无法获取 .flv 文件的正确 mime 类型
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【中文标题】无法获取 .flv 文件的正确 mime 类型【英文标题】：Unable to get the correct mime type of .flv file 【发布时间】：2011-05-26 19:02:05 【问题描述】：我想通过代码项目中的这个函数来获取本地 .flv 文件的 mime 类型 http://www.codeproject.com/KB/dotnet/ContentType.aspx
Public Function GetMIMEType(_
ByVal filepath As String) As String
Dim regPerm As RegistryPermission = _
New RegistryPermission(RegistryPermissionAccess.Read, _
"\\HKEY_CLASSES_ROOT")
Dim classesRoot As RegistryKey = Registry.ClassesRoot
Dim fi = New FileInfo(filepath)
Dim dotExt As String = LCase(fi.Extension)
Dim typeKey As RegistryKey = classesRoot.OpenSubKey(_
"MIME\Database\Content Type")
Dim keyname As String
For Each keyname In typeKey.GetSubKeyNames()
Dim curKey As RegistryKey = classesRoot.OpenSubKey( _
"MIME\Database\Content Type\" & keyname)
If LCase(curKey.GetValue("Extension")) = dotExt Then
'Debug.WriteLine("Content type was " & keyname)
Return keyname
End If
Next
End Function
但它返回 .flv 文件的 mime 类型为x-x509-ca-cert
【问题讨论】：
【参考方案1】：你的方法有几个缺点：
必须安装应用程序才能检测 mime 类型 某些 mime 类型（例如 htm 和 html）有多个扩展名，但在注册表中最多可以找到一个 扩展名本身并没有说明文件的真实内容（您可以手动更改）。尝试以下课程以获取 mime 类型。它们将通过嗅探文件的前 256 个字节（urlmon.dll - Internet Explorer 使用的 f.e.）和一组已知类型的组合来识别。
Imports System.Runtime.InteropServices
Imports System.IO
Public Class GetMimeType
'Test-Function'
Private Sub BtnGetMymeType_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnGetMymeType.Click
Dim fileSelector As New System.Windows.Forms.OpenFileDialog
If fileSelector.ShowDialog = Windows.Forms.DialogResult.OK Then
MessageBox.Show(MimeTypes.GetContentType(fileSelector.FileName))
End If
End Sub
End Class
Public Class MimeTypes
Private Shared knownTypes As List(Of String)
Private Shared mimeTypes As Dictionary(Of String, String)
<DllImport("urlmon.dll", CharSet:=CharSet.Auto)> _
Private Shared Function FindMimeFromData(ByVal pBC As UInt32, <MarshalAs(UnmanagedType.LPStr)> ByVal pwzUrl As String, <MarshalAs(UnmanagedType.LPArray)> ByVal pBuffer As Byte(), ByVal cbSize As UInt32, <MarshalAs(UnmanagedType.LPStr)> ByVal pwzMimeProposed As String, ByVal dwMimeFlags As UInt32, ByRef ppwzMimeOut As UInt32, ByVal dwReserverd As UInt32) As UInt32
End Function
Public Shared Function GetContentType(ByVal fileName As String) As String
If knownTypes Is Nothing OrElse mimeTypes Is Nothing Then InitializeMimeTypeLists()
Dim contentType As String = ""
Dim extension As String = IO.Path.GetExtension(fileName).Replace(".", "").ToLower
mimeTypes.TryGetValue(extension, contentType)
If String.IsNullOrEmpty(contentType) OrElse knownTypes.Contains(contentType) Then
Dim headerType As String = ScanFileForMimeType(fileName)
If headerType <> "application/octet-stream" OrElse String.IsNullOrEmpty(contentType) Then contentType = headerType
End If
Return contentType
End Function
Private Shared Function ScanFileForMimeType(ByVal fileName As String) As String
Try
Dim buffer As Byte() = New Byte(255)
Using fs As New FileStream(fileName, FileMode.Open)
Dim readLength As Integer = CInt(Math.Min(256, fs.Length))
