/* Part of SWI-Prolog Author: Jan Wielemaker E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org Copyright (c) 2002-2018, University of Amsterdam VU University Amsterdam All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ :- module(mimetype, [ file_mime_type/2, % +Path, -Type file_content_type/2, % +Path, -Type file_content_type/3 % +Path, ?MediaType, -Type ]). /** Determine mime-type for a file Simple library to guess the mime-type from the extension of a file. As various applications need to do this type ofinferencing it seems worthwhile to place this functionality in an extensible library. @tbd Consider content handling (using the Unix file command) @tbd Allow parameters? (e.g. text/html; charset=UTF-8) */ :- multifile mime:mime_extension/2, mime:text_mimetype/1, mime:charset/3. %! file_mime_type(+FileName, -MimeType) is semidet. % % True when MimeType is the mime-type to be used for sending % FileName. The default rules can be overridden and extended using % the hook mime:mime_extension/2. % % @param MimeType is a compound term of the form Type/SubType. file_mime_type(File, MimeType) :- file_name_extension(_, Ext, File), ( current_prolog_flag(windows, true) -> downcase_atom(Ext, Lower), mime_extension(Lower, MimeType) ; mime_extension(Ext, M0) -> MimeType = M0 ; downcase_atom(Ext, Lower), mime_extension(Lower, MimeType) ), !. file_mime_type(File, MimeType) :- file_base_name(File, Base), downcase_atom(Base, Lower), name_mimetype(Lower, Mime), !, MimeType = Mime. file_mime_type(_, MimeType) :- default_mimetype(MimeType). %! mime:mime_extension(+Ext, -MimeType) is semidet. % % Hook that is called by file_mime_type/2 before the default table % is examined. mime_extension(Ext, MimeType) :- ( mime:mime_extension(Ext, Mime) -> MimeType = Mime ; ext_mimetype(Ext, Mime) -> MimeType = Mime ). %! default_mimetype(-MimeType) is semidet. % % If the mime-type cannot be determined from the file extension, % this predicate is used as fallback. It takes the value from the % Prolog flag =default_mimetype=. To change the default, use e.g., % % == % :- set_prolog_flag(default_mimetype, text/plain). % == % % The initial default mime-type is =|application/unknown|=. Use % the value =|-|= to denote there is no default. :- create_prolog_flag(default_mimetype, application/unknown, [keep(true)]). default_mimetype(MimeType) :- current_prolog_flag(default_mimetype, MimeType), MimeType = _/_. %! ext_mimetype(+Extension, -MimeType) is semidet. % % Built-in table of file-name extension to mime-type mappings. % % @tbd Update this list, e.g., from % http://www.webmaster-toolkit.com/mime-types.shtml % plain text ext_mimetype(txt, text/plain). % markup ext_mimetype(htm, text/html). ext_mimetype(html, text/html). ext_mimetype(xhtml, application/'xhtml+xml'). ext_mimetype(sgml, text/'x-sgml'). ext_mimetype(sgm, text/'x-sgml'). ext_mimetype(xml, text/xml). ext_mimetype(css, text/css). ext_mimetype(xsl, text/xml). % Unclear what this should be. ext_mimetype(md, text/markdown). % Other data markup ext_mimetype(json, application/json). ext_mimetype(yaml, application/yaml). % Not official % semantic web stuff ext_mimetype(rdf, application/'rdf+xml'). ext_mimetype(rdfs, application/'rdf+xml'). ext_mimetype(owl, application/'rdf+xml'). ext_mimetype(ttl, application/turtle). ext_mimetype(nt, application/'n-triples'). ext_mimetype(nq, application/'n-quads'). % Prolog source ext_mimetype(pl, text/plain). % Other languages ext_mimetype(c, text/'x-c'). ext_mimetype(h, text/'x-c'). ext_mimetype(cc, text/'x-c'). ext_mimetype(py, text/'x-python'). ext_mimetype(java, text/'x-java'). ext_mimetype(sh, text/plain). % Packaged formats ext_mimetype(gz, application/'x-gzip'). ext_mimetype(zip, application/zip). ext_mimetype(tgz, application/'x-gtar'). % Some