            if (null !== $extension) {
+                break;
+            }
+        }
+
+        return $extension;
+    }
 }
diff --git a/src/Symfony/Component/HttpFoundation/File/MimeType/ExtensionGuesserInterface.php b/src/Symfony/Component/HttpFoundation/File/MimeType/ExtensionGuesserInterface.php
new file mode 100644
index 0000000000..a55124814e
--- /dev/null
+++ b/src/Symfony/Component/HttpFoundation/File/MimeType/ExtensionGuesserInterface.php
@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpFoundation\File\MimeType;
+
+/**
+ * Guesses the file extension corresponding to a given mime type
+ */
+interface ExtensionGuesserInterface
+{
+    /**
+     * Makes a best guess for a file extension, given a mime type
+     *
+     * @param  string $mimeType   The mime type
+     * @return string             The guessed extension or NULL, if none could be guessed
+     */
+    function guess($mimeType);
+
+}
diff --git a/src/Symfony/Component/HttpFoundation/File/MimeType/MimeTypeExtensionGuesser.php b/src/Symfony/Component/HttpFoundation/File/MimeType/MimeTypeExtensionGuesser.php
new file mode 100644
index 0000000000..3efa93e490
--- /dev/null
+++ b/src/Symfony/Component/HttpFoundation/File/MimeType/MimeTypeExtensionGuesser.php
@@ -0,0 +1,449 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpFoundation\File\Mimetype;
+
+/**
+ * Provides a best-guess mapping of mime type to file extension.
+ */
+class MimeTypeExtensionGuesser implements ExtensionGuesserInterface
+{
+    /**
+     * A map of mime types and their default extensions.
+     *
+     * @var array
+     */
+    protected $defaultExtensions = array(
+        'application/andrew-inset' => 'ez',
+        'application/appledouble' => 'base64',
+        'application/applefile' => 'base64',
+        'application/commonground' => 'dp',
+        'application/cprplayer' => 'pqi',
+        'application/dsptype' => 'tsp',
+        'application/excel' => 'xls',
+        'application/font-tdpfr' => 'pfr',
+        'application/futuresplash' => 'spl',
+        'application/hstu' => 'stk',
+        'application/hyperstudio' => 'stk',
+        'application/javascript' => 'js',
+        'application/mac-binhex40' => 'hqx',
+        'application/mac-compactpro' => 'cpt',
+        'application/mbed' => 'mbd',
+        'application/mirage' => 'mfp',
+        'application/msword' => 'doc',
+        'application/ocsp-request' => 'orq',
+        'application/ocsp-response' => 'ors',
+        'application/octet-stream' => 'bin',
+        'application/oda' => 'oda',
+        'application/ogg' => 'ogg',
+        'application/pdf' => 'pdf',
+        'application/x-pdf' => 'pdf',
+        'application/pgp-encrypted' => '7bit',
+        'application/pgp-keys' => '7bit',
+        'application/pgp-signature' => 'sig',
+        'application/pkcs10' => 'p10',
+        'application/pkcs7-mime' => 'p7m',
+        'application/pkcs7-signature' => 'p7s',
+        'application/pkix-cert' => 'cer',
+        'application/pkix-crl' => 'crl',
+        'application/pkix-pkipath' => 'pkipath',
+        'application/pkixcmp' => 'pki',
+        'application/postscript' => 'ps',
+        'application/presentations' => 'shw',
+        'application/prs.cww' => 'cw',
+        'application/prs.nprend' => 'rnd',
+        'application/quest' => 'qrt',
+        'application/rtf' => 'rtf',
+        'application/sgml-open-catalog' => 'soc',
