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yap-6.3/packages/http/http_parameters.pl

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2010-06-23 11:52:34 +01:00
/* $Id$
Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@cs.vu.nl
WWW: http://www.swi-prolog.org
Copyright (C): 2004-2009, University of 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 Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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_parameters,
[ http_parameters/2, % +Request, -Params
http_parameters/3 % +Request, -Params, +TypeG
]).
:- use_module(http_client).
:- use_module(http_mime_plugin).
:- use_module(http_hook).
:- use_module(library(debug)).
:- use_module(library(option)).
:- use_module(library(lists)).
:- use_module(library(error)).
:- meta_predicate
http_parameters(+, ?, :).
%% http_parameters(+Request, ?Parms) is det.
%% http_parameters(+Request, ?Parms, :Options) is det.
%
% Get HTTP GET or POST form-data, applying type validation,
% default values, etc. Provided options are:
%
% * attribute_declarations(:Goal)
% Causes the declarations for an attributed named A to be
% fetched using call(Goal, A, Declarations).
%
% * form_data(-Data)
% Return the data read from the GET por POST request as a
% list Name = Value. All data, including name/value pairs
% used for Parms, is unified with Data.
http_parameters(Request, Params) :-
http_parameters(Request, Params, []).
http_parameters(Request, Params, Options) :-
must_be(list, Params),
meta_options(is_meta, Options, QOptions),
option(attribute_declarations(DeclGoal), QOptions, -),
http_parms(Request, Params, DeclGoal, Form),
( memberchk(form_data(RForm), QOptions)
-> RForm = Form
; true
).
is_meta(attribute_declarations).
http_parms(Request, Params, DeclGoal, Data) :-
memberchk(method(post), Request),
memberchk(content_type(Content), Request),
form_data_content_type(Content), !,
debug(post_request, 'POST Request: ~p', [Request]),
http_read_data(Request, Data, []),
debug(post, 'POST Data: ~p', [Data]),
fill_parameters(Params, Data, DeclGoal).
http_parms(Request, Params, DeclGoal, Search) :-
( memberchk(search(Search), Request)
-> true
; Search = []
),
fill_parameters(Params, Search, DeclGoal).
:- multifile
form_data_content_type/1.
form_data_content_type('application/x-www-form-urlencoded').
%% fill_parameters(+ParamDecls, +FormData, +DeclGoal)
%
% Fill values from the parameter list
fill_parameters([], _, _).
fill_parameters([H|T], FormData, DeclGoal) :-
fill_parameter(H, FormData, DeclGoal),
fill_parameters(T, FormData, DeclGoal).
fill_parameter(H, _, _) :-
var(H), !,
instantiation_error(H).
fill_parameter(group(Members, _Options), FormData, DeclGoal) :- !,
fill_parameters(Members, FormData, DeclGoal).
fill_parameter(H, FormData, _) :-
H =.. [Name,Value,Options], !,
fill_param(Name, Value, Options, FormData).
fill_parameter(H, FormData, DeclGoal) :-
H =.. [Name,Value],
( call(DeclGoal, Name, Options)
-> true
; throw(error(existence_error(attribute_declaration, Name), _))
),
fill_param(Name, Value, Options, FormData).
fill_param(Name, Values, Options, FormData) :-
memberchk(zero_or_more, Options), !,
fill_param_list(FormData, Name, Values, Options).
fill_param(Name, Values, Options, FormData) :-
memberchk(list(Type), Options), !,
fill_param_list(FormData, Name, Values, [Type|Options]).
fill_param(Name, Value, Options, FormData) :-
( memberchk(Name=Value0, FormData),
Value0 \== '' % Not sure
-> check_type(Options, Name, Value0, Value)
; memberchk(default(Value), Options)
-> true
; memberchk(optional(true), Options)
-> true
; throw(error(existence_error(form_data, Name), _))
).
fill_param_list([], _, [], _).
fill_param_list([Name=Value0|Form], Name, [Value|VT], Options) :- !,
check_type(Options, Name, Value0, Value),
fill_param_list(Form, Name, VT, Options).
fill_param_list([_|Form], Name, VT, Options) :-
fill_param_list(Form, Name, VT, Options).
%% check_type(+Options, +FieldName, +ValueIn, -ValueOut) is det.
