context: // --------------------------------------------------------------------------
  // <copyright file="MimeHelpers.cs" company="-">
  //   Copyright (c) 2008-2019 Eser Ozvataf (eser@ozvataf.com). All rights reserved.
  //   Licensed under the Apache-2.0 license. See LICENSE file in the project root
  //   for full license information.
  //
  //   Web: http://eser.ozvataf.com/ GitHub: http://github.com/eserozvataf
  // </copyright>
  // <author>Eser Ozvataf (eser@ozvataf.com)</author>
  // --------------------------------------------------------------------------
  
  using System;
  using System.Collections.Generic;
  
  namespace Tassle {
      /// <summary>
      /// MimeUtils class.
      /// </summary>
      public static class MimeHelpers {
          // fields
  
          /// <summary>
          /// The mappings
          /// </summary>
          private static IDictionary<string, string> mappings = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
          {
              // combination of values from Windows 7 Registry and
              // from C:\Windows\System32\inetsrv\config\applicationHost.config
              // some added, including .7z and .dat
              { ".323", "text/h323" },
              { ".3g2", "video/3gpp2" },
              { ".3gp", "video/3gpp" },
              { ".3gp2", "video/3gpp2" },
              { ".3gpp", "video/3gpp" },
              { ".7z", "application/x-7z-compressed" },
              { ".aa", "audio/audible" },
              { ".AAC", "audio/aac" },
              { ".aaf", "application/octet-stream" },
              { ".aax", "audio/vnd.audible.aax" },
              { ".ac3", "audio/ac3" },
              { ".aca", "application/octet-stream" },
              { ".accda", "application/msaccess.addin" },
              { ".accdb", "application/msaccess" },
              { ".accdc", "application/msaccess.cab" },
              { ".accde", "application/msaccess" },
              { ".accdr", "application/msaccess.runtime" },
              { ".accdt", "application/msaccess" },
              { ".accdw", "application/msaccess.webapplication" },
              { ".accft", "application/msaccess.ftemplate" },
              { ".acx", "application/internet-property-stream" },
              { ".AddIn", "text/xml" },
              { ".ade", "application/msaccess" },
              { ".adobebridge", "application/x-bridge-url" },
              { ".adp", "application/msaccess" },
              { ".ADT", "audio/vnd.dlna.adts" },
              { ".ADTS", "audio/aac" },
              { ".afm", "application/octet-stream" },
              { ".ai", "application/postscript" },
              { ".aif", "audio/x-aiff" },
              { ".aifc", "audio/aiff" },
              { ".aiff", "audio/aiff" },
              { ".air", "application/vnd.adobe.air-application-installer-package+zip" },
              { ".amc", "application/x-mpeg" },
              { ".application", "application/x-ms-application" },
              { ".art", "image/x-jg" },
              { ".asa", "application/xml" },
              { ".asax", "application/xml" },
              { ".ascx", "application/xml" },
              { ".asd", "application/octet-stream" },
              { ".asf", "video/x-ms-asf" },
              { ".ashx", "application/xml" },
              { ".asi", "application/octet-stream" },
              { ".asm", "text/plain" },
              { ".asmx", "application/xml" },
              { ".aspx", "application/xml" },
              { ".asr", "video/x-ms-asf" },
              { ".asx", "video/x-ms-asf" },
              { ".atom", "application/atom+xml" },
              { ".au", "audio/basic" },
              { ".avi", "video/x-msvideo" },
              { ".axs", "application/olescript" },
              { ".bas", "text/plain" },
              { ".bcpio", "application/x-bcpio" },
              { ".bin", "application/octet-stream" },
              { ".bmp", "image/bmp" },
              { ".c", "text/plain" },
              { ".cab", "application/octet-stream" },
              { ".caf", "audio/x-caf" },
              { ".calx", "application/vnd.ms-office.calx" },
              { ".cat", "application/vnd.ms-pki.seccat" },
              { ".cc", "text/plain" },
