1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  2002-2012, University of Amsterdam
    7                              VU University Amsterdam
    8    All rights reserved.
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   10    Redistribution and use in source and binary forms, with or without
   11    modification, are permitted provided that the following conditions
   12    are met:
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   15       notice, this list of conditions and the following disclaimer.
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   18       notice, this list of conditions and the following disclaimer in
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   34*/
   35
   36:- module(mime_pack,
   37          [ mime_pack/3                 % +Input, +Stream, ?Boundary
   38          ]).   39:- use_module(mimetype).   40:- use_module(html_write).   41:- use_module(library(lists)).   42:- use_module(library(error)).

 mime_pack(+Inputs, +Out:stream, ?Boundary) is det

Pack a number of inputs into a MIME package using a specified or generated boundary. The generated boundary consists of the current time in milliseconds since the epoch and 10 random hexadecimal numbers. Inputs is a list of documents that is added to the mime message. Each element is one of:

Name = Value

Name the document. This emits a header of the form below. The filename is present if Value is of the form file(File). Value may be any of remaining value specifications.

Content-Disposition: form-data; name="Name"[; filename="<File>"

html(Tokens)

Tokens is a list of HTML tokens as produced by html//1. The token list is emitted using print_html/1.

file(File)

Emit the contents of File. The Content-type is derived from the File using file_mime_type/2. If the content-type is text/_, the file data is copied in text mode, which implies that it is read in the default encoding of the system and written using the encoding of the Out stream. Otherwise the file data is copied binary.

stream(In, Len)

Content is the next Len units from In. Data is copied using copy_stream_data/3. Units is bytes for binary streams and characters codes for text streams.

stream(In)

Content of the stream In, copied using copy_stream_data/2. This is often used with memory files (see new_memory_file/1).

mime(Attributes, Value, [])

Create a MIME header from Attributes and add Value, which can be any of remaining values of this list. Attributes may contain type(ContentType) and/or character_set(CharSet). This can be used to give a content-type to values that otherwise do not have a content-type. For example:

mime([type(text/html)], '<b>Hello World</b>', [])

mime([], , Parts)

Creates a nested multipart MIME message. Parts is passed as Inputs to a recursive call to mime_pack/2.

Atomic

Atomic values are passed to write/1. This embeds simple atoms and numbers.

Arguments:

Out	- is a stream opened for writing. Typically, it should be opened in text mode using UTF-8 encoding.

bug

- Does not validate that the boundary does not appear in any of the input documents.

  119mime_pack(Inputs, OutputStream, Boundary) :-
  120    make_boundary(Inputs, Boundary),
  121    pack_list(Inputs, OutputStream, Boundary).
  122
  123pack_list([], Out, Boundary) :-
  124    format(Out, '--~w--\r\n', [Boundary]).
  125pack_list([H|T], Out, Boundary) :-
  126    format(Out, '--~w\r\n', [Boundary]),
  127    pack(H, Out),
  128    format(Out, '\r\n', []),
  129    pack_list(T, Out, Boundary).
  130
  131pack(X, _Out) :-
  132    var(X),
  133    !,
  134    instantiation_error(X).
  135pack(Name=Value, Out) :-
  136    !,
  137    (   Value = file(FileName)
  138    ->  format(Out, 'Content-Disposition: form-data; name="~w"; filename="~w"\r\n',
  139               [Name, FileName])
  140    ;   format(Out, 'Content-Disposition: form-data; name="~w"\r\n', [Name])
  141    ),
  142    pack(Value, Out).
  143pack(html(HTML), Out) :-
  144    format(Out, 'Content-Type: text/html\r\n\r\n', []),
  145    print_html(Out, HTML).
  146pack(file(File), Out) :-
  147    !,
  148    (   file_mime_type(File, Type)
  149    ->  true
  150    ;   Type = text/plain
  151    ),
  152    format(Out, 'Content-Type: ~w\r\n\r\n', [Type]),
  153    (   Type = text/_
  154    ->  setup_call_cleanup(
  155            open(File, read, In),
  156            copy_stream_data(In, Out),
  157            close(In))
  158    ;   stream_property(Out, encoding(OldEncoding)),
  159        setup_call_cleanup(
  160            set_stream(Out, encoding(octet)),
  161            setup_call_cleanup(
  162                open(File, read, In, [type(binary)]),
  163                copy_stream_data(In, Out),
  164                close(In)),
  165            set_stream(Out, encoding(OldEncoding)))
  166    ).
  167pack(stream(In, Len), Out) :-
  168    !,
  169    format(Out, '\r\n', []),
  170    copy_stream_data(In, Out, Len).
  171pack(stream(In), Out) :-
  172    !,
  173    format(Out, '\r\n', []),
  174    copy_stream_data(In, Out).
  175pack(mime(Atts, Data, []), Out) :-             % mime_parse compatibility
  176    !,
  177    write_mime_attributes(Atts, Out),
  178    pack(Data, Out).
  179pack(mime(_Atts, '', Parts), Out) :-
  180    make_boundary(Parts, Boundary),
  181    format('Content-type: multipart/mixed; boundary=~w\r\n\r\n',
  182           [Boundary]),
  183    mime_pack(Parts, Out, Boundary).
  184pack(Atom, Out) :-
  185    atomic(Atom),
  186    !,
  187    format(Out, '\r\n', []),
  188    write(Out, Atom).
  189pack(Value, _) :-
  190    throw(error(type_error(mime_part, Value), _)).
  191
  192write_mime_attributes([], _) :- !.
  193write_mime_attributes(Atts, Out) :-
  194    select(type(Type), Atts, A1),
  195    !,
  196    (   select(character_set(CharSet), A1, A2)
  197    ->  format(Out, 'Content-type: ~w; charset=~w\r\n', [Type, CharSet]),
  198        write_mime_attributes(A2, Out)
  199    ;   format(Out, 'Content-type: ~w\r\n', [Type]),
  200        write_mime_attributes(A1, Out)
  201    ).
  202write_mime_attributes([_|T], Out) :-
  203    write_mime_attributes(T, Out).

 make_boundary(+Inputs, ?Boundary) is det

Generate a boundary. This should check all input sources whether the boundary is enclosed.

  211make_boundary(_, Boundary) :-
  212    atomic(Boundary),
  213    !.
  214make_boundary(_, Boundary) :-
  215    get_time(Now),
  216    A is random(1<<16),
  217    B is random(1<<16),
  218    C is random(1<<16),
  219    D is random(1<<16),
  220    E is random(1<<16),
  221    format(atom(Boundary), '------~3f~16r~16r~16r~16r~16r',
  222           [Now, A, B, C, D, E])