Move thumbnail loading to background tasks and add retry to image loading

Signed-off-by: trivernis <trivernis@protonmail.com>

mediarepo-api/src/client_api/error.rs

@@ -10,3 +10,6 @@ pub enum ApiError {
     #[error("The servers api version (version {server:?}) is incompatible with the api client {client:?}")]
     VersionMismatch { server: String, client: String },
 }
+
+unsafe impl Send for ApiError {}
+unsafe impl Sync for ApiError {}

mediarepo-api/src/tauri_plugin/custom_schemes.rs

@@ -1,5 +1,6 @@
+use crate::client_api::ApiClient;
 use crate::tauri_plugin::error::{PluginError, PluginResult};
-use crate::tauri_plugin::state::{ApiState, BufferState};
+use crate::tauri_plugin::state::{ApiState, AppState, AsyncTask, BufferState};
 use crate::types::identifier::FileIdentifier;
 use std::borrow::Cow;
 use std::collections::HashMap;
@@ -89,6 +90,7 @@ async fn content_scheme<R: Runtime>(app: &AppHandle<R>, request: &Request) -> Re
 async fn thumb_scheme<R: Runtime>(app: &AppHandle<R>, request: &Request) -> Result<Response> {
     let api_state = app.state::<ApiState>();
     let buf_state = app.state::<BufferState>();
+    let app_state = app.state::<AppState>();
 
     let url = Url::parse(request.uri())?;
     let hash = url
@@ -116,26 +118,50 @@ async fn thumb_scheme<R: Runtime>(app: &AppHandle<R>, request: &Request) -> Resu
             .mimetype(&buffer.mime)
             .body(buffer.buf)
     } else {
-        tracing::debug!("Fetching content from daemon");
+        tracing::debug!("Content not loaded. Singnaling retry.");
         let api = api_state.api().await?;
+        let buf_state = buf_state.inner().clone();
+
+        app_state
+            .add_async_task(build_fetch_thumbnail_task(
+                buf_state,
+                api,
+                hash.to_string(),
+                request.uri().to_string(),
+                width,
+                height,
+            ))
+            .await;
+
+        ResponseBuilder::new()
+            .mimetype("text/plain")
+            .status(301)
+            .header("Retry-After", "1")
+            .body("Content loading. Retry in 1s.".as_bytes().to_vec())
+    }
+}
+
+fn build_fetch_thumbnail_task(
+    buf_state: BufferState,
+    api: ApiClient,
+    hash: String,
+    request_uri: String,
+    width: u32,
+    height: u32,
+) -> AsyncTask {
+    AsyncTask::new(async move {
+        tracing::debug!("Fetching content from daemon");
         let (thumb, bytes) = api
             .file
             .get_thumbnail_of_size(
-                FileIdentifier::CD(hash.to_string()),
+                FileIdentifier::CD(hash),
                 ((height as f32 * 0.5) as u32, (width as f32 * 0.5) as u32),
                 ((height as f32 * 1.5) as u32, (width as f32 * 1.5) as u32),
             )
             .await?;
         tracing::debug!("Received {} content bytes", bytes.len());
-        buf_state.add_entry(
-            request.uri().to_string(),
-            thumb.mime_type.clone(),
-            bytes.clone(),
-        );
+        buf_state.add_entry(request_uri, thumb.mime_type.clone(), bytes.clone());
 
-        ResponseBuilder::new()
-            .mimetype(&thumb.mime_type)
-            .status(200)
-            .body(bytes)
-    }
+        Ok(())
+    })
 }

mediarepo-api/src/tauri_plugin/mod.rs

@@ -4,6 +4,8 @@ use tauri::{AppHandle, Builder, Invoke, Manager, Runtime};
 use state::ApiState;
 
 use crate::tauri_plugin::state::{AppState, BufferState};
+use futures::future;
+use std::mem;
 use std::thread;
 use std::time::Duration;
 
