Prepare LMS Setups

src/main/java/ch/ethz/seb/sebserver/gbl/util/Utils.java

@@ -8,7 +8,11 @@
 
 package ch.ethz.seb.sebserver.gbl.util;
 
+import java.io.IOException;
 import java.io.UnsupportedEncodingException;
+import java.net.InetSocketAddress;
+import java.net.Socket;
+import java.net.URL;
 import java.net.URLDecoder;
 import java.net.URLEncoder;
 import java.nio.ByteBuffer;
@@ -686,4 +690,20 @@ public final class Utils {
     public static String valueOrEmptyNote(final String value) {
         return StringUtils.isBlank(value) ? Constants.EMPTY_NOTE : value;
     }
+
+    /** This is used to verify if a given URL is available (valid)
+     * Uses java.net.Socket to try to connect to the given URL
+     *
+     * @param urlString the URL string
+     * @return true if SEB Server was able to ping the address. */
+    public static boolean pingHost(final String urlString) {
+        try (Socket socket = new Socket()) {
+            final URL url = new URL(urlString);
+            final int port = (url.getPort() >= 0) ? url.getPort() : 80;
+            socket.connect(new InetSocketAddress(url.getHost(), port), (int) Constants.SECOND_IN_MILLIS * 5);
+            return true;
+        } catch (final IOException e) {
+            return false; // Either timeout or unreachable or failed DNS lookup.
+        }
+    }
 }

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/lms/LmsAPITemplate.java

@@ -8,10 +8,6 @@
 
 package ch.ethz.seb.sebserver.webservice.servicelayer.lms;
 
-import java.io.IOException;
-import java.net.InetSocketAddress;
-import java.net.Socket;
-import java.net.URL;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashSet;
@@ -20,7 +16,6 @@ import java.util.Set;
 
 import org.apache.commons.lang3.StringUtils;
 
-import ch.ethz.seb.sebserver.gbl.Constants;
 import ch.ethz.seb.sebserver.gbl.api.EntityType;
 import ch.ethz.seb.sebserver.gbl.model.exam.Chapters;
 import ch.ethz.seb.sebserver.gbl.model.exam.Exam;
@@ -77,18 +72,12 @@ public interface LmsAPITemplate {
      * @return Collection of all QuizData from the given id set */
     Collection<Result<QuizData>> getQuizzes(Set<String> ids);
 
-    /** Get all QuizData for the set of QuizData identifiers from LMS API in a collection
+    /** Get the quiz data with specified identifier.
-     * of Result. If particular Quiz cannot be loaded because of errors or deletion,
-     * the Result will have an error reference.
      *
-     * NOTE: This method looks first in the cache for all given ids.
+     * Default implementation: Uses getQuizzes(Set<String> ids) and returns the first matching or an error.
-     * If all quizzes are cached, returns all from cache.
-     * If one quiz is not in the cache, requests all quizzes from the API and refreshes the cache
      *
-     * @param ids the Set of Quiz identifiers to get the QuizData for
+     * @param id the quiz data identifier
-     * @return Collection of all QuizData from the given id set */
+     * @return Result refer to the quiz data or to an error when happened */
-    Collection<Result<QuizData>> getQuizzesFromCache(Set<String> ids);
-
     default Result<QuizData> getQuiz(final String id) {
         if (StringUtils.isBlank(id)) {
             return Result.ofError(new RuntimeException("missing model id"));
@@ -100,6 +89,18 @@ public interface LmsAPITemplate {
                 .orElse(Result.ofError(new ResourceNotFoundException(EntityType.EXAM, id)));
     }
 