              { ".cd", "text/plain" },
              { ".cdda", "audio/aiff" },
              { ".cdf", "application/x-cdf" },
              { ".cer", "application/x-x509-ca-cert" },
              { ".chm", "application/octet-stream" },
              { ".class", "application/x-java-applet" },
              { ".clp", "application/x-msclip" },
              { ".cmx", "image/x-cmx" },
              { ".cnf", "text/plain" },
              { ".cod", "image/cis-cod" },
              { ".config", "application/xml" },
              { ".contact", "text/x-ms-contact" },
              { ".coverage", "application/xml" },
              { ".cpio", "application/x-cpio" },
              { ".cpp", "text/plain" },
              { ".crd", "application/x-mscardfile" },
              { ".crl", "application/pkix-crl" },
              { ".crt", "application/x-x509-ca-cert" },
              { ".cs", "text/plain" },
              { ".csdproj", "text/plain" },
              { ".csh", "application/x-csh" },
              { ".csproj", "text/plain" },
              { ".css", "text/css" },
              { ".csv", "application/octet-stream" },
              { ".cur", "application/octet-stream" },
              { ".cxx", "text/plain" },
              { ".dat", "application/octet-stream" },
              { ".datasource", "application/xml" },
              { ".dbproj", "text/plain" },
              { ".dcr", "application/x-director" },
              { ".def", "text/plain" },
              { ".deploy", "application/octet-stream" },
              { ".der", "application/x-x509-ca-cert" },
              { ".dgml", "application/xml" },
              { ".dib", "image/bmp" },
              { ".dif", "video/x-dv" },
              { ".dir", "application/x-director" },
              { ".disco", "text/xml" },
              { ".dll", "application/x-msdownload" },
              { ".dll.config", "text/xml" },
              { ".dlm", "text/dlm" },
              { ".doc", "application/msword" },
              { ".docm", "application/vnd.ms-word.document.macroEnabled.12" },
              { ".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document" },
              { ".dot", "application/msword" },
              { ".dotm", "application/vnd.ms-word.template.macroEnabled.12" },
              { ".dotx", "application/vnd.openxmlformats-officedocument.wordprocessingml.template" },
              { ".dsp", "application/octet-stream" },
              { ".dsw", "text/plain" },
              { ".dtd", "text/xml" },
              { ".dtsConfig", "text/xml" },
              { ".dv", "video/x-dv" },
              { ".dvi", "application/x-dvi" },
              { ".dwf", "drawing/x-dwf" },
              { ".dwp", "application/octet-stream" },
              { ".dxr", "application/x-director" },
              { ".eml", "message/rfc822" },
              { ".emz", "application/octet-stream" },
              { ".eot", "application/octet-stream" },
              { ".eps", "application/postscript" },
              { ".etl", "application/etl" },
              { ".etx", "text/x-setext" },
              { ".evy", "application/envoy" },
              { ".exe", "application/octet-stream" },
              { ".exe.config", "text/xml" },
              { ".fdf", "application/vnd.fdf" },
              { ".fif", "application/fractals" },
              { ".filters", "Application/xml" },
              { ".fla", "application/octet-stream" },
              { ".flr", "x-world/x-vrml" },
              { ".flv", "video/x-flv" },
              { ".fsscript", "application/fsharp-script" },
              { ".fsx", "application/fsharp-script" },
              { ".generictest", "application/xml" },
              { ".gif", "image/gif" },
              { ".group", "text/x-ms-group" },
              { ".gsm", "audio/x-gsm" },
              { ".gtar", "application/x-gtar" },
              { ".gz", "application/x-gzip" },
              { ".h", "text/plain" },
              { ".hdf", "application/x-hdf" },
              { ".hdml", "text/x-hdml" },
              { ".hhc", "application/x-oleobject" },
              { ".hhk", "application/octet-stream" },
              { ".hhp", "application/octet-stream" },
              { ".hlp", "application/winhlp" },
              { ".hpp", "text/plain" },