+        'application/sieve' => 'siv',
+        'application/smil' => 'smi',
+        'application/toolbook' => 'tbk',
+        'application/vnd.3gpp.pic-bw-large' => 'plb',
+        'application/vnd.3gpp.pic-bw-small' => 'psb',
+        'application/vnd.3gpp.pic-bw-var' => 'pvb',
+        'application/vnd.3gpp.sms' => 'sms',
+        'application/vnd.acucorp' => 'atc',
+        'application/vnd.adobe.xfdf' => 'xfdf',
+        'application/vnd.amiga.amu' => 'ami',
+        'application/vnd.blueice.multipass' => 'mpm',
+        'application/vnd.cinderella' => 'cdy',
+        'application/vnd.cosmocaller' => 'cmc',
+        'application/vnd.criticaltools.wbs+xml' => 'wbs',
+        'application/vnd.curl' => 'curl',
+        'application/vnd.data-vision.rdz' => 'rdz',
+        'application/vnd.dreamfactory' => 'dfac',
+        'application/vnd.fsc.weblaunch' => 'fsc',
+        'application/vnd.genomatix.tuxedo' => 'txd',
+        'application/vnd.hbci' => 'hbci',
+        'application/vnd.hhe.lesson-player' => 'les',
+        'application/vnd.hp-hpgl' => 'plt',
+        'application/vnd.ibm.electronic-media' => 'emm',
+        'application/vnd.ibm.rights-management' => 'irm',
+        'application/vnd.ibm.secure-container' => 'sc',
+        'application/vnd.ipunplugged.rcprofile' => 'rcprofile',
+        'application/vnd.irepository.package+xml' => 'irp',
+        'application/vnd.jisp' => 'jisp',
+        'application/vnd.kde.karbon' => 'karbon',
+        'application/vnd.kde.kchart' => 'chrt',
+        'application/vnd.kde.kformula' => 'kfo',
+        'application/vnd.kde.kivio' => 'flw',
+        'application/vnd.kde.kontour' => 'kon',
+        'application/vnd.kde.kpresenter' => 'kpr',
+        'application/vnd.kde.kspread' => 'ksp',
+        'application/vnd.kde.kword' => 'kwd',
+        'application/vnd.kenameapp' => 'htke',
+        'application/vnd.kidspiration' => 'kia',
+        'application/vnd.kinar' => 'kne',
+        'application/vnd.llamagraphics.life-balance.desktop' => 'lbd',
+        'application/vnd.llamagraphics.life-balance.exchange+xml' => 'lbe',
+        'application/vnd.lotus-1-2-3' => 'wks',
+        'application/vnd.mcd' => 'mcd',
+        'application/vnd.mfmp' => 'mfm',
+        'application/vnd.micrografx.flo' => 'flo',
+        'application/vnd.micrografx.igx' => 'igx',
+        'application/vnd.mif' => 'mif',
+        'application/vnd.mophun.application' => 'mpn',
+        'application/vnd.mophun.certificate' => 'mpc',
+        'application/vnd.mozilla.xul+xml' => 'xul',
+        'application/vnd.ms-artgalry' => 'cil',
+        'application/vnd.ms-asf' => 'asf',
+        'application/vnd.ms-excel' => 'xls',
+        'application/vnd.ms-excel.sheet.macroenabled.12' => 'xlsm',
+        'application/vnd.ms-lrm' => 'lrm',
+        'application/vnd.ms-powerpoint' => 'ppt',
+        'application/vnd.ms-project' => 'mpp',
+        'application/vnd.ms-tnef' => 'base64',
+        'application/vnd.ms-works' => 'base64',
+        'application/vnd.ms-wpl' => 'wpl',
+        'application/vnd.mseq' => 'mseq',
+        'application/vnd.nervana' => 'ent',
+        'application/vnd.nokia.radio-preset' => 'rpst',
+        'application/vnd.nokia.radio-presets' => 'rpss',
+        'application/vnd.oasis.opendocument.text' => 'odt',
+        'application/vnd.oasis.opendocument.text-template' => 'ott',
+        'application/vnd.oasis.opendocument.text-web' => 'oth',
