Bug 1546248 - Add attribution parameters to AMO links r=mstriemer

Differential Revision: https://phabricator.services.mozilla.com/D29479

--HG--
extra : moz-landing-system : lando

toolkit/mozapps/extensions/content/aboutaddons.js

@@ -162,6 +162,31 @@ function nl2br(text) {
   return frag;
 }
 
+/**
+ * Adds UTM parameters to a given URL, if it is an AMO URL.
+ *
+ * @param {string} contentAttribute
+ *        Identifies the part of the UI with which the link is associated.
+ * @param {string} url
+ * @returns {string}
+ *          The url with UTM parameters if it is an AMO URL.
+ *          Otherwise the url in unmodified form.
+ */
+function formatAmoUrl(contentAttribute, url) {
+  let parsedUrl = new URL(url);
+  let domain = `.${parsedUrl.hostname}`;
+  if (!domain.endsWith(".addons.mozilla.org") &&
+      // For testing: addons-dev.allizom.org and addons.allizom.org
+      !domain.endsWith(".allizom.org")) {
+    return url;
+  }
+
+  parsedUrl.searchParams.set("utm_source", "firefox-browser");
+  parsedUrl.searchParams.set("utm_medium", "firefox-browser");
+  parsedUrl.searchParams.set("utm_content", contentAttribute);
+  return parsedUrl.href;
+}
+
 // A wrapper around an item from the "results" array from AMO's discovery API.
 // See https://addons-server.readthedocs.io/en/latest/topics/api/discovery.html
 class DiscoAddonWrapper {
@@ -1182,7 +1207,8 @@ class RecommendedAddonCard extends HTMLElement {
       });
       // This is intentionally a link to the add-on listing instead of the
       // author page, because the add-on listing provides more relevant info.
-      authorInfo.querySelector("a").href = addon.amoListingUrl;
+      authorInfo.querySelector("a").href =
+        formatAmoUrl("discopane-entry-link", addon.amoListingUrl);
       authorInfo.hidden = false;
     }
   }
@@ -1698,9 +1724,10 @@ class DiscoveryPane extends HTMLElement {
           "personalized-extension-recommendations", "tab");
         break;
       case "open-amo":
-        windowRoot.ownerGlobal.openTrustedLinkIn(
-          Services.urlFormatter.formatURLPref("extensions.getAddons.link.url"),
-          "tab");
+        let amoUrl =
+          Services.urlFormatter.formatURLPref("extensions.getAddons.link.url");
+        amoUrl = formatAmoUrl("find-more-link-bottom", amoUrl);
+        windowRoot.ownerGlobal.openTrustedLinkIn(amoUrl, "tab");
         break;
     }
   }

toolkit/mozapps/extensions/test/browser/browser_html_discover_view.js

@@ -21,7 +21,7 @@ const {
 // The response must contain at least one theme, and one extension.
 const API_RESPONSE_FILE = RELATIVE_DIR + "discovery/api_response.json";
 
-const AMO_TEST_HOST = "addons.example.com";
+const AMO_TEST_HOST = "rewritten-for-testing.addons.allizom.org";
 
 const ArrayBufferInputStream =
   Components.Constructor("@mozilla.org/io/arraybuffer-input-stream;1",
@@ -320,6 +320,10 @@ add_task(async function discopane_with_real_api_data() {
     checkContent(".disco-addon-author [data-l10n-name='author']",
                  expectations.authorName);
 
+    let amoListingLink = card.querySelector(".disco-addon-author a");
+    ok(amoListingLink.search.includes("utm_source=firefox-browser"),
+       `Listing link should have attribution parameter, url=${amoListingLink}`);
+
     let actions = getVisibleActions(card);
     is(actions.length, 1, "Card should only have one install button");
     let installButton = actions[0];