Bug 1832074 — Parse referrer URL with URLDecoder

app/src/main/java/org/mozilla/fenix/components/metrics/InstallReferrerMetricsService.kt

@@ -13,6 +13,7 @@ import com.android.installreferrer.api.InstallReferrerStateListener
 import org.mozilla.fenix.GleanMetrics.PlayStoreAttribution
 import org.mozilla.fenix.ext.settings
 import org.mozilla.fenix.utils.Settings
+import java.net.URLDecoder
 
 /**
  * A metrics service used to derive the UTM parameters with the Google Play Install Referrer library.
@@ -83,7 +84,10 @@ class InstallReferrerMetricsService(private val context: Context) : MetricsServi
 
     @VisibleForTesting(otherwise = VisibleForTesting.PRIVATE)
     internal fun recordInstallReferrer(settings: Settings, url: String?) {
-        val params = url?.let(UTMParams::fromUrl)
+        if (url.isNullOrBlank()) {
+            return
+        }
+        val params = UTMParams.fromURLString(url)
         if (params == null || params.isEmpty()) {
             return
         }
@@ -143,14 +147,40 @@ data class UTMParams(
         const val UTM_TERM = "utm_term"
         const val UTM_CONTENT = "utm_content"
 
+        /**
+         * Try and unpack the referrer URL by successively URLDecoding the URL.
+         *
+         * Once the url ceases to decode anymore, it gives up.
+         */
+        fun fromURLString(string: String): UTMParams? {
+            // Look for the first time 'utm_' is detected, after the first '?'.
+            val utmIndex = string.indexOf("utm_", string.indexOf('?'))
+            if (utmIndex < 0) {
+                return null
+            }
+            var url = string.substring(utmIndex)
+            while (true) {
+                val params = fromQueryString(url)
+                if (!params.isEmpty()) {
+                    return params
+                }
+                val newValue = URLDecoder.decode(url, "UTF-8")
+                if (newValue == url) {
+                    break
+                }
+                url = newValue
+            }
+            return null
+        }
+
         /**
          * Derive a set of UTM parameters from a string URL.
          */
-        fun fromUrl(url: String): UTMParams =
+        fun fromQueryString(queryString: String): UTMParams =
             with(UrlQuerySanitizer()) {
                 allowUnregisteredParamaters = true
                 unregisteredParameterValueSanitizer = UrlQuerySanitizer.getUrlAndSpaceLegal()
-                parseUrl(url)
+                parseQuery(queryString)
                 UTMParams(
                     source = getValue(UTM_SOURCE),
                     medium = getValue(UTM_MEDIUM),

app/src/test/java/org/mozilla/fenix/components/metrics/InstallReferrerMetricsServiceTest.kt

@@ -10,6 +10,7 @@ import mozilla.components.service.glean.testing.GleanTestRule
 import mozilla.components.support.test.robolectric.testContext
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertFalse
+import org.junit.Assert.assertNotNull
 import org.junit.Assert.assertNull
 import org.junit.Assert.assertTrue
 import org.junit.Rule
@@ -28,24 +29,24 @@ internal class InstallReferrerMetricsServiceTest {
 
     @Test
     fun testUtmParamsFromUrl() {
-        assertEquals("SOURCE", UTMParams.fromUrl("https://example.com?utm_source=SOURCE").source)
-        assertEquals("MEDIUM", UTMParams.fromUrl("https://example.com?utm_medium=MEDIUM").medium)
-        assertEquals("CAMPAIGN", UTMParams.fromUrl("https://example.com?utm_campaign=CAMPAIGN").campaign)
-        assertEquals("TERM", UTMParams.fromUrl("https://example.com?utm_term=TERM").term)
-        assertEquals("CONTENT", UTMParams.fromUrl("https://example.com?utm_content=CONTENT").content)
+        assertEquals("SOURCE", UTMParams.fromQueryString("utm_source=SOURCE").source)
+        assertEquals("MEDIUM", UTMParams.fromQueryString("utm_medium=MEDIUM").medium)
+        assertEquals("CAMPAIGN", UTMParams.fromQueryString("utm_campaign=CAMPAIGN").campaign)
+        assertEquals("TERM", UTMParams.fromQueryString("utm_term=TERM").term)
+        assertEquals("CONTENT", UTMParams.fromQueryString("utm_content=CONTENT").content)
     }
 
