问题
I've just started on Rails again and have recently followed the Sitepoint guide to building an RSS Feed app. I followed the instructions verbatim, but am getting the error undefined method 'html_safe' for nil:NilClass. I've looked into the database and it seems Feedjira is not parsing the content or author attributes into the database.
After a quick google, I found the following issues on the Github page #178 and #176 dated back from August 13, but given the significant issue this causes I'm surprised there's not on it. It may be an error in my code which can be found here but I've checked and don't think it is.
Does anyone know of anything I'm doing wrong? I have altered the self.feed_classes in the feedjira documentation as suggested in Issue #176 but it still doesn't pick anything up.
回答1:
RSS and Atom Feeds don't offer a content attribute. The 'content' is provided as 'summary' attribute. So change
local_entry.update_attributes(content: entry.content, author: entry.author, url: entry.url, published: entry.published)
to
local_entry.update_attributes(content: entry.summary, author: entry.author, url: entry.url, published: entry.published)
Nevertheless, NewsFeeds are very fickle things. So you shouldn't rely on the existence of single attributes.
Have a look at your show.html.erb
<%= @entry.content.html_safe %>
You could for example use the safe navigation operator
<%= @entry&.content&.html_safe %>
Or inform the user, that no content is present
<% unless @entry.content.nil? %>
<%= @entry.content.html_safe %>
<% end %>
回答2:
OK. I found where the problem was. I cloned your project and fired up. Apparently your show.html.erb page from feeds is different from the one from the article, that's why you couldn't access to entries:
Yours => From the article
If you want to see the entries first create new feed, with name and description, and for example add these links for each feed:
http://epijobs.com/rss.xml
http://feedjira.com/blog/feed.xml
When you finish adding feeds, from your terminal in root app, run cd lib/task and finally run: bundle exec rake sync:feeds as it mentioned from the article:
The rake task loops through all the Feeds stored in the database and fetches the latest content for each one. From that, loop through the new Entries, creating or updating it in the database. We are updating every time to keep up with any change in the source content.
Now, if you go to this link below for example, or through link show first feed:
http://localhost:3000/feeds/1/entries
You should be able to see all entries for feed id 1.
I hope it helps.
来源：https://stackoverflow.com/questions/41650752/feedjira-not-adding-content-and-author