Added password authentication as server feature (#8716)

* Added authenticate and setPassword

* Added AuthPopup

* Added auth endpoint to UncivServer

* Fixed merge confict

* Added close button to AuthPopup

+ Fixed crash if no server is available

* Added entries to template properties

* Fixed setting password does not work

if authentication is required

+ Added server check on game startup in case the server has changed its feature set

* Added support for different passwords

on different servers

+ Cleanup for MultiplayerTab

* Added current password as hint

+ removed character hiding in auth popup
+ added popup to indicate auth success on connection check

android/assets/jsons/translations/template.properties

@@ -612,6 +612,16 @@ Days =
 Server limit reached! Please wait for [time] seconds = 
 File could not be found on the multiplayer server = 
 Unhandled problem, [errorMessage] = 
+Please enter your server password = 
+Set password = 
+Failed to set password! = 
+Password set successfully for server [serverURL] = 
+Password = 
+Your userId is password secured = 
+Set a password to secure your userId = 
+Authenticate = 
+This server does not support authentication = 
+Authentication failed = 
 
 # Save game menu
 

core/src/com/unciv/UncivGame.kt

@@ -197,6 +197,13 @@ class UncivGame(parameters: UncivGameParameters) : Game() {
 
         onlineMultiplayer = OnlineMultiplayer()
 
+        // Check if the server is available in case the feature set has changed
+        try {
+            onlineMultiplayer.checkServerStatus()
+        } catch (ex: Exception) {
+            debug("Couldn't connect to server: " + ex.message)
+        }
+
         ImageGetter.resetAtlases()
         ImageGetter.setNewRuleset(ImageGetter.ruleset)  // This needs to come after the settings, since we may have default visual mods
         if (settings.tileSet !in ImageGetter.getAvailableTilesets()) { // If one of the tilesets is no longer available, default back

core/src/com/unciv/logic/multiplayer/OnlineMultiplayer.kt

@@ -3,15 +3,19 @@ package com.unciv.logic.multiplayer
 import com.badlogic.gdx.files.FileHandle
 import com.unciv.Constants
 import com.unciv.UncivGame
+import com.unciv.json.json
 import com.unciv.logic.GameInfo
 import com.unciv.logic.GameInfoPreview
 import com.unciv.logic.civilization.NotificationCategory
 import com.unciv.logic.civilization.PlayerType
 import com.unciv.logic.event.EventBus
 import com.unciv.logic.multiplayer.storage.FileStorageRateLimitReached
+import com.unciv.logic.multiplayer.storage.MultiplayerAuthException
 import com.unciv.logic.multiplayer.storage.MultiplayerFileNotFoundException
 import com.unciv.logic.multiplayer.storage.OnlineMultiplayerFiles
 import com.unciv.ui.components.extensions.isLargerThan
+import com.unciv.logic.multiplayer.storage.SimpleHttp
+import com.unciv.utils.Log
 import com.unciv.utils.concurrency.Concurrency
 import com.unciv.utils.concurrency.Dispatcher
 import com.unciv.utils.concurrency.launchOnThreadPool
@@ -42,6 +46,7 @@ private val FILE_UPDATE_THROTTLE_PERIOD = Duration.ofSeconds(60)
 class OnlineMultiplayer {
     private val files = UncivGame.Current.files
     private val multiplayerFiles = OnlineMultiplayerFiles()
+    private var featureSet = ServerFeatureSet()
 
     private val savedGames: MutableMap<FileHandle, OnlineMultiplayerGame> = Collections.synchronizedMap(mutableMapOf())
 
@@ -50,6 +55,7 @@ class OnlineMultiplayer {
     private val lastCurGameRefresh: AtomicReference<Instant?> = AtomicReference()
 
     val games: Set<OnlineMultiplayerGame> get() = savedGames.values.toSet()
+    val serverFeatureSet: ServerFeatureSet get() = featureSet
 
     init {
         flow<Unit> {
@@ -178,6 +184,7 @@ class OnlineMultiplayer {
      *
      * @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time
      * @throws MultiplayerFileNotFoundException if the file can't be found
+     * @throws MultiplayerAuthException if the authentication failed
      * @return false if it's not the user's turn and thus resigning did not happen
      */
     suspend fun resign(game: OnlineMultiplayerGame): Boolean {
@@ -301,6 +308,7 @@ class OnlineMultiplayer {
     /**
      * @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time
      * @throws MultiplayerFileNotFoundException if the file can't be found
+     * @throws MultiplayerAuthException if the authentication failed
      */
     suspend fun updateGame(gameInfo: GameInfo) {
         debug("Updating remote game %s", gameInfo.gameId)
@@ -323,6 +331,67 @@ class OnlineMultiplayer {
                 && gameInfo.turns == preview.turns
     }
 
