Site code improvements

Better documentation, allow callbacks, ignore all local networks.

Fixes part of #10

bin/proxy

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+#
+# mitmproxy <https://mitmproxy.org> addon to serve count.js locally, instead of
+# the live version. It's the easiest way to test it manually for now (I need to
+# figure out how to unit test this stuff in a way that I like).
+#
+# Start with: ~/mitproxy -s ./proxy
+#
+# Can also use mitmweb with the same arguments for a web interface.
+#
+# TODO: looks like we can also use standard "replace" with "@path/to/file"?
+
+import mimetypes
+import mitmproxy.http
+import mitmproxy.ctx
+
+REPLACE = {
+        'static.goatcounter.com/count.min.js': './public/count.js',
+        'zgo.at/':                             '../zgo.at/index.html',
+}
+
+class InterceptCount:
+    def request(self, flow):
+        for remote, local in REPLACE.items():
+            if remote in flow.request.pretty_url:
+                with open(local) as fp:
+                    data = fp.read()
+                ct = mimetypes.MimeTypes().guess_type(local)[0]
+                flow.response = mitmproxy.http.HTTPResponse.make(200, data, {
+                    'Content-Type': ct,
+                })
+                mitmproxy.ctx.log.info('Replaced {} with {} ({})'.format(remote, local, ct))
+                break
+
+
+addons = [InterceptCount()]

hit.go

@@ -229,7 +229,7 @@ func cleanURL(ref string, refURL *url.URL) (string, *string, bool, bool) {
 	i := strings.Index(ref, "?")
 	if i == -1 {
 		// No parameters so no work.
-		return refURL.String()[2:], nil, changed, false
+		return strings.TrimLeft(refURL.String(), "/"), nil, changed, false
 	}
 	eq := ref[i+1:]
 	ref = ref[:i]

public/count.js

@@ -2,26 +2,44 @@
 // This file is part of GoatCounter and published under the terms of the AGPLv3,
 // which can be found in the LICENSE file or at gnu.org/licenses/agpl.html
 
+// See /bin/proxy on how to test this locally.
 (function() { 
 	'use strict';
 
 	var vars = window.vars || {};
 
 	// Find canonical location of the current page.
 	var get_location = function() {
-		var loc = window.location,
-			c = document.querySelector('link[rel="canonical"][href]');
-		// Parse in a tag to a Location object (canonical URL may be relative).
-		if (c) {
-			var a = document.createElement('a');
-			a.href = c.href;
-			loc = a;
+		var results = {p: vars.path, r: vars.referrer};
+
+		var rcb, pcb;
+		if (typeof(results.r) === 'function')
+			rcb = results.r;
+		if (typeof(results.p) === 'function')
+			pcb = results.p;
+
+		// Get referrer.
+		if (results.r === null || results.r === undefined)
+			results.r = document.referrer;
+		if (rcb)
+			results.r = rcb(results.r);
+
+		// Get path.
+		if (results.p === null || results.p === undefined) {
+			var loc = window.location,
+				c = document.querySelector('link[rel="canonical"][href]');
+			// Parse in a tag to a Location object (canonical URL may be relative).
+			if (c) {
+				var a = document.createElement('a');
+				a.href = c.href;
+				loc = a;
+			}
+			results.p = (loc.pathname + loc.search) || '/';
 		}
+		if (pcb)
+			results.p = pcb(results.p);
 
-		return {
-			p: (vars.path     || (loc.pathname + loc.search) || '/'),
-			r: (vars.referrer || document.referrer),
-		};
+		return results;
 	};
 
 	// Convert parameters to urlencoded string, starting with a ?
@@ -38,15 +56,25 @@
 	var count = function() {
 		// Don't track pages fetched with the browser's prefetch algorithm.
 		// See https://github.com/usefathom/fathom/issues/13
-		if ('visibilityState' in document && document.visibilityState === 'prerender') {
+		if ('visibilityState' in document && document.visibilityState === 'prerender')
+			return;
+
+		// Don't track private networks.
+		if (window.location.hostname.match(/localhost$/) ||
+			window.location.hostname.match(/^(127\.|10\.|172\.16\.|192\.168\.)/))
+				return;
+
+		var loc = get_location();
+
+		// null returned from user callback.
+		if (loc.p === null)
 			return;
-		}
 