              { ".hqx", "application/mac-binhex40" },
              { ".hta", "application/hta" },
              { ".htc", "text/x-component" },
              { ".htm", "text/html" },
              { ".html", "text/html" },
              { ".htt", "text/webviewhtml" },
              { ".hxa", "application/xml" },
              { ".hxc", "application/xml" },
              { ".hxd", "application/octet-stream" },
              { ".hxe", "application/xml" },
              { ".hxf", "application/xml" },
              { ".hxh", "application/octet-stream" },
              { ".hxi", "application/octet-stream" },
              { ".hxk", "application/xml" },
              { ".hxq", "application/octet-stream" },
              { ".hxr", "application/octet-stream" },
              { ".hxs", "application/octet-stream" },
              { ".hxt", "text/html" },
              { ".hxv", "application/xml" },
              { ".hxw", "application/octet-stream" },
              { ".hxx", "text/plain" },
              { ".i", "text/plain" },
              { ".ico", "image/x-icon" },
              { ".ics", "application/octet-stream" },
              { ".idl", "text/plain" },
              { ".ief", "image/ief" },
              { ".iii", "application/x-iphone" },
              { ".inc", "text/plain" },
              { ".inf", "application/octet-stream" },
              { ".inl", "text/plain" },
              { ".ins", "application/x-internet-signup" },
              { ".ipa", "application/x-itunes-ipa" },
              { ".ipg", "application/x-itunes-ipg" },
              { ".ipproj", "text/plain" },
              { ".ipsw", "application/x-itunes-ipsw" },
              { ".iqy", "text/x-ms-iqy" },
              { ".isp", "application/x-internet-signup" },
              { ".ite", "application/x-itunes-ite" },
              { ".itlp", "application/x-itunes-itlp" },
              { ".itms", "application/x-itunes-itms" },
              { ".itpc", "application/x-itunes-itpc" },
              { ".IVF", "video/x-ivf" },
              { ".jar", "application/java-archive" },
              { ".java", "application/octet-stream" },
              { ".jck", "application/liquidmotion" },
              { ".jcz", "application/liquidmotion" },
              { ".jfif", "image/pjpeg" },
              { ".jnlp", "application/x-java-jnlp-file" },
              { ".jpb", "application/octet-stream" },
              { ".jpe", "image/jpeg" },
              { ".jpeg", "image/jpeg" },
              { ".jpg", "image/jpeg" },
              { ".js", "application/x-javascript" },
              { ".jsx", "text/jscript" },
              { ".jsxbin", "text/plain" },
              { ".latex", "application/x-latex" },
              { ".library-ms", "application/windows-library+xml" },
              { ".lit", "application/x-ms-reader" },
              { ".loadtest", "application/xml" },
              { ".lpk", "application/octet-stream" },
              { ".lsf", "video/x-la-asf" },
              { ".lst", "text/plain" },
              { ".lsx", "video/x-la-asf" },
              { ".lzh", "application/octet-stream" },
              { ".m13", "application/x-msmediaview" },
              { ".m14", "application/x-msmediaview" },
              { ".m1v", "video/mpeg" },
              { ".m2t", "video/vnd.dlna.mpeg-tts" },
              { ".m2ts", "video/vnd.dlna.mpeg-tts" },
              { ".m2v", "video/mpeg" },
              { ".m3u", "audio/x-mpegurl" },
              { ".m3u8", "audio/x-mpegurl" },
              { ".m4a", "audio/m4a" },
              { ".m4b", "audio/m4b" },
              { ".m4p", "audio/m4p" },
              { ".m4r", "audio/x-m4r" },
              { ".m4v", "video/x-m4v" },
              { ".mac", "image/x-macpaint" },
              { ".mak", "text/plain" },
              { ".man", "application/x-troff-man" },
              { ".manifest", "application/x-ms-manifest" },
              { ".map", "text/plain" },
              { ".master", "application/xml" },
              { ".mda", "application/msaccess" },
              { ".mdb", "application/x-msaccess" },
              { ".mde", "application/msaccess" },
              { ".mdp", "application/octet-stream" },
              { ".me", "application/x-troff-me" },