+        'application/vnd.oasis.opendocument.text-master' => 'odm',
+        'application/vnd.oasis.opendocument.graphics' => 'odg',
+        'application/vnd.oasis.opendocument.graphics-template' => 'otg',
+        'application/vnd.oasis.opendocument.presentation' => 'odp',
+        'application/vnd.oasis.opendocument.presentation-template' => 'otp',
+        'application/vnd.oasis.opendocument.spreadsheet' => 'ods',
+        'application/vnd.oasis.opendocument.spreadsheet-template' => 'ots',
+        'application/vnd.oasis.opendocument.chart' => 'odc',
+        'application/vnd.oasis.opendocument.formula' => 'odf',
+        'application/vnd.oasis.opendocument.database' => 'odb',
+        'application/vnd.oasis.opendocument.image' => 'odi',
+        'application/vnd.openxmlformats-officedocument.wordprocessingml.document' => 'docx',
+        'application/vnd.openxmlformats-officedocument.wordprocessingml.template' => 'dotx',
+        'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' => 'xlsx',
+        'application/vnd.openxmlformats-officedocument.presentationml.presentation' => 'pptx',
+        'application/vnd.palm' => 'prc',
+        'application/vnd.picsel' => 'efif',
+        'application/vnd.pvi.ptid1' => 'pti',
+        'application/vnd.quark.quarkxpress' => 'qxd',
+        'application/vnd.sealed.doc' => 'sdoc',
+        'application/vnd.sealed.eml' => 'seml',
+        'application/vnd.sealed.mht' => 'smht',
+        'application/vnd.sealed.ppt' => 'sppt',
+        'application/vnd.sealed.xls' => 'sxls',
+        'application/vnd.sealedmedia.softseal.html' => 'stml',
+        'application/vnd.sealedmedia.softseal.pdf' => 'spdf',
+        'application/vnd.seemail' => 'see',
+        'application/vnd.smaf' => 'mmf',
+        'application/vnd.sun.xml.calc' => 'sxc',
+        'application/vnd.sun.xml.calc.template' => 'stc',
+        'application/vnd.sun.xml.draw' => 'sxd',
+        'application/vnd.sun.xml.draw.template' => 'std',
+        'application/vnd.sun.xml.impress' => 'sxi',
+        'application/vnd.sun.xml.impress.template' => 'sti',
+        'application/vnd.sun.xml.math' => 'sxm',
+        'application/vnd.sun.xml.writer' => 'sxw',
+        'application/vnd.sun.xml.writer.global' => 'sxg',
+        'application/vnd.sun.xml.writer.template' => 'stw',
+        'application/vnd.sus-calendar' => 'sus',
+        'application/vnd.vidsoft.vidconference' => 'vsc',
+        'application/vnd.visio' => 'vsd',
+        'application/vnd.visionary' => 'vis',
+        'application/vnd.wap.sic' => 'sic',
+        'application/vnd.wap.slc' => 'slc',
+        'application/vnd.wap.wbxml' => 'wbxml',
+        'application/vnd.wap.wmlc' => 'wmlc',
+        'application/vnd.wap.wmlscriptc' => 'wmlsc',
+        'application/vnd.webturbo' => 'wtb',
+        'application/vnd.wordperfect' => 'wpd',
+        'application/vnd.wqd' => 'wqd',
+        'application/vnd.wv.csp+wbxml' => 'wv',
+        'application/vnd.wv.csp+xml' => '8bit',
+        'application/vnd.wv.ssp+xml' => '8bit',
+        'application/vnd.yamaha.hv-dic' => 'hvd',
+        'application/vnd.yamaha.hv-script' => 'hvs',
+        'application/vnd.yamaha.hv-voice' => 'hvp',
+        'application/vnd.yamaha.smaf-audio' => 'saf',
+        'application/vnd.yamaha.smaf-phrase' => 'spf',
+        'application/vocaltec-media-desc' => 'vmd',
+        'application/vocaltec-media-file' => 'vmf',
