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) 2011-2020, VU University Amsterdam 7 All rights reserved. 8 9 Redistribution and use in source and binary forms, with or without 10 modification, are permitted provided that the following conditions 11 are met: 12 13 1. Redistributions of source code must retain the above copyright 14 notice, this list of conditions and the following disclaimer. 15 16 2. Redistributions in binary form must reproduce the above copyright 17 notice, this list of conditions and the following disclaimer in 18 the documentation and/or other materials provided with the 19 distribution. 20 21 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 29 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 31 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 32 POSSIBILITY OF SUCH DAMAGE. 33*/ 34 35:- module(http_files, 36 [ http_reply_from_files/3 % +Dir, +Options, +Request 37 ]). 38:- use_module(library(http/http_dispatch)). 39:- use_module(library(http/http_dirindex)). 40:- use_module(library(filesex)). 41:- use_module(library(lists)). 42:- use_module(library(option)). 43 44:- predicate_options(http_reply_from_files/3, 2, 45 [ indexes(list(atom)), 46 pass_to(http_dispatch:http_reply_file/3, 2), 47 pass_to(http_dirindex:http_reply_dirindex/3, 2) 48 ]). 49 50/** <module> Serve plain files from a hierarchy 51 52Although the SWI-Prolog Web Server is intended to serve documents that 53are computed dynamically, serving plain files is sometimes necessary. 54This small module combines the functionality of http_reply_file/3 and 55http_reply_dirindex/3 to act as a simple web-server. Such a server can 56be created using the following code sample, which starts a server at 57port 8080 that serves files from the current directory ('.'). Note that 58the handler needs a `prefix` option to specify that it must handle all 59paths that begin with the registed location of the handler. 60 61``` 62:- use_module(library(http/http_server)). 63:- use_module(library(http/http_files)). 64 65:- http_handler(root(.), http_reply_from_files('.', []), [prefix]). 66 67:- initialization(http_server([port(8080)]), main). 68``` 69 70@see pwp_handler/2 provides similar facilities, where .pwp files 71 can be used to add dynamic behaviour. 72*/ 73 74 75%! http_reply_from_files(+Dir, +Options, +Request) 76% 77% HTTP handler that serves files from the directory Dir. This 78% handler uses http_reply_file/3 to reply plain files. If the 79% request resolves to a directory, it uses the option =indexes= to 80% locate an index file (see below) or uses http_reply_dirindex/3 81% to create a listing of the directory. 82% 83% Options: 84% 85% * indexes(+List) 86% List of files tried to find an index for a directory. The 87% default is `['index.html']`. 88% 89% Note that this handler must be tagged as a =prefix= handler (see 90% http_handler/3 and module introduction). This also implies that 91% it is possible to override more specific locations in the 92% hierarchy using http_handler/3 with a longer path-specifier. 93% 94% When using http_handler/3 to bind this predicate to an HTTP 95% location, make sure it is bound to a location that ends in a `/`. 96% When using http:location/3 to define symbolic names to HTTP 97% locations this is written as 98% 99% :- http_handler(aliasname(.), 100% http_reply_from_files(srcdir, []), 101% [prefix]). 102% 103% @param Dir is either a directory or an path-specification as 104% used by absolute_file_name/3. This option provides 105% great flexibility in (re-)locating the physical files 106% and allows merging the files of multiple physical 107% locations into one web-hierarchy by using multiple 108% user:file_search_path/2 clauses that define the same 109% alias. 110% @see The hookable predicate file_mime_type/2 is used to 111% determine the ``Content-type`` from the file name. 112 113http_reply_from_files(Dir, Options, Request) :- 114 ( memberchk(path_info(PathInfo), Request) 115 -> true 116 ; PathInfo = '' 117 ), 118 http_safe_file(PathInfo, []), 119 locate_file(Dir, PathInfo, Result, ResultType, Options), 120 !, 121 reply(ResultType, Result, Options, Request). 122 123reply(file, Path, Options, Request) :- 124 http_reply_file(Path, [unsafe(true)|Options], Request). 125reply(index, Path, Options, Request) :- 126 http_reply_dirindex(Path, [unsafe(true)|Options], Request). 127reply(redirect, _, _, Request) :- 128 memberchk(path(Path), Request), 129 atom_concat(Path, /, NewLocation), 130 http_redirect(moved_temporary, NewLocation, Request). 131 132locate_file(Dir, PathInfo, Result, ResultType, Options) :- 133 absolute_file_name(Dir, DirPath, 134 [ file_type(directory), 135 access(read), 136 solutions(all) 137 ]), 138 directory_file_path(DirPath, PathInfo, Path), 139 ( exists_file(Path) 140 -> ResultType = file, 141 Result = Path 142 ; exists_directory(Path), 143 ( sub_atom(Path, _, _, 0, /) 144 -> ( option(indexes(Indexes), Options, ['index.html']), 145 member(Index, Indexes), 146 directory_file_path(Path, Index, IndexFile), 147 exists_file(IndexFile) 148 -> Result = IndexFile, 149 ResultType = file 150 ; Result = Path, 151 ResultType = index 152 ) 153 ; ResultType = redirect 154 ) 155 )