%
% Conversion of an HTTP form value. First tries the multifile hook
% http:convert_parameter/3 and next the built-in checks.
%
% @param Option List as provided with the parameter
% @param FieldName Name of the HTTP field (for better message)
% @param ValueIn Atom value as received from HTTP layer
% @param ValueOut Possibly converted final value
% @error type_error(Type, Value)
check_type([], _, Value, Value).
check_type([H|T], Field, Value0, Value) :-
( check_type_no_error(H, Value0, Value1)
-> check_type(T, Field, Value1, Value)
; format(string(Msg), 'HTTP parameter ~w', [Field]),
throw(error(type_error(H, Value0),
context(_, Msg)))
).
check_type_no_error(Type, In, Out) :-
http:convert_parameter(Type, In, Out), !.
check_type_no_error(Type, In, Out) :-
check_type3(Type, In, Out).
%% check_type3(+Type, +ValueIn, -ValueOut) is semidet.
%
% HTTP parameter type-check for types that need converting.
check_type3((T1;T2), In, Out) :- !,
( check_type_no_error(T1, In, Out)
-> true
; check_type_no_error(T2, In, Out)
).
check_type3(number, Atom, Number) :- !,
catch(atom_number(Atom, Number), _, fail).
check_type3(integer, Atom, Integer) :- !,
catch(atom_number(Atom, Integer), _, fail),
integer(Integer).
check_type3(nonneg, Atom, Integer) :- !,
catch(atom_number(Atom, Integer), _, fail),
integer(Integer),
Integer >= 0.
check_type3(float, Atom, Float) :- !,
catch(atom_number(Atom, Number), _, fail),
Float is float(Number).
check_type3(between(Low, High), Atom, Value) :- !,
atom_number(Atom, Number),
( (float(Low) ; float(High))
-> Value is float(Number)
; Value = Number
),
must_be(between(Low, High), Value).
check_type3(boolean, Atom, Bool) :- !,
truth(Atom, Bool).
check_type3(Type, Atom, Atom) :-
check_type2(Type, Atom).
%% check_type2(+Type, +ValueIn) is semidet.
%
% HTTP parameter type-check for types that need no conversion.
check_type2(oneof(Set), Value) :- !,
memberchk(Value, Set).
check_type2(length > N, Value) :- !,
atom_length(Value, Len),
Len > N.
check_type2(length >= N, Value) :- !,
atom_length(Value, Len),
Len >= N.
check_type2(length < N, Value) :- !,
atom_length(Value, Len),
Len < N.
check_type2(length =< N, Value) :- !,
atom_length(Value, Len),
Len =< N.
check_type2(_, _).
%% truth(+In, -Boolean) is semidet.
%
% Translate some commonly used textual representations for true
% and false into their canonical representation.
truth(true, true).
truth(yes, true).
truth(on, true).
truth('1', true).
truth(false, false).
truth(no, false).
truth(off, false).
truth('0', false).
/*******************************
* XREF SUPPORT *
*******************************/
:- multifile
prolog:called_by/2,
emacs_prolog_colours:goal_colours/2.
prolog:called_by(http_parameters(_,_,Options), [G+2]) :-
option(attribute_declarations(G), Options, _),
callable(G), !.
emacs_prolog_colours:goal_colours(http_parameters(_,_,Options),
built_in-[classify, classify, Colours]) :-
option_list_colours(Options, Colours).
option_list_colours(Var, error) :-
var(Var), !.
option_list_colours([], classify) :- !.
option_list_colours(Term, list-Elements) :-
Term = [_|_], !,
option_list_colours_2(Term, Elements).
option_list_colours(_, error).
option_list_colours_2(Var, classify) :-
var(Var).
option_list_colours_2([], []).
option_list_colours_2([H0|T0], [H|T]) :-
option_colours(H0, H),
option_list_colours_2(T0, T).
option_colours(Var, classify) :-
var(Var), !.
option_colours(_=_, built_in-[classify,classify]) :- !.
option_colours(attribute_declarations(_), % DCG = is a hack!
option(attribute_declarations)-[dcg]) :- !.
option_colours(Term, option(Name)-[classify]) :-
compound(Term),
Term =.. [Name,_Value], !.
option_colours(_, error).