linkyee Plugins

Plugins are small Ruby classes that run at build time to inject dynamic values into your linkyee site (GitHub stars, latest blog posts, last commit date, anything you can fetch from a URL). The build runs once on push and once a day via GitHub Actions, so plugins do not run in the user's browser — they just bake values into the generated HTML.

This wiki is the canonical reference for writing your own plugin. It is also the source of truth that the linkyee-plugin-builder Claude skill reads when an AI generates a plugin for you.

• How it works
• Plugin contract
• Quick start: your first plugin in 30 seconds
• Built-in plugins
• Helpers provided by the base class
• Common patterns (HTTP, JSON, scraping, caching)
• Rendering output in Liquid
• Debugging
• Letting AI write your plugin

---

How it works

config.yml ──► scaffold.rb ──► instantiate plugin ──► execute() ──► vars.<PluginName>
                                                                           │
                                                                           ▼
                                                          rendered into Liquid templates

1. You enable a plugin in config.yml under plugins:.
2. scaffold.rb requires ./plugins/<PluginName>.rb, instantiates the class with the YAML values, and calls execute().
3. The return value is stored in settings["vars"][<PluginName>].
4. Every string in config.yml (links, socials, title, footer…) and the theme's index.html is rendered through Liquid, so you can reference {{ vars.<PluginName> }} anywhere.
5. If a plugin raises, scaffold.rb logs the error and sets the value to nil — the build still succeeds.

---

Plugin contract

A plugin is a Ruby class that:

Rule	Detail
Inherits from Plugin	class MyPlugin < Plugin
Lives at ./plugins/MyPlugin.rb	Filename must match the class name
Implements execute	Returns a Liquid-renderable value (String, Number, Hash with String keys, Array, or nested combos)
Is defensive	Returns a safe default on network/parse failure — never raise
Has no side effects	Don't write files; just return data

That's it. No registration, no manifest.

---

Quick start

Add this to plugins/HelloPlugin.rb:

require_relative 'Plugin'

class HelloPlugin < Plugin
  def execute
    "Hello, #{params['name'] || 'world'}!"
  end
end

Enable it in config.yml:

plugins:
  - HelloPlugin:
      name: linkyee

footer: "{{ vars.HelloPlugin }}"

Run ruby scaffold.rb and open _output/index.html — the footer reads Hello, linkyee!.

---

Built-in plugins

Plugin	Purpose	Argument style
GithubRepoStarsCountPlugin	Star counts for one or more repos	List of owner/repo
GithubLastCommitPlugin	Latest commit sha / date / message	List of owner/repo
GithubProfilePlugin	Followers and public-repo count	List of GitHub usernames
RSSFeedPlugin	Latest items from an RSS / Atom feed (Medium, blogs, YouTube, podcasts)	List of feed URLs
CountdownPlugin	Days until / since target dates	Hash of label: YYYY-MM-DD
YouTubeChannelLatestVideoPlugin	Latest video for one or more YouTube channels	List of channel ID / @handle / channel URL

Each file is short — read them as templates when writing your own.

---

Helpers provided by the base class

Defined in Plugin.rb.

Argument accessors

args     # => first argument list, e.g. ["repo1", "repo2"]
params   # => first argument when it is a Hash, e.g. {"url" => "...", "limit" => 5}
data     # => the raw arguments array (escape hatch)

YAML list-style → use args:

- MyPlugin:
    - first
    - second

YAML hash-style → use params:

- MyPlugin:
    url: https://example.com
    limit: 5

http_get(url, headers: {}, redirect_limit: 5, timeout: 15)

GET an HTTP(S) URL with redirect following and a sensible User-Agent. Returns a Net::HTTPResponse or nil. Never raises.

res = http_get("https://example.com/data")
return [] unless res.is_a?(Net::HTTPSuccess)
process(res.body)

http_get_json(url, headers: {}, default: nil, ...)

