Contents

    Query Parameters

    query parameter details operation
    P=V P is a property chain, i.e. a sequence of dot-separated short names of properties. Select only items which have a value V for the final item in the chain. (V's value string is converted according to the range of that property.)
    min-P=V P is a property chain. Select only items whose P-value is at least V.
    max-P=V P is a property chain. Select only items whose P-value is at most V.
    minEx-P=V P is a property chain. Select only values whose P-value is more than V. (minEx means "minimum, exclusive of V")
    maxEx-P=V P is a property chain. Select only values whose P-value is less than V.
    exists-P=true P is a property chain. Select only items which have some P-value.
    exists-P=false P is a property chain. Select only items which do not have a P-value.
    lang-P=LANG
    reserved query parameter details effect
    _pageSize=N N is an integer greater than 0. Show N items on this page.
    _page=N N is an integer greater than 0. Show page N, where a page has X items on it as defined by _pageSize=X or by the API configuration or as the default of 10.
    _format=NAME NAME must be the name of one of the formats understood by this Elda (e.g., html, json). Render this query in the given format.
    _lang=LANG LANG is a language code, eg en, eh-uk, or the special language code none. Sets the default language(s), overriding anything set by the api:lang setting in the configuration. Query parameter values that are strings are given the default language code. The view will discard property values that are strings not in the the given languages, unless the only values are strings with no language, in which case those are displayed.
    _view=NAME NAME is the name of a view as defined in the configuration, or one of the predefined names description, all, or basic. Only the item properties specified in the view will be displayed.
    _properties=A,B,... A, B, ... are property chains P.Q.R, where P... are the short names of properties or the special wildcard property * meaning any property. The property chains are added to those of the view defined by _view or the configuration. (This applies even if that view is an all or description view which uses a SPARQL DESCRIBE to get property values rather than individual names.)
    _sort=A,B,... A, B, are comma-separated sort specifications: an optional - meaning "sort in reverse order" preceeding a property chain. The items are sorted according to the values of the specified properties.
    _orderBy=ORDER ORDER is a string suitable for use as a SPARQL ORDER BY clause. (This is useful only with _where as a query parameter or api:where in the configuration.) The items are ordered according to the ORDER BY clause.
    callback=F F must be a legal Javascript name. The result is a Javascript call F(J) where J is the JSON rendering of the result model.
    _metadata=NAME NAME should be one of the known metadata component names. That named metadata is included in the result model:
    • versions the available different views of this result.
    • bindings the term (shortname) and variable bindings.
    • execution details of the LDA processor, i.e. Elda, specifying where its code and documentation can be found.
    • formats the available different formats of this result.
    • all all of the above.
    The XSLT-driven HTML renderer automatically incorporates all of these.
    _template=TEMPLATE TEMPLATE must be a legal SPARQL CONSTRUCT body also legal as a WHERE body.
    _where=CLAUSE CLAUSE must be a legal SPARQL where clause. CLAUSE is used in the SPARQL query rather than any computed or configured where clause.
    _search=QUERY QUERY must be a legal text-search query. All the selected items must satisfy the query.
    _graph=URI URI should be the (suitably-encoded) URI of a graph in the datatset being queried. The generated SPARQL query specifies the graph with that name.

