Introduce SessionWellknownRetriever and implementation that uses a MatrixClient.

Author: bmarty

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?
+}

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)
 }

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()
+    }
+}

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,
-)

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,
+)