+    /**
+     * Checks if the server is alive and sets the [serverFeatureSet] accordingly.
+     * @return true if the server is alive, false otherwise
+     */
+    fun checkServerStatus(): Boolean {
+        var statusOk = false
+        SimpleHttp.sendGetRequest("${UncivGame.Current.settings.multiplayer.server}/isalive") { success, result, _ ->
+            statusOk = success
+            if (result.isNotEmpty()) {
+                featureSet = try {
+                    json().fromJson(ServerFeatureSet::class.java, result)
+                } catch (ex: Exception) {
+                    Log.error("${UncivGame.Current.settings.multiplayer.server} does not support server feature set")
+                    ServerFeatureSet()
+                }
+            }
+        }
+        return statusOk
+    }
+
+    /**
+     * @return true if the authentication was successful or the server does not support authentication.
+     * @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time
+     * @throws MultiplayerAuthException if the authentication failed
+     */
+    fun authenticate(password: String?): Boolean {
+        if (featureSet.authVersion == 0) {
+            return true
+        }
+
+
+        val settings = UncivGame.Current.settings.multiplayer
+
+        val success = multiplayerFiles.fileStorage().authenticate(
+            userId=settings.userId,
+            password=password ?: settings.passwords[settings.server] ?: ""
+        )
+        if (password != null && success) {
+            settings.passwords[settings.server] = password
+        }
+        return success
+    }
+
+    /**
+     * @return true if setting the password was successful, false otherwise.
+     * @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time
+     * @throws MultiplayerAuthException if the authentication failed
+     */
+    fun setPassword(password: String): Boolean {
+        if (
+            featureSet.authVersion > 0 &&
+            multiplayerFiles.fileStorage().setPassword(newPassword = password)
+        ) {
+            val settings = UncivGame.Current.settings.multiplayer
+            settings.passwords[settings.server] = password
+            return true
+        }
+
+        return false
+    }
+
     /**
      * Checks if [preview1] has a more recent game state than [preview2]
      */

core/src/com/unciv/logic/multiplayer/ServerFeatureSet.kt

@@ -0,0 +1,15 @@
+package com.unciv.logic.multiplayer
+
+
+/**
+ * This class is used to store the features of the server.
+ *
+ * We use version numbers instead of simple boolean
+ * to allow for future expansion and backwards compatibility.
+ *
+ * Everything is optional, so if a feature is not present, it is assumed to be 0.
+ * Dropbox does not support anything of this, so it will always be 0.
+ */
+data class ServerFeatureSet(
+    val authVersion: Int = 0,
+)

core/src/com/unciv/logic/multiplayer/storage/DropBox.kt

@@ -89,13 +89,12 @@ object DropBox: FileStorage {
         return json().fromJson(MetaData::class.java, reader.readText())
     }
 
-    override fun saveFileData(fileName: String, data: String, overwrite: Boolean) {
-        val overwriteModeString = if(!overwrite) "" else ""","mode":{".tag":"overwrite"}"""
+    override fun saveFileData(fileName: String, data: String) {
         dropboxApi(
             url="https://content.dropboxapi.com/2/files/upload",
             data=data,
             contentType="application/octet-stream",
-            dropboxApiArg = """{"path":"${getLocalGameLocation(fileName)}"$overwriteModeString}"""
+            dropboxApiArg = """{"path":"${getLocalGameLocation(fileName)}","mode":{".tag":"overwrite"}}"""
         )
     }
 
@@ -104,6 +103,14 @@ object DropBox: FileStorage {
         return BufferedReader(InputStreamReader(inputStream)).readText()
     }
 
+    override fun authenticate(userId: String, password: String): Boolean {
+        throw NotImplementedError()
+    }
+
+    override fun setPassword(newPassword: String): Boolean {
+        throw NotImplementedError()
+    }
+
     fun downloadFile(fileName: String): InputStream {
         val response = dropboxApi("https://content.dropboxapi.com/2/files/download",
                 contentType = "text/plain", dropboxApiArg = "{\"path\":\"$fileName\"}")

core/src/com/unciv/logic/multiplayer/storage/FileStorage.kt

@@ -6,6 +6,7 @@ import java.util.*
 class FileStorageConflictException : Exception()
 class FileStorageRateLimitReached(val limitRemainingSeconds: Int) : UncivShowableException("Server limit reached! Please wait for [${limitRemainingSeconds}] seconds")
 class MultiplayerFileNotFoundException(cause: Throwable?) : UncivShowableException("File could not be found on the multiplayer server", cause)
+class MultiplayerAuthException(cause: Throwable?) : UncivShowableException("Authentication failed", cause)
 
 interface FileMetaData {
     fun getLastModified(): Date?
@@ -14,9 +15,9 @@ interface FileMetaData {
 interface FileStorage {
     /**
      * @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time
-     * @throws FileStorageConflictException if the file already exists and [overwrite] is false
+     * @throws MultiplayerAuthException if the authentication failed
      */
-    fun saveFileData(fileName: String, data: String, overwrite: Boolean)
+    fun saveFileData(fileName: String, data: String)
     /**
      * @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time
      * @throws FileNotFoundException if the file can't be found
@@ -30,6 +31,17 @@ interface FileStorage {
     /**
      * @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time
      * @throws FileNotFoundException if the file can't be found
+     * @throws MultiplayerAuthException if the authentication failed
      */
     fun deleteFile(fileName: String)
+    /**
+     * @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time
+     * @throws MultiplayerAuthException if the authentication failed
+     */
+    fun authenticate(userId: String, password: String): Boolean
+    /**
+     * @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time
+     * @throws MultiplayerAuthException if the authentication failed
+     */
+    fun setPassword(newPassword: String): Boolean
 }

core/src/com/unciv/logic/multiplayer/storage/OnlineMultiplayerFiles.kt

@@ -5,6 +5,7 @@ import com.unciv.UncivGame
 import com.unciv.logic.GameInfo
 import com.unciv.logic.GameInfoPreview
 import com.unciv.logic.files.UncivFiles
+import com.unciv.ui.screens.savescreens.Gzip
 
