temporal files uploading functionality

ktor/server/src/jvmMain/kotlin/dev/inmo/micro_utils/ktor/server/ServerRoutingShortcuts.kt

@@ -92,6 +92,10 @@ class UnifiedRouter(
             call.respond(HttpStatusCode.BadRequest, "Request query parameters must contains $field")
         }
     }
+
+    companion object {
+        val default = defaultUnifiedRouter
+    }
 }
 
 val defaultUnifiedRouter = UnifiedRouter()

ktor/server/src/jvmMain/kotlin/dev/inmo/micro_utils/ktor/server/TemporalFilesRoutingConfigurator.kt

@@ -0,0 +1,132 @@
+package dev.inmo.micro_utils.ktor.server
+
+import com.benasher44.uuid.uuid4
+import dev.inmo.micro_utils.common.FileName
+import dev.inmo.micro_utils.common.MPPFile
+import dev.inmo.micro_utils.coroutines.launchSafelyWithoutExceptions
+import dev.inmo.micro_utils.ktor.common.DefaultTemporalFilesSubPath
+import dev.inmo.micro_utils.ktor.common.TemporalFileId
+import dev.inmo.micro_utils.ktor.server.configurators.ApplicationRoutingConfigurator
+import io.ktor.application.call
+import io.ktor.http.HttpStatusCode
+import io.ktor.http.content.PartData
+import io.ktor.http.content.streamProvider
+import io.ktor.request.receiveMultipart
+import io.ktor.response.respond
+import io.ktor.routing.Route
+import io.ktor.routing.post
+import kotlinx.coroutines.*
+import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import java.io.File
+import java.nio.file.Files
+import java.nio.file.attribute.FileTime
+
+class TemporalFilesRoutingConfigurator(
+    private val subpath: String = DefaultTemporalFilesSubPath,
+    private val unifiedRouter: UnifiedRouter = UnifiedRouter.default,
+    private val temporalFilesUtilizer: TemporalFilesUtilizer = TemporalFilesUtilizer
+) : ApplicationRoutingConfigurator.Element {
+    interface TemporalFilesUtilizer {
+        fun start(filesMap: MutableMap<TemporalFileId, MPPFile>, filesMutex: Mutex, onNewFileFlow: Flow<TemporalFileId>): Job
+
+        companion object : TemporalFilesUtilizer {
+            class ByTimerUtilizer(
+                private val removeMillis: Long,
+                private val scope: CoroutineScope
+            ) : TemporalFilesUtilizer {
+                override fun start(
+                    filesMap: MutableMap<TemporalFileId, MPPFile>,
+                    filesMutex: Mutex,
+                    onNewFileFlow: Flow<TemporalFileId>
+                ): Job = scope.launchSafelyWithoutExceptions {
+                    while (isActive) {
+                        val filesWithCreationInfo = filesMap.mapNotNull { (fileId, file) ->
+                            fileId to ((Files.getAttribute(file.toPath(), "creationTime") as? FileTime) ?.toMillis() ?: return@mapNotNull null)
+                        }
+                        if (filesWithCreationInfo.isEmpty()) {
+                            delay(removeMillis)
+                            continue
+                        }
+                        var min = filesWithCreationInfo.first()
+                        for (fileWithCreationInfo in filesWithCreationInfo) {
+                            if (fileWithCreationInfo.second < min.second) {
+                                min = fileWithCreationInfo
+                            }
+                        }
+                        delay(System.currentTimeMillis() - (min.second + removeMillis))
+                        filesMutex.withLock {
+                            filesMap.remove(min.first)
+                        } ?.delete()
+                    }
+
+                }
+            }
+
+            override fun start(
+                filesMap: MutableMap<TemporalFileId, MPPFile>,
+                filesMutex: Mutex,
+                onNewFileFlow: Flow<TemporalFileId>
+            ): Job = Job()
+        }
+    }
+
+    private val temporalFilesMap = mutableMapOf<TemporalFileId, MPPFile>()
+    private val temporalFilesMutex = Mutex()
+    private val filesFlow = MutableSharedFlow<TemporalFileId>()
+    val utilizerJob = temporalFilesUtilizer.start(temporalFilesMap, temporalFilesMutex, filesFlow.asSharedFlow())
+
+    override fun Route.invoke() {
+        post(subpath) {
+            unifiedRouter.apply {
+                val multipart = call.receiveMultipart()
+
+                var fileInfo: Pair<TemporalFileId, MPPFile>? = null
+                var part = multipart.readPart()
+
+                while (part != null) {
+                    if (part is PartData.FileItem) {
+                        break
+                    }
+                    part = multipart.readPart()
+                }
+
+                part ?.let {
+                    if (it is PartData.FileItem) {
+                        val fileId = TemporalFileId(uuid4().toString())
+                        val fileName = it.originalFileName ?.let { FileName(it) } ?: return@let
+                        fileInfo = fileId to File.createTempFile(fileId.string, ".${fileName.extension}").apply {
+                            outputStream().use { outputStream ->
+                                it.streamProvider().use {
+                                    it.copyTo(outputStream)
+                                }
+                            }
+                            deleteOnExit()
+                        }
+                    }
+                }
+
+                fileInfo ?.also { (fileId, file) ->
+                    temporalFilesMutex.withLock {
+                        temporalFilesMap[fileId] = file
+                    }
+                    call.respond(fileId.string)
+                    launchSafelyWithoutExceptions { filesFlow.emit(fileId) }
+                } ?: call.respond(HttpStatusCode.BadRequest)
+            }
+        }
+    }
+
+    suspend fun removeTemporalFile(temporalFileId: TemporalFileId) {
+        temporalFilesMutex.withLock {
+            temporalFilesMap.remove(temporalFileId)
+        }
+    }
+
+    fun getTemporalFile(temporalFileId: TemporalFileId) = temporalFilesMap[temporalFileId]
+
+    suspend fun getAndRemoveTemporalFile(temporalFileId: TemporalFileId) = temporalFilesMutex.withLock {
+        temporalFilesMap.remove(temporalFileId)
+    }
+}