1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
|
/* 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)).
/** <module> 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').
|