 /**
  * Allows access to games stored on a server for multiplayer purposes.
@@ -23,13 +24,26 @@ class OnlineMultiplayerFiles(
     fun fileStorage(): FileStorage {
         val identifier = if (fileStorageIdentifier == null) UncivGame.Current.settings.multiplayer.server else fileStorageIdentifier
 
-        return if (identifier == Constants.dropboxMultiplayerServer) DropBox else UncivServerFileStorage(identifier!!)
+        return if (identifier == Constants.dropboxMultiplayerServer) {
+            DropBox
+        } else {
+            val settings = UncivGame.Current.settings.multiplayer
+            UncivServerFileStorage.apply {
+                serverUrl = identifier!!
+                authHeader = mapOf(
+                    "Authorization" to "Basic ${Gzip.zip(settings.userId)}:${Gzip.zip(settings.passwords[settings.server] ?: "")}"
+                )
+            }
+        }
     }
 
-    /** @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time */
+    /**
+     * @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time
+     * @throws MultiplayerAuthException if the authentication failed
+     */
     suspend fun tryUploadGame(gameInfo: GameInfo, withPreview: Boolean) {
         val zippedGameInfo = UncivFiles.gameInfoToString(gameInfo, forceZip = true)
-        fileStorage().saveFileData(gameInfo.gameId, zippedGameInfo, true)
+        fileStorage().saveFileData(gameInfo.gameId, zippedGameInfo)
 
         // We upload the preview after the game because otherwise the following race condition will happen:
         // Current player ends turn -> Uploads Game Preview
@@ -48,13 +62,14 @@ class OnlineMultiplayerFiles(
      * the gameInfo, it is recommended to use tryUploadGame(gameInfo, withPreview = true)
      *
      * @throws FileStorageRateLimitReached if the file storage backend can't handle any additional actions for a time
+     * @throws MultiplayerAuthException if the authentication failed
      *
      * @see tryUploadGame
      * @see GameInfo.asPreview
      */
     suspend fun tryUploadGamePreview(gameInfo: GameInfoPreview) {
         val zippedGameInfo = UncivFiles.gameInfoToString(gameInfo)
-        fileStorage().saveFileData("${gameInfo.gameId}_Preview", zippedGameInfo, true)
+        fileStorage().saveFileData("${gameInfo.gameId}_Preview", zippedGameInfo)
     }
 
     /**

core/src/com/unciv/logic/multiplayer/storage/SimpleHttp.kt

@@ -16,11 +16,11 @@ import java.nio.charset.Charset
 private typealias SendRequestCallback = (success: Boolean, result: String, code: Int?)->Unit
 
 object SimpleHttp {
-    fun sendGetRequest(url: String, timeout: Int = 5000, action: SendRequestCallback) {
-        sendRequest(Net.HttpMethods.GET, url, "", timeout, action)
+    fun sendGetRequest(url: String, timeout: Int = 5000, header: Map<String, String>? = null, action: SendRequestCallback) {
+        sendRequest(Net.HttpMethods.GET, url, "", timeout, header, action)
     }
 
-    fun sendRequest(method: String, url: String, content: String, timeout: Int = 5000, action: SendRequestCallback) {
+    fun sendRequest(method: String, url: String, content: String, timeout: Int = 5000, header: Map<String, String>? = null, action: SendRequestCallback) {
         var uri = URI(url)
         if (uri.host == null) uri = URI("http://$url")
 
@@ -42,6 +42,10 @@ object SimpleHttp {
                 setRequestProperty("User-Agent", "Unciv/Turn-Checker-GNU-Terry-Pratchett")
             setRequestProperty("Content-Type", "text/plain")
 
+            for ((key, value) in header.orEmpty()) {
+                setRequestProperty(key, value)
+            }
+
             try {
                 if (content.isNotEmpty()) {
                     doOutput = true
@@ -60,7 +64,7 @@ object SimpleHttp {
                     if (errorStream != null) BufferedReader(InputStreamReader(errorStream)).readText()
                     else t.message!!
                 debug("Returning error message [%s]", errorMessageToReturn)
-                action(false, errorMessageToReturn, if (errorStream != null) responseCode else null)
+                action(false, errorMessageToReturn, responseCode)
             }
         }
     }

core/src/com/unciv/logic/multiplayer/storage/UncivServerFileStorage.kt

@@ -1,23 +1,31 @@
 package com.unciv.logic.multiplayer.storage
 
 import com.badlogic.gdx.Net
+import com.unciv.ui.screens.savescreens.Gzip
 import com.unciv.utils.debug
 import kotlin.Exception
 
