Backend: UI: Implements authentication.

backend/build.gradle

@@ -46,6 +46,7 @@ dependencies {
     implementation 'com.squareup.retrofit2:retrofit:2.9.0'
     implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
     implementation 'com.google.code.gson:gson:2.9.0'
+    implementation 'com.auth0.android:jwtdecode:2.0.2'
 
     // Realm
     implementation "io.realm.kotlin:library-base:${realm_version}"

backend/src/main/java/net/buzzert/kordophone/backend/db/CachedChatDatabase.kt

@@ -62,7 +62,7 @@ class CachedChatDatabase (private val realmConfig: RealmConfiguration) {
 
     // Flow for watching for message changes for a given conversation
     fun messagesChanged(conversation: ModelConversation): Flow<List<ModelMessage>> {
-        return realm.query(Conversation::class, "guid == '${conversation.guid}'")
+        return realm.query(Conversation::class, "guid == $0", conversation.guid)
             .find()
             .first()
             .messages
@@ -142,7 +142,7 @@ class CachedChatDatabase (private val realmConfig: RealmConfiguration) {
     }
 
     private fun getManagedConversationByGuid(guid: GUID): Conversation {
-        return realm.query(Conversation::class, "guid == '$guid'")
+        return realm.query(Conversation::class, "guid == $0", guid)
             .find()
             .first()
     }

backend/src/main/java/net/buzzert/kordophone/backend/server/APIClient.kt

@@ -1,12 +1,19 @@
 package net.buzzert.kordophone.backend.server
 
+import com.google.gson.Gson
+import kotlinx.coroutines.runBlocking
+import okhttp3.Authenticator
 import okhttp3.HttpUrl
+import okhttp3.Interceptor
 import okhttp3.OkHttpClient
 import okhttp3.Request
+import okhttp3.Response
+import okhttp3.Route
 import okhttp3.WebSocket
 import okhttp3.WebSocketListener
 import retrofit2.Retrofit
 import retrofit2.converter.gson.GsonConverterFactory
+import retrofit2.create
 import java.net.URL
 
 interface APIClient {
@@ -18,12 +25,86 @@ interface APIClient {
     ): WebSocket
 }
 
-class RetrofitAPIClient(private val baseURL: URL): APIClient {
+data class Authentication (
+    val username: String,
+    val password: String,
+)
+
+class TokenStore(val authentication: Authentication) {
+    var authenticationToken: String? = null
+}
+
+class AuthenticationInterceptor(
+    val tokenStore: TokenStore
+): Interceptor {
+    override fun intercept(chain: Interceptor.Chain): Response {
+        // If empty, allow the 401 to occur so we renew our token.
+        val token = tokenStore.authenticationToken ?:
+            return chain.proceed(chain.request())
+
+        val newRequest = chain.request().newBuilder()
+            .header("Authorization", "Bearer $token")
+            .build()
+
+        return chain.proceed(newRequest)
+    }
+}
+
+class TokenAuthenticator(
+    private val tokenStore: TokenStore,
+    private val baseURL: URL
+) : Authenticator {
     private val retrofit: Retrofit = Retrofit.Builder()
         .baseUrl(baseURL)
         .addConverterFactory(GsonConverterFactory.create())
         .build()
 
+    private val apiInterface: APIInterface
+        get() = retrofit.create(APIInterface::class.java)
+
+    override fun authenticate(route: Route?, response: Response): Request? {
+        // Fetch new token
+        val request = AuthenticationRequest(
+            username = tokenStore.authentication.username,
+            password = tokenStore.authentication.password
+        )
+
+        val token = runBlocking {
+            apiInterface.authenticate(request).body()
+        }
+
+        if (token == null) {
+            // Auth failure.
+            // TODO: How to bubble this up?
+            return null
+        }
+
+        // Update token store
+        tokenStore.authenticationToken = token.serializedToken
+
+        return response.request().newBuilder()
+            .header("Authorization", "Bearer ${token.serializedToken}")
+            .build()
+    }
+}
+
+class RetrofitAPIClient(
+    private val baseURL: URL,
+    private val authentication: Authentication,
+): APIClient {
+    private val tokenStore: TokenStore = TokenStore(authentication)
+
+    private val client: OkHttpClient = OkHttpClient.Builder()
+        .addInterceptor(AuthenticationInterceptor(tokenStore))
+        .authenticator(TokenAuthenticator(tokenStore, baseURL))
+        .build()
+
+    private val retrofit: Retrofit = Retrofit.Builder()
+        .client(client)
+        .baseUrl(baseURL)
+        .addConverterFactory(GsonConverterFactory.create())
+        .build()
+
     override fun getAPIInterface(): APIInterface {
         return retrofit.create(APIInterface::class.java)
     }

backend/src/main/java/net/buzzert/kordophone/backend/server/APIInterface.kt

@@ -1,5 +1,6 @@
 package net.buzzert.kordophone.backend.server
 
+import com.auth0.android.jwt.JWT
 import com.google.gson.annotations.SerializedName
 import net.buzzert.kordophone.backend.model.Conversation
 import net.buzzert.kordophone.backend.model.GUID
@@ -30,6 +31,23 @@ data class SendMessageResponse(
     val sentMessageGUID: String,
 )
 
