| name | halo-theme-dev |
| description | Use when creating or modifying a Halo CMS theme, writing Thymeleaf templates, configuring theme.yaml or settings.yaml, calling Finder APIs, using vite-plugin-halo-theme, defining theme settings forms, referencing static assets, implementing halo:comment or halo:footer extension points, defining model annotation fields (AnnotationSetting), adding i18n support, or handling error pages. Always use this skill when the user mentions themes, templates, Thymeleaf, theme configuration, or wants to customize the frontend appearance of a Halo site — even if they do not explicitly say "theme."
|
Halo Theme Development
Halo is built on Spring Boot + Spring WebFlux + Thymeleaf. Themes use Thymeleaf templates for frontend page rendering.
Important: Halo's APIs, VO field names, and template variables evolve across versions. Do not rely on training data for specific field names, method signatures, or type structures. When writing code that accesses template variables or calls Finder API methods, always fetch the relevant online doc from the References section below first.
Thymeleaf Quick Reference
Full docs: https://raw.githubusercontent.com/thymeleaf/thymeleaf-docs/refs/heads/master/docs/tutorials/3.1/usingthymeleaf.md
Core syntax cheatsheet:
<h1 th:text="${site.title}"></h1>
<div th:utext="${post.content.content}"></div>
<a th:href="@{${post.status.permalink}}">Post link</a>
<link rel="stylesheet" th:href="@{/assets/dist/style.css}" />
<li th:each="post : ${posts.items}" th:text="${post.spec.title}"></li>
<div th:if="${posts.hasNext()}">Next page</div>
<div th:unless="${posts.hasNext()}">Last page</div>
<div th:with="menu = ${menuFinder.getPrimary()}">...</div>
<div th:replace="~{fragments/header :: header}"></div>
<html th:replace="~{layout :: html(head = null, content = ~{::content})}">
<th:block th:fragment="content"></th:block>
</html>
<script th:inline="javascript">
var url = '[(${#theme.assets("/dist/main.iife.js")})]';
</script>
Development Workflow
- Create a theme folder under
themes/ in the Halo working directory (must match metadata.name in theme.yaml)
- Write
theme.yaml (required) and settings.yaml (optional)
- Create template files under
templates/
- Install and activate the theme in Console → Theme Management
- Visit the frontend to verify
Disable Thymeleaf caching during development: set env var SPRING_THYMELEAF_CACHE=false (Docker), or spring.thymeleaf.cache: false in config (source mode).
Starter Templates
The assets/ directory provides two ready-to-use theme templates:
assets/theme-minimal/ — Zero-build-tool minimal theme with all 8 template files; ideal for quick prototyping or simple themesassets/theme-vite/ — Vite project template with vite-plugin-halo-theme (recommended for new themes); includes partial layout reuse and CSS toolchain
Usage: copy the directory into themes/ in your Halo working directory, ensure the folder name matches metadata.name in theme.yaml, then install and activate in Console.
References Index
| File | Content | When to read |
|---|
| references/api-changelog.md | High-impact theme API changes by Halo version, with docs routes | Before using version-sensitive APIs or raising spec.requires |
| references/structure-and-config.md | Directory structure, theme.yaml fields, root screenshot, settings.yaml form definition | Creating a theme, configuring theme.yaml/settings.yaml |
| references/vite-plugin.md | vite-plugin-halo-theme integration guide, include/slot template syntax, TailwindCSS integration | Setting up a Vite-based theme (recommended) |
| references/templates.md | Template route mapping, available variables per template | Writing template files |
| references/global-variables.md | Global variables (site, theme, theme.config) and type definitions | Accessing site info or theme setting values |
| references/finder-apis.md | All Finder APIs (postFinder, categoryFinder, tagFinder, menuFinder, singlePageFinder, etc.) | Querying data from any template |
| references/static-resources.md | Static asset reference methods (@{}, #theme.assets()) | Referencing CSS/JS/images in plain HTML themes |
| references/template-tags.md | Custom tags (halo:comment extension point, halo:footer injection) | Integrating comment plugins, injecting footer code |
| references/i18n.md |