-class UncivServerFileStorage(val serverUrl: String, val timeout: Int = 30000) : FileStorage {
-    override fun saveFileData(fileName: String, data: String, overwrite: Boolean) {
-        SimpleHttp.sendRequest(Net.HttpMethods.PUT, fileUrl(fileName), data, timeout) {
-                success, result, _ ->
+object UncivServerFileStorage : FileStorage {
+    var authHeader: Map<String, String>? = null
+    var serverUrl: String = ""
+    var timeout: Int = 30000
+
+    override fun saveFileData(fileName: String, data: String) {
+        SimpleHttp.sendRequest(Net.HttpMethods.PUT, fileUrl(fileName), content=data, timeout=timeout, header=authHeader) {
+                success, result, code ->
             if (!success) {
                 debug("Error from UncivServer during save: %s", result)
-                throw Exception(result)
+                when (code) {
+                    401 -> throw MultiplayerAuthException(Exception(result))
+                    else -> throw Exception(result)
+                }
             }
         }
     }
 
     override fun loadFileData(fileName: String): String {
         var fileData = ""
-        SimpleHttp.sendGetRequest(fileUrl(fileName), timeout = timeout){
+        SimpleHttp.sendGetRequest(fileUrl(fileName), timeout=timeout, header=authHeader) {
                 success, result, code ->
             if (!success) {
                 debug("Error from UncivServer during load: %s", result)
@@ -37,7 +45,7 @@ class UncivServerFileStorage(val serverUrl: String, val timeout: Int = 30000) :
     }
 
     override fun deleteFile(fileName: String) {
-        SimpleHttp.sendRequest(Net.HttpMethods.DELETE, fileUrl(fileName), "", timeout) {
+        SimpleHttp.sendRequest(Net.HttpMethods.DELETE, fileUrl(fileName), content="", timeout=timeout, header=authHeader) {
                 success, result, code ->
             if (!success) {
                 when (code) {
@@ -48,5 +56,44 @@ class UncivServerFileStorage(val serverUrl: String, val timeout: Int = 30000) :
         }
     }
 
+    override fun authenticate(userId: String, password: String): Boolean {
+        var authenticated = false
+        authHeader = mapOf("Authorization" to "Basic ${Gzip.zip(userId)}:${Gzip.zip(password)}")
+        SimpleHttp.sendGetRequest("$serverUrl/auth", timeout=timeout, header=authHeader) {
+                success, result, code ->
+            if (!success) {
+                debug("Error from UncivServer during authentication: %s", result)
+                authHeader = null
+                when (code) {
+                    401 -> throw MultiplayerAuthException(Exception(result))
+                    else -> throw Exception(result)
+                }
+            } else {
+                authenticated = true
+            }
+        }
+        return authenticated
+    }
+
+    override fun setPassword(newPassword: String): Boolean {
+        if (authHeader == null)
+            return false
+
+        var setSuccessful = false
+        SimpleHttp.sendRequest(Net.HttpMethods.PUT, "$serverUrl/auth", content=Gzip.zip(newPassword), timeout=timeout, header=authHeader) {
+                success, result, code ->
+            if (!success) {
+                debug("Error from UncivServer during password set: %s", result)
+                when (code) {
+                    401 -> throw MultiplayerAuthException(Exception(result))
+                    else -> throw Exception(result)
+                }
+            } else {
+                setSuccessful = true
+            }
+        }
+        return setSuccessful
+    }
+
     private fun fileUrl(fileName: String) = "$serverUrl/files/$fileName"
 }

core/src/com/unciv/models/metadata/GameSettings.kt

@@ -220,6 +220,8 @@ enum class LocaleCode(var language: String, var country: String) {
 
 class GameSettingsMultiplayer {
     var userId = ""
+    var passwords = mutableMapOf<String, String>()
+    var userName: String = ""
     var server = Constants.uncivXyzServer
     var friendList: MutableList<FriendList.Friend> = mutableListOf()
     var turnCheckerEnabled = true

core/src/com/unciv/ui/popups/AuthPopup.kt

@@ -0,0 +1,41 @@
+package com.unciv.ui.popups
+
+import com.badlogic.gdx.scenes.scene2d.Stage
+import com.badlogic.gdx.scenes.scene2d.ui.TextButton
+import com.unciv.UncivGame
+import com.unciv.ui.components.UncivTextField
+import com.unciv.ui.components.extensions.onClick
+import com.unciv.ui.components.extensions.toTextButton
+import com.unciv.ui.screens.basescreen.BaseScreen
+
+class AuthPopup(stage: Stage, authSuccessful: ((Boolean) -> Unit)? = null)
+    : Popup(stage) {
+
+    constructor(screen: BaseScreen, authSuccessful: ((Boolean) -> Unit)? = null) : this(screen.stage, authSuccessful)
+
+    init {
+        val passwordField = UncivTextField.create("Password")
+        val button = "Authenticate".toTextButton()
+        val negativeButtonStyle = BaseScreen.skin.get("negative", TextButton.TextButtonStyle::class.java)
+
+        button.onClick {
+            try {
+                UncivGame.Current.onlineMultiplayer.authenticate(passwordField.text)
+                authSuccessful?.invoke(true)
+                close()
+            } catch (ex: Exception) {
+                innerTable.clear()
+                addGoodSizedLabel("Authentication failed").colspan(2).row()
+                add(passwordField).colspan(2).growX().pad(16f, 0f, 16f, 0f).row()
+                addCloseButton(style=negativeButtonStyle) { authSuccessful?.invoke(false) }.growX().padRight(8f)
+                add(button).growX().padLeft(8f)
+                return@onClick
+            }
+        }
+
+        addGoodSizedLabel("Please enter your server password").colspan(2).row()
+        add(passwordField).colspan(2).growX().pad(16f, 0f, 16f, 0f).row()
+        addCloseButton(style=negativeButtonStyle) { authSuccessful?.invoke(false) }.growX().padRight(8f)
+        add(button).growX().padLeft(8f)
+    }
+}

