「IE9や他のブラウザだと大丈夫なんですが、IE8では画像アップロード出来ません。」という話を聞いて、原因を調べてみたらこちらのようでした。
IEでjpegとPNG画像をアップロードする際、MIME Type(Content Type)が普通と違う件 – kanonjiの日記
この情報は、ブラウザの自己申告なため、悪意をもって全然別のMIME Typeを送信する事も可能*1ですが、IEもMIME Typeを偽装?してきます。
で、ドキュメント探したらここらへんみたい。
MIME Type Detection in Internet Explorer
When uploading files from the client to the Web server, Windows Internet Explorer uses FindMimeFromData to determine a MIME type.
うっっっｚ
>> pp Rack::Mime::MIME_TYPES
{".3gp"=>"video/3gpp",
".a"=>"application/octet-stream",
".ai"=>"application/postscript",
".aif"=>"audio/x-aiff",
".aiff"=>"audio/x-aiff",
".asc"=>"application/pgp-signature",
".asf"=>"video/x-ms-asf",
".asm"=>"text/x-asm",
".asx"=>"video/x-ms-asf",
".atom"=>"application/atom+xml",
".au"=>"audio/basic",
".avi"=>"video/x-msvideo",
".bat"=>"application/x-msdownload",
".bin"=>"application/octet-stream",
".bmp"=>"image/bmp",
".bz2"=>"application/x-bzip2",
".c"=>"text/x-c",
".cab"=>"application/vnd.ms-cab-compressed",
".cc"=>"text/x-c",
".chm"=>"application/vnd.ms-htmlhelp",
".class"=>"application/octet-stream",
".com"=>"application/x-msdownload",
".conf"=>"text/plain",
".cpp"=>"text/x-c",
".crt"=>"application/x-x509-ca-cert",
".css"=>"text/css",
".csv"=>"text/csv",
".cxx"=>"text/x-c",
".deb"=>"application/x-debian-package",
".der"=>"application/x-x509-ca-cert",
".diff"=>"text/x-diff",
".djv"=>"image/vnd.djvu",
".djvu"=>"image/vnd.djvu",
".dll"=>"application/x-msdownload",
".dmg"=>"application/octet-stream",
".doc"=>"application/msword",
".dot"=>"application/msword",
".dtd"=>"application/xml-dtd",
".dvi"=>"application/x-dvi",
".ear"=>"application/java-archive",
".eml"=>"message/rfc822",
".eps"=>"application/postscript",
".exe"=>"application/x-msdownload",
".f"=>"text/x-fortran",
".f77"=>"text/x-fortran",
".f90"=>"text/x-fortran",
".flv"=>"video/x-flv",
".for"=>"text/x-fortran",
".gem"=>"application/octet-stream",
".gemspec"=>"text/x-script.ruby",
".gif"=>"image/gif",
".gz"=>"application/x-gzip",
".h"=>"text/x-c",
".hh"=>"text/x-c",
".htm"=>"text/html",
".html"=>"text/html",
".ico"=>"image/vnd.microsoft.icon",
".ics"=>"text/calendar",
".ifb"=>"text/calendar",
".iso"=>"application/octet-stream",
".jar"=>"application/java-archive",
".java"=>"text/x-java-source",
".jnlp"=>"application/x-java-jnlp-file",
".jpeg"=>"image/jpeg",
".jpg"=>"image/jpeg",
".js"=>"application/javascript",
".json"=>"application/json",
".log"=>"text/plain",
".m3u"=>"audio/x-mpegurl",
".m4v"=>"video/mp4",
".man"=>"text/troff",
".mathml"=>"application/mathml+xml",
".mbox"=>"application/mbox",
".mdoc"=>"text/troff",
".me"=>"text/troff",
".mid"=>"audio/midi",
".midi"=>"audio/midi",
".mime"=>"message/rfc822",
".mml"=>"application/mathml+xml",
".mng"=>"video/x-mng",
".mov"=>"video/quicktime",
".mp3"=>"audio/mpeg",
".mp4"=>"video/mp4",
".mp4v"=>"video/mp4",
".mpeg"=>"video/mpeg",
".mpg"=>"video/mpeg",
".ms"=>"text/troff",
".msi"=>"application/x-msdownload",
".odp"=>"application/vnd.oasis.opendocument.presentation",
".ods"=>"application/vnd.oasis.opendocument.spreadsheet",
".odt"=>"application/vnd.oasis.opendocument.text",
".ogg"=>"application/ogg",
".p"=>"text/x-pascal",
".pas"=>"text/x-pascal",
".pbm"=>"image/x-portable-bitmap",
".pdf"=>"application/pdf",
".pem"=>"application/x-x509-ca-cert",
".pgm"=>"image/x-portable-graymap",
".pgp"=>"application/pgp-encrypted",
".pkg"=>"application/octet-stream",
".pl"=>"text/x-script.perl",
".pm"=>"text/x-script.perl-module",
".png"=>"image/png",
".pnm"=>"image/x-portable-anymap",
".ppm"=>"image/x-portable-pixmap",
".pps"=>"application/vnd.ms-powerpoint",
".ppt"=>"application/vnd.ms-powerpoint",
".ps"=>"application/postscript",
".psd"=>"image/vnd.adobe.photoshop",
".py"=>"text/x-script.python",
".qt"=>"video/quicktime",
".ra"=>"audio/x-pn-realaudio",
".rake"=>"text/x-script.ruby",
".ram"=>"audio/x-pn-realaudio",
".rar"=>"application/x-rar-compressed",
".rb"=>"text/x-script.ruby",
".rdf"=>"application/rdf+xml",
".roff"=>"text/troff",
".rpm"=>"application/x-redhat-package-manager",
".rss"=>"application/rss+xml",
".rtf"=>"application/rtf",
".ru"=>"text/x-script.ruby",
".s"=>"text/x-asm",
".sgm"=>"text/sgml",
".sgml"=>"text/sgml",
".sh"=>"application/x-sh",
".sig"=>"application/pgp-signature",
".snd"=>"audio/basic",
".so"=>"application/octet-stream",
".svg"=>"image/svg+xml",
".svgz"=>"image/svg+xml",
".swf"=>"application/x-shockwave-flash",
".t"=>"text/troff",
".tar"=>"application/x-tar",
".tbz"=>"application/x-bzip-compressed-tar",
".tcl"=>"application/x-tcl",
".tex"=>"application/x-tex",
".texi"=>"application/x-texinfo",
".texinfo"=>"application/x-texinfo",
".text"=>"text/plain",
".tif"=>"image/tiff",
".tiff"=>"image/tiff",
".torrent"=>"application/x-bittorrent",
".tr"=>"text/troff",
".txt"=>"text/plain",
".vcf"=>"text/x-vcard",
".vcs"=>"text/x-vcalendar",
".vrml"=>"model/vrml",
".war"=>"application/java-archive",
".wav"=>"audio/x-wav",
".wma"=>"audio/x-ms-wma",
".wmv"=>"video/x-ms-wmv",
".wmx"=>"video/x-ms-wmx",
".wrl"=>"model/vrml",
".wsdl"=>"application/wsdl+xml",
".xbm"=>"image/x-xbitmap",
".xhtml"=>"application/xhtml+xml",
".xls"=>"application/vnd.ms-excel",
".xml"=>"application/xml",
".xpm"=>"image/x-xpixmap",
".xsl"=>"application/xml",
".xslt"=>"application/xslt+xml",
".yaml"=>"text/yaml",
".yml"=>"text/yaml",
".zip"=>"application/zip"}おいそんなもんねーぞ