@@ -97,6 +99,7 @@ impl<R: Runtime> Plugin<R> for MediarepoPlugin<R> {
         app.manage(buffer_state.clone());
 
         let repo_state = AppState::load()?;
+        let background_tasks = repo_state.background_tasks();
         app.manage(repo_state);
 
         thread::spawn(move || loop {
@@ -104,6 +107,28 @@ impl<R: Runtime> Plugin<R> for MediarepoPlugin<R> {
             buffer_state.clear_expired();
             buffer_state.trim_to_size(MAX_BUFFER_SIZE);
         });
+        thread::spawn(move || {
+            tokio::runtime::Builder::new_current_thread()
+                .thread_name("background_tasks")
+                .enable_time()
+                .build()
+                .expect("failed to build background task runtime")
+                .block_on(async move {
+                    tracing::debug!("background task listener ready");
+                    loop {
+                        let tasks = mem::take(&mut *background_tasks.lock().await);
+
+                        if tasks.len() > 0 {
+                            tracing::debug!("executing {} async background tasks", tasks.len());
+                            future::join_all(tasks.into_iter().map(|t| t.exec())).await;
+                            tracing::debug!("background tasks executed");
+                        } else {
+                            tokio::time::sleep(Duration::from_millis(100)).await;
+                        }
+                    }
+                });
+            tracing::error!("background task executor exited!");
+        });
 
         Ok(())
     }

mediarepo-api/src/tauri_plugin/state.rs

@@ -1,12 +1,16 @@
 use std::collections::HashMap;
+use std::fmt::{Debug, Formatter};
+use std::future::Future;
 use std::mem;
 use std::ops::Deref;
+use std::pin::Pin;
 use std::sync::Arc;
 use std::time::Duration;
 
 use parking_lot::Mutex;
 use parking_lot::RwLock as ParkingRwLock;
 use tauri::async_runtime::RwLock;
+use tokio::sync::Mutex as TokioMutex;
 use tokio::time::Instant;
 
 use crate::client_api::ApiClient;
@@ -169,6 +173,7 @@ pub struct AppState {
     pub active_repo: Arc<RwLock<Option<Repository>>>,
     pub settings: Arc<RwLock<Settings>>,
     pub running_daemons: Arc<RwLock<HashMap<String, DaemonCli>>>,
+    pub background_tasks: Arc<TokioMutex<Vec<AsyncTask>>>,
 }
 
 impl AppState {
@@ -180,6 +185,7 @@ impl AppState {
             active_repo: Default::default(),
             settings: Arc::new(RwLock::new(settings)),
             running_daemons: Default::default(),
+            background_tasks: Default::default(),
         };
 
         Ok(state)
@@ -218,4 +224,37 @@ impl AppState {
 
         Ok(())
     }
+
+    pub async fn add_async_task(&self, task: AsyncTask) {
+        self.background_tasks.lock().await.push(task);
+    }
+
+    pub fn background_tasks(&self) -> Arc<TokioMutex<Vec<AsyncTask>>> {
+        self.background_tasks.clone()
+    }
+}
+
+pub struct AsyncTask {
+    inner: Pin<Box<dyn Future<Output = PluginResult<()>>>>,
+}
+
+impl Debug for AsyncTask {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        "AsyncTask".fmt(f)
+    }
 }
+
+impl AsyncTask {
+    pub fn new<F: 'static + Future<Output = PluginResult<()>>>(inner: F) -> Self {
+        Self {
+            inner: Box::pin(inner),
+        }
+    }
+
+    pub async fn exec(self) -> PluginResult<()> {
+        self.inner.await
+    }
+}
+
+unsafe impl Send for AsyncTask {}
+unsafe impl Sync for AsyncTask {}

mediarepo-ui/src/app/components/shared/app-common/content-aware-image/content-aware-image.component.html

@@ -1,5 +1,6 @@
 <div #imageContainer (window:resize)="this.adjustSize(image, imageContainer)" class="image-container">
-    <img #image (load)="this.adjustSize(image, imageContainer)" [class.scale-height]="(!scaleWidth) && maximizeHeight"
-         [class.scale-width]="scaleWidth && maximizeWidth" [src]="this.imageSrc"
+    <img #image (error)="this.onImageLoadError($event, image)" (load)="this.onImageLoad(image, imageContainer)"
+         [class.scale-height]="(!scaleWidth) && maximizeHeight" [class.scale-width]="scaleWidth && maximizeWidth"
+         [src]="this.imageSrc"
          [style]="{borderRadius: this.borderRadius}" alt="">
 </div>

mediarepo-ui/src/app/components/shared/app-common/content-aware-image/content-aware-image.component.ts

