Difference between revisions of "GeoNetwork library"
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The given generic resource's body must contain an XML Serialization of ''org.gcube.spatial.data.geonetwork.iso.EnvironmentConfiguration'' class. | The given generic resource's body must contain an XML Serialization of ''org.gcube.spatial.data.geonetwork.iso.EnvironmentConfiguration'' class. | ||
− | === | + | ===Configuration retrieval=== |
The gcube generic resource is found submitting a query to the [[ic-client]] with the following parameters. | The gcube generic resource is found submitting a query to the [[ic-client]] with the following parameters. | ||
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The cache TTL, along with the query parameters value can be configured by editing the [[#Properties file]]. | The cache TTL, along with the query parameters value can be configured by editing the [[#Properties file]]. | ||
− | === | + | ===Configure environment=== |
''Geonetwork'' library allows administrator to easily configure their environment constants. The following snippets shows how : | ''Geonetwork'' library allows administrator to easily configure their environment constants. The following snippets shows how : | ||
<source lang="java"> | <source lang="java"> | ||
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The method ''config.publish()'' creates and publishes a generic resource with the configured name and secondary type (see [[#Properties file]]). | The method ''config.publish()'' creates and publishes a generic resource with the configured name and secondary type (see [[#Properties file]]). | ||
− | === | + | ===Configuration parameters=== |
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Revision as of 16:09, 14 July 2016
A library to interact with GeoNetwork's REST Interface to publish/modify/delete and search for Metadata.The library is designed on top of geoserver-manager library, developed by GeoSolutions. Metadata objects managed by the library are compliant to standard specification ISO 19115:2003/19139. Default configuration of the library interacts exploits Featherweight Stack functionalities to discover geonetwork available in the infrastructure.
Contents
Module overview
The library is distributed as the artifact
<dependency> <groupId>org.gcube.spatial.data</groupId> <artifactId>geonetwork</artifactId> <version>...</version> </dependency>
ISO 19115:2003 metadata compliance
Metadata objects used by the libraries implement GeoAPI interfaces, which are fully compliant to ISO 19115:2003/19139. Current implementation is based on GeoToolkit Metadata module.
Dependecies
The library declares these dependecies to external third parties artifacts
<dependency> <groupId>it.geosolutions</groupId> <artifactId>geonetwork-manager</artifactId> <version>1.1</version> </dependency> <dependency> <groupId>org.geotoolkit</groupId> <artifactId>geotk-metadata</artifactId> <version>3.20-geoapi-3.0</version> </dependency> <dependency> <groupId>org.w3c</groupId> <artifactId>dom</artifactId> <version>2.3.0-jaxb-1.0.6</version> </dependency> <dependency> <groupId>org.geotoolkit</groupId> <artifactId>geotk-referencing</artifactId> <version>3.20-geoapi-3.0</version> </dependency>
Using the library
The library acts as a wrapper to the functionalities exposed by the geonetwork-manager library. The methods offered by the library are splitted in three different interfaces :
- org.gcube.spatial.data.geonetwork.GeoNetworkReader : declares methods to access metadata stored in geonetwork
- org.gcube.spatial.data.geonetwork.GeoNetworkPublisher : extends GeoNetworkReader, and declares methods to publish/update/delete metadata in geonetwork
- org.gcube.spatial.data.geonetwork.GeoNetworkAdministration : extends GeoNetworkPublisher, and declares methods to manage users and groups on GeoNetwork (available from 3.0.0)
The class org.gcube.spatial.data.geonetwork.GeoNetwork offers two static members to obtain implementations of the above interfaces :
- public static GeoNetworkAdministration get() throws Exception : uses the current settings of ConfigurationManager to get a Configuration implementation.
- public static GeoNetworkAdministration get(Configuration config) : uses the passed Configuration implementation.
See #Configuration to get more information.