fs.Read(buffer, 0, readLength)
End Using
Dim mimeType As UInt32
FindMimeFromData(0, Nothing, buffer, 256, Nothing, 0, mimeType, 0)
Dim mimeTypePtr As IntPtr = New IntPtr(mimeType)
Dim mime As String = Marshal.PtrToStringUni(mimeTypePtr)
Marshal.FreeCoTaskMem(mimeTypePtr)
If String.IsNullOrEmpty(mime) Then mime = "application/octet-stream"
Return mime
Catch ex As Exception
Return "application/octet-stream"
End Try
End Function
Private Shared Sub InitializeMimeTypeLists()
knownTypes = New String() "text/plain", "text/html", "text/xml", "text/richtext", "text/scriptlet", _
"audio/x-aiff", "audio/basic", "audio/mid", "audio/wav", _
"image/gif", "image/jpeg", "image/pjpeg", "image/png", "image/x-png", "image/tiff", "image/bmp", _
"image/x-xbitmap", "image/x-jg", "image/x-emf", "image/x-wmf", "video/avi", "video/mpeg", _
"application/octet-stream", "application/postscript", "application/base64", "application/macbinhex40", _
"application/pdf", "application/xml", "application/atom+xml", "application/rss+xml", _
"application/x-compressed", "application/x-zip-compressed", "application/x-gzip-compressed", _
"application/java", "application/x-msdownload" _
.ToList
mimeTypes = New Dictionary(Of String, String)
With mimeTypes
.Add("3dm", "x-world/x-3dmf")
.Add("3dmf", "x-world/x-3dmf")
.Add("a", "application/octet-stream")
.Add("aab", "application/x-authorware-bin")
.Add("aam", "application/x-authorware-map")
.Add("aas", "application/x-authorware-seg")
.Add("abc", "text/vnd.abc")
.Add("acgi", "text/html")
.Add("afl", "video/animaflex")
.Add("ai", "application/postscript")
.Add("aif", "audio/aiff")
.Add("aifc", "audio/aiff")
.Add("aiff", "audio/aiff")
.Add("aim", "application/x-aim")
.Add("aip", "text/x-audiosoft-intra")
.Add("ani", "application/x-navi-animation")
.Add("aos", "application/x-nokia-9000-communicator-add-on-software")
.Add("aps", "application/mime")
.Add("arc", "application/octet-stream")
.Add("arj", "application/arj")
.Add("art", "image/x-jg")
.Add("asf", "video/x-ms-asf")
.Add("asm", "text/x-asm")
.Add("asp", "text/asp")
.Add("asx", "application/x-mplayer2")
.Add("au", "audio/basic")
.Add("avi", "video/avi")
.Add("avs", "video/avs-video")
.Add("bcpio", "application/x-bcpio")
.Add("bin", "application/octet-stream")
.Add("bm", "image/bmp")
.Add("bmp", "image/bmp")
.Add("boo", "application/book")
.Add("book", "application/book")
.Add("boz", "application/x-bzip2")
.Add("bsh", "application/x-bsh")
.Add("bz", "application/x-bzip")
.Add("bz2", "application/x-bzip2")
.Add("c", "text/plain")
.Add("c++", "text/plain")
.Add("cat", "application/vnd.ms-pki.seccat")
.Add("cc", "text/plain")
.Add("ccad", "application/clariscad")
.Add("cco", "application/x-cocoa")
.Add("cdf", "application/cdf")
.Add("cer", "application/pkix-cert")
.Add("cha", "application/x-chat")
.Add("chat", "application/x-chat")
.Add("class", "application/java")
.Add("com", "application/octet-stream")
.Add("conf", "text/plain")
.Add("cpio", "application/x-cpio")
.Add("cpp", "text/x-c")
.Add("cpt", "application/x-cpt")
.Add("crl", "application/pkcs-crl")
