1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker 4 E-mail: J.Wielemaker@uva.nl 5 WWW: http://www.swi-prolog.org 6 Copyright (C): 2009, University of Amsterdam 7 8 This program is free software; you can redistribute it and/or 9 modify it under the terms of the GNU General Public License 10 as published by the Free Software Foundation; either version 2 11 of the License, or (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public 19 License along with this library; if not, write to the Free Software 20 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21 22 As a special exception, if you link this library with other files, 23 compiled with a Free Software compiler, to produce an executable, this 24 library does not by itself cause the resulting executable to be covered 25 by the GNU General Public License. This exception does not however 26 invalidate any other reasons why the executable file might be covered by 27 the GNU General Public License. 28*/ 29 30:- module(http_exception, 31 [ map_exception_to_http_status/3 32 ]). 33 34/** <module> Internal module of the HTTP server 35 36@see http_header.pl, http_wrapper.pl 37*/ 38 39%% map_exception_to_http_status(+Exception, -Reply, -HdrExtra) 40% 41% Map certain defined exceptions to special reply codes. The 42% http(not_modified) provides backward compatibility to 43% http_reply(not_modified). 44 45map_exception_to_http_status(http(not_modified), 46 not_modified, 47 [connection('Keep-Alive')]) :- !. 48map_exception_to_http_status(http_reply(Reply), 49 Reply, 50 [connection(Close)]) :- !, 51 ( keep_alive(Reply) 52 -> Close = 'Keep-Alive' 53 ; Close = close 54 ). 55map_exception_to_http_status(http_reply(Reply, HdrExtra0), 56 Reply, 57 HdrExtra) :- !, 58 ( memberchk(close(_), HdrExtra0) 59 -> HdrExtra = HdrExtra0 60 ; HdrExtra = [close(Close)|HdrExtra0], 61 ( keep_alive(Reply) 62 -> Close = 'Keep-Alive' 63 ; Close = close 64 ) 65 ). 66map_exception_to_http_status(error(existence_error(http_location, Location), _), 67 not_found(Location), 68 [connection(close)]) :- !. 69map_exception_to_http_status(error(permission_error(_, http_location, Location), _), 70 forbidden(Location), 71 [connection(close)]) :- !. 72map_exception_to_http_status(error(threads_in_pool(_Pool), _), 73 busy, 74 [connection(close)]) :- !. 75map_exception_to_http_status(E, 76 resource_error(E), 77 [connection(close)]) :- 78 resource_error(E), !. 79map_exception_to_http_status(E, 80 bad_request(E), 81 [connection(close)]) :- 82 bad_request_error(E), !. 83map_exception_to_http_status(E, 84 server_error(E), 85 [connection(close)]). 86 87resource_error(error(resource_error(_), _)). 88 89bad_request_error(error(domain_error(http_request, _), _)). 90 91%% keep_alive(+Reply) is semidet. 92% 93% If true for Reply, the default is to keep the connection open. 94 95keep_alive(not_modified). 96keep_alive(file(_Type, _File)). 97keep_alive(tmp_file(_Type, _File)). 98keep_alive(stream(_In, _Len)). 99keep_alive(cgi_stream(_In, _Len)). 100 101 102 /******************************* 103 * IDE SUPPORT * 104 *******************************/ 105 106% See library('trace/exceptions') 107 108:- multifile 109 prolog:general_exception/2. 110 111prolog:general_exception(http_reply(_), http_reply(_)). 112prolog:general_exception(http_reply(_,_), http_reply(_,_)). 113