feat: switch to Feedsmith library

[macieklamberski]

check list

• Add test cases for the changes.
• Passed the CI test.

Description

This PR replaces the current use of Feed library with Feedsmith to add support for hub links.

Recently, I stumbled upon the PR #240 and Issue #239, which has been pending due to lack of hub links support in the Feed library. As the creator of Feedsmith, I believe it could serve as a suitable alternative because:

• It's flexible enough to cover all feed generation needs
• It uses battle-tested fast-xml-parser for parsing and generating
• Extra: Includes built-in feed format detection should you consider replacing the existing detectFeedType function

Regarding changes, I tried to maintain existing functionality with as minimal changes as possible to reduce confusion. If you'd be interested, I can make it more readable by breaking logic into smaller functions for easier maintanence/testing.

[SukkaW]

There is some duplicated code across different formats. Is it possible to remove duplicate codes?

[macieklamberski]

Sure! I applied some changes and described here: #249 (comment).

[coveralls]

coverage: 98.611% (-1.4%) from 100.0%
when pulling 9849399 on macieklamberski:feat/feedsmith-integration
into 3fb6c3b on hexojs:master.

[macieklamberski]

Apologies for the amount of changes, but they're all focused on making the code more DRY.

The changes: 9ada4a7

TL;DR

1. Moved logic of getting posts from module.exports to composePosts.
2. Created composeFeed function to build the intermediate feed object.
3. Moved code of building items into composeItem function.
4. Then, these functions create intermediate objects passed down to dedicated generateRss and generateAtom.
5. Created more tests for hub and author fields (can add more if needed).

Full

I reworked the lib/generator.js to split the code into smaller sub-functions. This was necessary because of the difference between Feed and Feedsmith.

• Feed accepts shared (but limiting) object allowing to create Atom/RSS feeds.
• Feedsmith requires creating dedicated objects for each feed format.

To DRY the code I also created intermediate functions (composeFeed, composeItem, composeItemContent, ...), then used them to generate the final objects passed down to functions generating each feed format.

The changes do not affect the existing functionality, tests implemented in the previous dev branch (with Feed integration) still work. I also added a few new ones.

I compiled 2 tables comparing source of the data used to generate feeds and put them at the end of this post.

Questions

1. Comments field: The old template-based implementation included a <comments> element in RSS items when post.comments was truthy. This was removed in the dev branch. Was it an intentional change or limitation of Feed library? Should this be included in the refactored code?
2. Feed updated date: The current version now matches master branch behavior (posts.first().updated || posts.first().date), but the dev branch didn't set this field explicitly, causing the Feed library to fall back to new Date() (current time). Was this change in dev intentional or accidental?

Old vs New Atom Feed

Field	Master Branch	Current Branch
Feed Level
title	config.title	⚪ Same
icon	config.feed.icon (via full_url_for) || gravatar(config.email)	⚪ Same
subtitle	config.subtitle	config.subtitle || config.description
link[rel=self]	full_url_for(path)	⚪ Same
link[rel=hub]	config.feed.hub	⚪ Same
link[rel=alternate]	config.url (normalized)	⚪ Same
updated	posts.first().updated || posts.first().date	⚪ Same
id	config.url (normalized)	⚪ Same
author.name	config.author	⚪ Same
author.email	config.email	⚪ Same
generator	'Hexo' with uri='https://hexo.io/'	⚪ Same
rights	🟡 Not present	config.author && 'All rights reserved ${year}, ${config.author}'
Entry Level
title	post.title	⚪ Same
link	post.permalink (via uriencode)	full_url_for(post.permalink) with encodeURL
id	post.permalink (via uriencode)	⚪ Same
published	post.date	⚪ Same
updated	post.updated || post.date	⚪ Same
content	post.content.replace(/[\x00-\x1F\x7F]/g, '') (if config.feed.content)	⚪ Same
summary	post.description || post.intro || post.excerpt || post.content.substring(0, config.feed.content_limit)	post.description || post.intro || post.excerpt || post.content.substring(0, config.feed.content_limit || 140)
content[type=image]	full_url_for(post.image)	🔴 Removed
link[rel=enclosure]	🟡 Not present	full_url_for(post.image) (if post.image)
category	post.categories.toArray() + post.tags.toArray() with term and scheme=permalink	⚪ Same
authors	🟡 Not present	[{name: config.author, email: config.email}] (if config.author)

Old vs New RSS Feed

Field	Master Branch	Current Branch
Channel Level
title	config.title	⚪ Same
link	config.url (normalized)	⚪ Same
image.url	config.feed.icon (via full_url_for) || gravatar(config.email)	⚪ Same
image.title	config.title	⚪ Same
image.link	config.url (normalized)	⚪ Same
atom:link[rel=self]	full_url_for(path) with type='application/rss+xml'	⚪ Same
atom:link[rel=hub]	config.feed.hub	⚪ Same
description	config.description	config.subtitle || config.description
pubDate	posts.first().updated || posts.first().date	⚪ Same
generator	'http://hexo.io/'	'Hexo'
copyright	🟡 Not present	config.author && 'All rights reserved ${year}, ${config.author}'
language	🟡 Not present	config.language
Item Level
title	post.title	⚪ Same
link	post.permalink (via uriencode)	full_url_for(post.permalink) with encodeURL
guid	post.permalink (via uriencode)	⚪ Same
pubDate	post.date	⚪ Same
description	post.description || post.intro || post.excerpt || post.content.substring(0, config.feed.content_limit)	post.description || post.intro || post.excerpt || post.content.substring(0, config.feed.content_limit || 140)
enclosure	config.url + post.image (if post.image)	full_url_for(post.image) (if post.image)
content:encoded	post.content.replace(/[\x00-\x1F\x7F]/g, '') (if config.feed.content)	⚪ Same
category	post.categories.toArray() + post.tags.toArray() with domain=config.url + category.path / tag.path	post.categories.toArray() + post.tags.toArray() with domain=category.permalink / tag.permalink
author	🟡 Not present	config.email (config.author) || config.email || config.author
comments	post.permalink + '#disqus_thread' (if post.comments)	🔴 Removed