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/* Part of SWI-Prolog
Author: Jan Wielemaker
E-mail: J.Wielemaker@cs.vu.nl
WWW: http://www.swi-prolog.org
Copyright (C): 2011, VU University 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 General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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_files,
[ http_reply_from_files/3 % +Dir, +Options, +Request
]).
:- use_module(library(http/http_dispatch)).
:- use_module(library(http/http_dirindex)).
:- use_module(library(filesex)).
:- use_module(library(lists)).
:- use_module(library(option)).
:- predicate_options(http_reply_from_files/3, 2, [indexes(list(atom))]).
/** <module> Serve plain files from a hierarchy
Although the SWI-Prolog web-server is intended to serve documents that
needed to be computed dynamically, serving plain files is sometimes
necessary. This small module combines the functionality of
http_reply_file/3 and http_reply_dirindex/3 to act as a simple
web-server. Such a server can be created using the following code
sample, which starts a server at port 8080 that serves files from the
current directory ('.'). Note that the handler needs a =prefix= option
to specify it must handle all paths that begin with the registed
location of the handler.
==
:- use_module(library(http/thread_httpd)).
:- use_module(library(http/http_dispatch)).
:- http_handler(root(.), http_reply_from_files('.', []), [prefix]).
:- initialization
http_server(http_dispatch, [port(8080)]).
==
@see pwp_handler/2 provides similar facilities, where .pwp files
can be used to add dynamic behaviour.
*/
%% http_reply_from_files(+Dir, +Options, +Request)
%
% HTTP handler that serves files from the directory Dir. This
% handler uses http_reply_file/3 to reply plain files. If the
% request resolves to a directory, it uses the option =indexes= to
% locate an index file (see below) or uses http_reply_dirindex/3
% to create a listing of the directory.
%
% Options:
%
% * indexes(+List)
% List of files tried to find an index for a directory. The
% default is ['index.html'].
%
% Note that this handler must be tagged as a =prefix= handler (see
% http_handler/3 and module introduction). This also implies that
% it is possible to override more specific locations in the
% hierarchy using http_handler/3 with a longer path-specifier.
%
% @param Dir is either a directory or an path-specification as
% used by absolute_file_name/3. This option provides
% great flexibility in (re-)locating the physical files
% and allows merging the files of multiple physical
% locations into one web-hierarchy by using multiple
% user:file_search_path/2 clauses that define the same
% alias.
% @see The hookable predicate file_mime_type/2 is used to
% determine the =|Content-type|= from the file name.
http_reply_from_files(Dir, Options, Request) :-
( memberchk(path_info(PathInfo), Request)
-> true
; PathInfo = ''
),
http_safe_file(PathInfo, []),
locate_file(Dir, PathInfo, Path, IsFile, Options),
( IsFile == true
-> http_reply_file(Path, [unsafe(true)], Request)
; http_reply_dirindex(Path, [unsafe(true)], Request)
).
locate_file(Dir, PathInfo, Result, IsFile, Options) :-
absolute_file_name(Dir, DirPath,
[ file_type(directory),
access(read),
solutions(all)
]),
directory_file_path(DirPath, PathInfo, Path),
( exists_file(Path)
-> IsFile = true,
Result = Path
; exists_directory(Path),
( option(indexes(Indexes), Options, ['index.html']),
member(Index, Indexes),
directory_file_path(Path, Index, IndexFile),
exists_file(IndexFile)
-> Result = IndexFile,
IsFile = true
; Result = Path,
IsFile = false
)
).
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