 		// Add image to send request.
 		var img = document.createElement('img');
 		img.setAttribute('alt', '');
 		img.setAttribute('aria-hidden', 'true');
-		img.src = window.counter + to_params(get_location());
+		img.src = window.counter + to_params(loc);
 		img.addEventListener('load', function() {
 			document.body.removeChild(img)
 		}, false);

tpl/_backend_sitecode.gohtml

@@ -1,9 +1,5 @@
-<script>
+<pre>&lt;script&gt;
 	(function() {
-		if (window.location.hostname.indexOf('localhost') &gt; -1) {
-			return;
-		}
-
 		var script = document.createElement('script');
 		window.counter = 'https://{{.Site.Code}}.{{.Domain}}/count'
 		script.async = 1;
@@ -12,4 +8,41 @@
 		var ins = document.getElementsByTagName('script')[0];
 		ins.parentNode.insertBefore(script, ins)
 	})();
-&lt;/script&gt;
+&lt;/script&gt;</pre>
+
+{{if eq .Path "/settings"}}
+<p>You can optionally pass variables manually by using the <code>vars</code> object. Supported keys:</p>
+
+<ul>
+	<li><code>path</code> – Path to the current page that's recorded, without
+		domain (e.g. <code>/path/page.html</code>).</li>
+
+	<li><code>referrer</code> – Referrer value; can be URL
+		(<code>https://example.com</code>) or any string
+		(<code>June Newsletter</code>). Default is to use the Referer
+		header.</li>
+</ul>
+
+<p>The default value will be used if the value is <code>null</code> or
+<code>undefined</code> (but <em>not</em> on empty string!) The value can be used
+as a callback too: the default value is passed and the return is used. The view
+will be ignored if the return value from the <code>path</code> callback is
+<code>null</code>.</p>
+
+<p>Example:</p>
+
+<pre>window.vars = {
+	path: function(p) {
+		// Don't track the home page.
+		if (p === '/')
+			return null;
+		// Remove .html from all other page links.
+		else
+			return p.replace(/\.html$/, '');
+	},
+
+	// Very simplistic method to get referrer from URL (e.g. ?ref=Newsletter)
+	referrer: (window.location.search ? window.location.search.split('=')[1] : null),
+};</pre>
+
+{{end}}

tpl/backend.gohtml

@@ -6,10 +6,12 @@
 		data yet.<br>
 		Make sure the site is set up correctly with the code below inserted just
 		before the closing &lt;/body&gt; tag:</p>
-		<pre>{{template "_backend_sitecode.gohtml" .}}</pre>
+		{{template "_backend_sitecode.gohtml" .}}
 
 		<p><small>This message will disappear once we receive data; you will
-		still be able to see the site code in <a href="/settings">settings</a>.</small></p>
+			still be able to see the site code in
+			<a href="/settings#site-code">settings</a>, which also contains
+			further documentation.</small></p>
 	</div>
 {{end}}
 

tpl/backend_settings.gohtml

@@ -1,6 +1,6 @@
 {{template "_backend_top.gohtml" .}}
 
-<h2 id="settings">Settings</h2>
+<h2>Settings</h2>
 <div class="form-wrap">
 	<form method="post" action="/save" class="vertical">
 		<input type="hidden" name="csrf" value="{{.User.CSRFToken}}">
@@ -75,30 +75,9 @@
 
 {{end}}
 
-<h2 id="code">Site code</h2>
+<h2 id="site-code">Site code</h2>
 <p>Insert the code below just before the closing &lt;/body&gt; tag:</p>
-<pre>{{template "_backend_sitecode.gohtml" .}}</pre>
-
-<p><code>window.counter</code> is the endpoint which records the path and
-referrer.</p>
-
-<p><code>window.vars</code> is an optional setting to set the <code>path</code>
-and/or <code>referrer</code>; for example:</p>
-
-<pre>
-(function() {
-	if (window.location.hostname.indexOf('localhost') &gt; -1) {
-		return;
-	}
-
-	window.vars = {
-		path:     '/foo',
-		referrer: 'bar',
-	};
-
-	// .. code above ..
-})();
-</pre>
+{{template "_backend_sitecode.gohtml" .}}
 
 {{/*
 <h2 id="domain">Custom domain</h2>