CUNY Academic Commons

On a lark, I flushed the object cache, and the redirect behavior corrected itself.

This, along with backtrack info I collected, suggests strongly to me that:
- A call to `home_url()` in `redirect_canonical()` was incorrectly returning bmcccetls.commons instead of the mapped domain, which was triggering the redirect
- `home_url()` was returning the wrong value because the `domain_mapping_siteurl()` filter callback was not working properly
- This was probably caused by domain_mapping_get_data_by_id() incorrectly returning a null result for the blog ID
- Since this was fixed by a cache flush (and everything looks OK in the database tables) it means that a null result for the blog ID must have been incorrectly stored in the cache.

If this reasoning is correct, the questions are (a) why did a bad value get cached, and (b) are there techniques we can put into place to mitigate this sort of problem in the future? Even if it means not caching null values (ie forcing a database hit for non-mapped domains)? Ray, any thoughts you have would be welcome.

Thanks so much for the very quick response! Thankfully, I can now send out the weekly CETLS newsletter with links to our blog and events.

Boone, can you pass me the backtrace log if you still have it?

If not, no problem. I'll take a closer look.

Thanks for the careful thinking about this, Ray. Knowing that a null result corresponds to a DB connection error is helpful. I'm happy to go ahead with your fix. Do you think this warrants a hotfix? It's a severe problem but it appears to be extremely rare.

It's a good thing I didn't push the update as a hotfix because I found a bug that caused a redirect loop in the admin area as a result of the previous change:
https://github.com/cuny-academic-commons/cac/commit/eaaa6af50fa399026fa8c9cc12c7a2a96ec937e6

I think that because the redirect loop is a rare occurrence, we can hold off until the next maintenance release.

That's funny - I was going to report that, but when I went in today to make sure I had the details correct, it was no longer happening. I guess that's because you fixed it!