Implement plugin state (closes #603) (#622)

.gitignore

@@ -52,3 +52,4 @@ out/
 /app/src/main/frontend/**/*.js.map
 /app/src/main/frontend/generated/
 /torrent_dotfiles/
+*.state.json

plugin-api/build.gradle.kts

@@ -1,5 +1,7 @@
 import com.vanniktech.maven.publish.SonatypeHost
 
+val jacksonVersion = "2.19.1"
+
 plugins {
     kotlin("jvm")
     `java-library`
@@ -11,6 +13,10 @@ group = "org.gameyfin"
 dependencies {
     // PF4J (shared)
     api("org.pf4j:pf4j:${rootProject.extra["pf4jVersion"]}")
+
+    // JSON serialization
+    compileOnly("com.fasterxml.jackson.core:jackson-databind:$jacksonVersion")
+    implementation("com.fasterxml.jackson.module:jackson-module-kotlin:$jacksonVersion")
 }
 
 mavenPublishing {

plugin-api/src/main/kotlin/org/gameyfin/pluginapi/core/wrapper/GameyfinPlugin.kt

@@ -1,7 +1,14 @@
 package org.gameyfin.pluginapi.core.wrapper
 
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.module.kotlin.KotlinModule
 import org.pf4j.Plugin
 import org.pf4j.PluginWrapper
+import java.nio.file.Files
+import java.nio.file.Path
+import kotlin.io.path.createFile
+import kotlin.io.path.exists
+import kotlin.io.path.fileSize
 
 /**
  * Abstract base class for all Gameyfin plugins.
@@ -25,20 +32,17 @@ abstract class GameyfinPlugin(wrapper: PluginWrapper) : Plugin(wrapper) {
          * Supported logo file formats.
          */
         val SUPPORTED_LOGO_FORMATS: List<String> = listOf("png", "jpg", "jpeg", "gif", "svg", "webp")
-
-        /**
-         * Reference to the current plugin instance.
-         */
-        lateinit var plugin: GameyfinPlugin
-            private set
     }
 
     /**
-     * Initializes the plugin and sets the static plugin reference.
+     * State file for the plugin, used to persist plugin-specific state.
      */
-    init {
-        plugin = this
-    }
+    val stateFile: Path = Path.of("${wrapper.pluginId}.state.json")
+
+    /**
+     * JSON serializer for serializing and deserializing plugin state.
+     */
+    val objectMapper: ObjectMapper = ObjectMapper().registerModule(KotlinModule.Builder().build())
 
     /**
      * Checks if the plugin contains a logo file in any supported format.
@@ -73,4 +77,18 @@ abstract class GameyfinPlugin(wrapper: PluginWrapper) : Plugin(wrapper) {
 
         return null
     }
+
+    inline fun <reified T> loadState(): T? {
+        if (!stateFile.exists() || stateFile.fileSize() == 0L) return null
+        return Files.newBufferedReader(stateFile).use {
+            objectMapper.readValue(it.readText(), T::class.java)
+        }
+    }
+
+    inline fun <reified T> saveState(state: T) {
+        if (!stateFile.exists()) stateFile.createFile()
+        Files.newBufferedWriter(stateFile).use {
+            it.write(objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(state))
+        }
+    }
 }

plugins/build.gradle.kts

@@ -21,6 +21,7 @@ subprojects {
     apply(plugin = "org.jetbrains.kotlin.jvm")
 
     dependencies {
+        compileOnly(kotlin("stdlib"))
         compileOnly(project(":plugin-api"))
     }
 

plugins/torrentdownload/src/main/kotlin/org/gameyfin/plugins/download/torrent/TorrentDownloadPlugin.kt

@@ -33,6 +33,8 @@ class TorrentDownloadPlugin(wrapper: PluginWrapper) : ConfigurableGameyfinPlugin
         private lateinit var communicationManager: CommunicationManager
 
         private lateinit var plugin: TorrentDownloadPlugin
+
+        private lateinit var state: TorrentDownloadPluginState
     }
 
     init {
@@ -70,14 +72,8 @@ class TorrentDownloadPlugin(wrapper: PluginWrapper) : ConfigurableGameyfinPlugin
         )
     )
 