Same as http_get but parses the body as JSON. Returns default on any failure (network, non-2xx, malformed JSON).

data = http_get_json("https://api.github.com/repos/#{repo}", default: {})
data["stargazers_count"] || 0

cache(key) { ... }

Memoize across plugin instances within a single build. Useful when several plugins share data (e.g. multiple GitHub plugins hitting the same repo).

cache("repo:#{repo}") { http_get_json("https://api.github.com/repos/#{repo}") }

log(msg)

Prints to stderr with the plugin class as prefix. Visible in GitHub Actions logs.

log("falling back to cached value")

---

Common patterns

1. JSON API

class WeatherPlugin < Plugin
  def execute
    args.each_with_object({}) do |city, out|
      json = http_get_json("https://wttr.in/#{city}?format=j1", default: {})
      out[city] = json.dig("current_condition", 0, "temp_C") || "?"
    end
  end
end

2. HTML scraping (when no API is available)

require 'nokogiri'

class HNFrontPagePlugin < Plugin
  def execute
    res = http_get("https://news.ycombinator.com/")
    return [] unless res.is_a?(Net::HTTPSuccess)

    Nokogiri::HTML(res.body).css(".titleline > a").first(5).map do |a|
      { "title" => a.text, "url" => a["href"] }
    end
  end
end

3. Safe defaults

Always return the same shape on success and failure — Liquid templates break ugly when a Hash becomes a String:

empty = { "count" => 0, "label" => "" }
return empty unless res.is_a?(Net::HTTPSuccess)

4. Reading a secret / token (the only safe way)

⚠️ Never put credentials in config.yml or in a plugin's .rb source. config.yml is committed to git and rendered into the public gh-pages site; once a token lands in commit history, treat it as compromised.

The only acceptable storage for an API key, PAT, OAuth token, or similar is a GitHub Actions repository secret, exposed to the build via env-var, read from ENV inside the plugin.

Three-step setup:

1. Add the repo secret — GitHub → your repo → Settings → Secrets and variables → Actions → New repository secret. Name it (e.g. MEDIUM_TOKEN), paste the value.
2. Pass it through the workflow — edit .github/workflows/build.yml and add an env: block to the Deploy step:

   - name: Deploy
     env:
       MEDIUM_TOKEN: ${{ secrets.MEDIUM_TOKEN }}
     run: bash deploy.sh
   

3. Read it in the plugin — and bail gracefully if missing:

   token = ENV["MEDIUM_TOKEN"]
   return [] if token.nil? || token.empty?
   http_get_json(url, headers: { "Authorization" => "Bearer #{token}" })
   

For local development, export the same env var in your shell before running bundle exec ruby ./scaffold.rb. Do not check it into .envrc / .env files that might be committed; if you use direnv, add .envrc to .gitignore.

Document the secret name in the plugin file's header comment so the next maintainer knows what to provision.

---

Rendering output in Liquid

Anything execute returns lands at vars.<PluginName>. Examples:

# Scalar
title: "{{ vars.HelloPlugin }}"

# Hash lookup by key
text: "{{ vars.GithubRepoStarsCountPlugin['ZhgChgLi/linkyee'] }} Stars"

# Nested hash
text: "Last update: {{ vars.GithubLastCommitPlugin['ZhgChgLi/linkyee'].date }}"

# Iteration (works in theme index.html, not in config.yml string fields)
{% for post in vars.RSSFeedPlugin['https://blog.zhgchg.li/feed'] %}
  <a href="{{ post.url }}">{{ post.title }}</a>
{% endfor %}

Important:

• Use String keys in returned hashes ("name", not :name). Liquid cannot look up symbol keys.
• config.yml only renders inline {{ ... }}, not {% for %} blocks. For loops/conditionals, edit the theme's index.html.

---

Debugging

Run the build locally and watch stderr:

ruby scaffold.rb
# look for: [MyPlugin] http_get(...) failed: ...
# or:       [scaffold] Plugin 'MyPlugin' failed: ...

Inspect the rendered output:

open _output/index.html

If a {{ vars.X }} reference renders as empty, the plugin probably returned nil — check the build log for the failure reason.

You can also puts arbitrary debug data from inside execute; it goes to the build log without affecting the page.

---

Letting AI write your plugin

Open this repo with Claude Code and just describe what you want, e.g.:

"Add a plugin that shows the current weather in Taipei in the footer."

"Add a plugin that fetches the latest 3 posts from my Medium feed and lists them as additional links."

The bundled linkyee-plugin-builder skill knows this contract and will: read your config.yml → confirm the data source and shape → generate plugins/<YourPlugin>.rb → wire it up in config.yml → run ruby scaffold.rb to verify.