/* Part of SWI-Prolog Author: Jan Wielemaker E-mail: J.Wielemaker@vu.nl WWW: http://www.swi-prolog.org Copyright (c) 2014-2022, University of Amsterdam VU University Amsterdam SWI-Prolog Solutions b.v. 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(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)) -> ( debugging(multipart(bom)) -> stream_property(Stream, encoding(Enc)), debug(multipart(bom), "BOM: ~q", [Enc]) ; true ) ; 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, _Encoding, Name=Value, Options) :- memberchk(filename(_), Params), option(on_filename(Goal), Options), !, % Always save files binary % set_encoding(Encoding, Stream, 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').