     @Test
     fun testUtmParamsFromUrlWithSpaces() {
-        assertEquals("WITH SPACE", UTMParams.fromUrl("https://example.com?utm_source=WITH+SPACE").source)
-        assertEquals("WITH SPACE", UTMParams.fromUrl("https://example.com?utm_medium=WITH%20SPACE").medium)
-        assertEquals("WITH SPACE", UTMParams.fromUrl("https://example.com?utm_campaign=WITH SPACE").campaign)
+        assertEquals("WITH SPACE", UTMParams.fromQueryString("utm_source=WITH+SPACE").source)
+        assertEquals("WITH SPACE", UTMParams.fromQueryString("utm_medium=WITH%20SPACE").medium)
+        assertEquals("WITH SPACE", UTMParams.fromQueryString("utm_campaign=WITH SPACE").campaign)
     }
 
     @Test
     fun testUtmParamsFromUrlWithMissingParams() {
-        assertNull(UTMParams.fromUrl("https://example.com?missing=").source)
-        assertEquals("", UTMParams.fromUrl("https://example.com?utm_source=").source)
+        assertNull(UTMParams.fromQueryString("missing=").source)
+        assertEquals("", UTMParams.fromQueryString("utm_source=").source)
     }
 
     @Test
@@ -117,7 +118,7 @@ internal class InstallReferrerMetricsServiceTest {
 
         val expected = UTMParams(source = "SOURCE", medium = "MEDIUM", campaign = "CAMPAIGN", content = "CONTENT", term = "TERM")
         val observed = UTMParams.fromSettings(settings)
-        assertEquals(observed, expected)
+        assertEquals(expected, observed)
 
         assertEquals("SOURCE", PlayStoreAttribution.source.testGetValue())
         assertEquals("MEDIUM", PlayStoreAttribution.medium.testGetValue())
@@ -139,4 +140,43 @@ internal class InstallReferrerMetricsServiceTest {
         val service = InstallReferrerMetricsService(context)
         assertEquals(MetricServiceType.Marketing, service.type)
     }
+
+    @Test
+    fun testDecodeReferrerUrl() {
+        // Example from https://developers.google.com/analytics/devguides/collection/android/v4/campaigns#google-play-url-builder
+        val params = UTMParams.fromURLString(
+            "https://play.google.com/store/apps/details?id=com.example.application" +
+                "&referrer=utm_source%3Dgoogle" +
+                "%26utm_medium%3Dcpc" +
+                "%26utm_term%3Drunning%252Bshoes" +
+                "%26utm_content%3Dlogolink" +
+                "%26utm_campaign%3Dspring_sale",
+        )
+        assertNotNull(params)
+
+        val expected = UTMParams(
+            source = "google",
+            medium = "cpc",
+            campaign = "spring_sale",
+            content = "logolink",
+            term = "running+shoes",
+        )
+
+        assertEquals(expected, params)
+    }
+
+    @Test
+    fun testDecodeReferrerAdMobUrl() {
+        val expected = UTMParams(source = "SOURCE", medium = "MEDIUM", campaign = "CAMPAIGN", content = "CONTENT", term = "TERM")
+        // Generated with https://developers.google.com/analytics/devguides/collection/android/v4/campaigns#google-play-url-builder
+        val fromUrl = UTMParams.fromURLString(
+            "https://play.google.com/store/apps/details?id=org.mozilla.fenix&referrer=utm_source%3DSOURCE%26utm_medium%3DMEDIUM%26utm_term%3DTERM%26utm_content%3DCONTENT%26utm_campaign%3DCAMPAIGN%26anid%3Dadmob",
+        )
+        assertNotNull(fromUrl)
+        assertEquals(expected, fromUrl)
+
+        val fromReferrerAttribute = UTMParams.fromURLString("utm_source%3DSOURCE%26utm_medium%3DMEDIUM%26utm_term%3DTERM%26utm_content%3DCONTENT%26utm_campaign%3DCAMPAIGN%26anid%3Dadmob")
+        assertNotNull(fromReferrerAttribute)
+        assertEquals(expected, fromReferrerAttribute)
+    }
 }