.Add("css", "text/css")
.Add("def", "text/plain")
.Add("der", "application/x-x509-ca-cert")
.Add("dif", "video/x-dv")
.Add("dir", "application/x-director")
.Add("dl", "video/dl")
.Add("doc", "application/msword")
.Add("dot", "application/msword")
.Add("dp", "application/commonground")
.Add("drw", "application/drafting")
.Add("dump", "application/octet-stream")
.Add("dv", "video/x-dv")
.Add("dvi", "application/x-dvi")
.Add("dwf", "drawing/x-dwf (old)")
.Add("dwg", "application/acad")
.Add("dxf", "application/dxf")
.Add("eps", "application/postscript")
.Add("es", "application/x-esrehber")
.Add("etx", "text/x-setext")
.Add("evy", "application/envoy")
.Add("exe", "application/octet-stream")
.Add("f", "text/plain")
.Add("f90", "text/x-fortran")
.Add("fdf", "application/vnd.fdf")
.Add("fif", "image/fif")
.Add("fli", "video/fli")
.Add("flv", "video/x-flv")
.Add("for", "text/x-fortran")
.Add("fpx", "image/vnd.fpx")
.Add("g", "text/plain")
.Add("g3", "image/g3fax")
.Add("gif", "image/gif")
.Add("gl", "video/gl")
.Add("gsd", "audio/x-gsm")
.Add("gtar", "application/x-gtar")
.Add("gz", "application/x-compressed")
.Add("h", "text/plain")
.Add("help", "application/x-helpfile")
.Add("hgl", "application/vnd.hp-hpgl")
.Add("hh", "text/plain")
.Add("hlp", "application/x-winhelp")
.Add("htc", "text/x-component")
.Add("htm", "text/html")
.Add("html", "text/html")
.Add("htmls", "text/html")
.Add("htt", "text/webviewhtml")
.Add("htx", "text/html")
.Add("ice", "x-conference/x-cooltalk")
.Add("ico", "image/x-icon")
.Add("idc", "text/plain")
.Add("ief", "image/ief")
.Add("iefs", "image/ief")
.Add("iges", "application/iges")
.Add("igs", "application/iges")
.Add("ima", "application/x-ima")
.Add("imap", "application/x-httpd-imap")
.Add("inf", "application/inf")
.Add("ins", "application/x-internett-signup")
.Add("ip", "application/x-ip2")
.Add("isu", "video/x-isvideo")
.Add("it", "audio/it")
.Add("iv", "application/x-inventor")
.Add("ivr", "i-world/i-vrml")
.Add("ivy", "application/x-livescreen")
.Add("jam", "audio/x-jam")
.Add("jav", "text/plain")
.Add("java", "text/plain")
.Add("jcm", "application/x-java-commerce")
.Add("jfif", "image/jpeg")
.Add("jfif-tbnl", "image/jpeg")
.Add("jpe", "image/jpeg")
.Add("jpeg", "image/jpeg")
.Add("jpg", "image/jpeg")
.Add("jps", "image/x-jps")
.Add("js", "application/x-javascript")
.Add("jut", "image/jutvision")
.Add("kar", "audio/midi")
.Add("ksh", "application/x-ksh")
.Add("la", "audio/nspaudio")
.Add("lam", "audio/x-liveaudio")
.Add("latex", "application/x-latex")
.Add("lha", "application/lha")
.Add("lhx", "application/octet-stream")
.Add("list", "text/plain")
.Add("lma", "audio/nspaudio")
.Add("log", "text/plain")
.Add("lsp", "application/x-lisp")
.Add("lst", "text/plain")
.Add("lsx", "text/x-la-asf")
.Add("ltx", "application/x-latex")
.Add("lzh", "application/octet-stream")
.Add("lzx", "application/lzx")
.Add("m", "text/plain")
.Add("m1v", "video/mpeg")
.Add("m2a", "audio/mpeg")
.Add("m2v", "video/mpeg")
.Add("m3u", "audio/x-mpequrl")
.Add("man", "application/x-troff-man")