document formats ext_mimetype(pdf, application/pdf). ext_mimetype(doc, application/msword). % Java classes ext_mimetype(class, application/'octet-stream'). ext_mimetype(jar, application/'x-java-archive'). % JavaScript and WASM ext_mimetype(js, text/javascript). ext_mimetype(wasm, application/wasm). ext_mimetype(data, application/'octet-stream'). % Visual Basic Script :-( ext_mimetype(vbs, text/vbscript). % Some image formats ext_mimetype(jpg, image/jpeg). ext_mimetype(jpeg, image/jpeg). ext_mimetype(gif, image/gif). ext_mimetype(png, image/png). ext_mimetype(tif, image/tiff). ext_mimetype(tiff, image/tiff). ext_mimetype(xpm, image/'x-xpixmap'). ext_mimetype(ico, image/'x-ico'). ext_mimetype(svg, image/'svg+xml'). % Google earth ext_mimetype(kml, application/'vnd.google-earth.kml+xml'). ext_mimetype(kmz, application/'vnd.google-earth.kmz'). % Flash ext_mimetype(swf, application/'x-shockwave-flash'). ext_mimetype(flv, video/'x-flv'). % MP3 ext_mimetype(mp3, audio/mpeg). % Downloads ext_mimetype(rpm, application/'x-rpm'). ext_mimetype(exe, application/'x-executable'). %! name_mimetype(+DownCaseFileName, -MimeType) is semidet. % % Determine the mime-type of files based on the entire filename. name_mimetype(makefile, text/plain). name_mimetype(configure, text/plain). name_mimetype('configure.in', text/plain). name_mimetype('configure.ac', text/plain). name_mimetype('makefile.in', text/plain). name_mimetype('makefile.am', text/plain). name_mimetype('readme.in', text/plain). %! text_mimetype(+MimeType) is semidet. % % True when documents of MimeType are text documents and thus may need % a charset specification. text_mimetype(MimeType) :- mime:text_mimetype(MimeType), !. text_mimetype(text/_). %! file_content_type(+File:atom, -ContentType:atom) is det. %! file_content_type(+File:atom, ?MediaType, -ContentType:atom) is det. % % True if File should be served using =|ContentType:|= ContentType. It % takes the following steps: % % 1. Determine the media type using file_mime_type/2, unless % already specified using file_content_type/3. % 2. Determine it is a text file using text_mimetype/1 % 3. Use the charset from the Prolog flag `default_charset` % % The behavior is controlled by several hooks and a flag. % % - mime:mime_extension/2 defines the media type % - mime:text_mimetype/1 defines the media type is text % - mime:charset/3 derives the charset for a file with a given % media type, if the media type is text according to % mime:text_mimetype/1. % - If mime:text_mimetype/1 succeeds and mime:charset/3 fails, the % flag `default_charset` defines the charset unless it is set % to `-`. The flag set by default to =UTF-8= if the Prolog % flag `encoding` is set to `utf8`. file_content_type(File, ContentType) :- file_content_type(File, _, ContentType). file_content_type(File, MediaType, ContentType) :- ( ground(MediaType) -> true ; file_mime_type(File, MediaType) ), ( text_mimetype(MediaType), ( mime:charset(File, MediaType, Charset0) -> Charset = Charset0 ; default_charset(Charset) ) -> format(atom(ContentType), '~w; charset=~w', [MediaType, Charset]) ; format(atom(ContentType), '~w', [MediaType]) ). %! mime:charset(+File, +MediaType, -Charset) is semidet. % % Hook that determines the Charset for File that has media type % MediaType. This hook allows overruling file_content_type/2. % % @see mime:text_mimetype/1. default_charset(Charset) :- current_prolog_flag(default_charset, Charset), Charset \== (-). set_default_charset :- current_prolog_flag(default_charset, _), !. set_default_charset :- current_prolog_flag(encoding, utf8), !, set_prolog_flag(default_charset, 'UTF-8'). set_default_charset. :- initialization(set_default_charset).