+        'application/vocaltec-talker' => 'vtk',
+        'application/watcherinfo+xml' => 'wif',
+        'application/wordperfect5.1' => 'wp5',
+        'application/x-123' => 'wk',
+        'application/x-7th_level_event' => '7ls',
+        'application/x-authorware-bin' => 'aab',
+        'application/x-authorware-map' => 'aam',
+        'application/x-authorware-seg' => 'aas',
+        'application/x-bcpio' => 'bcpio',
+        'application/x-bleeper' => 'bleep',
+        'application/x-bzip2' => 'bz2',
+        'application/x-cdlink' => 'vcd',
+        'application/x-chat' => 'chat',
+        'application/x-chess-pgn' => 'pgn',
+        'application/x-compress' => 'z',
+        'application/x-cpio' => 'cpio',
+        'application/x-cprplayer' => 'pqf',
+        'application/x-csh' => 'csh',
+        'application/x-cu-seeme' => 'csm',
+        'application/x-cult3d-object' => 'co',
+        'application/x-debian-package' => 'deb',
+        'application/x-director' => 'dcr',
+        'application/x-dvi' => 'dvi',
+        'application/x-envoy' => 'evy',
+        'application/x-futuresplash' => 'spl',
+        'application/x-gtar' => 'gtar',
+        'application/x-gzip' => 'gz',
+        'application/x-hdf' => 'hdf',
+        'application/x-hep' => 'hep',
+        'application/x-html+ruby' => 'rhtml',
+        'application/x-httpd-miva' => 'mv',
+        'application/x-httpd-php' => 'phtml',
+        'application/x-ica' => 'ica',
+        'application/x-imagemap' => 'imagemap',
+        'application/x-ipix' => 'ipx',
+        'application/x-ipscript' => 'ips',
+        'application/x-java-archive' => 'jar',
+        'application/x-java-jnlp-file' => 'jnlp',
+        'application/x-java-serialized-object' => 'ser',
+        'application/x-java-vm' => 'class',
+        'application/x-javascript' => 'js',
+        'application/x-koan' => 'skp',
+        'application/x-latex' => 'latex',
+        'application/x-mac-compactpro' => 'cpt',
+        'application/x-maker' => 'frm',
+        'application/x-mathcad' => 'mcd',
+        'application/x-midi' => 'mid',
+        'application/x-mif' => 'mif',
+        'application/x-msaccess' => 'mda',
+        'application/x-msdos-program' => 'com',
+        'application/x-msdownload' => 'base64',
+        'application/x-msexcel' => 'xls',
+        'application/x-msword' => 'doc',
+        'application/x-netcdf' => 'nc',
+        'application/x-ns-proxy-autoconfig' => 'pac',
+        'application/x-pagemaker' => 'pm5',
+        'application/x-perl' => 'pl',
+        'application/x-pn-realmedia' => 'rp',
+        'application/x-python' => 'py',
+        'application/x-quicktimeplayer' => 'qtl',
+        'application/x-rar-compressed' => 'rar',
+        'application/x-ruby' => 'rb',
+        'application/x-sh' => 'sh',
+        'application/x-shar' => 'shar',
+        'application/x-shockwave-flash' => 'swf',
+        'application/x-sprite' => 'spr',
+        'application/x-spss' => 'sav',
+        'application/x-spt' => 'spt',
+        'application/x-stuffit' => 'sit',
+        'application/x-sv4cpio' => 'sv4cpio',
+        'application/x-sv4crc' => 'sv4crc',
+        'application/x-tar' => 'tar',
+        'application/x-tcl' => 'tcl',
+        'application/x-tex' => 'tex',
+        'application/x-texinfo' => 'texinfo',
+        'application/x-troff' => 't',
+        'application/x-troff-man' => 'man',
