Fallback to the default push gateway on error

libraries/pushproviders/unifiedpush/src/main/kotlin/io/element/android/libraries/pushproviders/unifiedpush/UnifiedPushGatewayResolver.kt

@@ -63,8 +63,9 @@ class DefaultUnifiedPushGatewayResolver(
                         UnifiedPushGatewayResolverResult.NoMatrixGateway
                     }
                 } catch (throwable: Throwable) {
-                    if ((throwable as? HttpException)?.code() == HttpURLConnection.HTTP_NOT_FOUND) {
-                        Timber.tag(loggerTag.value).i("Checking for UnifiedPush endpoint yielded 404, using fallback")
+                    val code = (throwable as? HttpException)?.code()
+                    if (code in NoMatrixGatewayResp) {
+                        Timber.tag(loggerTag.value).i("Checking for UnifiedPush endpoint yielded $code, using fallback")
                         UnifiedPushGatewayResolverResult.NoMatrixGateway
                     } else {
                         Timber.tag(loggerTag.value).e(throwable, "Error checking for UnifiedPush endpoint")
@@ -74,4 +75,14 @@ class DefaultUnifiedPushGatewayResolver(
             }
         }
     }
+
+    companion object {
+        private val NoMatrixGatewayResp = listOf<Int>(
+            HttpURLConnection.HTTP_UNAUTHORIZED,
+            HttpURLConnection.HTTP_FORBIDDEN,
+            HttpURLConnection.HTTP_NOT_FOUND,
+            HttpURLConnection.HTTP_BAD_METHOD,
+            HttpURLConnection.HTTP_NOT_ACCEPTABLE
+        )
+    }
 }

libraries/pushproviders/unifiedpush/src/main/kotlin/io/element/android/libraries/pushproviders/unifiedpush/UnifiedPushGatewayUrlResolver.kt

@@ -28,8 +28,9 @@ class DefaultUnifiedPushGatewayUrlResolver(
     ): String {
         return when (gatewayResult) {
             is UnifiedPushGatewayResolverResult.Error -> {
-                // Use previous gateway if any, or the provided one
-                unifiedPushStore.getPushGateway(instance) ?: gatewayResult.gateway
+                // Use previous gateway if any, or the default one
+                unifiedPushStore.getPushGateway(instance)
+                    ?: defaultPushGatewayHttpUrlProvider.provide()
             }
             UnifiedPushGatewayResolverResult.ErrorInvalidUrl,
             UnifiedPushGatewayResolverResult.NoMatrixGateway -> {

libraries/pushproviders/unifiedpush/src/test/kotlin/io/element/android/libraries/pushproviders/unifiedpush/DefaultUnifiedPushGatewayResolverTest.kt

@@ -118,7 +118,7 @@ class DefaultUnifiedPushGatewayResolverTest {
     }
 
     @Test
-    fun `when a custom url is forbidden (403), Error is returned`() = runTest {
+    fun `when a custom url is forbidden (403), NoMatrixGateway is returned`() = runTest {
         val unifiedPushApiFactory = FakeUnifiedPushApiFactory(
             discoveryResponse = {
                 throw HttpException(Response.error<Unit>(HttpURLConnection.HTTP_FORBIDDEN, "".toResponseBody()))
@@ -129,6 +129,36 @@ class DefaultUnifiedPushGatewayResolverTest {
         )
         val result = sut.getGateway("http://custom.url")
         assertThat(unifiedPushApiFactory.baseUrlParameter).isEqualTo("http://custom.url")
+        assertThat(result).isEqualTo(UnifiedPushGatewayResolverResult.NoMatrixGateway)
+    }
+
+    @Test
+    fun `when a custom url is not acceptable (406), NoMatrixGateway is returned`() = runTest {
+        val unifiedPushApiFactory = FakeUnifiedPushApiFactory(
+            discoveryResponse = {
+                throw HttpException(Response.error<Unit>(HttpURLConnection.HTTP_NOT_ACCEPTABLE, "".toResponseBody()))
+            }
+        )
+        val sut = createDefaultUnifiedPushGatewayResolver(
+            unifiedPushApiFactory = unifiedPushApiFactory
+        )
+        val result = sut.getGateway("http://custom.url")
+        assertThat(unifiedPushApiFactory.baseUrlParameter).isEqualTo("http://custom.url")
+        assertThat(result).isEqualTo(UnifiedPushGatewayResolverResult.NoMatrixGateway)
+    }
+
+    @Test
+    fun `when a custom url is internal error (500), Error is returned`() = runTest {
+        val unifiedPushApiFactory = FakeUnifiedPushApiFactory(
+            discoveryResponse = {
+                throw HttpException(Response.error<Unit>(HttpURLConnection.HTTP_INTERNAL_ERROR, "".toResponseBody()))
+            }
+        )
+        val sut = createDefaultUnifiedPushGatewayResolver(
+            unifiedPushApiFactory = unifiedPushApiFactory
+        )
+        val result = sut.getGateway("http://custom.url")
+        assertThat(unifiedPushApiFactory.baseUrlParameter).isEqualTo("http://custom.url")
         assertThat(result).isEqualTo(UnifiedPushGatewayResolverResult.Error("http://custom.url/_matrix/push/v1/notify"))
     }
 

libraries/pushproviders/unifiedpush/src/test/kotlin/io/element/android/libraries/pushproviders/unifiedpush/DefaultUnifiedPushGatewayUrlResolverTest.kt

@@ -59,7 +59,7 @@ class DefaultUnifiedPushGatewayUrlResolverTest {
     }
 
     @Test
-    fun `resolve Error returns the url if no current url is available`() {
+    fun `resolve Error returns the default gateway url if no current url is available`() {
         val sut = createDefaultUnifiedPushGatewayUrlResolver(
             unifiedPushStore = FakeUnifiedPushStore(
                 getPushGatewayResult = { instance ->
@@ -72,7 +72,7 @@ class DefaultUnifiedPushGatewayUrlResolverTest {
             gatewayResult = UnifiedPushGatewayResolverResult.Error("aUrl"),
             instance = "instance",
         )
-        assertThat(result).isEqualTo("aUrl")
+        assertThat(result).isEqualTo(FakeDefaultPushGatewayHttpUrlProvider().provide())
     }
 
     private fun createDefaultUnifiedPushGatewayUrlResolver(