              { ".mfp", "application/x-shockwave-flash" },
              { ".mht", "message/rfc822" },
              { ".mhtml", "message/rfc822" },
              { ".mid", "audio/mid" },
              { ".midi", "audio/mid" },
              { ".mix", "application/octet-stream" },
              { ".mk", "text/plain" },
              { ".mmf", "application/x-smaf" },
              { ".mno", "text/xml" },
              { ".mny", "application/x-msmoney" },
              { ".mod", "video/mpeg" },
              { ".mov", "video/quicktime" },
              { ".movie", "video/x-sgi-movie" },
              { ".mp2", "video/mpeg" },
              { ".mp2v", "video/mpeg" },
              { ".mp3", "audio/mpeg" },
              { ".mp4", "video/mp4" },
              { ".mp4v", "video/mp4" },
              { ".mpa", "video/mpeg" },
              { ".mpe", "video/mpeg" },
              { ".mpeg", "video/mpeg" },
              { ".mpf", "application/vnd.ms-mediapackage" },
              { ".mpg", "video/mpeg" },
              { ".mpp", "application/vnd.ms-project" },
              { ".mpv2", "video/mpeg" },
              { ".mqv", "video/quicktime" },
              { ".ms", "application/x-troff-ms" },
              { ".msi", "application/octet-stream" },
              { ".mso", "application/octet-stream" },
              { ".mts", "video/vnd.dlna.mpeg-tts" },
              { ".mtx", "application/xml" },
              { ".mvb", "application/x-msmediaview" },
              { ".mvc", "application/x-miva-compiled" },
              { ".mxp", "application/x-mmxp" },
              { ".nc", "application/x-netcdf" },
              { ".nsc", "video/x-ms-asf" },
              { ".nws", "message/rfc822" },
              { ".ocx", "application/octet-stream" },
              { ".oda", "application/oda" },
              { ".odc", "text/x-ms-odc" },
              { ".odh", "text/plain" },
              { ".odl", "text/plain" },
              { ".odp", "application/vnd.oasis.opendocument.presentation" },
              { ".ods", "application/oleobject" },
              { ".odt", "application/vnd.oasis.opendocument.text" },
              { ".one", "application/onenote" },
              { ".onea", "application/onenote" },
              { ".onepkg", "application/onenote" },
              { ".onetmp", "application/onenote" },
              { ".onetoc", "application/onenote" },
              { ".onetoc2", "application/onenote" },
              { ".orderedtest", "application/xml" },
              { ".osdx", "application/opensearchdescription+xml" },
              { ".p10", "application/pkcs10" },
              { ".p12", "application/x-pkcs12" },
              { ".p7b", "application/x-pkcs7-certificates" },
              { ".p7c", "application/pkcs7-mime" },
              { ".p7m", "application/pkcs7-mime" },
              { ".p7r", "application/x-pkcs7-certreqresp" },
              { ".p7s", "application/pkcs7-signature" },
              { ".pbm", "image/x-portable-bitmap" },
              { ".pcast", "application/x-podcast" },
              { ".pct", "image/pict" },
              { ".pcx", "application/octet-stream" },
              { ".pcz", "application/octet-stream" },
              { ".pdf", "application/pdf" },
              { ".pfb", "application/octet-stream" },
              { ".pfm", "application/octet-stream" },
              { ".pfx", "application/x-pkcs12" },
              { ".pgm", "image/x-portable-graymap" },
              { ".pic", "image/pict" },
              { ".pict", "image/pict" },
              { ".pkgdef", "text/plain" },
              { ".pkgundef", "text/plain" },
              { ".pko", "application/vnd.ms-pki.pko" },
              { ".pls", "audio/scpls" },
              { ".pma", "application/x-perfmon" },
              { ".pmc", "application/x-perfmon" },
              { ".pml", "application/x-perfmon" },
              { ".pmr", "application/x-perfmon" },
              { ".pmw", "application/x-perfmon" },
              { ".png", "image/png" },
              { ".pnm", "image/x-portable-anymap" },
              { ".pnt", "image/x-macpaint" },
              { ".pntg", "image/x-macpaint" },
              { ".pnz", "image/png" },
              { ".pot", "application/vnd.ms-powerpoint" },