+        'application/x-troff-me' => 'me',
+        'application/x-troff-ms' => 'ms',
+        'application/x-twinvq' => 'vqf',
+        'application/x-twinvq-plugin' => 'vqe',
+        'application/x-ustar' => 'ustar',
+        'application/x-vmsbackup' => 'bck',
+        'application/x-wais-source' => 'src',
+        'application/x-wingz' => 'wz',
+        'application/x-word' => 'base64',
+        'application/x-wordperfect6.1' => 'wp6',
+        'application/x-x509-ca-cert' => 'crt',
+        'application/x-zip-compressed' => 'zip',
+        'application/xhtml+xml' => 'xhtml',
+        'application/zip' => 'zip',
+        'audio/3gpp' => '3gpp',
+        'audio/amr' => 'amr',
+        'audio/amr-wb' => 'awb',
+        'audio/basic' => 'au',
+        'audio/evrc' => 'evc',
+        'audio/l16' => 'l16',
+        'audio/midi' => 'mid',
+        'audio/mpeg' => 'mp3',
+        'audio/prs.sid' => 'sid',
+        'audio/qcelp' => 'qcp',
+        'audio/smv' => 'smv',
+        'audio/vnd.audiokoz' => 'koz',
+        'audio/vnd.digital-winds' => 'eol',
+        'audio/vnd.everad.plj' => 'plj',
+        'audio/vnd.lucent.voice' => 'lvp',
+        'audio/vnd.nokia.mobile-xmf' => 'mxmf',
+        'audio/vnd.nortel.vbk' => 'vbk',
+        'audio/vnd.nuera.ecelp4800' => 'ecelp4800',
+        'audio/vnd.nuera.ecelp7470' => 'ecelp7470',
+        'audio/vnd.nuera.ecelp9600' => 'ecelp9600',
+        'audio/vnd.sealedmedia.softseal.mpeg' => 'smp3',
+        'audio/voxware' => 'vox',
+        'audio/x-aiff' => 'aif',
+        'audio/x-mid' => 'mid',
+        'audio/x-midi' => 'mid',
+        'audio/x-mpeg' => 'mp2',
+        'audio/x-mpegurl' => 'mpu',
+        'audio/x-pn-realaudio' => 'rm',
+        'audio/x-pn-realaudio-plugin' => 'rpm',
+        'audio/x-realaudio' => 'ra',
+        'audio/x-wav' => 'wav',
+        'chemical/x-csml' => 'csm',
+        'chemical/x-embl-dl-nucleotide' => 'emb',
+        'chemical/x-gaussian-cube' => 'cube',
+        'chemical/x-gaussian-input' => 'gau',
+        'chemical/x-jcamp-dx' => 'jdx',
+        'chemical/x-mdl-molfile' => 'mol',
+        'chemical/x-mdl-rxnfile' => 'rxn',
+        'chemical/x-mdl-tgf' => 'tgf',
+        'chemical/x-mopac-input' => 'mop',
+        'chemical/x-pdb' => 'pdb',
+        'chemical/x-rasmol' => 'scr',
+        'chemical/x-xyz' => 'xyz',
+        'drawing/dwf' => 'dwf',
+        'drawing/x-dwf' => 'dwf',
+        'i-world/i-vrml' => 'ivr',
+        'image/bmp' => 'bmp',
+        'image/cewavelet' => 'wif',
+        'image/cis-cod' => 'cod',
+        'image/fif' => 'fif',
+        'image/gif' => 'gif',
+        'image/ief' => 'ief',
+        'image/jp2' => 'jp2',
+        'image/jpeg' => 'jpg',
+        'image/jpm' => 'jpm',
+        'image/jpx' => 'jpf',
+        'image/pict' => 'pic',
+        'image/pjpeg' => 'jpg',
+        'image/png' => 'png',
+        'image/targa' => 'tga',
+        'image/tiff' => 'tif',
+        'image/vn-svf' => 'svf',
+        'image/vnd.dgn' => 'dgn',
+        'image/vnd.djvu' => 'djvu',
+        'image/vnd.dwg' => 'dwg',
+        'image/vnd.glocalgraphics.pgb' => 'pgb',
+        'image/vnd.microsoft.icon' => 'ico',
+        'image/vnd.ms-modi' => 'mdi',
+        'image/vnd.sealed.png' => 'spng',
+        'image/vnd.sealedmedia.softseal.gif' => 'sgif',
+        'image/vnd.sealedmedia.softseal.jpg' => 'sjpg',
+        'image/vnd.wap.wbmp' => 'wbmp',
+        'image/x-bmp' => 'bmp',