.Add("map", "application/x-navimap")
.Add("mar", "text/plain")
.Add("mbd", "application/mbedlet")
.Add("mc$", "application/x-magic-cap-package-1.0")
.Add("mcd", "application/mcad")
.Add("mcf", "image/vasa")
.Add("mcp", "application/netmc")
.Add("me", "application/x-troff-me")
.Add("mht", "message/rfc822")
.Add("mhtml", "message/rfc822")
.Add("mid", "audio/midi")
.Add("midi", "audio/midi")
.Add("mif", "application/x-frame")
.Add("mime", "message/rfc822")
.Add("mjf", "audio/x-vnd.audioexplosion.mjuicemediafile")
.Add("mjpg", "video/x-motion-jpeg")
.Add("mm", "application/base64")
.Add("mme", "application/base64")
.Add("mod", "audio/mod")
.Add("moov", "video/quicktime")
.Add("mov", "video/quicktime")
.Add("movie", "video/x-sgi-movie")
.Add("mp2", "audio/mpeg")
.Add("mp3", "audio/mpeg3")
.Add("mpa", "audio/mpeg")
.Add("mpc", "application/x-project")
.Add("mpe", "video/mpeg")
.Add("mpeg", "video/mpeg")
.Add("mpg", "video/mpeg")
.Add("mpga", "audio/mpeg")
.Add("mpp", "application/vnd.ms-project")
.Add("mpt", "application/x-project")
.Add("mpv", "application/x-project")
.Add("mpx", "application/x-project")
.Add("mrc", "application/marc")
.Add("ms", "application/x-troff-ms")
.Add("mv", "video/x-sgi-movie")
.Add("my", "audio/make")
.Add("mzz", "application/x-vnd.audioexplosion.mzz")
.Add("nap", "image/naplps")
.Add("naplps", "image/naplps")
.Add("nc", "application/x-netcdf")
.Add("ncm", "application/vnd.nokia.configuration-message")
.Add("nif", "image/x-niff")
.Add("niff", "image/x-niff")
.Add("nix", "application/x-mix-transfer")
.Add("nsc", "application/x-conference")
.Add("nvd", "application/x-navidoc")
.Add("o", "application/octet-stream")
.Add("oda", "application/oda")
.Add("omc", "application/x-omc")
.Add("omcd", "application/x-omcdatamaker")
.Add("omcr", "application/x-omcregerator")
.Add("p", "text/x-pascal")
.Add("p10", "application/pkcs10")
.Add("p12", "application/pkcs-12")
.Add("p7a", "application/x-pkcs7-signature")
.Add("p7c", "application/pkcs7-mime")
.Add("pas", "text/pascal")
.Add("pbm", "image/x-portable-bitmap")
.Add("pcl", "application/vnd.hp-pcl")
.Add("pct", "image/x-pict")
.Add("pcx", "image/x-pcx")
.Add("pdf", "application/pdf")
.Add("pfunk", "audio/make")
.Add("pgm", "image/x-portable-graymap")
.Add("pic", "image/pict")
.Add("pict", "image/pict")
.Add("pkg", "application/x-newton-compatible-pkg")
.Add("pko", "application/vnd.ms-pki.pko")
.Add("pl", "text/plain")
.Add("plx", "application/x-pixclscript")
.Add("pm", "image/x-xpixmap")
.Add("png", "image/png")
.Add("pnm", "application/x-portable-anymap")
.Add("pot", "application/mspowerpoint")
.Add("pov", "model/x-pov")
.Add("ppa", "application/vnd.ms-powerpoint")
.Add("ppm", "image/x-portable-pixmap")
.Add("pps", "application/mspowerpoint")
.Add("ppt", "application/mspowerpoint")
.Add("ppz", "application/mspowerpoint")
.Add("pre", "application/x-freelance")
.Add("prt", "application/pro_eng")
.Add("ps", "application/postscript")
.Add("psd", "application/octet-stream")
.Add("pvu", "paleovu/x-pv")
.Add("pwz", "application/vnd.ms-powerpoint")
