URI Resolver

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The URI Resolver is a RESTful service which gives access via HTTP(s) to different gCube Resolver services and gCube Applications (like GisViewer) used into the D4Science Infrastructure.


The artifact is available on Nexus with the following coordinates:


Runtime Resource

The address and the configuration information of the servlet are registered on the gCube Information System as Runtime Resource (RR).

You can see the configuration through Monitor service (https://services.d4science.org/infrastructure-monitor) searching in the root scope the RR with following:


You must copy such runtime resource in VRE scope if it is need to work at VRE level


The following code snippet can be used to retrieve from the gCube Information System the info to configure the resolver

	XQuery query = queryFor(ServiceEndpoint.class);
	query.addCondition("$resource/Profile/Name/text() eq 'HTTP-URI-Resolver'").setResult("$resource/Profile/AccessPoint");
	DiscoveryClient<AccessPoint> client = clientFor(AccessPoint.class);
	List<AccessPoint> endpoints = client.submit(query);
	if (endpoints.size() == 0)
		throw new Exception("No Resolver available");
	//Base Address
        //Query URL parameter

Retrieve web service endpoint

The service endpoint URL [URI_RESOLVER_SERVICE_ENDPOINT] of Resolver services is:

for the development environment


for the production environment



SMP Resolver

The first version of the component is able to give HTTP resolution to SMP protocol URIs [1].

Once deployed in a SmartGear container as Tomcat, the service can be used to resolve SMP URIs as follows:

URL url = new URL("http://<hostname>:<port>/uri-resolver/smp?smp-uri=smp://.....);

The HTTP URI can be also used to retrieve files using wget or trough a Web Browser:


Apart from the smp-uri mandatory parameter, two optional paramters can be used:

  • fileName : to specify the output file name ( default: fromStorageManager)
  • contentType : to specify the output file content-type ( default: unknown/unknown)

SMP-ID Resolver

The resolver is able to give HTTP resolution to storage resource by ID [2].


For instance, in the development environment you can download the following file with WGET command or through a Web Browser by using the link:


Apart from the smp-id mandatory parameter, SMP-ID Resolver uses two optional parameters (in the query string):

  • fileName : to specify the output file name (default: fromStorageManager)
  • contentType : to specify the output file content-type (default: unknown/unknown)

The two default cases above will be used if and only if the file name and content-type (mime type) cannot be read from metadata of the file saved in the Storage.

Therefore, in this order:

- Either fileName is read from query string or is read from storage metadata otherwise is default: "fromStorageManager"

- Either contentype is read from query string or is read from storage metadata otherwise is default: "unknown/unknown"


This works as #SMP-ID Resolver using links having the format:



STORAGE-ID Resolver implements the HTTP doHead operation. It performs a payload validation (checking if it exists in the storage area) for the resource ID required:

- if the payload exists: it returns status 200 the content-type and content-disposition of the file in the HTTP response;

- if the payload does not exist: it returns status 404 in the HTTP response.

GIS Resolver

The first version of the component is able to give HTTP resolution (as redirect to Gis Viewer Application) to display and navigate on map the gis layers stored in iMarine Geonetwork #iMarine_GeoNetwork

The Gis Resolver can be used to resolve Gis Layer using a Web Browser link as follows:


The link must include two mandatory parameters:

  • gis-UUID : to specify the Metadata Universally Unique Identifier (UUID - used in iMarine Geonetwork). The UUID identifies the gis layer which you want to show in Gis Viewer Application
  • scope : to specify the "scope" for discovering the iMarine GeoNetwork service (e.g. scope=/gcube/devsec/devVRE)
Runtime Resource

In order to work, it is necessary to copy from Root scope (/d4science.research-infrastructures.eu) to the VRE where Gis-Resolver must work, the runtime resource with following coordinates:

Generic Resource for Gis Viewer Application

It is necessary to edit the generic resource "Gis Viewer Application" in the Root scope (/d4science.research-infrastructures.eu) adding the VRE scope where the GisViewerApplication must work.

The Generic Resource "Gis Viewer Application" coordiantes are:

<Name>Gis Viewer Application</Name>


This works as an HTTP Resolver to get/resolve a link to a "Catalogue Entity" stored in one of the instances of gCube Data Catalogue

A Catalogue Entity is either a "group" or an "organization" or a "product" of gCube Data Catalogue.

Create an Item URL via HTTP POST

The resolver provides HTTP POST operation to build a link to a "Catalogue Entity" stored into a specific gCube Data Catalogue.

In order to give a catalogue link for a catalogue entity is needed to pass in the body of the POST request a JSON with the fields:

  • gcube_scope as mandatory field. It is the gcube scope where to search the gCube Catalogue Portlet;
  • entity_context as mandatory field. It can be: "dataset" or "product", "group", "organization";
  • entity_name as mandatory field. It is the entity name, that is its CKAN URL.

Where the JSON format is the following one:

"gcube_scope" : "[gcube_scope value]",
"entity_context" : "[entity_context value]",
"entity_name" : "[entity_name value]"
How to create the Catalogue Link

You need to perform a POST request to the resolver


by using:

- the header parameter Content-Type: application/json;

- the body with the JSON format as above specified (the response returns an HTTP link).

