Update post doesn't seem to refresh cache

[timheuer]

I may be missing something but looking at the code on FileBlogService.SavePost it does not appear that an update will actually update the _cache -- if the post is new it is added, but if the post is updated, then as long as the _cache object is not rebuild (I can't see where that is invalidated other than app restart) then an updated post is never going to be resident in the cache. Am I missing something?

[madskristensen]

Isn't there cache invalidation happening automatically when the .xml file is being touched on disk?

[timheuer]

@madskristensen It doesn't appear so. There is HTTP output caching, but even when that is invalidated, the FileBlogService service still gets from the in-memory data cache. Initialize() calls LoadPosts() which creates the _cache object that is used everywhere. In SavePost if it is new then _cache.Add() is called, but only if new...if it isn't, there is no updating of the _cache object or re-trigger of LoadPosts or anything...as far as I can tell.

In practice this also seems to be the case. When I make an edit to a post, it is pretty much never reflected until the app is restarted.

[am11]

BlogController.UpdatePost() gets the same object reference as the one in cache when we update an existing post, so cache reload is not required. For the new posts, this condition gets satisfied:

Miniblog.Core/src/Services/FileBlogService.cs

Lines 140 to 144 in 58804ff

	if (!_cache.Contains(post))
	{
	_cache.Add(post);
	SortCache();
	}

When I make an edit to a post, it is pretty much never reflected until the app is restarted.

I have not seen this behavior in my deployment or on the demo website: https://miniblogcore.azurewebsites.net/ (both using FileBlogService). The changes get instantly reflected.