-    @OptIn(ExperimentalPathApi::class)
     override fun start() {
-        // Currently Gameyfin does not support storing plugin state
-        // and since we can't associate the torrent files with a game path after a restart
-        // we just delete the directory on startup.
-        if (Files.exists(TORRENT_FILE_DIRECTORY)) {
-            TORRENT_FILE_DIRECTORY.deleteRecursively()
-        }
+
         Files.createDirectories(TORRENT_FILE_DIRECTORY)
 
         tracker = Tracker(config("trackerPort"), getTrackerUri().toString())
@@ -95,6 +91,27 @@ class TorrentDownloadPlugin(wrapper: PluginWrapper) : ConfigurableGameyfinPlugin
             SelectorFactoryImpl(),
             FirstAvailableChannel(clientPort, clientPort)
         )
+
+        state = loadState<TorrentDownloadPluginState>() ?: TorrentDownloadPluginState()
+
+        state.torrentFilesMetadata.forEach {
+            // Check if the torrent and game files exist and
+            // that the game files have not been modified since the torrent file was created
+            if (Files.exists(it.torrentFile) && Files.exists(it.gameFile) &&
+                it.gameFile.getLastModifiedTime().toInstant().isBefore(it.torrentFile.getLastModifiedTime().toInstant())
+            ) {
+                tracker.announce(TrackedTorrent.load(it.torrentFile.toFile()))
+                communicationManager.addTorrent(
+                    it.torrentFile.toString(),
+                    getRootPath(it.gameFile).toString(),
+                    FullyPieceStorageFactory.INSTANCE
+                )
+            } else {
+                state.torrentFilesMetadata.remove(it)
+            }
+        }
+
+        saveState(state)
     }
 
     override fun stop() {
@@ -146,6 +163,14 @@ class TorrentDownloadPlugin(wrapper: PluginWrapper) : ConfigurableGameyfinPlugin
         )
     }
 
+    private fun getRootPath(gameFilesPath: Path): Path {
+        return if (gameFilesPath.isDirectory()) {
+            gameFilesPath
+        } else {
+            gameFilesPath.parent
+        }
+    }
+
     @Extension(ordinal = 2)
     class TorrentDownloadProvider : DownloadProvider {
         private val log = LoggerFactory.getLogger(TorrentDownloadProvider::class.java)
@@ -180,10 +205,19 @@ class TorrentDownloadPlugin(wrapper: PluginWrapper) : ConfigurableGameyfinPlugin
             tracker.announce(TrackedTorrent.load(torrentFile.toFile()))
             communicationManager.addTorrent(
                 torrentFile.toString(),
-                getRootPath(gameFilesPath).toString(),
+                plugin.getRootPath(gameFilesPath).toString(),
                 FullyPieceStorageFactory.INSTANCE
             )
 
+            state.torrentFilesMetadata.add(
+                TorrentFileMetadata(
+                    torrentFile = torrentFile,
+                    gameFile = gameFilesPath
+                )
+            )
+
+            plugin.saveState(state)
+
             return torrentFile
         }
 
@@ -192,18 +226,10 @@ class TorrentDownloadPlugin(wrapper: PluginWrapper) : ConfigurableGameyfinPlugin
                 .numHashingThreads(Runtime.getRuntime().availableProcessors() * 2)
                 .createdBy(plugin.javaClass.name)
                 .addFile(gameFilesPath)
-                .rootPath(getRootPath(gameFilesPath))
+                .rootPath(plugin.getRootPath(gameFilesPath))
                 .announce(plugin.getTrackerUri().toString())
                 .privateFlag(plugin.config("privateMode"))
                 .build()
         }
-
-        private fun getRootPath(gameFilesPath: Path): Path {
-            return if (gameFilesPath.isDirectory()) {
-                gameFilesPath
-            } else {
-                gameFilesPath.parent
-            }
-        }
     }
 }

plugins/torrentdownload/src/main/kotlin/org/gameyfin/plugins/download/torrent/TorrentDownloadPluginState.kt

@@ -0,0 +1,12 @@
+package org.gameyfin.plugins.download.torrent
+
+import java.nio.file.Path
+
+data class TorrentDownloadPluginState(
+    val torrentFilesMetadata: MutableList<TorrentFileMetadata> = mutableListOf()
+)
+
+data class TorrentFileMetadata(
+    val torrentFile: Path,
+    val gameFile: Path
+)

plugins/torrentdownload/src/main/resources/MANIFEST.MF

@@ -1,4 +1,4 @@
-Plugin-Version: 1.0.0.beta1
+Plugin-Version: 1.0.0.beta2
 Plugin-Class: org.gameyfin.plugins.download.torrent.TorrentDownloadPlugin
 Plugin-Id: org.gameyfin.plugins.download.torrent
 Plugin-Name: Torrent Download