Merge pull request #114 from lat-lon/handbookCaching

Enhance documentation about server side caching of HTML view

deegree-ogcapi-documentation/src/main/asciidoc/help.adoc

@@ -42,3 +42,8 @@ How to deploy multiple instances of deegree OAF webapp?::
 
   Multiple deployments of the webapp are possible. Since each instance of the runtime environment can host one or more webapp. For every deployed webapp there must be a deegree workspace available with the name *_ogcapi-workspace_*. It is possible that multiple instances of the webapp can share one single instance of a deegree workspace, for example a setup serving the same data by multiple instances in a load-balancing scenario. To serve different data configured in different deegree workspace's you need to run multiple instances of the runtime environment.
 Use the environment variable `DEEGREE_WORKSPACE_ROOT` to set the path to the deegree workspace directory. Read further in section <<configuration>> about the deegree workspace and configuration files.
+
+How to configure server side caching for HTML view?::
+
+  Server side caching must be disabled to access the HTML view of deegree OGC API. This is because the HTML view is generated from the JSON resource on-the-fly. Otherwise a client may show outdated content from the cache which was generated by a different client request.
+  When requesting any resource of deegree OGC API the HTTP request header `Cache-Control: no-cache` shall be set to prevent caching. This also applies to proxy servers between the actual client and the deegree OGC API instance.