[rest] Add no-cache directive to cached REST responses (#3970)

Fixes openhab/openhab-webui#2102.

This forces the browser to revalidate the cache every time it is accessed to ensure the data is always fresh.
See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control#directives.

This is approach is also suggested in the mdn web docs, see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control#up-to-date_contents_always.

Signed-off-by: Florian Hotze <florianh_dev@icloud.com>

bundles/org.openhab.core.automation.rest/src/main/java/org/openhab/core/automation/rest/internal/RuleResource.java

@@ -188,6 +188,7 @@ public Response get(@Context SecurityContext securityContext, @Context Request r
                     .map(rule -> EnrichedRuleDTOMapper.map(rule, ruleManager, managedRuleProvider));
 
             CacheControl cc = new CacheControl();
+            cc.setNoCache(true);
             cc.setMustRevalidate(true);
             cc.setPrivate(true);
             rules = dtoMapper.limitToFields(rules, "uid,templateUID,name,visibility,description,tags,editable");

bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/item/ItemResource.java

@@ -271,6 +271,7 @@ public Response getItems(final @Context UriInfo uriInfo, final @Context HttpHead
                     "name,label,type,groupType,function,category,editable,groupNames,link,tags,metadata,commandDescription,stateDescription");
 
             CacheControl cc = new CacheControl();
+            cc.setNoCache(true);
             cc.setMustRevalidate(true);
             cc.setPrivate(true);
             return Response.ok(new Stream2JSONInputStream(itemStream)).lastModified(lastModifiedDate).cacheControl(cc)

bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/tag/TagResource.java

@@ -133,6 +133,7 @@ public Response getTags(final @Context Request request, final @Context UriInfo u
         }
 
         CacheControl cc = new CacheControl();
+        cc.setNoCache(true);
         cc.setMustRevalidate(true);
         cc.setPrivate(true);
 
@@ -165,6 +166,7 @@ public Response getTagAndSubTags(final @Context Request request,
         }
 
         CacheControl cc = new CacheControl();
+        cc.setNoCache(true);
         cc.setMustRevalidate(true);
         cc.setPrivate(true);
 

bundles/org.openhab.core.io.rest.core/src/main/java/org/openhab/core/io/rest/core/internal/thing/ThingResource.java

@@ -328,6 +328,7 @@ public Response getAll(@Context Request request,
             }
 
             CacheControl cc = new CacheControl();
+            cc.setNoCache(true);
             cc.setMustRevalidate(true);
             cc.setPrivate(true);
             thingStream = dtoMapper.limitToFields(thingStream, "UID,label,bridgeUID,thingTypeUID,location,editable");

bundles/org.openhab.core.io.rest.ui/src/main/java/org/openhab/core/io/rest/ui/internal/UIResource.java

@@ -168,6 +168,7 @@ public Response getAllComponents(@Context Request request, @PathParam("namespace
             }
 
             CacheControl cc = new CacheControl();
+            cc.setNoCache(true);
             cc.setMustRevalidate(true);
             cc.setPrivate(true);
             return Response.ok(new Stream2JSONInputStream(components)).lastModified(lastModifiedDate).cacheControl(cc)

bundles/org.openhab.core.io.rest/src/main/java/org/openhab/core/io/rest/internal/resources/SystemInfoResource.java

@@ -119,6 +119,7 @@ public Response getUoMInfo(final @Context Request request, final @Context UriInf
         }
 
         CacheControl cc = new CacheControl();
+        cc.setNoCache(true);
         cc.setMustRevalidate(true);
         cc.setPrivate(true);