/**
* check the top level component/app and get dependencies.
*
* <p>This routine checks to see that we have a valid top level component. If our top level
* component is out of sync, we have to ignore it here, but we _must_ force the client to not
* cache the response.
*
* <p>If there is a QFE, we substitute the QFE descriptor for the one given us, and continue.
* Again, we cannot allow caching.
*
* <p>Finally, if there is no descriptor given, we simply ignore the request and give them an
* empty response. Which is done here by returning null.
*
* <p>Also note that this handles the 'if-modified-since' header, as we want to tell the browser
* that nothing changed in that case.
*
* @param request the request (for exception handling)
* @param response the response (for exception handling)
* @param context the context to get the definition.
* @return the set of descriptors we are sending back, or null in the case that we handled the
* response.
* @throws IOException if there was an IO exception handling a client out of sync exception
* @throws ServletException if there was a problem handling the out of sync
*/
@Override
public Set<DefDescriptor<?>> verifyTopLevel(
HttpServletRequest request, HttpServletResponse response, AuraContext context)
throws IOException {
DefDescriptor<? extends BaseComponentDef> appDesc = context.getApplicationDescriptor();
context.setPreloading(true);
if (appDesc == null) {
//
// This means we have nothing to say to the client, so the response is
// left completely empty.
//
return null;
}
long ifModifiedSince = request.getDateHeader(HttpHeaders.IF_MODIFIED_SINCE);
String uid = context.getUid(appDesc);
try {
try {
definitionService.updateLoaded(appDesc);
if (uid != null && ifModifiedSince != -1) {
//
// In this case, we have an unmodified descriptor, so just tell
// the client that.
//
response.sendError(HttpServletResponse.SC_NOT_MODIFIED);
return null;
}
} catch (ClientOutOfSyncException coose) {
//
// We can't actually handle an out of sync here, since we are doing a
// resource load. We have to ignore it, and continue as if nothing happened.
// But in the process, we make sure to set 'no-cache' so that the result
// is thrown away. This may actually not give the right result in bizarre
// corner cases... beware cache inconsistencies on revert after a QFE.
//
// We actually probably should do something different, like send a minimalist
// set of stuff to make the client re-try.
//
this.setNoCache(response);
String oosUid = definitionService.getUid(null, appDesc);
return definitionService.getDependencies(oosUid);
}
} catch (QuickFixException qfe) {
//
// A quickfix exception means that we couldn't compile something.
// In this case, we still want to preload things, but we want to preload
// quick fix values, note that we force NoCache here.
//
this.setNoCache(response);
this.handleServletException(qfe, true, context, request, response, true);
return null;
}
this.setLongCache(response);
if (uid == null) {
uid = context.getUid(appDesc);
}
return definitionService.getDependencies(uid);
}
