[DO NOT MERGE] Stream web analytics data to Umami

app/privacy-policy.md

@@ -0,0 +1,33 @@
+---
+layout: page
+caption:
+title: Privacy policy
+---
+
+This privacy policy explains how NHS England uses information when you visit the Digital Prevention Services Portfolio (DPSP) website.
+
+## Information we collect
+
+When you visit this website, we collect your IP address, user agent, page URL and title, referring page, language and screen information. A user agent is information about the browser and operating system you use to access a website.
+
+We use this information to understand how the website is being used and to improve it. We do not use it to identify you directly.
+
+## How we store information
+
+We use your IP address and user agent to create a pseudonymous identifier for analytics. Pseudonymised information is still personal data under data protection law.
+
+We keep this identifier for up to 2 months, after which it is deleted. We keep the other analytics data, excluding your IP address, for up to 2 years. Once the identifier is deleted, the remaining data is anonymised.
+
+## Our legal obligations
+
+We have obligations under the UK General Data Protection Regulation (UK GDPR) and the Data Protection Act 2018. Our lawful basis for processing this information is **public task**. This means we process it because it is necessary for us to carry out a task in the public interest or in the exercise of official authority.
+
+## Your rights
+
+You have rights over your personal information, including the right to ask for a copy of it, to have inaccurate information corrected and, in some circumstances, to ask for it to be deleted or for its use to be restricted.
+
+## Contacting us
+
+If you have questions about this privacy policy or how we use information, email [england.dpsp-front-door@nhs.net](mailto:england.dpsp-front-door@nhs.net). You can also contact the NHS England Data Protection Officer through the [NHS England privacy notice](https://www.england.nhs.uk/contact-us/privacy-notice/).
+
+You can read more about how NHS England handles personal information and your data protection rights in the [NHS England privacy notice](https://www.england.nhs.uk/contact-us/privacy-notice/).

eleventy.config.mjs

@@ -3,6 +3,23 @@ import yaml from 'js-yaml'
 
 const serviceName = 'Digital prevention services (DPSP)'
 
+// The host serving the Umami script and receiving analytics events.
+const analyticsHost = 'https://analytics.digital-prevention-services.nhs.uk'
+
+// The Umami website ID, available in the website's Umami settings.
+const analyticsWebsiteId = '046780c9-3684-4ded-a9d2-bdf361faf561'
+
+// Hash of the exact inline script emitted by the NHS plugin, used by the CSP.
+// If that script changes, hash its contents with the command below,
+// replacing '<script contents>' with the JavaScript between the <script> tags
+// in the generated HTML body (currently: document.body.className += ' js-enabled' + ('noModule' in HTMLScriptElement.prototype ? ' nhsuk-frontend-supported' : '');).
+// Do not use the external Umami <script defer src="..."> tag for this hash.
+// That external script is allowed by the CSP separately by script-src via analyticsHost.
+// printf '%s' "<script contents>" | openssl dgst -sha256 -binary | openssl base64 -A
+// Prefix the result with 'sha256-' and update this value.
+const cspInlineScriptHash =
+  'sha256-tDOvXJi1PXbg0CWjLCCYSNHRXtps26K4JXkE3M6u/c0='
+
 export default function (eleventyConfig) {
   eleventyConfig.addPlugin(nhsukEleventyPlugin, {
     titleSuffix: `NHS ${serviceName}`,
@@ -54,12 +71,45 @@ export default function (eleventyConfig) {
           {
             text: 'About us',
             href: '/about'
+          },
+          {
+            text: 'Privacy policy',
+            href: '/privacy-policy'
           }
         ]
       }
     }
   })
 
+  // The NHS plugin does not provide a way to add a script to the <head>, so use this approach instead
+  eleventyConfig.addTransform('analytics-script', (content) => {
+    if (!content.includes('<head>')) return content
+
+    return content.replace(
+      '<head>',
+      // GitHub Pages cannot set response headers, so enforce the basic CSP in the document head.
+      // Keep the analytics host in both script-src and connect-src: Umami loads its script and sends events there.
+      `<head>
+<meta http-equiv="Content-Security-Policy" content="default-src 'self';
+  script-src 'self' ${analyticsHost} '${cspInlineScriptHash}';
+  connect-src 'self' ${analyticsHost};
+  style-src 'self';
+  img-src 'self' data:;
+  font-src 'self' https://assets.nhs.uk;
+  object-src 'none';
+  base-uri 'self';
+  form-action 'self';
+  frame-src 'none';">
+` +
+        // Load Umami asynchronously for analytics.
+        // The host and website ID are configured in the variables above.
+        `<script defer src="${analyticsHost}/script.js"
+  data-website-id="${analyticsWebsiteId}"
+  data-host-url="${analyticsHost}"
+  data-domains="www.digital-prevention-services.nhs.uk"></script>`
+    )
+  })
+
   // Allow YAML to be used for data
   eleventyConfig.addDataExtension('yaml', (contents) => yaml.load(contents))