Spurious empty <summary> elements in atom feed #82

magical · 2020-08-18T00:20:22Z

I have a feed in which items have a non-empty Content but an empty Description. This should result in an atom feed with a <content> element for the item but no <summary> element, but it seems that the feeds package always emits a <summary> element, even if it is empty.

https://play.golang.org/p/gE3aNOkeIqb

The feeds package should not should not emit a <summary> element if Item.Content is set but Item.Description is blank. Its presence may mislead feed readers into displaying the (empty) summary, ignoring the post content.

I'm currently working around the issue like this, but would prefer if this wasn't necessary.

atomFeed := (&feeds.Atom{feed}).AtomFeed()
for i := range atomFeed.Entries {
	atomFeed.Entries[i].Summary = nil
}

Versions

Go version: go version go1.14.3 linux/amd64
package version: 6f6e20dd3953594cd869cf981fb806440685cd21

Steps to Reproduce

How can the bug be triggered?

See code snippet below.

Output:

<?xml version="1.0" encoding="UTF-8"?><feed xmlns="http://www.w3.org/2005/Atom">
  <title>A blog</title>
  <id>http://example.net/</id>
  <updated>2009-11-10T23:00:00Z</updated>
  <link href="http://example.net/"></link>
  <author>
    <name>Test User</name>
    <email>foo@example.net</email>
  </author>
  <entry>
    <title>Blog post</title>
    <updated>2009-11-10T23:00:00Z</updated>
    <id>tag:example.net,2009-11-10:/1</id>
    <content type="html">Full contents of the blog post</content>
    <link href="http://example.net/1" rel="alternate"></link>
    <summary type="html"></summary>
    <author>
      <name>Test User</name>
      <email>test@example.net</email>
    </author>
  </entry>
</feed>

Expected behavior

What output or behaviour were you expecting instead?

Expected output

<?xml version="1.0" encoding="UTF-8"?><feed xmlns="http://www.w3.org/2005/Atom">
  <title>A blog</title>
  <id>http://example.net/</id>
  <updated>2009-11-10T23:00:00Z</updated>
  <link href="http://example.net/"></link>
  <author>
    <name>Test User</name>
    <email>foo@example.net</email>
  </author>
  <entry>
    <title>Blog post</title>
    <updated>2009-11-10T23:00:00Z</updated>
    <id>tag:example.net,2009-11-10:/1</id>
    <content type="html">Full contents of the blog post</content>
    <link href="http://example.net/1" rel="alternate"></link>
    <author>
      <name>Test User</name>
      <email>test@example.net</email>
    </author>
  </entry>
</feed>

Code Snippets

https://play.golang.org/p/gE3aNOkeIqb

package main

import (
	"log"
	"os"
	"time"

	"github.com/gorilla/feeds"
)

func main() {
	now := time.Now()
	feed := &feeds.Feed{
		Title:   "A blog",
		Link:    &feeds.Link{Href: "http://example.net/"},
		Author:  &feeds.Author{Name: "Test User", Email: "foo@example.net"},
		Created: now,
	}

	feed.Items = []*feeds.Item{
		&feeds.Item{
			Title:   "Blog post",
			Link:    &feeds.Link{Href: "http://example.net/1"},
			Content: "Full contents of the blog post",
			Author:  &feeds.Author{Name: "Test User", Email: "test@example.net"},
			Created: now,
		},
	}

	err := feed.WriteAtom(os.Stdout)
	if err != nil {
		log.Fatal(err)
	}
}

The text was updated successfully, but these errors were encountered:

elithrar · 2020-08-18T00:24:09Z

If you'd like to submit a PR with tests, I'd be happy to review and merge.

When creating an AtomEntry from an Item, only set Summary if item.Description is non-empty, like we already do for Content. Currently we always emit a <summary> element, even if the item has a non-empty <content> element. Having an empty <summary> in this case may be confusing for feed consumers. The Atom RFC explicitly says that a <summary> is not required in general. (There are a couple special cases where it is required, but they aren't relevant here.) https://tools.ietf.org/html/rfc4287#section-4.1.1.1 Fixes gorilla#82

stale · 2020-10-17T20:33:21Z