              { ".potm", "application/vnd.ms-powerpoint.template.macroEnabled.12" },
              { ".potx", "application/vnd.openxmlformats-officedocument.presentationml.template" },
              { ".ppa", "application/vnd.ms-powerpoint" },
              { ".ppam", "application/vnd.ms-powerpoint.addin.macroEnabled.12" },
              { ".ppm", "image/x-portable-pixmap" },
              { ".pps", "application/vnd.ms-powerpoint" },
              { ".ppsm", "application/vnd.ms-powerpoint.slideshow.macroEnabled.12" },
              { ".ppsx", "application/vnd.openxmlformats-officedocument.presentationml.slideshow" },
              { ".ppt", "application/vnd.ms-powerpoint" },
              { ".pptm", "application/vnd.ms-powerpoint.presentation.macroEnabled.12" },
              { ".pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation" },
              { ".prf", "application/pics-rules" },
              { ".prm", "application/octet-stream" },
              { ".prx", "application/octet-stream" },
              { ".ps", "application/postscript" },
              { ".psc1", "application/PowerShell" },
              { ".psd", "application/octet-stream" },
              { ".psess", "application/xml" },
              { ".psm", "application/octet-stream" },
              { ".psp", "application/octet-stream" },
              { ".pub", "application/x-mspublisher" },
              { ".pwz", "application/vnd.ms-powerpoint" },
              { ".qht", "text/x-html-insertion" },
              { ".qhtm", "text/x-html-insertion" },
              { ".qt", "video/quicktime" },
              { ".qti", "image/x-quicktime" },
              { ".qtif", "image/x-quicktime" },
              { ".qtl", "application/x-quicktimeplayer" },
              { ".qxd", "application/octet-stream" },
              { ".ra", "audio/x-pn-realaudio" },
              { ".ram", "audio/x-pn-realaudio" },
              { ".rar", "application/octet-stream" },
              { ".ras", "image/x-cmu-raster" },
              { ".rat", "application/rat-file" },
              { ".rc", "text/plain" },
              { ".rc2", "text/plain" },
              { ".rct", "text/plain" },
              { ".rdlc", "application/xml" },
              { ".resx", "application/xml" },
              { ".rf", "image/vnd.rn-realflash" },
              { ".rgb", "image/x-rgb" },
              { ".rgs", "text/plain" },
              { ".rm", "application/vnd.rn-realmedia" },
              { ".rmi", "audio/mid" },
              { ".rmp", "application/vnd.rn-rn_music_package" },
              { ".roff", "application/x-troff" },
              { ".rpm", "audio/x-pn-realaudio-plugin" },
              { ".rqy", "text/x-ms-rqy" },
              { ".rtf", "application/rtf" },
              { ".rtx", "text/richtext" },
              { ".ruleset", "application/xml" },
              { ".s", "text/plain" },
              { ".safariextz", "application/x-safari-safariextz" },
              { ".scd", "application/x-msschedule" },
              { ".sct", "text/scriptlet" },
              { ".sd2", "audio/x-sd2" },
              { ".sdp", "application/sdp" },
              { ".sea", "application/octet-stream" },
              { ".searchConnector-ms", "application/windows-search-connector+xml" },
              { ".setpay", "application/set-payment-initiation" },
              { ".setreg", "application/set-registration-initiation" },
              { ".settings", "application/xml" },
              { ".sgimb", "application/x-sgimb" },
              { ".sgml", "text/sgml" },
              { ".sh", "application/x-sh" },
              { ".shar", "application/x-shar" },
              { ".shtml", "text/html" },
              { ".sit", "application/x-stuffit" },
              { ".sitemap", "application/xml" },
              { ".skin", "application/xml" },
              { ".sldm", "application/vnd.ms-powerpoint.slide.macroEnabled.12" },
              { ".sldx", "application/vnd.openxmlformats-officedocument.presentationml.slide" },
              { ".slk", "application/vnd.ms-excel" },
              { ".sln", "text/plain" },
              { ".slupkg-ms", "application/x-ms-license" },
              { ".smd", "audio/x-smd" },
              { ".smi", "application/octet-stream" },
