preparing

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

@@ -8,6 +8,7 @@
 
 package ch.ethz.seb.sebserver.webservice.servicelayer.lms.impl.olat;
 
+import java.net.URISyntaxException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
@@ -20,10 +21,16 @@ import org.apache.commons.lang3.StringUtils;
 import org.joda.time.DateTime;
 import org.springframework.cache.CacheManager;
 import org.springframework.core.env.Environment;
+import org.springframework.http.client.ClientHttpRequestFactory;
+import org.springframework.security.oauth2.client.OAuth2RestTemplate;
+import org.springframework.security.oauth2.client.token.grant.client.ClientCredentialsResourceDetails;
 
+import ch.ethz.seb.sebserver.ClientHttpRequestFactoryService;
 import ch.ethz.seb.sebserver.gbl.api.APIMessage;
 import ch.ethz.seb.sebserver.gbl.async.AsyncService;
+import ch.ethz.seb.sebserver.gbl.client.ClientCredentialService;
 import ch.ethz.seb.sebserver.gbl.client.ClientCredentials;
+import ch.ethz.seb.sebserver.gbl.client.ProxyData;
 import ch.ethz.seb.sebserver.gbl.model.Domain.LMS_SETUP;
 import ch.ethz.seb.sebserver.gbl.model.exam.Chapters;
 import ch.ethz.seb.sebserver.gbl.model.exam.Exam;
@@ -45,6 +52,8 @@ import ch.ethz.seb.sebserver.webservice.servicelayer.lms.impl.AbstractCachedCour
 public class OlatLmsAPITemplate extends AbstractCachedCourseAccess implements LmsAPITemplate {
 
     // TODO add needed dependencies here
+    private final ClientHttpRequestFactoryService clientHttpRequestFactoryService;
+    private final ClientCredentialService clientCredentialService;
     private final APITemplateDataSupplier apiTemplateDataSupplier;
     private final Long lmsSetupId;
 
@@ -52,6 +61,8 @@ public class OlatLmsAPITemplate extends AbstractCachedCourseAccess implements Lm
 
             // TODO if you need more dependencies inject them here and set the reference
 
+            final ClientHttpRequestFactoryService clientHttpRequestFactoryService,
+            final ClientCredentialService clientCredentialService,
             final APITemplateDataSupplier apiTemplateDataSupplier,
             final AsyncService asyncService,
             final Environment environment,
@@ -59,6 +70,8 @@ public class OlatLmsAPITemplate extends AbstractCachedCourseAccess implements Lm
 
         super(asyncService, environment, cacheManager);
 
+        this.clientHttpRequestFactoryService = clientHttpRequestFactoryService;
+        this.clientCredentialService = clientCredentialService;
         this.apiTemplateDataSupplier = apiTemplateDataSupplier;
         this.lmsSetupId = apiTemplateDataSupplier.getLmsSetup().id;
     }
@@ -288,4 +301,34 @@ public class OlatLmsAPITemplate extends AbstractCachedCourseAccess implements Lm
         return Result.ofRuntimeError("TODO");
     }
 
+    // TODO: This is an example of how to create a RestTemplate for the service to access the LMS API
+    //       The example deals with a Http based API that is secured by an OAuth2 client-credential flow.
+    //       You might need some different template, then you have to adapt this code
+    //       To your needs.
+    private OAuth2RestTemplate createRestTemplate(final String accessTokenRequestPath) throws URISyntaxException {
+
+        final LmsSetup lmsSetup = this.apiTemplateDataSupplier.getLmsSetup();
+        final ClientCredentials credentials = this.apiTemplateDataSupplier.getLmsClientCredentials();
+        final ProxyData proxyData = this.apiTemplateDataSupplier.getProxyData();
+
+        final CharSequence plainClientId = credentials.clientId;
+        final CharSequence plainClientSecret = this.clientCredentialService
+                .getPlainClientSecret(credentials)
+                .getOrThrow();
+
+        final ClientCredentialsResourceDetails details = new ClientCredentialsResourceDetails();
+        details.setAccessTokenUri(lmsSetup.lmsApiUrl + accessTokenRequestPath);
+        details.setClientId(plainClientId.toString());
+        details.setClientSecret(plainClientSecret.toString());
+
+        final ClientHttpRequestFactory clientHttpRequestFactory = this.clientHttpRequestFactoryService
+                .getClientHttpRequestFactory(proxyData)
+                .getOrThrow();
+
+        final OAuth2RestTemplate template = new OAuth2RestTemplate(details);
+        template.setRequestFactory(clientHttpRequestFactory);
+
+        return template;
+    }
+
 }