Changes in 3.0.0
Along with gcube 4.0, comes a new version of the library : 3.0.0. Basic usage of the library remains at most the same, even if some important feature have changed, thus some refactoring might be needed anyway. The following is a list of the main changes in the library, please refer to the rest of this page for more detailed information
- Introduced GeoNetworkAdministration interface to manage groups and users on GeoNetwork
- Configuration compliant with gcube 4.0.0 SDI publishing policies
- Automatic generation of scope configuration if none is present
- Improved publishing checks against current configuration
- Improved model and faults management
User management
Library version 2.0
From version 2.0.0 the library refers to the guidelines stated in GeoNetwork administration in particular :
- applications should publish their metadata in the current scope group
- applications should publish as <SCOPE_PUBLIC_USER> metadata with scope visibility
- applications should publish as <SCOPE_PRIVATE_USER> metadata with private (per user) visibility
Login
Unless the client calls the method public void login(LoginLevel level)throws AuthorizationException declared by GeoNetworkReader interface, all calls to geonetwork are sent without login thus :
- queries return only public metadata
- access to metadata with no public access will fail
- methods which change the current geonetwork state will fail
The following LoginLevels are defined :
- DEFAULT
- SCOPE
- PRIVATE
see #Configuration for details on how the related credentials are used.
Library Version 3.0
From version 3.0.0 the publication guidelines suggest that:
- metadata that should be visible only inside the current scope : use current scope's private group on GeoNetwork
- metadata that should be visible in the current scope and in parent ones : use current scope's public group on GeoNetwork
Login
Unless the client calls the method public void login(LoginLevel level)throws AuthorizationException declared by GeoNetworkReader interface, all calls to geonetwork are sent without login thus :
- queries return only public metadata
- access to metadata with no public access will fail
- methods which change the current geonetwork state will fail
Please note that by calling login method, the user specifies publishing behavior according to the current scope configuration involving the target group to use:
- DEFAULT : uses <SCOPE_USER> and publish into the default publishing group for the current scope;
- SCOPE : uses <SCOPE_USER> and publish into the <PUBLIC_GROUP> for the current scope;
- PRIVATE : uses <SCOPE_USER> and publish into the <PRIVATE_GROUP> for the current scope;
- ADMIN : uses administration privileges, thus no check/ constraint are performed;
- CKAN : uses read-only ckan user for that scope;
see #Configuration for details on how the related credentials are used.
Geonetwork instances discovery
The geonetwork library relies on instances of org.gcube.spatial.data.geonetwork.configuration.Configuration interface in order to retrieve needed information to interact with geonetwork REST interface. The following snippets show how to set Configuration implementation to be used by the library :
Implicit Configuration
Using ConfigurationManager to set the class implementing Configuration. Every following instantiation of GeoNetworkReader will use a new object of the given Configuration implementing class.
//MyConfiguration must implement org.gcube.spatial.data.geonetwork.configuration.Configuration ConfigurationManager.setConfiguration(MyConfiguration.class); ... GeoNetworkReader reader1=GeoNetwork.get(); ... GeoNetworkReader reader2=GeoNetwork.get(); ... GeoNetworkPublisher publisher1=GeoNetwork.get();
Explicit Configuration
Explicit Configuration implementation declaration.
//MyConfiguration must implement org.gcube.spatial.data.geonetwork.configuration.Configuration GeoNetworkReader reader1=GeoNetwork.get(new MyConfiguration()); ... GeoNetworkReader reader2=GeoNetwork.get(new MyConfiguration()); ... GeoNetworkPublisher publisher1=GeoNetwork.get(new MyConfiguration());
Default Configuration
By default, the library uses implementation of the class org.gcube.spatial.data.geonetwork.configuration.DefaultConfiguration. This implementation is based on the ic-client, and relies on the gCube information system in order to get the needed parameters to interact with geonetwork REST interface. The convention used by this implementation are the one stated in GeoNetwork Runtime Resource Definition.
Changes in 3.0.0
From version 3.0.0 the interface org.gcube.spatial.data.geonetwork.configuration.Configuration has been completely changed in order to manage gcube4.0.0 SDI publishing policies as described in GeoNetwork Runtime Resource Definition.
