From 76849c4374ce464e09d296312f69c7e4ac5a4bc7 Mon Sep 17 00:00:00 2001
From: Benoit Marty <benoit@matrix.org>
Date: Fri, 8 Aug 2025 13:35:44 +0200
Subject: [PATCH] Introduce SessionWellknownRetriever and implementation that
 uses a MatrixClient.

---
 .../api/SessionWellknownRetriever.kt          | 13 +++++
 libraries/wellknown/impl/build.gradle.kts     |  1 +
 .../impl/DefaultSessionWellknownRetriever.kt  | 49 +++++++++++++++++++
 .../impl/DefaultWellknownRetriever.kt         | 14 ------
 .../libraries/wellknown/impl/Mapper.kt        | 26 ++++++++++
 5 files changed, 89 insertions(+), 14 deletions(-)
 create mode 100644 libraries/wellknown/api/src/main/kotlin/io/element/android/libraries/wellknown/api/SessionWellknownRetriever.kt
 create mode 100644 libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultSessionWellknownRetriever.kt
 create mode 100644 libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/Mapper.kt

diff --git a/libraries/wellknown/api/src/main/kotlin/io/element/android/libraries/wellknown/api/SessionWellknownRetriever.kt b/libraries/wellknown/api/src/main/kotlin/io/element/android/libraries/wellknown/api/SessionWellknownRetriever.kt
new file mode 100644
index 0000000000..7f7b9b983f
--- /dev/null
+++ b/libraries/wellknown/api/src/main/kotlin/io/element/android/libraries/wellknown/api/SessionWellknownRetriever.kt
@@ -0,0 +1,13 @@
+/*
+ * Copyright 2025 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.wellknown.api
+
+interface SessionWellknownRetriever {
+    suspend fun getWellKnown(): WellKnown?
+    suspend fun getElementWellKnown(): ElementWellKnown?
+}
diff --git a/libraries/wellknown/impl/build.gradle.kts b/libraries/wellknown/impl/build.gradle.kts
index a9c1a1e9bf..0754ce6184 100644
--- a/libraries/wellknown/impl/build.gradle.kts
+++ b/libraries/wellknown/impl/build.gradle.kts
@@ -27,6 +27,7 @@ dependencies {
     implementation(libs.serialization.json)
     implementation(projects.libraries.architecture)
     implementation(projects.libraries.core)
+    implementation(projects.libraries.matrix.api)
     implementation(projects.libraries.network)
     implementation(projects.libraries.wellknown.api)
 }
diff --git a/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultSessionWellknownRetriever.kt b/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultSessionWellknownRetriever.kt
new file mode 100644
index 0000000000..259f7848b3
--- /dev/null
+++ b/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultSessionWellknownRetriever.kt
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2025 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.wellknown.impl
+
+import com.squareup.anvil.annotations.ContributesBinding
+import io.element.android.libraries.core.extensions.mapCatchingExceptions
+import io.element.android.libraries.di.SessionScope
+import io.element.android.libraries.matrix.api.MatrixClient
+import io.element.android.libraries.wellknown.api.ElementWellKnown
+import io.element.android.libraries.wellknown.api.SessionWellknownRetriever
+import io.element.android.libraries.wellknown.api.WellKnown
+import kotlinx.serialization.json.Json
+import timber.log.Timber
+import javax.inject.Inject
+
+@ContributesBinding(SessionScope::class)
+class DefaultSessionWellknownRetriever @Inject constructor(
+    private val matrixClient: MatrixClient,
+) : SessionWellknownRetriever {
+    private val parser by lazy { Json { ignoreUnknownKeys = true } }
+    private val domain by lazy { matrixClient.userIdServerName() }
+
+    override suspend fun getWellKnown(): WellKnown? {
+        val url = "https://$domain/.well-known/matrix/client"
+        return matrixClient
+            .getUrl(url)
+            .mapCatchingExceptions { String(it) }
+            .mapCatchingExceptions { parser.decodeFromString(InternalWellKnown.serializer(), it) }
+            .onFailure { Timber.e(it, "Failed to retrieve .well-known from $domain") }
+            .map { it.map() }
+            .getOrNull()
+    }
+
+    override suspend fun getElementWellKnown(): ElementWellKnown? {
+        val url = "https://$domain/.well-known/element/element.json"
+        return matrixClient
+            .getUrl(url)
+            .mapCatchingExceptions { String(it) }
+            .mapCatchingExceptions { parser.decodeFromString(InternalElementWellKnown.serializer(), it) }
+            .onFailure { Timber.e(it, "Failed to retrieve Element .well-known from $domain") }
+            .map { it.map() }
+            .getOrNull()
+    }
+}
diff --git a/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultWellknownRetriever.kt b/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultWellknownRetriever.kt
index 4149d24df6..0d45f60be5 100644
--- a/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultWellknownRetriever.kt
+++ b/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/DefaultWellknownRetriever.kt
@@ -53,17 +53,3 @@ class DefaultWellknownRetriever @Inject constructor(
         }
     }
 }
-
-private fun InternalElementWellKnown.map() = ElementWellKnown(
-    registrationHelperUrl = registrationHelperUrl,
-    enforceElementPro = enforceElementPro,
-)
-
-private fun InternalWellKnown.map() = WellKnown(
-    homeServer = homeServer?.map(),
-    identityServer = identityServer?.map(),
-)
-
-private fun InternalWellKnownBaseConfig.map() = WellKnownBaseConfig(
-    baseURL = baseURL,
-)
diff --git a/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/Mapper.kt b/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/Mapper.kt
new file mode 100644
index 0000000000..8625571c62
--- /dev/null
+++ b/libraries/wellknown/impl/src/main/kotlin/io/element/android/libraries/wellknown/impl/Mapper.kt
@@ -0,0 +1,26 @@
+/*
+ * Copyright 2025 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.wellknown.impl
+
+import io.element.android.libraries.wellknown.api.ElementWellKnown
+import io.element.android.libraries.wellknown.api.WellKnown
+import io.element.android.libraries.wellknown.api.WellKnownBaseConfig
+
+internal fun InternalElementWellKnown.map() = ElementWellKnown(
+    registrationHelperUrl = registrationHelperUrl,
+    enforceElementPro = enforceElementPro,
+)
+
+internal fun InternalWellKnown.map() = WellKnown(
+    homeServer = homeServer?.map(),
+    identityServer = identityServer?.map(),
+)
+
+internal fun InternalWellKnownBaseConfig.map() = WellKnownBaseConfig(
+    baseURL = baseURL,
+)