[Feature] Full-text search for blog posts

[khaines]

Overview

Blog posts need searchable content. Users expect to find posts by keyword. Two main approaches:

Option A: Client-side search (lunr.js / Pagefind)

• Generate a search index JSON at content scan time
• Serve at /search-index.json
• Client-side JavaScript library (lunr.js, Pagefind, Fuse.js) does the search
• Pros: No server load, works with CDN, offline-capable
• Cons: Requires JavaScript (currently none), index size grows with content, initial page load penalty
• BlogFlow fit: Contradicts "no JavaScript required" philosophy in current CSS

Option B: Server-side search (bleve / built-in)

• In-memory search index built during content scan (bleve or simple inverted index)
• GET /search?q=keyword returns matching posts
• Pros: No JS required, fast, server-controlled ranking
• Cons: Memory overhead, not cached by CDN, adds server complexity
• BlogFlow fit: Aligns with server-rendered philosophy

Option C: Pagefind (static, no runtime JS framework)

• Pagefind generates a search index + tiny UI widget at build time
• Works with static HTML output
• Pros: Lightweight (~6KB), works without framework, good UX
• Cons: Still requires JS execution, needs post-scan index generation step

Requirements (regardless of approach)

• Search by title, tags, and body content
• Results show title, excerpt, date, relevance score
• Handles Unicode content (matches urlize i18n work)
• Configurable: search.enabled: true in site.yaml
• Accessible: keyboard-navigable results

Open questions

• Does search fit BlogFlow's "just add markdown" simplicity?
• Is JS acceptable in the default theme, or should search be opt-in via theme override?
• Should we support search in the embedded defaults theme or only in custom themes?