volto-rss-provider

The volto-rss-provider add-on enables RSS feed generation for a Volto site. It uses the rss_feed content type, which contains a listing block for querying items to be displayed in the RSS feed. The feed can be accessed via URLs like http://<website-domain>/<path-to-feed>/rss.xml.

To use this volto addon, you also need to install the backend addon that frames the rss_feed content type.

Features

• Generates RSS feeds using Express middleware.
• Supports Atom format for the feed.
• Customizable feed options based on the rss_feed content type.
• Allows users to specify tags, which become categories in the RSS feed.
• Supports a variety of item options, including authors, categories, and enclosures, such as images.

Setting Up the RSS Feed

The rss_feed content type includes a listing block. Use the listing block to query the items you want to display in the feed. The generated feed will include the specified items in RSS XML format.

Feed Options

The following options are supported for the RSS feed:

• title: The title of the RSS feed, truncated to a maximum length specified by max_title_length.
• description: A description of the RSS feed, truncated to a maximum length specified by max_description_length.
• feed_url: The URL to the RSS feed.
• site_url: The URL to the site the feed is for.
• generator: The name of the feed generator, statically set as "RSS Feed Generator".
• language: The language of the feed content.
• pubDate: The publication date of the feed, derived from the effective field of the rss_feed content type.
• categories: Tags specified in the rss_feed content type, used as categories for the RSS feed.

Item Options

The following options are supported for each item in the RSS feed:

• title: The title of the item, truncated to a maximum length specified by max_title_length.
• description: The description of the item, truncated to a maximum length specified by max_description_length.
• url: The URL to the item.
• date: The date the item became publicly available, derived from the effective field of the item.
• author: The authors of the item, derived from the listCreators data field and set by the Creators option.
• categories: The categories for the item, derived from the Subject data field and set by the Tags option.
• enclosure: This field typically represents media files (like images) associated with the item. The code checks for an image in the item’s image_field and its associated scales in image_scales. If found, it generates an enclosure with the image’s URL, MIME type, and size.

Image Precedence

The precedence for images in the RSS feed is as follows:

1. previewImage (if available)
2. leadImage (if previewImage is not available)
3. null (if neither previewImage nor leadImage is available)

Accessing the RSS Feed

After setting up the rss_feed content type and configuring the listing block, you can access the generated RSS feed at:

http://<website-domain>/<path-to-feed>/rss.xml

This URL will return the RSS feed in XML format.

RSS Feed Generation

This add-on uses the rss npm package to generate the RSS feed.

Caveats

• Image Enclosure Size: For the image included in the enclosure of each RSS feed item, we are using its preview scale. However, due to limitations in retrieving the actual size of the preview image, the size of the original image is used instead in the enclosure. This may result in a discrepancy between the displayed image size and the reported size in the RSS feed.