.Add("py", "text/x-script.phyton")
.Add("pyc", "applicaiton/x-bytecode.python")
.Add("qcp", "audio/vnd.qcelp")
.Add("qd3", "x-world/x-3dmf")
.Add("qd3d", "x-world/x-3dmf")
.Add("qif", "image/x-quicktime")
.Add("qt", "video/quicktime")
.Add("qtc", "video/x-qtc")
.Add("qti", "image/x-quicktime")
.Add("qtif", "image/x-quicktime")
.Add("ra", "audio/x-pn-realaudio")
.Add("ram", "audio/x-pn-realaudio")
.Add("ras", "application/x-cmu-raster")
.Add("rast", "image/cmu-raster")
.Add("rexx", "text/x-script.rexx")
.Add("rf", "image/vnd.rn-realflash")
.Add("rgb", "image/x-rgb")
.Add("rm", "application/vnd.rn-realmedia")
.Add("rmi", "audio/mid")
.Add("rmm", "audio/x-pn-realaudio")
.Add("rmp", "audio/x-pn-realaudio")
.Add("rng", "application/ringing-tones")
.Add("rnx", "application/vnd.rn-realplayer")
.Add("roff", "application/x-troff")
.Add("rp", "image/vnd.rn-realpix")
.Add("rpm", "audio/x-pn-realaudio-plugin")
.Add("rt", "text/richtext")
.Add("rtf", "text/richtext")
.Add("rtx", "application/rtf")
.Add("rv", "video/vnd.rn-realvideo")
.Add("s", "text/x-asm")
.Add("s3m", "audio/s3m")
.Add("saveme", "application/octet-stream")
.Add("sbk", "application/x-tbook")
.Add("scm", "application/x-lotusscreencam")
.Add("sdml", "text/plain")
.Add("sdp", "application/sdp")
.Add("sdr", "application/sounder")
.Add("sea", "application/sea")
.Add("set", "application/set")
.Add("sgm", "text/sgml")
.Add("sgml", "text/sgml")
.Add("sh", "application/x-bsh")
.Add("shtml", "text/html")
.Add("sid", "audio/x-psid")
.Add("sit", "application/x-sit")
.Add("skd", "application/x-koan")
.Add("skm", "application/x-koan")
.Add("skp", "application/x-koan")
.Add("skt", "application/x-koan")
.Add("sl", "application/x-seelogo")
.Add("smi", "application/smil")
.Add("smil", "application/smil")
.Add("snd", "audio/basic")
.Add("sol", "application/solids")
.Add("spc", "application/x-pkcs7-certificates")
.Add("spl", "application/futuresplash")
.Add("spr", "application/x-sprite")
.Add("sprite", "application/x-sprite")
.Add("src", "application/x-wais-source")
.Add("ssi", "text/x-server-parsed-html")
.Add("ssm", "application/streamingmedia")
.Add("sst", "application/vnd.ms-pki.certstore")
.Add("step", "application/step")
.Add("stl", "application/sla")
.Add("stp", "application/step")
.Add("sv4cpio", "application/x-sv4cpio")
.Add("sv4crc", "application/x-sv4crc")
.Add("svf", "image/vnd.dwg")
.Add("svr", "application/x-world")
.Add("swf", "application/x-shockwave-flash")
.Add("t", "application/x-troff")
.Add("talk", "text/x-speech")
.Add("tar", "application/x-tar")
.Add("tbk", "application/toolbook")
.Add("tcl", "application/x-tcl")
.Add("tcsh", "text/x-script.tcsh")
.Add("tex", "application/x-tex")
.Add("texi", "application/x-texinfo")
.Add("texinfo", "application/x-texinfo")
.Add("text", "text/plain")
.Add("tgz", "application/x-compressed")
.Add("tif", "image/tiff")
.Add("tr", "application/x-troff")
.Add("tsi", "audio/tsp-audio")
.Add("tsp", "audio/tsplayer")
.Add("tsv", "text/tab-separated-values")
.Add("turbot", "image/florian")
.Add("txt", "text/plain")
