Per section/subsection feeds (#1128)

* Per section/subsection feeds

* Added `generate_feed` variable to section front matter.
* Generate atom/rss feeds for sections/subsections that have the
`generate_feed` variable set to true (false by default); this works
independent of the `generate_feed` variable in the root `config.toml`
file, however, the name (and template) of the feed file for each section
is the same as `feed_filename` in `config.toml`, just located in the
root of each section.
* Slightly edited `atom.xml` and `rss.xml` so that they include the
section title (if any), and the url of a section, if it's a section
feed.

* Section feeds: tests

* Changed a couple of sections' front matter in order to generate feeds
for them for the test.
* Changed the can_build_feed test in site package to can_build_feeds and
included some assertions to make sure that section feeds are generated
when requested.

* Section feeds: documentation

* Added information about the section front matter variable
`generate_feed` in the section content page.
* Added information about section feeds in the feeds template page.

* Section feeds fix: use section.path for feed path

components/front_matter/src/section.rs

@@ -60,6 +60,9 @@ pub struct SectionFrontMatter {
     /// redirect to this
     #[serde(skip_serializing)]
     pub aliases: Vec<String>,
+    /// Whether to generate a feed for the current section
+    #[serde(skip_serializing)]
+    pub generate_feed: bool,
     /// Any extra parameter present in the front matter
     pub extra: Map<String, Value>,
 }
@@ -105,6 +108,7 @@ impl Default for SectionFrontMatter {
             transparent: false,
             page_template: None,
             aliases: Vec::new(),
+            generate_feed: false,
             extra: Map::new(),
         }
     }

components/site/src/lib.rs

@@ -901,6 +901,24 @@ impl Site {
             }
         }
 
+        if section.meta.generate_feed {
+            let library = &self.library.read().unwrap();
+            let pages = section
+                .pages
+                .iter()
+                .map(|k| library.get_page_by_key(*k))
+                .collect();
+            self.render_feed(
+                pages,
+                Some(&PathBuf::from(&section.path[1..])),
+                &section.lang,
+                |mut context: Context| {
+                    context.insert("section", &section.to_serialized(library));
+                    context
+                },
+            )?;
+        }
+
         // Copy any asset we found previously into the same directory as the index.html
         for asset in &section.assets {
             let asset_path = asset.as_path();

components/site/tests/site.rs

@@ -613,7 +613,7 @@ fn can_build_site_with_pagination_for_taxonomy() {
 }
 
 #[test]
-fn can_build_feed() {
+fn can_build_feeds() {
     let (_, _tmp_dir, public) = build_site("test_site");
 
     assert!(&public.exists());
@@ -622,6 +622,14 @@ fn can_build_feed() {
     assert!(file_contains!(public, "atom.xml", "Extra Syntax"));
     // Next is posts/simple.md
     assert!(file_contains!(public, "atom.xml", "Simple article with shortcodes"));
+
+    // Test section feeds
+    assert!(file_exists!(public, "posts/tutorials/programming/atom.xml"));
+    // It contains both sections articles
+    assert!(file_contains!(public, "posts/tutorials/programming/atom.xml", "Python tutorial"));
+    assert!(file_contains!(public, "posts/tutorials/programming/atom.xml", "Rust"));
+    // It doesn't contain articles from other sections
+    assert!(!file_contains!(public, "posts/tutorials/programming/atom.xml", "Extra Syntax"));
 }
 
 #[test]

components/templates/src/builtins/atom.xml

@@ -2,13 +2,20 @@
 <feed xmlns="http://www.w3.org/2005/Atom" xml:lang="{{ lang }}">
 	<title>{{ config.title }}
 		{%- if term %} - {{ term.name }}
+    {%- elif section.title %} - {{ section.title }}
 		{%- endif -%}
 	</title>
 	{%- if config.description %}
 	<subtitle>{{ config.description }}</subtitle>
 	{%- endif %}
 	<link href="{{ feed_url | safe }}" rel="self" type="application/atom+xml"/>
-	<link href="{{ config.base_url | safe }}"/>
+  <link href="
+      {%- if section -%}
+        {{ section.permalink | escape_xml | safe }}
+      {%- else -%}
+        {{ config.base_url | escape_xml | safe }}
+      {%- endif -%}
+    "/>
 	<generator uri="https://www.getzola.org/">Zola</generator>
 	<updated>{{ last_updated | date(format="%+") }}</updated>
 	<id>{{ feed_url | safe }}</id>

components/templates/src/builtins/rss.xml

@@ -1,8 +1,17 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <rss xmlns:atom="http://www.w3.org/2005/Atom" version="2.0">
     <channel>
-        <title>{{ config.title }}</title>
+      <title>{{ config.title }}
-        <link>{{ config.base_url | escape_xml | safe }}</link>
+        {%- if term %} - {{ term.name }}
+        {%- elif section.title %} - {{ section.title }}
+        {%- endif -%}
+      </title>
+        <link>{%- if section -%}
+            {{ section.permalink | escape_xml | safe }}
+          {%- else -%}
+            {{ config.base_url | escape_xml | safe }}
+          {%- endif -%}
+        </link>
         <description>{{ config.description }}</description>
         <generator>Zola</generator>
         <language>{{ config.default_language }}</language>

docs/content/documentation/content/section.md

@@ -93,6 +93,12 @@ transparent = false
 # current one. This takes an array of paths, not URLs.
 aliases = []
 
+# If set to "true", a feed file will be generated for this section at the
+# section's root path. This is independent of the site-wide variable of the same
+# name. The section feed will only include posts from that respective feed, and
+# not from any other sections, including sub-sections under that section.
+generate_feed = false
+
 # Your own data.
 [extra]
 ```

docs/content/documentation/templates/feeds/index.md

@@ -33,6 +33,13 @@ Feeds for taxonomy terms get two more variables, using types from the
 - `taxonomy`: of type `TaxonomyConfig`
 - `term`: of type `TaxonomyTerm`, but without `term.pages` (use `pages` instead)
 
+You can also enable separate feeds for each section by setting the
+`generate_feed` variable to true in the respective section's front matter.
+Section feeds will use the same template as indicated in the `config.toml` file.
+Section feeds, in addition to the five feed template variables, get the
+`section` variable from the [section
+template](@/documentation/templates/pages-sections.md).
+
 Enable feed autodiscovery allows feed readers and browsers to notify user about a RSS or Atom feed available on your web site. So it is easier for user to subscribe.
 As an example this is how it looks like using [Firefox](https://en.wikipedia.org/wiki/Mozilla_Firefox) [Livemarks](https://addons.mozilla.org/en-US/firefox/addon/livemarks/?src=search) addon.
 

test_site/content/posts/_index.md

@@ -5,4 +5,5 @@ template = "section_paginated.html"
 insert_anchor_links = "left"
 sort_by = "date"
 aliases = ["another-old-url/index.html"]
+generate_feed = true
 +++

test_site/content/posts/tutorials/programming/_index.md

@@ -2,6 +2,7 @@
 title = "Programming"
 sort_by = "weight"
 weight = 1
+generate_feed = true
 
 [extra]
 we_have_extra = "variables"