Add <image> element to RSS channel

The patch works as expected and adds the Image element to the RSS channel. The following patch cleans up the field labels to remove some unnecessary formatting.

1. Reproducing undesirable behavior. Creating 2 test articles with images, and an RSS view & display of articles. Located where it appears an image option should be: "Feed: Row Style Options". Confirmed "Image" is not one of the options.
2. Applying patch: $ curl -l https://www.drupal.org/files/issues/2018-04-13/rss-feed-image-2924204-4.patch | git apply -v
3. Applied clean.
4. Canceled out of the view creation.
5. Deleted the view I had created (apparently it had already been created at this point).
6. drush cr
7. Redoing step 1: still don't see an "Image" option.

I may be testing this incorrectly, given that @wjackson already indicated it was working as expected. So, leaving this as "Needs review".

Steps to reproduce would be helpful. Happy to re-test once those are provided.

Nevermind, figured it out. This is for an image for the feed, not for each feed item. Located under the display's "Format" -> "Settings", with "RSS Feed" selected". Re-testing:

1. Create 1 test article. Not sure it's needed, but.. meh.
2. Creating an articles view.
3. Creating a feed display.
4. Checking Format -> Format -> Settings.
5. No image option available. Undesirable behavior confirmed. Also gave it a path, saved it, and looked in data. Confirmed no image info.
6. Applying patch: curl -l https://www.drupal.org/files/issues/2018-04-13/rss-feed-image-2924204-4.patch | git apply -v
7. Applied clean.
8. drush cr
9. Exited out and deleted my articles view.
10. Redoing steps 2 through 5: success, image option available (screenshot embedded at bottom of this comment). Added URL, and it appears in feed data.
11. Unfortunately, the feed data looks a little messed up both visually and functionally. See below:

<channel>
    <title></title>
    <link>http://sprint-20180413-0916.ddev.local:8080/articles</link>
    <description></description>
    <language>en</language>
          <image>
        <url>http://www.google.com/image</url>
        <title></title>
        <link>http://sprint-20180413-0916.ddev.local:8080/articles</link>
      </image>

I think this "Needs work", but feel free to correct that if I'm wrong. Also, this will probably require tests? I won't add "Needs tests" just yet, since the patch doesn't appear to be working.

Looking at the RSS 2.0 image spec:
https://validator.w3.org/feed/docs/rss2.html#ltimagegtSubelementOfLtchan...

Looks like the title and link tags are part of the spec, which I didn't realize. So, it looks like this is only visually messed up, not functionally.

Also, should the link tag should be linking to the site, not necessarily the view? Dunno. The language doesn't seem to clarify. Regardless, that seems like nitpicking.

Am I get this right, this patch will provide one global image for an whole rss view?
Why not adding it here as per row e.g.
url="http://www.foo.com/movie.mov"
fileSize="12216320"
type="video/quicktime"
medium="video"
isDefault="true"
expression="full"
bitrate="128"
framerate="25"
samplingrate="44.1"
channels="2"
duration="185"
height="200"
width="300"
lang="en" />?

This patch seems to only allow for an image for the entire `RSS`, not single rows that are returned in the feed.

I am adding reference to related issue that will return <enclosure> for each item returned. Patch #4 will only add the Image element to the RSS channel.

Rerolling patch for testing on 8.9.x

And yes ... this is different functionality from attaching an image to each item, please check the RSS spec.

Core doesn't really care about tidy whitespace ... but I see that's what's being requested here.

Hmmm new tests ...

Ugh ... apologies, I changed the whitespace ~ updated the hash.

I'm not a patch wizard, have only done this a handful of times, but I think there might be some text at the top of the patch in #20 (from, date, subject) that is interfering with my ability to apply the patch. Not sure if other people experience this as well. I'm using composer.

Hiya!

Nah that's standard formatting; https://git-scm.com/docs/git-format-patch

It's more likely that it just needs rerolling for the current 8.9.x-dev branch.

#20 is working for me on D8.9.7, but there are 7 extra "+" symbols that are actually outputted in the feed.

#20 seems to be working on D9.2.9.

That's odd - there are double ++ in the patch ... that'll be why. I'll reroll it a bit later.

#30 working on D9.2.9 with php 7.4. Thanks!

The Needs Review Queue Bot tested this issue. It either no longer applies to Drupal core, or fails the Drupal core commit checks. Therefore, this issue status is now "Needs work".

Apart from a re-roll or rebase, this issue may need more work to address feedback in the issue or MR comments. To progress an issue, incorporate this feedback as part of the process of updating the issue. This helps other contributors to know what is outstanding.

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Rerolled for 11.x.

Believe this will need test coverage as well.

Thanks!

Rerolled for 10.2.x