Metadata generation facilities
Instances of org.opengis.metadata.Metadata interface can be generated in very different ways. However, we identified a common set of information which every application should include in its published metadata. Providing a common way to generate these metadata entry aims to :
- Reduce the needed effort to generate metadata from the developer's point of view;
- Reuse of code;
- Common behavior to gather common information (see #Infrastructure configuration);
- Check project's constraints (see GCube Object Metadata).
GcubeISOMetadata class
The utility class org.gcube.spatial.data.geonetwork.iso.GcubeISOMetadata lets developers to simply specify the metadata information strictly needed for the generation, relying on internal logic for generic behavior.
Instantiating
A GcubeISOMetadata instance should be generated for each publishing request, but this behavior depends on the caller application logic. At construction time, common information fetched from the gCube IS is loaded. Queries to IS are done via the ic-client, so be sure that a proper scope is setted via org.gcube.common.scope.api.ScopeProvider. Loaded configuration is represented by instances of the class org.gcube.spatial.data.geonetwork.iso.EnvironmentConfiguration see #EnvironmentConfiguration class.
import org.gcube.spatial.data.geonetwork.iso.EnvironmentConfiguration; import org.gcube.spatial.data.geonetwork.iso.GcubeISOMetadata; import org.gcube.common.scope.api.ScopeProvider; .... ScopeProvider.instance.set(...); GcubeISOMetadata meta=new GcubeISOMetadata(); EnvironmentConfiguration configuration = meta.getConfig(); System.out.println("Current configuration is "+configuration);
Filling parameters
The GcubeISOMetadata class exposes setter/add methods to let users specify metadata information. The following is a list of attributes that can be set along with their cardinality. Attributes which cardinality can be more then 1 are setted via the related addXXX() method, while setXXX() methods are provided for the other ones.
Attribute Name | Type | Cardinality |
---|---|---|
User | java.lang.String | 1
|
Title | java.lang.String | 1 |
Date | java.lang.Date | 1 |
Presentation Form | org.opengis.metadata.citation.PresentationForm | 1 |
Abstract | java.lang.String | 1 |
Purpose | java.lang.String | 1 |
Credits | java.lang.String | 1..N |
Descriptive Keyword | java.lang.String | 1..N |
Topic Category | org.opengis.metadata.identification.TopicCategory | 1..N |
Extent | org.geotoolkit.metadata.iso.extent.DefaultExtent | 1 |
Geometric Object Type | org.opengis.metadata.spatial.GeometricObjectType | 1 |
Geometry Count | int | 1 |
Topology Level | org.opengis.metadata.spatial.TopologyLevel | 1 |
Resolution | double | 1 |
Graphic Overview | String | 0..N |
The following snippets shows how this parameters are set :
import org.gcube.spatial.data.geonetwork.iso.EnvironmentConfiguration; import org.gcube.spatial.data.geonetwork.iso.GcubeISOMetadata; import org.gcube.spatial.data.geonetwork.iso.Thesaurus; import org.geotoolkit.metadata.iso.extent.DefaultExtent; import org.opengis.metadata.citation.PresentationForm; import org.opengis.metadata.identification.TopicCategory; import org.opengis.metadata.spatial.GeometricObjectType; import org.opengis.metadata.spatial.TopologyLevel; ... GcubeISOMetadata meta=new GcubeISOMetadata(); //Setter methods meta.setAbstractField(...); meta.setCreationDate(...); meta.setExtent(DefaultExtent.WORLD); meta.setGeometricObjectType(GeometricObjectType.SURFACE); meta.setPresentationForm(PresentationForm.MAP_DIGITAL); meta.setPurpose(...); meta.setResolution(...); meta.setTitle(..); meta.setTopologyLevel(TopologyLevel.GEOMETRY_ONLY); meta.setUser(...); //Add methods meta.addCredits(..); meta.addGraphicOverview(...); //Need to get keywords referred Thesaurus Thesaurus generalThesaurus=meta.getConfig().getThesauri().get(...); meta.addKeyword(..., generalThesaurus); meta.addKeyword(..., generalThesaurus); meta.addTopicCategory(TopicCategory.BIOTA);
Getting the metadata
Once the metadata information have been set to the GCubeISOMetadata instance, the caller can obtain the metadata to publish just by calling its public org.opengis.metadata.Metadata getMetadata() method. In case any mandatory value is missing a MissingInformationException is thrown.
