1 files changed, 233 insertions, 0 deletions
diff --git a/BRMSGateway/src/main/java/org/onap/policy/brms/api/nexus/NexusRestWrapper.java b/BRMSGateway/src/main/java/org/onap/policy/brms/api/nexus/NexusRestWrapper.java
new file mode 100644
index 000000000..afa3e3794
--- /dev/null
+++ b/BRMSGateway/src/main/java/org/onap/policy/brms/api/nexus/NexusRestWrapper.java
@@ -0,0 +1,233 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP Policy Engine
+ * ================================================================================
+ * Copyright (C) 2018 Ericsson Intellectual Property. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.brms.api.nexus;
+
+import com.google.gson.Gson;
+
+import java.net.URI;
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.ws.rs.client.Client;
+import javax.ws.rs.client.ClientBuilder;
+import javax.ws.rs.client.Invocation.Builder;
+import javax.ws.rs.core.Response;
+
+import org.onap.policy.brms.api.nexus.pojo.NexusArtifact;
+import org.onap.policy.brms.api.nexus.pojo.NexusRepository;
+import org.onap.policy.brms.api.nexus.pojo.NexusSearchResult;
+import org.onap.policy.common.logging.flexlogger.FlexLogger;
+import org.onap.policy.common.logging.flexlogger.Logger;
+
+/**
+ * The Class NexusRestWrapper provides a Java API to a Nexus repository, wrapping the Nexus REST interface.
+ */
+public class NexusRestWrapper {
+    private static final Logger LOGGER = FlexLogger.getLogger(NexusRestWrapper.class.getName());
+
+    // A web client for issuing REST requests to the Nexus server
+    private final Client client;
+
+    // The URL of the Nexus server
+    private final String nexusServerUrl;
+
+    // Credentials for Nexus server logins
+    private String nexusUser;
+    private String nexusPassword;
+
+    /**
+     * Instantiates a new Nexus REST agent.
+     *
+     * @param nexusServerUrl the URL of the Nexus server as a string
+     * @throws NexusRestWrapperException on errors on the Nexus server URL
+     */
+    public NexusRestWrapper(final String nexusServerUrl) throws NexusRestWrapperException {
+        LOGGER.trace("new NexusRestWrapper: nexusServerUrl=" + nexusServerUrl);
+
+        if (isNullOrBlank(nexusServerUrl)) {
+            throw new NexusRestWrapperException("nexusServerUrl must be specified for the Nexus server");
+        }
+
+        this.nexusServerUrl = nexusServerUrl;
+
+        // Create a client for RST calls towards the Nexus server
+        client = ClientBuilder.newClient();
+    }
+
+    /**
+     * Instantiates a new Nexus REST agent with credentials.
+     *
+     * @param nexusServerUrl the URL of the Nexus server as a string
+     * @param nexusUser the Nexus userid
+     * @param nexusPassword the Nexus password
+     * @throws NexusRestWrapperException on parameter exceptions
+     */
+    public NexusRestWrapper(final String nexusServerUrl, final String nexusUser, final String nexusPassword)
+            throws NexusRestWrapperException {
+        LOGGER.trace("new NexusRestWrapper: nexusServerUrl=" + nexusServerUrl);
+
+        if (isNullOrBlank(nexusServerUrl)) {
+            throw new NexusRestWrapperException("nexusServerUrl must be specified for the Nexus server");
+        }
+
+        if (isNullOrBlank(nexusUser) || isNullOrBlank(nexusPassword)) {
+            throw new NexusRestWrapperException("nexuusUser and nexusPassword must both be specified");
+        }
+
+        this.nexusServerUrl = nexusServerUrl;
+        this.nexusUser = nexusUser;
+        this.nexusPassword = nexusPassword;
+
+        // Create a client for RST calls towards the Nexus server
+        client = ClientBuilder.newClient();
+
+        LOGGER.trace("NexusRestWrapper created: nexusServerUrl=" + nexusServerUrl);
+    }
+
+    /**
+     * Close the REST client.
+     */
+    public void close() {
+        LOGGER.trace("NexusRestWrapper closing: url=" + nexusServerUrl);
+
+        // Close the web client
+        client.close();
+
+        LOGGER.trace("NexusRestWrapper closed: url=" + nexusServerUrl);
+    }
+
+    /**
+     * Find an artifact in the Nexus server.
