/**
* 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);
}
/**
* Handle an exception in the servlet.
*
* <p>This routine should be called whenever an exception has surfaced to the top level of the
* servlet. It should not be overridden unless Aura is entirely subsumed. Most special cases can
* be handled by the Aura user by implementing {@link ExceptionAdapter ExceptionAdapter}.
*
* @param t the throwable to write out.
* @param quickfix is this exception a valid quick-fix
* @param context the aura context.
* @param request the request.
* @param response the response.
* @param written true if we have started writing to the output stream.
* @throws IOException if the output stream does.
* @throws ServletException if send404 does (should not generally happen).
*/
@Override
public void handleServletException(
Throwable t,
boolean quickfix,
AuraContext context,
HttpServletRequest request,
HttpServletResponse response,
boolean written)
throws IOException {
try {
Throwable mappedEx = t;
boolean map = !quickfix;
Format format = context.getFormat();
//
// This seems to fail, though the documentation implies that you can do
// it.
//
// if (written && !response.isCommitted()) {
// response.resetBuffer();
// written = false;
// }
if (!written) {
// Should we only delete for JSON?
setNoCache(response);
}
if (mappedEx instanceof IOException) {
//
// Just re-throw IOExceptions.
//
throw (IOException) mappedEx;
} else if (mappedEx instanceof NoAccessException) {
Throwable cause = mappedEx.getCause();
String denyMessage = mappedEx.getMessage();
map = false;
if (cause != null) {
//
// Note that the exception handler can remap the cause here.
//
cause = exceptionAdapter.handleException(cause);
denyMessage += ": cause = " + cause.getMessage();
}
//
// Is this correct?!?!?!
//
if (format != Format.JSON) {
this.send404(request.getServletContext(), request, response);
if (!isProductionMode(context.getMode())) {
// Preserve new lines and tabs in the stacktrace since this is directly being written on
// to the
// page
denyMessage = "<pre>" + AuraTextUtil.escapeForHTML(denyMessage) + "</pre>";
response.getWriter().println(denyMessage);
}
return;
}
} else if (mappedEx instanceof QuickFixException) {
if (isProductionMode(context.getMode())) {
//
// In production environments, we want wrap the quick-fix. But be a little careful here.
// We should never mark the top level as a quick-fix, because that means that we gack
// on every mis-spelled app. In this case we simply send a 404 and bolt.
//
if (mappedEx instanceof DefinitionNotFoundException) {
DefinitionNotFoundException dnfe = (DefinitionNotFoundException) mappedEx;
if (dnfe.getDescriptor() != null
&& dnfe.getDescriptor().equals(context.getApplicationDescriptor())) {
// We're in production and tried to hit an aura app that doesn't exist.
// just show the standard 404 page.
this.send404(request.getServletContext(), request, response);
return;
}
}
map = true;
mappedEx = new AuraUnhandledException("404 Not Found (Application Error)", mappedEx);
}
}
if (map) {
mappedEx = exceptionAdapter.handleException(mappedEx);
}
PrintWriter out = response.getWriter();
//
// If we have written out data, We are kinda toast in this case.
// We really want to roll it all back, but we can't, so we opt
// for the best we can do. For HTML we can do nothing at all.
//
if (format == Format.JSON) {
if (!written) {
out.write(CSRF_PROTECT);
}
//
// If an exception happened while we were emitting JSON, we want the
// client to ignore the now-corrupt data structure. 404s and 500s
// cause the client to prepend /*, so we can effectively erase the
// bad data by appending a */ here and then serializing the exception
// info.
//
out.write("*/");
//
// Unfortunately we can't do the following now. It might be possible
// in some cases, but we don't want to go there unless we have to.
//
}
if (format == Format.JS || format == Format.CSS) {
// Make sure js and css doesn't get cached in browser, appcache, etc
response.setStatus(HttpStatus.SC_INTERNAL_SERVER_ERROR);
}
if (format == Format.JSON
|| format == Format.HTML
|| format == Format.JS
|| format == Format.CSS) {
//
// We only write out exceptions for HTML or JSON.
// Seems bogus, but here it is.
//
// Start out by cleaning out some settings to ensure we don't
// check too many things, leading to a circular failure. Note
// that this is still a bit dangerous, as we seem to have a lot
// of magic in the serializer.
//
// Clear the InstanceStack before trying to serialize the exception since the Throwable has
// likely
// rendered the stack inaccurate, and may falsely trigger NoAccessExceptions.
InstanceStack stack = this.contextService.getCurrentContext().getInstanceStack();
List<String> list = stack.getStackInfo();
for (int count = list.size(); count > 0; count--) {
stack.popInstance(stack.peek());
}
serializationService.write(mappedEx, null, out);
if (format == Format.JSON) {
out.write("/*ERROR*/");
}
}
} catch (IOException ioe) {
throw ioe;
} catch (Throwable death) {
//
// Catch any other exception and log it. This is actually kinda bad, because something has
// gone horribly wrong. We should write out some sort of generic page other than a 404,
// but at this point, it is unclear what we can do, as stuff is breaking right and left.
//
try {
response.setStatus(HttpStatus.SC_INTERNAL_SERVER_ERROR);
exceptionAdapter.handleException(death);
if (!isProductionMode(context.getMode())) {
response.getWriter().println(death.getMessage());
}
} catch (IOException ioe) {
throw ioe;
} catch (Throwable doubleDeath) {
// we are totally hosed.
if (!isProductionMode(context.getMode())) {
response.getWriter().println(doubleDeath.getMessage());
}
}
} finally {
this.contextService.endContext();
}
}