/* Part of ClioPatria SeRQL and SPARQL server Author: Jan Wielemaker E-mail: J.Wielemaker@cs.vu.nl WWW: http://www.swi-prolog.org Copyright (C): 2010, University of Amsterdam, 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(cliopatria, []). /** ClioPatria hooks This module declares the _hooks_ an application may define to extend or modify some of ClioPatria's behaviour. Hooks are =multifile= defined predicates that -typically- have no default definition. Code using the hook typically first calls the hook. If the hook succeeds the task is considered done. Otherwise some default action is performed. For example, a property myprefix:componentName can be added as a property that provides a label using this code: == :- use_module(cliopatria(hooks)). rdf_label:label_property(myprefix:componentName). == The example below adds an item to =Help= popup of ClioPatria: == :- use_module(cliopatria(hooks)). :- use_module(library(http/http_dispatch)). cliopatria:menu_item(help/about, 'About'). :- http_handler(root(about), about, []). about(Request) :- == */ :- multifile menu_item/2, menu_label/2, menu_popup_order/2, rdf_label:label_property/1, bnode_label//1, % +Resource display_link//2, % +RDFObject, +Options resource_link/2, % +URI, -URL list_resource//2, % +URI, +Options user_preference_db/2, % ?Property, ?Value user_preference_default/2, % ?Property, ?Value page_body//1, % +Body page_body//2, % +Style, +Body server_address//0, logo//0, predicate_order/2, % +P, -Order context_graph/2, % +R, -RDF context_graph/3, % +R, -RDF, +Options context_predicate/2, % +R, -Pred node_shape/3, % +R, -Shape, +Options bag_shape/3. % +Members, -Shape, +Options /******************************* * THE MENU * *******************************/ %% menu_item(?Item, ?Label) % % This hook adds an item to the ClioPatria menu. Item is a term of % the form [rank=]popup/item, where _popup_ denotes the name of % the popup menu and _item_ is a (new) item to be added to the % popup. The _item_ is the handler-identifier of the HTTP handler % that implements the item (see http_handler/3). Label is the % label displayed. _rank_ defines the position inside the popup. % The built-in items are numbered 100,200,... % % For example, if we want to add a new item to the *Repository* % menu after *|Load from library|* that crawls LOD data, we can % use the following code: % % == % :- use_module(cliopatria(hooks)). % :- use_module(library(http/http_dispatch)). % % :- handler(cliopatria('crawl_lod_form'), crawl_lod_form, []). % % cliopatria:menu_item(400=repository/crawl_lod_form, 'Crawl LOD'). % % crawl_lod_form(Request) :- % ... % == % % @see The menu_label/2 and menu_popup_order/2 hooks provide % further control over the menu. % @see cp_menu:menu_item/2 implements the default menu. %% menu_label(+Id, -Label) % % This hook allows for dynamic or redefined (e.g., multilingual) % labels. It is called both for popup-identifiers and % item-identifiers. %% menu_popup_order(+Id, -Location:integer) % % This hook controls the order of the popup-item of ClioPatria's % menu. /******************************* * LABELS * *******************************/ %% rdf_label:label_property(?Property) % % True if the value of Property can be used to (non-uniquely) % describe an object to the user. This hook provides additional % facts to cp_label:label_property/1. %% bnode_label(+Resource)// % % HTML-write DCG rule that produces an HTML description for the % given RDF blank node. See cp_label:bnode_label//1. %% display_link(+RDFObject)// % % HTML-write DCG rule that produces an HTML description for the % given RDFObject (a resource or literal) with an appropriate % link. This predicate is called by the RDF browser to present RDF % triples. %% resource_link(+URI, -URL)// % % URL is the link created by rdf_link//1 for URI. The default % opens the ClioPatria `local view'. % % @see cpa_browse:list_resource/1 is the handler addressed by the % default link. % @see cp_label:resource_link/2 calls the hook. /******************************* * LOCAL VIEW * *******************************/ %% list_resource(+URI, +Options)// % % This hook is called by cpa_browse:list_resource//2, which % display the `local view' page for a resource. This can be used % to create a different page for describing a resource and still % using overall infrastructure such as rdf_link//1. /******************************* * USER/SESSION PREFERENCES * *******************************/ %% user_preference_db(?Property:atom, ?Value:rdf_object) is nondet. % % Query properties for the current user/session. This mechanism % allows code to access information about the user/session without % committing to a particular implementation. The predicate and % values are compatible with RDF to allow implementing the user % database in RDF, typically using the OpenID as subject. %% user_preference_default(?Property:atom, ?Value:rdf_object) is nondet. % % Provides defaults for the user_preference/2. % % @see user_preference_db/2 /******************************* * SKINS * *******************************/ %% page_body(+Body)// is semidet. %% page_body(+Style, +Body)// is semidet. % % Emit the body of the page. This can be used to provide a % different skin for ClioPatria. The Style argument is passed from % reply_html_page/3. The file skin(cliopatria) defines the overall % skin and first calls cliopatria:page_body//2, if this fails % cliopatria:page_body//1 and if this fails too it uses the % default page. %% server_address// % % HTML-write DCG rule that writes the address of the server. If % you want to maintain its normal position in the page layout, % this should create an element of class =address= using the class % =cliopatria=. %% logo// % % Logo placed left of the menu-bar. Must be an object that has % `float:left` style. /******************************* * RDF BROWSING * *******************************/ %% predicate_order(+Pred, -Order) is semidet. % % Define the order in which predicates appear in the local view. % The Order is an integer. The system ordering is defined by % cpa_browse:p_order/2. Predicates that are not explicitly ordered % are placed at the end of the table an ordered alphabetically. % % Predicates that have order `0' are _deleted_ from the table. %% context_graph(+R, -RDF, +Options) is semidet. % % @deprecated Use context_graph/3. %% context_graph(+R, -RDF, +Options) is semidet. % % This hook redefines the context graph shown by the RDF browser % for the resource R. RDF is a list of rdf(S,P,O) triples that % describe the context. Typically only object-triples are used, % although that is not a requirement. % % @see This predicate hooks cpa_browse:context_graph/3. Please % visit the soure to learn about available building % blocks. %% context_predicate(+Subject, -Predicate) is nondet. % % True when rdf(Subject, Predicate, _) must be included in the % context graph for Subject. %% node_shape(+URI, -Shape, +Options) is semidet. % % Compute the desired shape for a GraphViz node representing URI. % % @param URI is the resource for which to determine the shape % @param Shape is a list Name(Value) for parameters given to % GraphViz. % @param Options provides additional guidance. Currently it % may provide start(StartURI) to indicate the graph is a % context node for the resource StartURI. % @see http://www.graphviz.org/doc/info/shapes.html %% node_shape(+Bag, -Shape, +Options) is semidet. % % Compute the desired properties for a table used to display a bag % of resources. Shape options include: % % - max(Max) % Only show the first Max members of the bag. Default is 5. % - shape(Shape) % Basic shape % - style(Style) % Style options % - max_label_length(Chars) % Truncate labels that have more then Chars characters. % % @param Bag is a list of member resources