    Configuration

    resource property value meaning
    an API api:sparqlEndpoint some_resource The designated resource identifies the SPARQL endpoint that this API fetches its information from.
    an API api:prefixMapping some_resource some_resource is an api:PrefixMapping element, probably written using blank nodes, giving additional prefixes for this configuration. The prefixes present in the result include the prefixes of this configuration model and any api:prefixMappings in this configuration. (A result model may drop prefixes it does not use.)
    an API or endpoint elda:licence some_resource some_resource is a licence resource with arbitrary properties which are embedded in the metadata for a generated view page. The properties rdfs:label and foaf:depiction are recognised by the velocity renderer which displays them on a generated page.
    An endpoint has all the licences of its API as well as any configured on the endpoint itself.
    an API or endpoint elda:notice some_resource some_resource is a notice resource with arbitrary properties which are embedded into the metadata for a generated view page.
    An endpoint inherits the notice configured on its API.
    an api:PrefixMapping api:prefix "prefix" prefix is the prefix of this prefix mapping.
    an api:PrefixMapping api:namespace "namespace" namespace is the namespace of this prefix mapping, i.e. what the prefix represents.
    the API a api:ListEndpoint This endpoint is a list endpoint that can show multiple items selected by filters.
    any endpoint api:uriTemplate "/path/with/{var}" This endpoint is invoked when the URI path matches the template. The variable var is bound to the last segment of the path.
    an item endpoint a api:ItemEndpoint This endpoint is an item endpoint showing the single item specified by the associated api:itemTemplate.
    an API or endpoint elda:graphTemplate "URI/with/{var}" The SPARQL query specifies the variable-expanded form of the given URI as the GRAPH URI for this query. Graph templates attached to an API apply to all endpoints that do not have their own template.
    the API api:itemTemplate some_resource The single item displayed is the one named in some_resource with any variable references {name} replaced with their values.
    the API api:base some_resource If specified, all Elda's constructed URIs (such as those for different views or formats of the displayed page) will use that base URI with the path and query parameters supplied in the request. This means that a server at location A can generate URIs as though it were at location B (from which it may have been redirected).
    the API api:endpoint some_resource The given some_resource is an endpoint. It must be defined somewhere in this configuration.
    api or endpoint api:variable some_resource (usually a blank node) Declares an API variable. The resource is usually a blank node with rdf:type api:Variable. The name, type, and value of the variable are given by properties of some_resource.
    a api:Variable api:name "name" Specifies the name of the variable.
    a api:Variable api:type some_resource Specifies the type of this variable. If not specified, the value of the variable will be a plain literal.
    a api:Variable api:value some RDF resource or literal Specifies the value of this variable. May be over-ridden by a query parameter binding.
    api or endpoint api:maxPageSize positive integer N The maximum page size for this endpoint, or the default for endpoints of this API, is N.
    api or endpoint api:defaultPageSize positive integer N The default page size for this endpoint, or the default for endpoints of this API, is N.
    api or endpoint api:select some_resource The endpoint, or by default other endoints of this API, selects its list of items using the selector some_resource.
    an api:Selector api:where "where clause" This selector uses the specified where clause as the where clause in the SPARQL query to select items. Any SPARQL query variables ?var that are defined as API variables are replaced by the value of that variable.
    an api:Selector api:filter "chain1=value1, chain2=value2..." The chains are property chains, ie dot-separated shortnames of properties. Items are selected only if the value of their property chain is equal to the given value.
    an api:Selector api:parent anotherSelector This selector includes any filters of the given parent selector anotherSelector.
    an api:Selector api:orderBy order by clause The selected items are sorted according to the given SPARQL order by clause. Note that this is useful only with the query parameter _where or using api:where in a selector.
    an api:Selector api:sort "A, B..." The selected items are sorted according to the sort specification, where A and B (etc) are property chains possibly preceeded by - for reverse order.
    api or endpoint api:lang "language code" The default language for this endpoint or endpoints of this API are given as language codes, e.g. en-us or cy.
    api or endpoint api:defaultViewer some_resource This endpoint, or all endpoints of this API, has as default viewer some_resource, which may be one of the three builtin viewers
    • api:basicViewer (show rdfs:label and rdf:type)
    • api:describeViewer (show whatever a SPARQL DESCRIBE produces)
    • api:labelledDescribeViewer (show DESCRIBE plus any labels of all resources)
    or a resource (often a blank node) of type api:Viewer with api:property or api:properties properties (see below).
    api or endpoint api:template
    an api:Viewer api:properties "chain1,chain2..." The viewer should include properties and values for all of the given property chains (which may include the wildcard property *).
    an api:Viewer api:property (property1, property2 ...) The viewer should include a property chain with the given properties in that order. (Note that the properties are identified by their full URI or CURIE, not their shortname.)
    api or endpoint api:defaultFormatter some_resource The default formatter of this endpoint, or all the endpoints of this API, is that described in the api:Formatter some_resource.
    api or endpoint api:formatter some_resource some_resource is a permissable formatter of this endpoint or all endpoints of this API.
    aProperty api:structured boolean If the boolean is true, the JSON rendering of aProperty values will always include their datatypes and languages.