/* Part of SWI-Prolog Author: Jan Wielemaker E-mail: J.Wielemaker@cs.vu.nl WWW: http://www.swi-prolog.org Copyright (C): 2009, 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., 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(uri, [ uri_components/2, % ?URI, ?Components uri_data/3, % ?Field, +Components, ?Data uri_data/4, % +Field, +Components, -Data, -New uri_normalized/2, % +URI, -NormalizedURI uri_normalized_iri/2, % +URI, -NormalizedIRI uri_normalized/3, % +URI, +Base, -NormalizedURI uri_normalized_iri/3, % +URI, +Base, -NormalizedIRI uri_resolve/3, % +URI, +Base, -AbsURI uri_is_global/1, % +URI uri_query_components/2, % ?QueryString, ?NameValueList uri_authority_components/2, % ?Authority, ?Components uri_authority_data/3, % ?Field, ?Components, ?Data % Encoding uri_encoded/3, % +Component, ?Value, ?Encoded uri_file_name/2, % ?URI, ?Path uri_iri/2 % ?URI, ?IRI ]). :- use_module(library(shlib)). :- use_foreign_library(foreign(uri)). /** Process URIs This library provides high-performance C-based primitives for manipulating URIs. We decided for a C-based implementation for the much better performance on raw character manipulation. Notably, URI handling primitives are used in time-critical parts of RDF processing. This implementation is based on RFC-3986: http://labs.apache.org/webarch/uri/rfc/rfc3986.html The URI processing in this library is rather liberal. That is, we break URIs according to the rules, but we do not validate that the components are valid. Also, percent-decoding for IRIs is liberal. It first tries UTF-8; then ISO-Latin-1 and finally accepts %-characters verbatim. Earlier experience has shown that strict enforcement of the URI syntax results in many errors that are accepted by many other web-document processing tools. */ %% uri_components(+URI, -Components) is det. %% uri_components(-URI, +Components) is det. % % Break a URI into its 5 basic components according to the % RFC-3986 regular expression: % % == % ^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))? % 12 3 4 5 6 7 8 9 % == % % @param Components is a term uri_components(Scheme, Authority, % Path, Search, Fragment). See uri_data/3 for accessing this % structure. %% uri_data(?Field, +Components, ?Data) is semidet. % % Provide access the uri_component structure. Defined field-names % are: =scheme=, =authority=, =path=, =search= and =fragment= uri_data(scheme, uri_components(S, _, _, _, _), S). uri_data(authority, uri_components(_, A, _, _, _), A). uri_data(path, uri_components(_, _, P, _, _), P). uri_data(search, uri_components(_, _, _, S, _), S). uri_data(fragment, uri_components(_, _, _, _, F), F). %% uri_data(+Field, +Components, +Data, -NewComponents) is semidet. % % NewComponents is the same as Components with Field set to Data. uri_data(scheme, uri_components(_, A, P, Q, F), S, uri_components(S, A, P, Q, F)). uri_data(authority, uri_components(S, _, P, Q, F), A, uri_components(S, A, P, Q, F)). uri_data(path, uri_components(S, A, _, Q, F), P, uri_components(S, A, P, Q, F)). uri_data(search, uri_components(S, A, P, _, F), Q, uri_components(S, A, P, Q, F)). uri_data(fragment, uri_components(S, A, P, Q, _), F, uri_components(S, A, P, Q, F)). %% uri_normalized(+URI, -NormalizedURI) is det. % % NormalizedURI is the normalized form of URI. Normalization is % syntactic and involves the following steps: % % * 6.2.2.1. Case Normalization % * 6.2.2.2. Percent-Encoding Normalization % * 6.2.2.3. Path Segment Normalization %% uri_normalized_iri(+URI, -NormalizedIRI) is det. % % As uri_normalized/2, but percent-encoding is translated into IRI % Unicode characters. The translation is liberal: valid UTF-8 % sequences of %-encoded bytes are mapped to the Unicode % character. Other %XX-sequences are mapped to the corresponding % ISO-Latin-1 character and sole % characters are left untouched. % % @see uri_iri/2. %% uri_is_global(+URI) is semidet. % % True if URI has a scheme. The semantics is the same as the code % below, but the implementation is more efficient as it does not % need to parse the other components, nor needs to bind the % scheme. % % == % uri_is_global(URI) :- % uri_components(URI, Components), % uri_data(Components, scheme, Scheme), % nonvar(Scheme). % == %% uri_resolve(+URI, +Base, -GlobalURI) is det. % % Resolve a possibly local URI relative to Base. This implements % http://labs.apache.org/webarch/uri/rfc/rfc3986.html#relative-transform %% uri_normalized(+URI, +Base, -NormalizedGlobalURI) is det. % % NormalizedGlobalURI is the normalized global version of URI. % Behaves as if defined by: % % == % uri_normalized(URI, Base, NormalizedGlobalURI) :- % uri_resolve(URI, Base, GlobalURI), % uri_normalized(GlobalURI, NormalizedGlobalURI). % == %% uri_normalized_iri(+URI, +Base, -NormalizedGlobalIRI) is det. % % NormalizedGlobalIRI is the normalized global IRI of URI. Behaves % as if defined by: % % == % uri_normalized(URI, Base, NormalizedGlobalIRI) :- % uri_resolve(URI, Base, GlobalURI), % uri_normalized_iri(GlobalURI, NormalizedGlobalIRI). % == %% uri_query_components(+String, -Query) is det. %% uri_query_components(-String, +Query) is det. % % Perform encoding and decoding of an URI query string. Query is a % list of fully decoded (Unicode) Name=Value pairs. In mode (-,+), % query elements of the forms Name(Value) and Name-Value are also % accepted to enhance interoperability with the option and pairs % libraries. E.g. % % == % ?- uri_query_components(QS, [a=b, c('d+w'), n-'VU Amsterdam']). % QS = 'a=b&c=d%2Bw&n=VU%20Amsterdam'. % % ?- uri_query_components('a=b&c=d%2Bw&n=VU%20Amsterdam', Q). % Q = [a=b, c='d+w', n='VU Amsterdam']. % == %% uri_authority_components(+Authority, -Components) is det. %% uri_authority_components(-Authority, +Components) is det. % % Break-down the authority component of a URI. The fields of the % structure Components can be accessed using uri_authority_data/3. %% uri_authority_data(+Field, ?Components, ?Data) is semidet. % % Provide access the uri_authority structure. Defined field-names % are: =user=, =password=, =host= and =port= uri_authority_data(user, uri_authority(U, _, _, _), U). uri_authority_data(password, uri_authority(_, P, _, _), P). uri_authority_data(host, uri_authority(_, _, H, _), H). uri_authority_data(port, uri_authority(_, _, _, P), P). %% uri_encoded(+Component, +Value, -Encoded) is det. %% uri_encoded(+Component, -Value, +Encoded) is det. % % Encoded is the URI encoding for Value. When encoding % (Value->Encoded), Component specifies the URI component where % the value is used. It is one of =query_value=, =fragment= or % =path=. Besides alphanumerical characters, the following % characters are passed verbatim (the set is split in logical % groups according to RFC3986). % % $ query_value, fragment : % "-._~" | "!$'()*,;" | ":@" | "/?" % $ path : % "-._~" | "!$&'()*,;=" | ":@" | "/" %% uri_iri(+URI, -IRI) is det. %% uri_iri(-URI, +IRI) is det. % % Convert between a URI, encoded in US-ASCII and an IRI. An IRI is % a fully expanded Unicode string. Unicode strings are first % encoded into UTF-8, after which %-encoding takes place. % % @error syntax_error(Culprit) in mode (+,-) if URI is not a % legally percent-encoded UTF-8 string. %% uri_file_name(+URI, -FileName) is semidet. %% uri_file_name(-URI, +FileName) is det. % % Convert between a URI and a local file_name. This protocol is % covered by RFC 1738. Please note that file-URIs use _absolute_ % paths. The mode (-, +) translates a possible relative path into % an absolute one. uri_file_name(URI, FileName) :- nonvar(URI), !, uri_components(URI, Components), uri_data(scheme, Components, file), ( uri_data(authority, Components, '') -> true ; uri_data(authority, Components, localhost) ), uri_data(path, Components, FileNameEnc), uri_encoded(path, FileName0, FileNameEnc), delete_leading_slash(FileName0, FileName). uri_file_name(URI, FileName) :- nonvar(FileName), !, absolute_file_name(FileName, Path0), ensure_leading_slash(Path0, Path), uri_encoded(path, Path, PathEnc), uri_data(scheme, Components, file), uri_data(authority, Components, ''), uri_data(path, Components, PathEnc), uri_components(URI, Components). %% ensure_leading_slash(+WinPath, -Path). %% delete_leading_slash(+Path, -WinPath). % % Deal with the fact that absolute paths in Windows start with a % drive letter rather than a /. For URIs we need a path that % starts with a /. ensure_leading_slash(Path, SlashPath) :- ( sub_atom(Path, 0, _, _, /) -> SlashPath = Path ; atom_concat(/, Path, SlashPath) ). :- if(current_prolog_flag(windows, true)). delete_leading_slash(Path, WinPath) :- atom_concat(/, WinPath, Path), is_absolute_file_name(WinPath), !. :- endif. delete_leading_slash(Path, Path).