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

@@ -13,7 +13,9 @@ import org.springframework.context.annotation.Lazy;
 import org.springframework.core.env.Environment;
 import org.springframework.stereotype.Service;
 
+import ch.ethz.seb.sebserver.ClientHttpRequestFactoryService;
 import ch.ethz.seb.sebserver.gbl.async.AsyncService;
+import ch.ethz.seb.sebserver.gbl.client.ClientCredentialService;
 import ch.ethz.seb.sebserver.gbl.model.institution.LmsSetup.LmsType;
 import ch.ethz.seb.sebserver.gbl.profile.WebServiceProfile;
 import ch.ethz.seb.sebserver.gbl.util.Result;
@@ -33,15 +35,21 @@ import ch.ethz.seb.sebserver.webservice.servicelayer.lms.LmsAPITemplateFactory;
  * as usual. Just add the additionally needed dependencies used to build a OlatLmsAPITemplate. */
 public class OlatLmsAPITemplateFactory implements LmsAPITemplateFactory {
 
+    private final ClientHttpRequestFactoryService clientHttpRequestFactoryService;
+    private final ClientCredentialService clientCredentialService;
     private final AsyncService asyncService;
     private final Environment environment;
     private final CacheManager cacheManager;
 
     public OlatLmsAPITemplateFactory(
+            final ClientHttpRequestFactoryService clientHttpRequestFactoryService,
+            final ClientCredentialService clientCredentialService,
             final AsyncService asyncService,
             final Environment environment,
             final CacheManager cacheManager) {
 
+        this.clientHttpRequestFactoryService = clientHttpRequestFactoryService;
+        this.clientCredentialService = clientCredentialService;
         this.asyncService = asyncService;
         this.environment = environment;
         this.cacheManager = cacheManager;
@@ -56,6 +64,8 @@ public class OlatLmsAPITemplateFactory implements LmsAPITemplateFactory {
     public Result<LmsAPITemplate> create(final APITemplateDataSupplier apiTemplateDataSupplier) {
         return Result.tryCatch(() -> {
             return new OlatLmsAPITemplate(
+                    this.clientHttpRequestFactoryService,
+                    this.clientCredentialService,
                     apiTemplateDataSupplier,
                     this.asyncService,
                     this.environment,

src/main/resources/config/application-dev-ws.properties

@@ -51,21 +51,6 @@ sebserver.webservice.lms.openedx.api.token.request.paths=/oauth2/access_token
 sebserver.webservice.lms.moodle.api.token.request.paths=
 sebserver.webservice.lms.address.alias=lms.mockup.com=lms.address.alias
 
-# NOTE: This is a temporary work-around for SEB Restriction API within Open edX SEB integration plugin to
-#       apply on load-balanced infrastructure or infrastructure that has several layers of cache.
-#       The reason for this is that the API (Open edX system) internally don't apply a resource-change that is
-#       done within HTTP API call immediately from an outside perspective.
-#       After a resource-change on the API is done, the system toggles between the old and the new resource
-#       while constantly calling GET. This usually happens for about a minute or two then it stabilizes on the new resource
-#
-#       This may source on load-balancing or internally caching on Open edX side.
-#       To mitigate this effect the SEB Server can be configured to apply a resource-change on the
-#       API several times in a row to flush as match caches and reach as match as possible server instances.
-#
-#       Since this is a brute-force method to mitigate the problem, this should only be a temporary
-#       work-around until a better solution on Open edX SEB integration side has been found and applied.
-#sebserver.webservice.lms.openedx.seb.restriction.push-count=10
-
 # actuator configuration
 management.server.port=${server.port}
 management.endpoints.web.base-path=/management