.Add("uil", "text/x-uil")
.Add("uni", "text/uri-list")
.Add("unis", "text/uri-list")
.Add("unv", "application/i-deas")
.Add("uri", "text/uri-list")
.Add("uris", "text/uri-list")
.Add("ustar", "application/x-ustar")
.Add("uu", "application/octet-stream")
.Add("vcd", "application/x-cdlink")
.Add("vcs", "text/x-vcalendar")
.Add("vda", "application/vda")
.Add("vdo", "video/vdo")
.Add("vew", "application/groupwise")
.Add("viv", "video/vivo")
.Add("vivo", "video/vivo")
.Add("vmd", "application/vocaltec-media-desc")
.Add("vmf", "application/vocaltec-media-file")
.Add("voc", "audio/voc")
.Add("vos", "video/vosaic")
.Add("vox", "audio/voxware")
.Add("vqe", "audio/x-twinvq-plugin")
.Add("vqf", "audio/x-twinvq")
.Add("vql", "audio/x-twinvq-plugin")
.Add("vrml", "application/x-vrml")
.Add("vrt", "x-world/x-vrt")
.Add("vsd", "application/x-visio")
.Add("vst", "application/x-visio")
.Add("vsw", "application/x-visio")
.Add("w60", "application/wordperfect6.0")
.Add("w61", "application/wordperfect6.1")
.Add("w6w", "application/msword")
.Add("wav", "audio/wav")
.Add("wb1", "application/x-qpro")
.Add("wbmp", "image/vnd.wap.wbmp")
.Add("web", "application/vnd.xara")
.Add("wiz", "application/msword")
.Add("wk1", "application/x-123")
.Add("wmf", "windows/metafile")
.Add("wml", "text/vnd.wap.wml")
.Add("wmlc", "application/vnd.wap.wmlc")
.Add("wmls", "text/vnd.wap.wmlscript")
.Add("wmlsc", "application/vnd.wap.wmlscriptc")
.Add("word", "application/msword")
.Add("wp", "application/wordperfect")
.Add("wp5", "application/wordperfect")
.Add("wp6", "application/wordperfect")
.Add("wpd", "application/wordperfect")
.Add("wq1", "application/x-lotus")
.Add("wri", "application/mswrite")
.Add("wrl", "application/x-world")
.Add("wrz", "model/vrml")
.Add("wsc", "text/scriplet")
.Add("wsrc", "application/x-wais-source")
.Add("wtk", "application/x-wintalk")
.Add("xbm", "image/x-xbitmap")
.Add("xdr", "video/x-amt-demorun")
.Add("xgz", "xgl/drawing")
.Add("xif", "image/vnd.xiff")
.Add("xl", "application/excel")
.Add("xla", "application/excel")
.Add("xlb", "application/excel")
.Add("xlc", "application/excel")
.Add("xld", "application/excel")
.Add("xlk", "application/excel")
.Add("xll", "application/excel")
.Add("xlm", "application/excel")
.Add("xls", "application/excel")
.Add("xlt", "application/excel")
.Add("xlv", "application/excel")
.Add("xlw", "application/excel")
.Add("xm", "audio/xm")
.Add("xml", "text/xml")
.Add("xmz", "xgl/movie")
.Add("xpix", "application/x-vnd.ls-xpix")
.Add("xpm", "image/x-xpixmap")
.Add("x-png", "image/png")
.Add("xsr", "video/x-amt-showrun")
.Add("xwd", "image/x-xwd")
.Add("xyz", "chemical/x-pdb")
.Add("z", "application/x-compress")
.Add("zip", "application/x-compressed")
.Add("zoo", "application/octet-stream")
.Add("zsh", "text/x-script.zsh")
End With
End Sub
End Class
当 mime 类型未知并且仅知道它是 application/octet-stream 是不够的时，您必须更新此列表。检查扩展名是否为 txt 但 mime 类型为二进制数据可能就足够了，因为这意味着该文件不是它所伪装的。
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服务器网站报错：由于扩展配置问题无法提供您请求的页面，请添加MIME映射，针对mp4，flv文件类型无法打开。
让IIS服务器支持flv,f4v,mp4在线播放(2003,2008)