How do I import RSS feeds with Images into Drupal 8 to create an auto-posting Blog?
Well I've been grappling with this issue for a full week and have sorted it now (well very nearly!). Although Drupal 8 has been out for about two years most of the richer functionality and theming still exists only on Drupal 7. So I've been dredging through solutions articles but they all stop at admitting defeat over Drupal 8 and mentioning dev versions and heavy coding workarounds, etc.
So to cut my long story short, and I hope others find this if they need it, you essentially have two good options for importing from an RSS feed to create an auto-posting blog on Drupal 8:
1. Aggregator - included in the Drupal 8 core and works wonderfully except no image import at all (I tried custom mappings and everything else).
2. Feeds Module - lots of people complained about it not being ready and I experienced the errors too, but 8.x-3.x-dev is working from http://bit.ly/2BgNxzz.
The key is to keep it simple. I had tried to map some fields to pull the images in etc, and the imports were giving me a meaningless " error. How I solved it was to cut all the mappings out, then it imported complete with the image, and I slowly added back each extra field I was still wanting (one at a time). So despite many articles saying Feeds is not ready and you need to code lots of extras in, it is probably no longer an issue. I am using the RSS/Atom parser with the Node processor, which creates Article content type. I then created a View which filters on Published Articles and sorts by the Published Date field. It's working nicely now and the site search looks through over 680 of my blog posts.
But I don't have it working perfectly yet. I still have one snag and that is the cron job runs and reports that the RSS import happened without errors, but the new posts are not actually being detected and created. If (on Admin/Content/Feeds) I choose the manual import it runs, imports and creates the new posts fine. Seems many have this problem and I'm still looking for an easy solution for it. But give me another week and I'm sure I'll find a way.
For now, my newly created Drupal site is not in main production use but can be seen at http://drupal.gadgeteer.co.za. It's a full rework and a newer lighter version of my Wordpress site that is still at https://gadgeteer.co.za. When I'm happy with the new one, I'll shut down the WordPress one and use that main URL for the Drupal site. Although I've had doubts about starting out on Drupal version 8 it has been a lot of fun learning it this last week, and makes me realise I really miss my old software coding days.... I just feel so rusty now but having Google and the Internet does make it a lot easier!