+data class AuthenticationRequest(
+    @SerializedName("username")
+    val username: String,
+
+    @SerializedName("password")
+    val password: String,
+)
+
+data class AuthenticationResponse(
+    @SerializedName("jwt")
+    val serializedToken: String,
+) {
+    fun decodeToken(): JWT {
+        return JWT(serializedToken)
+    }
+}
+
 interface APIInterface {
     @GET("/version")
     suspend fun getVersion(): ResponseBody
@@ -50,6 +68,9 @@ interface APIInterface {
 
     @POST("/markConversation")
     suspend fun markConversation(@Query("guid") conversationGUID: String): Response<Void>
+
+    @POST("/authenticate")
+    suspend fun authenticate(@Body request: AuthenticationRequest): Response<AuthenticationResponse>
 }
 
 class ResponseDecodeError(val response: ResponseBody): Exception(response.string())

backend/src/main/java/net/buzzert/kordophone/backend/server/ChatRepository.kt

@@ -32,7 +32,7 @@ const val REPO_LOG: String = "ChatRepository"
 const val CONVERSATION_MESSAGE_SYNC_COUNT = 10
 
 class ChatRepository(
-    private val apiClient: APIClient,
+    apiClient: APIClient,
     private val database: CachedChatDatabase,
 ) {
     sealed class Error {
@@ -84,14 +84,26 @@ class ChatRepository(
         val requestGuid: GUID,
     )
 
-    private val apiInterface = apiClient.getAPIInterface()
+    private var apiInterface = apiClient.getAPIInterface()
     private val outgoingMessageQueue: ArrayBlockingQueue<OutgoingMessageInfo> = ArrayBlockingQueue(16)
     private var outgoingMessageThread: Thread? = null
     private val _messageDeliveredChannel = MutableSharedFlow<MessageDeliveredEvent>()
     private val _errorEncounteredChannel = MutableSharedFlow<Error>()
 
-    private val updateMonitor = UpdateMonitor(apiClient)
+    private var updateMonitor = UpdateMonitor(apiClient)
     private var updateWatchJob: Job? = null
+    private var updateWatchScope: CoroutineScope? = null
+
+    fun updateAPIClient(client: APIClient) {
+        this.apiInterface = client.getAPIInterface()
+        this.updateMonitor = UpdateMonitor(client)
+
+        // Restart update watch job, if necessary.
+        if (this.updateWatchJob != null) {
+            stopWatchingForUpdates()
+            beginWatchingForUpdates(updateWatchScope!!)
+        }
+    }
 
     suspend fun getVersion(): String {
         return apiInterface.getVersion().string()
@@ -111,6 +123,7 @@ class ChatRepository(
             }
         }
 
+        updateWatchScope = scope
         updateMonitor.beginMonitoringUpdates()
     }
 

backend/src/test/java/net/buzzert/kordophone/backend/MockServer.kt

@@ -14,6 +14,8 @@ import net.buzzert.kordophone.backend.model.Message
 import net.buzzert.kordophone.backend.model.UpdateItem
 import net.buzzert.kordophone.backend.server.APIClient
 import net.buzzert.kordophone.backend.server.APIInterface
+import net.buzzert.kordophone.backend.server.AuthenticationRequest
+import net.buzzert.kordophone.backend.server.AuthenticationResponse
 import net.buzzert.kordophone.backend.server.SendMessageRequest
 import net.buzzert.kordophone.backend.server.SendMessageResponse
 import net.buzzert.kordophone.backend.server.authenticatedWebSocketURL
@@ -257,4 +259,15 @@ class MockServerInterface(private val server: MockServer): APIInterface {
         server.markConversationAsRead(conversationGUID)
         return Response.success(null)
     }
+
+    override suspend fun authenticate(request: AuthenticationRequest): Response<AuthenticationResponse> {
+        // Anything goes!
+        val response = AuthenticationResponse(
+                "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9." +
+                "eyJ1c2VybmFtZSI6InRlc3QiLCJleHAiOjE3MDk3OTQ5NjB9." +
+                "82UcI1gB4eARmgrKwAY6JnbEdWLXou1GWp29scnUhi8"
+        )
+
+        return Response.success(response)
+    }
 }