core/src/com/unciv/ui/popups/options/MultiplayerTab.kt

@@ -5,8 +5,10 @@ import com.badlogic.gdx.Gdx
 import com.badlogic.gdx.scenes.scene2d.ui.Table
 import com.badlogic.gdx.scenes.scene2d.ui.TextField
 import com.unciv.Constants
+import com.unciv.UncivGame
 import com.unciv.logic.multiplayer.OnlineMultiplayer
-import com.unciv.logic.multiplayer.storage.SimpleHttp
+import com.unciv.logic.multiplayer.storage.FileStorageRateLimitReached
+import com.unciv.logic.multiplayer.storage.MultiplayerAuthException
 import com.unciv.models.UncivSound
 import com.unciv.models.metadata.GameSetting
 import com.unciv.models.metadata.GameSettings
@@ -24,6 +26,7 @@ import com.unciv.ui.components.extensions.onClick
 import com.unciv.ui.components.extensions.toGdxArray
 import com.unciv.ui.components.extensions.toLabel
 import com.unciv.ui.components.extensions.toTextButton
+import com.unciv.ui.popups.AuthPopup
 import com.unciv.utils.concurrency.Concurrency
 import com.unciv.utils.concurrency.launchOnGLThread
 import java.time.Duration
@@ -145,7 +148,7 @@ private fun addMultiplayerServerOptions(
 
     serverIpTable.add("Server address".toLabel().onClick {
         multiplayerServerTextField.text = Gdx.app.clipboard.contents
-        }).row()
+        }).colspan(2).row()
     multiplayerServerTextField.onChange {
         val isCustomServer = OnlineMultiplayer.usesCustomServer()
         connectionToServerButton.isEnabled = isCustomServer
@@ -162,26 +165,65 @@ private fun addMultiplayerServerOptions(
         settings.save()
     }
 
-    serverIpTable.add(multiplayerServerTextField).minWidth(optionsPopup.stageToShowOn.width / 2).growX()
-    tab.add(serverIpTable).colspan(2).fillX().row()
+    serverIpTable.add(multiplayerServerTextField)
+        .minWidth(optionsPopup.stageToShowOn.width / 2)
+        .colspan(2).growX().padBottom(8f).row()
 
-    tab.add("Reset to Dropbox".toTextButton().onClick {
+    serverIpTable.add("Reset to Dropbox".toTextButton().onClick {
         multiplayerServerTextField.text = Constants.dropboxMultiplayerServer
         for (refreshSelect in toUpdate) refreshSelect.update(false)
         settings.save()
-    }).colspan(2).row()
+    })
 
-    tab.add(connectionToServerButton.onClick {
+    serverIpTable.add(connectionToServerButton.onClick {
         val popup = Popup(optionsPopup.stageToShowOn).apply {
             addGoodSizedLabel("Awaiting response...").row()
+            open(true)
         }
-        popup.open(true)
 
-        successfullyConnectedToServer(settings) { success, _, _ ->
-            popup.addGoodSizedLabel(if (success) "Success!" else "Failed!").row()
-            popup.addCloseButton()
+        successfullyConnectedToServer { connectionSuccess, authSuccess ->
+            if (connectionSuccess && authSuccess) {
+                popup.reuseWith("Success!", true)
+            } else if (connectionSuccess) {
+                popup.close()
+                AuthPopup(optionsPopup.stageToShowOn) {
+                    success -> popup.apply{
+                        reuseWith(if (success) "Success!" else "Failed!", true)
+                        open(true)
+                    }
+                }.open(true)
+            } else {
+                popup.reuseWith("Failed!", true)
+            }
         }
-    }).colspan(2).row()
+    }).row()
+
+    if (UncivGame.Current.onlineMultiplayer.serverFeatureSet.authVersion > 0) {
+        val passwordTextField = UncivTextField.create(
+            settings.multiplayer.passwords[settings.multiplayer.server] ?: "Password"
+        )
+        val setPasswordButton = "Set password".toTextButton()
+
+        serverIpTable.add("Set password".toLabel()).padTop(16f).colspan(2).row()
+        serverIpTable.add(passwordTextField).colspan(2).growX().padBottom(8f).row()
+
+        val passwordStatusTable = Table().apply {
+            add(
+                if (settings.multiplayer.passwords.containsKey(settings.multiplayer.server)) {
+                    "Your userId is password secured"
+                } else {
+                    "Set a password to secure your userId"
+                }.toLabel()
+            )
+            add(setPasswordButton.onClick {
+                setPassword(passwordTextField.text, optionsPopup)
+            }).padLeft(16f)
+        }
+
+        serverIpTable.add(passwordStatusTable).colspan(2).row()
+    }
+
+    tab.add(serverIpTable).colspan(2).fillX().row()
 }
 
 private fun addTurnCheckerOptions(
@@ -216,11 +258,83 @@ private fun addTurnCheckerOptions(
     return turnCheckerSelect
 }
 
-private fun successfullyConnectedToServer(settings: GameSettings, action: (Boolean, String, Int?) -> Unit) {
+private fun successfullyConnectedToServer(action: (Boolean, Boolean) -> Unit) {
     Concurrency.run("TestIsAlive") {
-        SimpleHttp.sendGetRequest("${settings.multiplayer.server}/isalive") { success, result, code ->
+        try {
+            val connectionSuccess = UncivGame.Current.onlineMultiplayer.checkServerStatus()
+            var authSuccess = false
+            if (connectionSuccess) {
+                try {
+                    authSuccess = UncivGame.Current.onlineMultiplayer.authenticate(null)
+                } catch (_: Exception) {
+                    // We ignore the exception here, because we handle the failed auth onGLThread
+                }
+            }
             launchOnGLThread {
-                action(success, result, code)
+                action(connectionSuccess, authSuccess)
+            }
+        } catch (_: Exception) {
+            launchOnGLThread {
+                action(false, false)
+            }
+        }
+    }
+}
+
+private fun setPassword(password: String, optionsPopup: OptionsPopup) {
+    if (password.isNullOrBlank())
+        return
+
+    val popup = Popup(optionsPopup.stageToShowOn).apply {
+        addGoodSizedLabel("Awaiting response...").row()
+        open(true)
+    }
+
+    if (UncivGame.Current.onlineMultiplayer.serverFeatureSet.authVersion == 0) {
+        popup.reuseWith("This server does not support authentication", true)
+        return
+    }
+
+    successfullySetPassword(password) { success, ex ->
+        if (success) {
+            popup.reuseWith(
+                "Password set successfully for server [${optionsPopup.settings.multiplayer.server}]",
+                true
+            )
+        } else {
+            if (ex is MultiplayerAuthException) {
+                AuthPopup(optionsPopup.stageToShowOn) { authSuccess ->
+                    // If auth was successful, try to set password again
+                    if (authSuccess) {
+                        popup.close()
+                        setPassword(password, optionsPopup)
+                    } else {
+                        popup.reuseWith("Failed to set password!", true)
+                    }
+                }.open(true)
+                return@successfullySetPassword
+            }
+
+            val message = when (ex) {
+                is FileStorageRateLimitReached -> "Server limit reached! Please wait for [${ex.limitRemainingSeconds}] seconds"
+                else -> "Failed to set password!"
+            }
+
+            popup.reuseWith(message, true)
+        }
+    }
+}
+
+private fun successfullySetPassword(password: String, action: (Boolean, Exception?) -> Unit) {
+    Concurrency.run("SetPassword") {
+        try {
+            val setSuccess = UncivGame.Current.onlineMultiplayer.setPassword(password)
+            launchOnGLThread {
+                action(setSuccess, null)
+            }
+        } catch (ex: Exception) {
+            launchOnGLThread {
+                action(false, ex)
             }
         }
     }

core/src/com/unciv/ui/screens/multiplayerscreens/EditMultiplayerGameInfoScreen.kt

@@ -3,6 +3,7 @@ package com.unciv.ui.screens.multiplayerscreens
 import com.badlogic.gdx.graphics.Color
 import com.badlogic.gdx.scenes.scene2d.ui.TextButton.TextButtonStyle
 import com.unciv.logic.multiplayer.OnlineMultiplayerGame
+import com.unciv.logic.multiplayer.storage.MultiplayerAuthException
 import com.unciv.models.translations.tr
 import com.unciv.ui.screens.pickerscreens.PickerScreen
 import com.unciv.ui.popups.ConfirmPopup
@@ -15,6 +16,7 @@ import com.unciv.ui.components.extensions.enable
 import com.unciv.ui.components.extensions.onClick
 import com.unciv.ui.components.extensions.toLabel
 import com.unciv.ui.components.extensions.toTextButton
+import com.unciv.ui.popups.AuthPopup
 import com.unciv.utils.concurrency.Concurrency
 import com.unciv.utils.concurrency.launchOnGLThread
 
@@ -116,6 +118,15 @@ class EditMultiplayerGameInfoScreen(val multiplayerGame: OnlineMultiplayerGame)
                     }
                 }
             } catch (ex: Exception) {
+                if (ex is MultiplayerAuthException) {
+                    launchOnGLThread {
+                        AuthPopup(this@EditMultiplayerGameInfoScreen) {
+                            success -> if (success) resign(multiplayerGame)
+                        }.open(true)
+                    }
+                    return@runOnNonDaemonThreadPool
+                }
+
                 val (message) = LoadGameScreen.getLoadExceptionMessage(ex)
                 launchOnGLThread {
                     popup.reuseWith(message, true)

core/src/com/unciv/ui/screens/worldscreen/WorldScreen.kt

@@ -22,6 +22,7 @@ import com.unciv.logic.event.EventBus
 import com.unciv.logic.map.MapVisualization
 import com.unciv.logic.multiplayer.MultiplayerGameUpdated
 import com.unciv.logic.multiplayer.storage.FileStorageRateLimitReached
+import com.unciv.logic.multiplayer.storage.MultiplayerAuthException
 import com.unciv.logic.trade.TradeEvaluation
 import com.unciv.models.TutorialTrigger
 import com.unciv.models.ruleset.tile.ResourceType
@@ -35,6 +36,7 @@ import com.unciv.ui.components.extensions.setFontSize
 import com.unciv.ui.components.extensions.toLabel
 import com.unciv.ui.components.extensions.toTextButton
 import com.unciv.ui.images.ImageGetter
+import com.unciv.ui.popups.AuthPopup
 import com.unciv.ui.popups.Popup
 import com.unciv.ui.popups.ToastPopup
 import com.unciv.ui.popups.hasOpenPopups
@@ -624,16 +626,25 @@ class WorldScreen(
                 try {
                     game.onlineMultiplayer.updateGame(gameInfoClone)
                 } catch (ex: Exception) {
-                    val message = when (ex) {
-                        is FileStorageRateLimitReached -> "Server limit reached! Please wait for [${ex.limitRemainingSeconds}] seconds"
-                        else -> "Could not upload game!"
-                    }
-                    launchOnGLThread { // Since we're changing the UI, that should be done on the main thread
-                        val cantUploadNewGamePopup = Popup(this@WorldScreen)
-                        cantUploadNewGamePopup.addGoodSizedLabel(message).row()
-                        cantUploadNewGamePopup.addCloseButton()
-                        cantUploadNewGamePopup.open()
+                    if (ex is MultiplayerAuthException) {
+                        launchOnGLThread {
+                            AuthPopup(this@WorldScreen) {
+                                success -> if (success) nextTurn()
+                            }.open(true)
+                        }
+                    } else {
+                        val message = when (ex) {
+                            is FileStorageRateLimitReached -> "Server limit reached! Please wait for [${ex.limitRemainingSeconds}] seconds"
+                            else -> "Could not upload game!"
+                        }
+                        launchOnGLThread { // Since we're changing the UI, that should be done on the main thread
+                            val cantUploadNewGamePopup = Popup(this@WorldScreen)
+                            cantUploadNewGamePopup.addGoodSizedLabel(message).row()
+                            cantUploadNewGamePopup.addCloseButton()
+                            cantUploadNewGamePopup.open()
+                        }
                     }
+
                     this@WorldScreen.isPlayersTurn = true // Since we couldn't push the new game clone, then it's like we never clicked the "next turn" button
                     this@WorldScreen.shouldUpdate = true
                     return@runOnNonDaemonThreadPool

docs/Developers/Building-Locally.md

@@ -78,7 +78,7 @@ The simple multiplayer host included in the sources can be set up to debug or ru
 -   In Android Studio, Run > Edit configurations.
     -   Click "+" to add a new configuration
     -   Choose "Application" and name the config, e.g. "UncivServer"
-    -   Set the module to `Unciv.server.main` (`Unciv.server` for Studio versions Bumblebee or below), main class to `com.unciv.app.server.DesktopLauncher` and `<repo_folder>/android/assets/` as the Working directory, OK to close the window.
+    -   Set the module to `Unciv.server.main` (`Unciv.server` for Studio versions Bumblebee or below), main class to `com.unciv.app.server.UncivServer` and `<repo_folder>/android/assets/` as the Working directory, OK to close the window.
 -   Select the UncivServer configuration and click the green arrow button to run! Or start a debug session as above.
 
 To build a jar file, refer to [Without Android Studio](#Without-Android-Studio) and replace 'desktop' with 'server'. That is, run `./gradlew server:dist` and when it's done look for /server/build/libs/UncivServer.jar

server/src/com/unciv/app/server/UncivServer.kt

@@ -2,11 +2,14 @@ package com.unciv.app.server
 
 import com.github.ajalt.clikt.core.CliktCommand
 import com.github.ajalt.clikt.parameters.options.default
+import com.github.ajalt.clikt.parameters.options.flag
 import com.github.ajalt.clikt.parameters.options.option
 import com.github.ajalt.clikt.parameters.types.int
 import com.github.ajalt.clikt.parameters.types.restrictTo
 import io.ktor.application.*
+import io.ktor.features.*
 import io.ktor.http.*
+import io.ktor.request.*
 import io.ktor.response.*
 import io.ktor.routing.*
 import io.ktor.server.engine.*
@@ -15,6 +18,7 @@ import io.ktor.utils.io.jvm.javaio.*
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
 import java.io.File
+import java.util.concurrent.TimeUnit
 
 
 internal object UncivServer {
@@ -35,23 +39,92 @@ private class UncivServerRunner : CliktCommand() {
         help = "Multiplayer file's folder"
     ).default("MultiplayerFiles")
 
+    private val authV1Enabled by option(
+        "-a", "-auth",
+        envvar = "UncivServerAuth",
+        help = "Enable Authentication"
+    ).flag("-no-auth", default = false)
+
     override fun run() {
         serverRun(port, folder)
     }
 
+    // region Auth
+    private val authMap: MutableMap<String, String> = mutableMapOf()
+
+    private fun loadAuthFile() {
+        val authFile = File("server.auth")
+        if (!authFile.exists()) {
+            echo("No server.auth file found, creating one")
+            authFile.createNewFile()
+        } else {
+            authMap.putAll(
+                authFile.readLines().map { it.split(":") }.associate { it[0] to it[1] }
+            )
+        }
+    }
+
+    private fun saveAuthFile() {
+        val authFile = File("server.auth")
+        authFile.writeText(authMap.map { "${it.key}:${it.value}" }.joinToString("\n"))
+    }
+
+    /**
+     * @return true if either auth is disabled, no password is set for the current player,
+     * or the password is correct
+     */
+    private fun validateGameAccess(file: File, authString: String?): Boolean {
+        if (!authV1Enabled || !file.exists())
+            return true
+
+        // If auth is enabled, an auth string is required
+        if (authString == null || !authString.startsWith("Basic "))
+            return false
+
+        // Extract the user id and password from the auth string
+        val (userId, password) = authString.drop(6).split(":")
+
+        if (authMap[userId] == null || authMap[userId] == password)
+            return true
+
+        return false
+
+        // TODO Check if the user is the current player and validate its password this requires decoding the game file
+    }
+
+    private fun validateAuth(authString: String?): Boolean {
+        if (!authV1Enabled)
+            return true
+        // If auth is enabled a auth string is required
+        if (authString == null || !authString.startsWith("Basic "))
+            return false
+
+        val (userId, password) = authString.drop(6).split(":")
+        if (authMap[userId] == null || authMap[userId] == password)
+            return true
+        return false
+    }
+    // endregion Auth
+
     private fun serverRun(serverPort: Int, fileFolderName: String) {
         val portStr: String = if (serverPort == 80) "" else ":$serverPort"
         echo("Starting UncivServer for ${File(fileFolderName).absolutePath} on http://localhost$portStr")
-        embeddedServer(Netty, port = serverPort) {
+        val server = embeddedServer(Netty, port = serverPort) {
             routing {
                 get("/isalive") {
                     log.info("Received isalive request from ${call.request.local.remoteHost}")
-                    call.respondText("true")
+                    call.respondText("{authVersion: ${if (authV1Enabled) "1" else "0"}}")
                 }
                 put("/files/{fileName}") {
                     val fileName = call.parameters["fileName"] ?: throw Exception("No fileName!")
                     log.info("Receiving file: ${fileName}")
                     val file = File(fileFolderName, fileName)
+
+                    if (!validateGameAccess(file, call.request.headers["Authorization"])) {
+                        call.respond(HttpStatusCode.Unauthorized)
+                        return@put
+                    }
+
                     withContext(Dispatchers.IO) {
                         file.outputStream().use {
                             call.request.receiveChannel().toInputStream().copyTo(it)
@@ -69,19 +142,52 @@ private class UncivServerRunner : CliktCommand() {
                         return@get
                     }
                     val fileText = withContext(Dispatchers.IO) { file.readText() }
+
                     call.respondText(fileText)
                 }
-                delete("/files/{fileName}") {
-                    val fileName = call.parameters["fileName"] ?: throw Exception("No fileName!")
-                    log.info("Deleting file: $fileName")
-                    val file = File(fileFolderName, fileName)
-                    if (!file.exists()) {
-                        call.respond(HttpStatusCode.NotFound, "File does not exist")
-                        return@delete
+                if (authV1Enabled) {
+                    get("/auth") {
+                        log.info("Received auth request from ${call.request.local.remoteHost}")
+                        val authHeader = call.request.headers["Authorization"]
+                        if (validateAuth(authHeader)) {
+                            call.respond(HttpStatusCode.OK)
+                        } else {
+                            call.respond(HttpStatusCode.Unauthorized)
+                        }
+                    }
+                    put("/auth") {
+                        log.info("Received auth password set from ${call.request.local.remoteHost}")
+                        val authHeader = call.request.headers["Authorization"]
+                        if (validateAuth(authHeader)) {
+                            val userId = authHeader?.drop(6)?.split(":")?.get(0)
+                            if (userId != null) {
+                                authMap[userId] = call.receiveText()
+                                call.respond(HttpStatusCode.OK)
+                            } else {
+                                call.respond(HttpStatusCode.BadRequest)
+                            }
+                        } else {
+                            call.respond(HttpStatusCode.Unauthorized)
+                        }
                     }
-                    file.delete()
                 }
             }
-        }.start(wait = true)
+        }.start(wait = false)
+
+        if (authV1Enabled) {
+            loadAuthFile()
+        }
+
+        echo("Server running on http://localhost$portStr! Press Ctrl+C to stop")
+        Runtime.getRuntime().addShutdownHook(Thread {
+            echo("Shutting down server...")
+
+            if (authV1Enabled) {
+                saveAuthFile()
+            }
+
+            server.stop(1, 5, TimeUnit.SECONDS)
+        })
+        Thread.currentThread().join()
     }
 }