ScopeProvider.instance.set("/gcube/devsec"); GcubeISOMetadata meta=new GcubeISOMetadata(); // Set information .... // Print out the metadata XML.marshal(meta.getMetadata(),System.out);
Extending default behaviour
GCubeISOMetadata class can be extended in order to enhance its purpose and behaviour. In the following example we define our MyApplicationIsoMetadata class in order to :
- Automatically set application default values when instatiating;
- Add new mandatory fields to generate data quality information to our metadata, via :
- Adding new member to our class
- Override of protected method checkConstraints
- Override of public method getMetadata()
import org.gcube.spatial.data.geonetwork.iso.GcubeISOMetadata; import org.gcube.spatial.data.geonetwork.iso.MissingInformationException; import org.opengis.metadata.Metadata; //Extends org.gcube.spatial.data.geonetwork.iso.GcubeISOMetadata public class MyApplicationIsoMetadata extends GcubeISOMetadata { //We want this citation to be automatically added to credits private static final String applicationCitation="...."; //Our mandatory field private String mandatoryField=null; public MyApplicationIsoMetadata() throws Exception { //Let the super class initialize itself super(); //Let's add our citation to credits this.getCredits().add(applicationCitation); } @Override protected void checkConstraints() throws MissingInformationException { // We let the super class to perform its checks before continuing super.checkConstraints(); // Custom check against mandatoryField if(mandatoryField==null) throw new MissingInformationException(); } @Override public Metadata getMetadata() throws URISyntaxException,MissingInformationException { Metadata toReturn=super.getMetadata(); //We set our mandatory field to the metadata ........ return toReturn; } public String getMandatoryField() { return mandatoryField; } public void setMandatoryField(String mandatoryField) { this.mandatoryField = mandatoryField; } }
EnvironmentConfiguration class
Common metadata values (i.e. project citation, project name etc.) are loaded from a gCube generic resource that must be accessible in the current scope. The given generic resource's body must contain an XML Serialization of org.gcube.spatial.data.geonetwork.iso.EnvironmentConfiguration class.
Configuration retrieval
The gcube generic resource is found submitting a query to the ic-client with the following parameters.
- Secondary Type [default value = ISO]
- Resource Name [default value = MetadataConstants]
The Generic resource is cached to avoid overhead in querying the IS. The cache TTL, along with the query parameters value can be configured by editing the #Properties file.
Configure environment
Geonetwork library allows administrator to easily configure their environment constants. The following snippets shows how :
import org.gcube.spatial.data.geonetwork.iso.EnvironmentConfiguration; import org.gcube.common.scope.api.ScopeProvider; import org.gcube.common.resources.gcore.GenericResource; .... //Create the configuration EnvironmentConfiguration config=new EnvironmentConfiguration(); //Set all the values in the configuration ... //We set the scope where to Publish the configuration ScopeProvider.instance.set(...); //Let's actually publish the configuration GenericResource res=config.publish(); //Just some output log here String id=res.id(); System.out.println("Published configuration [res ID = "+id+"] under scope "+ScopeProvider.instance.get());
The method config.publish() creates and publishes a generic resource with the configured name and secondary type (see #Properties file).
Configuration parameters
Property | Type | Cardinality |
---|---|---|
Protocol declarations | ||
WMS protocol | java.lang.String | 0..1 |
WFS protocol | java.lang.String | 0..1 |
WCS protocol | java.lang.String | 0..1 |
HTTP protocol | java.lang.String | 0..1 |
Project citation | ||
Project Name | java.lang.String | 0..1 |
Project Citation | java.lang.String | 0..1
|
Distributor Role | ||
Distributor individual name | java.lang.String | 0..1 |
Distributor e-mail | java.lang.String | 0..1 |
Distributor organization name | java.lang.String | 0..1 |
Distributor web site | java.lang.String | 0..1
|
Provider Role | ||
Provider individual name | java.lang.String | 0..1 |
Provider e-mail | java.lang.String | 0..1 |
Provider organization name | java.lang.String | 0..1 |
Provider web site | java.lang.String | 0..1 |
License | ||
License | java.lang.String | 0..1 |
Thesauri Map | ||
Theaurus | org.gcube.spatial.data.geonetwork.iso.Thesaurus | 0..N |
Thesaurus class
Thesaurus class represents a thesaurus declaration for a given keyword set in ISO metadata (see ISO 19115:2003/19139).