An instance of body could be [ex. 1]:

"gcube_scope" : "/gcube/devsec/devVRE",
"entity_context" : "dataset",
"entity_name" : "sarda-sarda"

The HTTP Response returned:

The response returns in the body a "brief URL" in clear of kind:

[URI_RESOLVER_SERVICE_ENDPOINT]/[ctlg|ctlg-p|ctlg-d|ctlg-o|ctlg-g]/[VRE_NAME]/[entity_name value]


ctlg | ctlg-p | ctlg-d | ctlg-o | ctlg-g are codes to resolve the couple "catalogue"-"entity_context_value", in detail:

ctlg -> this one is default value to refer a 'product'|'dataset'

ctlg-p|d -> to refer respectively a 'product'|'dataset'

ctlg-o -> to refer an 'organization'

ctlg-g -> to refer a 'group'

For instance, using the request of [ex. 1] in the development environment, the HTTP response returns in the body the URL:


Resolve a link via HTTP GET

The resolver provides HTTP GET operation to give HTTP resolution (as HTTP redirect) for displaying the 'entity_name' through an instance of "gCube Data Catalogue Portlet" (this last one is resolved by the 'gcube_scope' used to generate the catalogue link)

Geonetwork Resolver

The 'Geonetwork Resolver' is a "middle tier" (like a Proxy) to perform queries on gCube Geonetwork services. It uses the 'Geonetwork Manager library' to discovery Geonetwork configurations like: Geonetwork service end-point, Geonetwork accounts and so on. Using the Geonetwork configurations discovered the resolver performs authentication on Geonetwork (if needed) and then forward the requests received to harvesting metadata on that Geonetwork. Authentication is needed to get layers stored as private on Geonetwork.

The resolver is reachable by HTTP GET request and supports the following protocol:


In detail, the protocol parameters are:

  • SCOPE (mandatory): the gCube scope used via 'Geonetwork Manager library' to discovery the Geonetwork service end-point and other configurations (like Geonetwork accounts and so on). It must be separated by character pipe '|'. i.e. gcube|devNext|NextNext;
  • MODE (mandatory): must be 'VRE' or 'HARVEST'. To harvest at VRE level or External GEONETWORK level;
  • VISIBILITY (mandatory): must be 'PUB' or 'PRV'. When PUB: only public layer/s is/are returned. When PRV: only private layer/s is/are returned;
  • FILTER_KEY/FILTER_VALUE (mandatory): couple key/value passed in the path to filter on one of geonetwork:info field returned by ISO19139 schema. Only layer/s complying the filter criteria are returned (i.e. The filter category/interactiveResources returns only the layers belonging to GN category "Interactive resources"). The default value must be null/null if you don't want to apply any filter;
  • REQUEST DELIMITER (mandatory). must be '$$'. It is the delimiter to specify the end of the path.

i.e. CKAN harvester configured to retrieve metadata by the URL: https://data.d4science.org/geonetwork/d4science.research-infrastructures.eu%7CgCubeApps%7CRPrototypingLab/VRE/PRV/null/null/$$


  • GEONETWORK_RESOLVER_BASE_URL has value: https://data.d4science.org, so the Geonetwork Resolver service endepoint is: https://data.d4science.org/geonetwork;
  • SCOPE has value: 'd4science.research-infrastructures.eu|gCubeApps|RPrototypingLab';
  • MODE has value: 'VRE';
  • FILTER_KEY has value: null and FILTER_VALUE has value: null;
  • VISIBILITY has value: 'PRV';

It retrieves all private layers of the VRE RPrototypingLab.

Uri Resolver Manager

The Uri Resolver Manager is a library to get a public link of a resource reachable from a (Gcube) Http Resolver

At moment, the resource types are GIS or SMP reachable from Uri-Resolver and Gis-Resolver.

The Uri Resolver Manager look up the (Generic Resource) "Uri-Resolver-Map" to read the mapping: Application Type -> (Runtime Resource of its) Resolver, e.g. GIS -> Gis-Resolver, SMP -> HTTP-URI-Resolver

The mandatory parameters to forward correctly the HTTP request to Resolver are dynamically read from Runtime Resource


The artifact is available on Nexus with the following coordinates:


A simple java How-to:

public static void main(String[] args) {
		try {
			UriResolverManager resolver = new UriResolverManager("GIS");
			Map<String, String> params = new HashMap<String, String>();
			params.put("gis-UUID", "eb1a1b63-f324-47ee-9522-b8f5803e19ec");
			params.put("scope", "/gcube/devsec/devVRE");
			String shortLink = resolver.getLink(params, true); //true, link is shorted otherwise none
		} catch (UriResolverMapException e) {
		} catch (IllegalArgumentException e) {
		}catch (Exception e) {
Generic Resource

In order to work, it is necessary to copy from Root scope (/d4science.research-infrastructures.eu) to the VRE where Uri Resolver Manager must work, the generic resource with following coordinates: