Proxy with Caddy

Two handle blocks rewrite your paths and reverse-proxy them to MetricRaven.

Set it up

1. Add a reusable snippet

   Caddyfile

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   # Top of the same Caddyfile, outside any site block
   (metricraven_upstream) {
   	header_up Host {upstream_hostport}
   	# The visitor's IP. Behind a CDN or load balancer, set trusted_proxies first.
   	header_up X-Visitor-IP {client_ip}
   	header_up -Cookie
   	header_up -Authorization
   	header_up -Referer
   }

2. Add the handlers to your site block

   Replace example.com with your existing site address and keep your current directives below the two handlers.

   Caddyfile

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   # Caddyfile · Caddy 2.7 or later
   example.com {
   	@metricravenScript {
   		method GET
   		path /a/script
   	}
   	handle @metricravenScript {
   		rewrite * /js/script.js
   		reverse_proxy https://metricraven.com {
   			import metricraven_upstream
   			header_down Cache-Control "public, max-age=3600"
   		}
   	}
   
   	@metricravenEvent {
   		method POST
   		path /a/event
   	}
   	handle @metricravenEvent {
   		rewrite * /api/v1/collect
   		reverse_proxy https://metricraven.com {
   			import metricraven_upstream
   			header_down Cache-Control "no-store"
   		}
   	}
   
   	# ...your existing site configuration
   }

3. Reload Caddy

   terminal

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   caddy reload --config /etc/caddy/Caddyfile

4. Point your script tag at your own paths

   Replace your MetricRaven tag with this one. src loads the tracker from your domain and data-api sends its events there too.

   Your website's shared layout

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   <script defer src="/a/script" data-api="/a/event" data-site-id="YOUR_SITE_ID"></script>

Notes

• {client_ip} needs Caddy 2.7 or later. Behind a CDN or load balancer, set trusted_proxies in the global servers options so it is the visitor, not the proxy.
• header_up Host {upstream_hostport} is required for an HTTPS upstream; without it the request reaches MetricRaven with your site's hostname and fails.

How the proxy works and which headers it must send: Use your own domain.