+        'image/x-cmu-raster' => 'ras',
+        'image/x-freehand' => 'fh4',
+        'image/x-png' => 'png',
+        'image/x-portable-anymap' => 'pnm',
+        'image/x-portable-bitmap' => 'pbm',
+        'image/x-portable-graymap' => 'pgm',
+        'image/x-portable-pixmap' => 'ppm',
+        'image/x-rgb' => 'rgb',
+        'image/x-xbitmap' => 'xbm',
+        'image/x-xpixmap' => 'xpm',
+        'image/x-xwindowdump' => 'xwd',
+        'message/external-body' => '8bit',
+        'message/news' => '8bit',
+        'message/partial' => '8bit',
+        'message/rfc822' => '8bit',
+        'model/iges' => 'igs',
+        'model/mesh' => 'msh',
+        'model/vnd.parasolid.transmit.binary' => 'x_b',
+        'model/vnd.parasolid.transmit.text' => 'x_t',
+        'model/vrml' => 'wrl',
+        'multipart/alternative' => '8bit',
+        'multipart/appledouble' => '8bit',
+        'multipart/digest' => '8bit',
+        'multipart/mixed' => '8bit',
+        'multipart/parallel' => '8bit',
+        'text/comma-separated-values' => 'csv',
+        'text/css' => 'css',
+        'text/html' => 'html',
+        'text/plain' => 'txt',
+        'text/prs.fallenstein.rst' => 'rst',
+        'text/richtext' => 'rtx',
+        'text/rtf' => 'rtf',
+        'text/sgml' => 'sgml',
+        'text/tab-separated-values' => 'tsv',
+        'text/vnd.net2phone.commcenter.command' => 'ccc',
+        'text/vnd.sun.j2me.app-descriptor' => 'jad',
+        'text/vnd.wap.si' => 'si',
+        'text/vnd.wap.sl' => 'sl',
+        'text/vnd.wap.wml' => 'wml',
+        'text/vnd.wap.wmlscript' => 'wmls',
+        'text/x-hdml' => 'hdml',
+        'text/x-setext' => 'etx',
+        'text/x-sgml' => 'sgml',
+        'text/x-speech' => 'talk',
+        'text/x-vcalendar' => 'vcs',
+        'text/x-vcard' => 'vcf',
+        'text/xml' => 'xml',
+        'ulead/vrml' => 'uvr',
+        'video/3gpp' => '3gp',
+        'video/dl' => 'dl',
+        'video/gl' => 'gl',
+        'video/mj2' => 'mj2',
+        'video/mpeg' => 'mpeg',
+        'video/quicktime' => 'mov',
+        'video/vdo' => 'vdo',
+        'video/vivo' => 'viv',
+        'video/vnd.fvt' => 'fvt',
+        'video/vnd.mpegurl' => 'mxu',
+        'video/vnd.nokia.interleaved-multimedia' => 'nim',
+        'video/vnd.objectvideo' => 'mp4',
+        'video/vnd.sealed.mpeg1' => 's11',
+        'video/vnd.sealed.mpeg4' => 'smpg',
+        'video/vnd.sealed.swf' => 'sswf',
+        'video/vnd.sealedmedia.softseal.mov' => 'smov',
+        'video/vnd.vivo' => 'vivo',
+        'video/x-fli' => 'fli',
+        'video/x-ms-asf' => 'asf',
+        'video/x-ms-wmv' => 'wmv',
+        'video/x-msvideo' => 'avi',
+        'video/x-sgi-movie' => 'movie',
+        'x-chemical/x-pdb' => 'pdb',
+        'x-chemical/x-xyz' => 'xyz',
+        'x-conference/x-cooltalk' => 'ice',
+        'x-drawing/dwf' => 'dwf',
+        'x-world/x-d96' => 'd',
+        'x-world/x-svr' => 'svr',
+        'x-world/x-vream' => 'vrw',
+        'x-world/x-vrml' => 'wrl',
+    );
+
+    /**
+     * Returns the extension based on the mime type.
+     *
+     * If the mime type is unknown, returns null.
+     *
+     * @return string|null The guessed extension or null if it cannot be guessed
+     */
+    public function guess($mimeType)
+    {
+        return isset($this->defaultExtensions[$mimeType]) ? $this->defaultExtensions[$mimeType] : null;
+    }
+
+}