              { ".smx", "audio/x-smd" },
              { ".smz", "audio/x-smd" },
              { ".snd", "audio/basic" },
              { ".snippet", "application/xml" },
              { ".snp", "application/octet-stream" },
              { ".sol", "text/plain" },
              { ".sor", "text/plain" },
              { ".spc", "application/x-pkcs7-certificates" },
              { ".spl", "application/futuresplash" },
              { ".src", "application/x-wais-source" },
              { ".srf", "text/plain" },
              { ".SSISDeploymentManifest", "text/xml" },
              { ".ssm", "application/streamingmedia" },
              { ".sst", "application/vnd.ms-pki.certstore" },
              { ".stl", "application/vnd.ms-pki.stl" },
              { ".sv4cpio", "application/x-sv4cpio" },
              { ".sv4crc", "application/x-sv4crc" },
              { ".svc", "application/xml" },
              { ".swf", "application/x-shockwave-flash" },
              { ".t", "application/x-troff" },
              { ".tar", "application/x-tar" },
              { ".tcl", "application/x-tcl" },
              { ".testrunconfig", "application/xml" },
              { ".testsettings", "application/xml" },
              { ".tex", "application/x-tex" },
              { ".texi", "application/x-texinfo" },
              { ".texinfo", "application/x-texinfo" },
              { ".tgz", "application/x-compressed" },
              { ".thmx", "application/vnd.ms-officetheme" },
              { ".thn", "application/octet-stream" },
              { ".tif", "image/tiff" },
              { ".tiff", "image/tiff" },
              { ".tlh", "text/plain" },
              { ".tli", "text/plain" },
              { ".toc", "application/octet-stream" },
              { ".tr", "application/x-troff" },
              { ".trm", "application/x-msterminal" },
              { ".trx", "application/xml" },
              { ".ts", "video/vnd.dlna.mpeg-tts" },
              { ".tsv", "text/tab-separated-values" },
              { ".ttf", "application/octet-stream" },
              { ".tts", "video/vnd.dlna.mpeg-tts" },
              { ".txt", "text/plain" },
              { ".u32", "application/octet-stream" },
              { ".uls", "text/iuls" },
              { ".user", "text/plain" },
              { ".ustar", "application/x-ustar" },
              { ".vb", "text/plain" },
              { ".vbdproj", "text/plain" },
              { ".vbk", "video/mpeg" },
              { ".vbproj", "text/plain" },
              { ".vbs", "text/vbscript" },
              { ".vcf", "text/x-vcard" },
              { ".vcproj", "Application/xml" },
              { ".vcs", "text/plain" },
              { ".vcxproj", "Application/xml" },
              { ".vddproj", "text/plain" },
              { ".vdp", "text/plain" },
              { ".vdproj", "text/plain" },
              { ".vdx", "application/vnd.ms-visio.viewer" },
              { ".vml", "text/xml" },
              { ".vscontent", "application/xml" },
              { ".vsct", "text/xml" },
              { ".vsd", "application/vnd.visio" },
              { ".vsi", "application/ms-vsi" },
              { ".vsix", "application/vsix" },
              { ".vsixlangpack", "text/xml" },
              { ".vsixmanifest", "text/xml" },
              { ".vsmdi", "application/xml" },
              { ".vspscc", "text/plain" },
              { ".vss", "application/vnd.visio" },
              { ".vsscc", "text/plain" },
              { ".vssettings", "text/xml" },
              { ".vssscc", "text/plain" },
              { ".vst", "application/vnd.visio" },
              { ".vstemplate", "text/xml" },
              { ".vsto", "application/x-ms-vsto" },
              { ".vsw", "application/vnd.visio" },
              { ".vsx", "application/vnd.visio" },
              { ".vtx", "application/vnd.visio" },
              { ".wav", "audio/wav" },
              { ".wave", "audio/wav" },
              { ".wax", "audio/x-ms-wax" },
              { ".wbk", "application/msword" },
              { ".wbmp", "image/vnd.wap.wbmp" },
              { ".wcm", "application/vnd.ms-works" },
              { ".wdb", "application/vnd.ms-works" },
  
gt:             { ".wdp", "image/vnd.ms-photo" },