Initial commit, blog system works

.lua/feed.lua

@@ -0,0 +1,70 @@
+-- feed.lua — Atom feed (RFC 4287) for published blog posts.
+
+local db     = require "db"
+local md     = require "md"
+local config = require "config"
+
+local M = {}
+
+local XML_ESC = {
+  ["&"] = "&amp;", ["<"] = "&lt;", [">"] = "&gt;",
+  ['"'] = "&quot;", ["'"] = "&apos;",
+}
+local function xesc(s)
+  return (tostring(s or ""):gsub("[&<>\"']", XML_ESC))
+end
+
+M.FEED_LIMIT = 20
+
+--- Build the Atom feed document.  Returns the XML string.
+function M.atom()
+  local base   = config.base_url()
+  local title  = config.get("site_title")
+  local author = config.get("site_author")
+  local posts  = db.list_published_page("blog", M.FEED_LIMIT, 0)
+
+  -- Feed-level updated: newest updated_at, or "now" for an empty feed.
+  local feed_updated = os.date("!%Y-%m-%dT%H:%M:%SZ")
+  if posts[1] then
+    feed_updated = posts[1].updated_at
+    for _, p in ipairs(posts) do
+      if p.updated_at > feed_updated then feed_updated = p.updated_at end
+    end
+  end
+
+  local out = {
+    '<?xml version="1.0" encoding="utf-8"?>',
+    '<feed xmlns="http://www.w3.org/2005/Atom">',
+    "<title>" .. xesc(title) .. "</title>",
+    '<link href="' .. xesc(base) .. '/"/>',
+    '<link rel="self" type="application/atom+xml" href="' .. xesc(base) .. '/atom.xml"/>',
+    "<id>" .. xesc(base) .. "/</id>",
+    "<updated>" .. xesc(feed_updated) .. "</updated>",
+  }
+  if author ~= "" then
+    out[#out + 1] = "<author><name>" .. xesc(author) .. "</name></author>"
+  end
+  local tagline = config.get("site_tagline")
+  if tagline ~= "" then
+    out[#out + 1] = "<subtitle>" .. xesc(tagline) .. "</subtitle>"
+  end
+
+  for _, p in ipairs(posts) do
+    local url = base .. "/blog/" .. EscapePath(p.slug)
+    out[#out + 1] = "<entry>"
+      .. "<title>" .. xesc(p.title) .. "</title>"
+      .. '<link href="' .. xesc(url) .. '"/>'
+      .. "<id>" .. xesc(url) .. "</id>"
+      .. "<published>" .. xesc(p.created_at) .. "</published>"
+      .. "<updated>" .. xesc(p.updated_at) .. "</updated>"
+      .. (p.summary ~= ""
+          and ("<summary>" .. xesc(p.summary) .. "</summary>") or "")
+      .. '<content type="html">' .. xesc(md.render(p.body)) .. "</content>"
+      .. "</entry>"
+  end
+
+  out[#out + 1] = "</feed>"
+  return table.concat(out, "\n")
+end
+
+return M