+     *
+     * @param searchParameters
+     *        the search parameters to use for the search
+     * @return the list of artifacts found that match the requested artifact
+     * @throws NexusRestWrapperException
+     *         Exceptions accessing the Nexus server
+     */
+    public NexusSearchResult findArtifact(final NexusRestSearchParameters searchParameters)
+            throws NexusRestWrapperException {
+
+        LOGGER.trace("new search with search parameters: " + searchParameters);
+
+        // Issue the REST request to perform the search
+        URI searchUri = searchParameters.getSearchUri(nexusServerUrl);
+
+        LOGGER.debug("search URI is: " + searchUri.toString());
+
+        // Compose the REST request
+        Builder requestBuilder = client.target(searchUri).request("application/json");
+        getAuthorizationHeader(requestBuilder);
+
+        // Issue the REST request
+        Response response = requestBuilder.get();
+
+        LOGGER.debug("search response is: " + response.toString());
+
+        // Check the HTTP response code for the search
+        if (Response.Status.OK.getStatusCode() != response.getStatus()) {
+            LOGGER.warn("search to URI " + searchUri.toString() + "failed, response was: " + response.toString());
+            throw new NexusRestWrapperException("query to Nexus failed with message: " + response.toString());
+        }
+
+        try {
+            // Get the JSON string with the the search result
+            String responseString = response.readEntity(String.class);
+
+            // Parse the returned JSON into result POJOs
+            NexusSearchResult searchResult = new Gson().fromJson(responseString, NexusSearchResult.class);
+
+            // We now need to expand the release and snapshot URL paths for each artifact
+            expandArtifactUrlPaths(searchResult);
+
+            return searchResult;
+        } catch (Exception e) {
+            LOGGER.warn("processing of result from search to URI " + searchUri
+                    + " failed with message " + e.getMessage());
+            throw new NexusRestWrapperException(
+                    "processing of result from query to Nexus failed with message: " + e.getMessage(), e);
+        }
+    }
+
+    /**
+     * Get the authorisation header for the user name and password.
+     * @param requestBuilder the request builder to add authorization to
+     * @return the authorisation header
+     */
+    private Builder getAuthorizationHeader(Builder requestBuilder) {
+        if (null != nexusUser && null != nexusPassword) {
+            String userPassString = nexusUser + ":" + nexusPassword;
+            requestBuilder.header("Authorization", "Basic "
+                    + java.util.Base64.getEncoder().encodeToString(userPassString.getBytes()));
+        }
+
+        return requestBuilder;
+    }
+
+    /**
+     * Use the Repository URLs in the search result to create a release and snapshot URL path for each artifact.
+     * @param searchResult the results of a Nexus server search
+     */
+    private void expandArtifactUrlPaths(NexusSearchResult searchResult) {
+        // Create a map of repositories for doing lookups
+        Map<String, NexusRepository> repositoryMap = new HashMap<>();
+
+        for (NexusRepository repository : searchResult.getRepoDetailsList()) {
+            repositoryMap.put(repository.getRepositoryId(), repository);
+        }
+
+        for (NexusArtifact artifact : searchResult.getArtifactList()) {
+            artifact.setUrlPath(composeArtifactUrlPath(repositoryMap, artifact));
+        }
+    }
+
+    /**
+     * Compose an artifact URL path using the repository and artifact details for the artifact.
+     * @param repositoryMap the available repositories
+     * @param artifact the artifact
+     * @return the URL path
+     */
+    private String composeArtifactUrlPath(Map<String, NexusRepository> repositoryMap, NexusArtifact artifact) {
+        // We always have one hit
+        NexusRepository repository = repositoryMap.get(artifact.getArtifactHits().get(0).getRepositoryId());
+
+        return new StringBuilder()
+                .append(repository.getRepositoryUrl())
+                .append("/content/")
+                .append(artifact.getGroupId().replace('.', '/'))
+                .append('/')
+                .append(artifact.getArtifactId())
+                .append('/')
+                .append(artifact.getVersion())
+                .append('/')
+                .append(artifact.getArtifactId())
+                .append('-')
+                .append(artifact.getVersion())
+                .toString();
+    }
+
+    /**
+     * Check if a string is null or all white space.
+     */
+    private boolean isNullOrBlank(final String parameter) {
+        return null == parameter || parameter.trim().isEmpty();
+    }
+}