/* Part of SWI-Prolog Author: Jan Wielemaker E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org Copyright (C): 2014, University of Amsterdam VU University Amsterdam This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA As a special exception, if you link this library with other files, compiled with a Free Software compiler, to produce an executable, this library does not by itself cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU General Public License. */ :- module(http_multipart_plugin, [ ]). :- use_module(http_stream). :- use_module(http_header). :- use_module(library(debug)). :- use_module(library(option)). /** Multipart form-data plugin This plugin for library(http_client) automatically translates messages with content-type =|multipart/form-data|= into a list of Name = Value pairs, greatly simplifying the processing of forms with this type. After loading this plugin, multipart form-data can be accessed through http_parameters/3 from library(http/http_parameters) or http_read_data/3 from library(http/http_client). */ :- multifile http_client:http_convert_data/4, http_parameters:form_data_content_type/1. %% http_client:http_convert_data(+In, +Fields, -Data, +Options) is semidet. % % Convert =|multipart/form-data|= messages for http_read_data/3. % This plugin adds the folling options to http_read_data/3: % % * form_data(+AsForm) % If the content-type is =|multipart/form-data|=, return the % form-data either in one of the following formats: % % - AsForm = form % A list of Name=Value, where Value is an atom. % - AsForm = mime % A list of mime(Properties, Value, []). This is a backward % compatibility mode, emulating library(http/http_mime_plugin). % Note that if the disposition contains a =filename= % property, the data is read as binary unless there is a % charset parameter in the Content-Type stating otherwise, % while the old library would use UTF-8 for text files. % % * input_encoding(+Encoding) % Encoding to be used for parts that have no =filename= % disposition and no Content-Type with a charset indication. % This is typically the case for input widgets and browsers % encode this using the encoding of the page. As the SWI-Prolog % http library emits pages in UTF-8, the default is =utf8=. % % * on_filename(:CallBack) % If a part with a =filename= disposition is found and this % option is given, call CallBack as below. `Stream` is the % multipart input stream, which has octet (raw) encoding. % `Value` is returned as result. Note that the callback % may wish to save the result into a file and return e.g., % file(Path) to indicate where the file was saved. % % call(:CallBack, +Stream, -Value, +Options). % % The Options list contains information from the part header. % It always contains name(Name) and filename(FileName). It % may contain a term media(Type/SubType, Params) if the part % contains a Content-Type header. http_client:http_convert_data(In, Fields, Data, Options) :- memberchk(content_type(Type), Fields), multipart_type(Type, Boundary), !, setup_call_cleanup( multipart_open(In, Stream, [boundary(Boundary)]), process_parts(Stream, Data, Options), close(Stream)). %% multipart_type(+Type, -Boundary) is semidet. % % True if Type is of the form =|multipart/form-data; % boundary="..."|= and Boundary is a string describing the % boundary. multipart_type(Type, Boundary) :- http_parse_header_value(content_type, Type, media(multipart/'form-data', Params)), memberchk(boundary=Boundary, Params). process_parts(Stream, [Part|More], Options) :- http_read_header(Stream, HTTPHeader), part_header(HTTPHeader, Params, Name, Encoding), part_value(Stream, Name, Params, Encoding, Part, Options), debug(multipart(content), 'Got ~q~n', [Part]), ( multipart_open_next(Stream) -> process_parts(Stream, More, Options) ; More = [] ). set_encoding(text, Stream, _) :- !, ( set_stream(Stream, encoding(bom)) -> stream_property(Stream, encoding(Enc)), debug(multipart(bom), 'BOM: ~q', [Enc]) ; set_stream(Stream, encoding(iso_latin_1)) % RFC2616, sec. 3.7.1 ). set_encoding(input, Stream, Options) :- !, option(input_encoding(Enc), Options, utf8), set_stream(Stream, encoding(Enc)). set_encoding(Enc, Stream, _) :- set_stream(Stream, encoding(Enc)). %% part_header(+PartHeader, -Params, -Name, -Encoding) is det. % % Extract the form-field Name, the content Encoding and possible % other properties of the form-field. Extra properties are: % % - filename(Name) % - media(Type/SubType, MediaParams) part_header(PartHeader, Extra, Name, Encoding) :- memberchk(content_disposition(disposition('form-data', DProps)), PartHeader), memberchk(name=Name, DProps), ( filename(DProps, Extra, Extra1) -> part_encoding(PartHeader, Extra1, Encoding) ; Encoding = input, Extra = [] ). filename(DProps, Extra, Tail) :- memberchk(filename=FileName, DProps), !, Extra = [filename(FileName)|Tail]. part_encoding(PartHeader, Extra, Encoding) :- memberchk(content_type(TypeA), PartHeader), http_parse_header_value(content_type, TypeA, MediaType), !, Extra = [MediaType], media_type_encoding(MediaType, Encoding). media_type_encoding(media(_Type, Params), Encoding) :- memberchk(charset=CharSet, Params), charset_encoding(CharSet, Encoding). media_type_encoding(media(Type/SubType, _Params), Encoding) :- media_encoding(Type, SubType, Encoding). charset_encoding(CharSet, utf8) :- sub_atom_icasechk(CharSet, _, 'utf-8'), !. charset_encoding(_, octet). media_encoding(text, _, text) :- !. media_encoding(_, _, octet). %% part_value(+Stream, +Name, +Params, +Encoding, -Part, +Options) part_value(Stream, Name, Params, Encoding, Part, Options) :- option(form_data(mime), Options), !, set_encoding(Encoding, Stream, Options), Part = mime([disposition('form-data'),name(Name)|Properties], Atom, []), mime_properties(Params, Properties), read_string(Stream, _, String), atom_string(Atom, String). part_value(Stream, Name, Params, _, Name=Value, Options) :- memberchk(filename(_), Params), option(on_filename(Goal), Options), !, call(Goal, Stream, Value, [name(Name)|Params]). part_value(Stream, Name, _, Encoding, Name=Value, Options) :- set_encoding(Encoding, Stream, Options), read_string(Stream, _, String), atom_string(Value, String). mime_properties([], []). mime_properties([media(Type/SubType, Params)|T0], [type(ContentType)|T]) :- !, atomic_list_concat([Type, SubType], /, ContentType), ( memberchk(charset(CharSet), Params) -> T = [character_set(CharSet)|T1] ; T = T1 ), mime_properties(T0, T1). mime_properties([H|T0], [H|T]) :- mime_properties(T0, T). http_parameters:form_data_content_type(ContentType) :- sub_atom(ContentType, 0, _, _, 'multipart/form-data').