[
https://issues.apache.org/jira/browse/SIS-387?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17799444#comment-17799444
]
Martin Desruisseaux edited comment on SIS-387 at 12/21/23 2:57 PM:
-------------------------------------------------------------------
Done on the {{geoapi-4.0}} development branch (will be merged to the {{main}}
branch later). The redirection in above issue description has also been ported.
was (Author: desruisseaux):
Done on the `geoapi-4.0` development branch (will be merged to the `main`
branch later). The redirection in above issue description has also been ported.
> Automatically resolve links in metadata document
> ------------------------------------------------
>
> Key: SIS-387
> URL: https://issues.apache.org/jira/browse/SIS-387
> Project: Spatial Information Systems
> Issue Type: Task
> Components: Metadata
> Affects Versions: 0.7, 0.8, 1.0, 1.1, 1.2, 1.3, 1.4
> Reporter: Martin Desruisseaux
> Assignee: Martin Desruisseaux
> Priority: Minor
> Fix For: 1.5
>
>
> The {{ReferenceResolver}} class allows user to specify what Apache SIS should
> do when its unmarshal an element defined only by a link to an on-line
> document. Current implementation does nothing. As a side effect of SIS-345
> work, an implementation resolving all links were provided by Image Matters.
> The code has been extracted in this task for allowing to handle SIS-345
> (upgrade to ISO 19115-3) and this task separately.
> {code:java}
> package org.apache.sis.xml;
> import java.io.IOException;
> import java.net.HttpURLConnection;
> import java.net.MalformedURLException;
> import java.net.URL;
> import javax.xml.bind.JAXBException;
> import javax.xml.bind.Unmarshaller;
> import org.apache.sis.util.Version;
> import org.apache.sis.xml.MarshalContext;
> import org.apache.sis.xml.MarshallerPool;
> import org.apache.sis.xml.ReferenceResolver;
> import org.apache.sis.xml.XLink;
> import org.apache.sis.xml.XML;
> /**
> * This class is used to resolve external references in ISO metadata when
> unmarshalling.
> * It will <em>always</em> attempt to resolve external references, and will
> return null
> * if it fails to do so.
> *
> * @author Cullen Rombach (Image Matters)
> */
> public class AllReferenceResolver extends ReferenceResolver {
> private Version metadataVersion;
> private MarshallerPool pool;
> /**
> * Constructor.
> *
> * @param metadataVersion the version of metadata to unmarshal (e.g. ISO
> 19139)
> */
> public AllReferenceResolver(Version metadataVersion) throws JAXBException
> {
> super();
> this.metadataVersion = metadataVersion;
> }
> @Override
> public <T> T resolve(MarshalContext context, Class<T> type, XLink link) {
> T content = super.resolve(context, type, link);
> try {
> if (content == null) {
> // Cast the URI in the XLink to a URL.
> URL href = link.getHRef().toURL();
> // Used for storing a redirect URL if necessary.
> URL newHref = href;
> // Flag to see if a redirect is necessary.
> Boolean redirect = true;
> while (redirect) {
> // Only check for redirects on HTTP and HTTPS connections.
> if (newHref.getProtocol().contains("http")) {
> // Open a connection to the URL to check for a
> redirect if it uses HTTP protocol.
> HttpURLConnection connection = (HttpURLConnection)
> newHref.openConnection();
> // Check HTTP status for a possible redirect.
> int status = connection.getResponseCode();
> // If we need to redirect, do so.
> if (status == HttpURLConnection.HTTP_MOVED_TEMP
> || status == HttpURLConnection.HTTP_MOVED_PERM
> || status ==
> HttpURLConnection.HTTP_SEE_OTHER) {
> // If we need to redirect, get the new URL.
> newHref = new
> URL(connection.getHeaderField("Location"));
> } // Otherwise, flag that no redirect is necessary.
> else {
> redirect = false;
> }
> } // If the link doesn't use HTTP protocol, don't check
> for a redirect.
> else {
> redirect = false;
> }
> }
> // Build an Unmarshaller (and the MarshallerPool it belongs
> to).
> Unmarshaller unmarshaller =
> acquireUnmarshaller(metadataVersion);
> // If there was a redirect, unmarshal the new URL.
> if (!newHref.equals(href)) {
> content = type.cast(unmarshaller.unmarshal(newHref));
> pool.recycle(unmarshaller);
> } // Otherwise, unmarshal the original URL.
> else if (href != null) {
> content = type.cast(unmarshaller.unmarshal(href));
> pool.recycle(unmarshaller);
> }
> }
> // If any sort of exception occurred, just return whatever the
> parent class found.
> } catch (MalformedURLException e) {
> return content;
> } catch (JAXBException e) {
> return content;
> } catch (IOException e) {
> return content;
> }
> return content;
> }
> /**
> * Get an unmarshaller with its own AllReferenceResolver that operates on
> the given metadata version.
> *
> * @return a new Unmarshaller.
> */
> private Unmarshaller acquireUnmarshaller(Version metadataVersion) throws
> JAXBException {
> pool = new MarshallerPool(null);
> Unmarshaller unmarshaller = pool.acquireUnmarshaller();
> // Set metadata version for unmarshalling.
> unmarshaller.setProperty(XML.METADATA_VERSION, metadataVersion);
> // Set resolver for external references.
> unmarshaller.setProperty(XML.RESOLVER, new
> AllReferenceResolver(metadataVersion));
> return unmarshaller;
> }
> }
> {code}
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