The following is the list of its members.
Property | Type | Cardinality |
---|---|---|
Type | org.opengis.metadata.identification.KeywordType | 1 |
Title | java.lang.String | 1 |
Citation date | java.util.Date | 1 |
Citation description | java.lang.String | 0..1 |
Citation uri | java.lang.String | 0..1 |
Citation organization | java.lang.String | 0..1 |
Authored | boolean | 1 |
Example Code
Querying for metadata
import it.geosolutions.geonetwork.util.GNSearchRequest; import it.geosolutions.geonetwork.util.GNSearchResponse; import org.opengis.metadata.Metadata; import org.gcube.spatial.data.geonetwork.GeoNetwork; import org.gcube.spatial.data.geonetwork.GeoNetworkReader; ... // Get the reader GeoNetworkReader reader=GeoNetwork.get(); ... //Configure search request GNSearchRequest req=new GNSearchRequest(); req.addParam(GNSearchRequest.Param.any,"....."); req.addConfig(GNSearchRequest.Config.similarity, "1"); ... //Get the result representation GNSearchResponse resp=gn.query(req); ... //Iterate through results and access found metadata for(GNSearchResponse.GNMetadata metadata:resp){ Metadata meta=reader.getById(metadata.getUUID()); ... }
Publishing metadata
import it.geosolutions.geonetwork.util.GNInsertConfiguration; import org.opengis.metadata.Metadata; import org.gcube.spatial.data.geonetwork.GeoNetwork; import org.gcube.spatial.data.geonetwork.GeoNetworkPublisher; import org.gcube.spatial.data.geonetwork.LoginLevel; ... //Get the publisher GeoNetworkPublisher publisher=GeoNetwork.get(); ... //Cannot publish without logging in publisher.login(...); ... //Configure publish request GNInsertConfiguration config=publisher..getCurrentUserConfiguration("dataset", "_none_"); //Publish Metadata object Metadata toPublish=.... long publishedObjectId=publisher.insertMetadata(config, toPublish); ... //Publish Metadata file File myMetadataFile=... long publishedFileId=publisher.insertMetadata(config, myMetadataFile);
Publishing from 3.0.0
From 3.0.0 the library performs various checks on GNInsertConfiguration values. In order to publish with a valid configuration (compliant with gcube4.0.0 policies) users can and are encouraged to use the following snippet code instead of creating a new instance of the class GNInsertConfiguration.
... //Get the publisher GeoNetworkPublisher publisher=GeoNetwork.get(); ... //Cannot publish without logging in publisher.login(...); ... //Get publish configuration GNInsertConfiguration config=publisher.getCurrentUserConfiguration("datasets", "_none_"); ...
Change Metadata Privileges
import it.geosolutions.geonetwork.util.GNPriv; import it.geosolutions.geonetwork.util.GNPrivConfiguration; import org.gcube.spatial.data.geonetwork.GeoNetwork; import org.gcube.spatial.data.geonetwork.GeoNetworkPublisher; import org.gcube.spatial.data.geonetwork.LoginLevel; ... //Get the publisher GeoNetworkPublisher publisher=GeoNetwork.get(); ... //Cannot modify privileges without login publisher.login(...); ... //Configure privileges GNPrivConfiguration privConfig=new GNPrivConfiguration(); privConfig.addPrivileges(publisher.getConfiguration().getScopeGroup(),EnumSet.of(GNPriv.VIEW)); ... //Set the privileges long myMetadataId=... publisher.setPrivileges(myMetadataId, privConfig);