Caching

OpenGraph+ reads HTTP cache headers from your pages to decide when to re-render social card images. Middleman generates static files, so cache headers are set by your hosting provider.

This page covers the Middleman side. For how OpenGraph+ handles caching at the HTTP level, see the HTTP Caching guide.

Netlify

Create a _headers file in your source/ directory:

# source/_headers
/*
  Cache-Control: public, max-age=604800

Or use netlify.toml:

[[headers]]
  for = "/*"
  [headers.values]
    Cache-Control = "public, max-age=604800"

Vercel

Add headers to your vercel.json:

{
  "headers": [
    {
      "source": "/(.*)",
      "headers": [
        { "key": "Cache-Control", "value": "public, max-age=604800" }
      ]
    }
  ]
}

Cloudflare Pages

Create a _headers file in your source/ directory:

# source/_headers
/*
  Cache-Control: public, max-age=604800

Meta tag overrides

Always available regardless of hosting provider. Add these to your layout’s <head>:

<meta property="og:plus:cache:max_age" content="86400">
<meta property="og:plus:cache:etag" content="<%= current_page.data.version || 'v1' %>">

When the etag changes, OpenGraph+ re-renders even if the cache hasn’t expired. Using current_page.data.version lets you control cache invalidation from frontmatter:

# In your page's frontmatter
---
title: My Page
version: "rev-5"
---

See the HTTP Caching guide for the full reference on cache headers and meta tag overrides.

Purging

Force an immediate re-render from the OpenGraph+ dashboard by purging the cached image for any URL.

Recommendations

Page type	Strategy
Static pages	Long TTL via hosting headers (7 days)
Blog posts	Medium TTL (1 day) + etag meta tag
Frequently updated	Short TTL + etag for instant invalidation