+    /** Get all QuizData for the set of QuizData identifiers from LMS API in a collection
+     * of Result. If particular Quiz cannot be loaded because of errors or deletion,
+     * the Result will have an error reference.
+     *
+     * NOTE: This method looks first in the cache if existing for all given ids.
+     * If all quizzes are cached, returns all from cache.
+     * If one quiz is not in the cache, requests all quizzes from the API and refreshes the cache
+     *
+     * @param ids the Set of Quiz identifiers to get the QuizData for
+     * @return Collection of all QuizData from the given id set */
+    Collection<Result<QuizData>> getQuizzesFromCache(Set<String> ids);
+
     /** Convert a an anonymous or temporary user session identifier from SEB Client into a user
      * account details.
      *
@@ -152,19 +153,4 @@ public interface LmsAPITemplate {
      * @return Result refer to the given Exam if successful or to an error if not */
     Result<Exam> releaseSEBClientRestriction(Exam exam);
 
-    /** This is used to verify if a given LMS Setup URL is available (valid)
-     *
-     * @param urlString the URL string given by the LMS Setup attribute
-     * @return true if SEB Server was able to ping the address. */
-    static boolean pingHost(final String urlString) {
-        try (Socket socket = new Socket()) {
-            final URL url = new URL(urlString);
-            final int port = (url.getPort() >= 0) ? url.getPort() : 80;
-            socket.connect(new InetSocketAddress(url.getHost(), port), (int) Constants.SECOND_IN_MILLIS * 5);
-            return true;
-        } catch (final IOException e) {
-            return false; // Either timeout or unreachable or failed DNS lookup.
-        }
-    }
-
 }

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/lms/impl/CourseAccess.java

@@ -97,7 +97,7 @@ public abstract class CourseAccess {
             final List<QuizData> cached = allQuizzesSupplier().getAllCached();
             final List<QuizData> available = (cached != null)
                     ? cached
-                    : quizzesSupplier(ids).get();
+                    : Collections.emptyList();
 
             final Map<String, QuizData> quizMapping = available
                     .stream()

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/lms/impl/edx/OpenEdxRestTemplateFactory.java

@@ -42,7 +42,7 @@ import ch.ethz.seb.sebserver.gbl.model.Domain.LMS_SETUP;
 import ch.ethz.seb.sebserver.gbl.model.institution.LmsSetup;
 import ch.ethz.seb.sebserver.gbl.model.institution.LmsSetupTestResult;
 import ch.ethz.seb.sebserver.gbl.util.Result;
-import ch.ethz.seb.sebserver.webservice.servicelayer.lms.LmsAPITemplate;
+import ch.ethz.seb.sebserver.gbl.util.Utils;
 
 final class OpenEdxRestTemplateFactory {
 
@@ -84,7 +84,7 @@ final class OpenEdxRestTemplateFactory {
                     "lmsSetup:lmsUrl:notNull"));
         } else {
             // try to connect to the url
-            if (!LmsAPITemplate.pingHost(this.lmsSetup.lmsApiUrl)) {
+            if (!Utils.pingHost(this.lmsSetup.lmsApiUrl)) {
                 missingAttrs.add(APIMessage.fieldValidationError(
                         LMS_SETUP.ATTR_LMS_URL,
                         "lmsSetup:lmsUrl:url.invalid"));

src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/lms/impl/moodle/MoodleRestTemplateFactory.java

@@ -50,7 +50,6 @@ import ch.ethz.seb.sebserver.gbl.model.institution.LmsSetup;
 import ch.ethz.seb.sebserver.gbl.model.institution.LmsSetupTestResult;
 import ch.ethz.seb.sebserver.gbl.util.Result;
 import ch.ethz.seb.sebserver.gbl.util.Utils;
-import ch.ethz.seb.sebserver.webservice.servicelayer.lms.LmsAPITemplate;
 
 class MoodleRestTemplateFactory {
 
@@ -95,7 +94,7 @@ class MoodleRestTemplateFactory {
                     "lmsSetup:lmsUrl:notNull"));
         } else {
             // try to connect to the url
-            if (!LmsAPITemplate.pingHost(this.lmsSetup.lmsApiUrl)) {
+            if (!Utils.pingHost(this.lmsSetup.lmsApiUrl)) {
                 missingAttrs.add(APIMessage.fieldValidationError(
                         LMS_SETUP.ATTR_LMS_URL,
                         "lmsSetup:lmsUrl:url.invalid"));