@@ -4,9 +4,11 @@ import {
     Component,
     DoCheck,
     ElementRef,
+    EventEmitter,
     Input,
     OnDestroy,
     OnInit,
+    Output,
     ViewChild
 } from "@angular/core";
 import {SafeResourceUrl} from "@angular/platform-browser";
@@ -23,11 +25,17 @@ export class ContentAwareImageComponent implements OnInit, DoCheck, OnDestroy {
     @Input() maximizeWidth: boolean = true;
     @Input() borderRadius: string | undefined;
     @Input() decoding: "async" | "sync" | "auto" = "auto";
-    @ViewChild("image") image?: ElementRef<HTMLImageElement>;
+    @Input() maxRetry = 3;
+    @Input() retryDelay = 200;
+    @ViewChild("image") imageElement?: ElementRef<HTMLImageElement>;
     @ViewChild("imageContainer") imageContainer?: ElementRef<HTMLDivElement>;
+    @Output() appLoadEnd = new EventEmitter<void>();
+    @Output() appLoadError = new EventEmitter<void>();
+
     scaleWidth = false;
     private previousHeight = 0;
     private previousWidth = 0;
+    private retryCount = 0;
     private readonly checkInterval?: number;
 
     constructor(private changeDetector: ChangeDetectorRef) {
@@ -35,8 +43,8 @@ export class ContentAwareImageComponent implements OnInit, DoCheck, OnDestroy {
     }
 
     public ngOnInit(): void {
-        if (this.image) {
-            this.image.nativeElement.decoding = this.decoding;
+        if (this.imageElement) {
+            this.imageElement.nativeElement.decoding = this.decoding;
             this.changeDetector.detach();
         }
     }
@@ -50,9 +58,14 @@ export class ContentAwareImageComponent implements OnInit, DoCheck, OnDestroy {
     }
 
     public checkSize(): void {
-        if (this.image?.nativeElement && this.imageContainer?.nativeElement) {
-            this.adjustSize(this.image.nativeElement, this.imageContainer.nativeElement);
+        if (this.imageElement?.nativeElement && this.imageContainer?.nativeElement) {
+            this.adjustSize(this.imageElement.nativeElement, this.imageContainer.nativeElement);
+        }
     }
+
+    public onImageLoad(image: HTMLImageElement, imageContainer: HTMLDivElement): void {
+        this.adjustSize(image, imageContainer);
+        this.appLoadEnd.emit();
     }
 
     /**
@@ -77,4 +90,17 @@ export class ContentAwareImageComponent implements OnInit, DoCheck, OnDestroy {
             }
         }
     }
+
+    public onImageLoadError(error: ErrorEvent, image: HTMLImageElement): void {
+        const imageSrc = image.src;
+
+        if (this.retryCount < this.maxRetry) {
+            this.retryCount++;
+            setTimeout(() => {
+                image.src = imageSrc;
+            }, this.retryDelay * this.retryCount);
+        } else {
+            this.appLoadError.emit();
+        }
+    }
 }

mediarepo-ui/src/app/components/shared/file/file-card/file-card.component.html

@@ -4,7 +4,9 @@
     <app-middle-centered *ngIf="this.loading">
         <div class="loading-indicator"></div>
     </app-middle-centered>
-    <app-file-thumbnail *ngIf="!this.loading"
+    <app-file-thumbnail
+        (loadEnd)="this.loading = false"
+        [class.hidden]="this.loading"
         [fileChanged]="this.fileChanged"
         [file]="this.entry.data"
         class="entry-image"></app-file-thumbnail>

mediarepo-ui/src/app/components/shared/file/file-card/file-card.component.scss

@@ -66,3 +66,7 @@
         height: 2em;
     }
 }
+
+.hidden {
+    display: none;
+}

mediarepo-ui/src/app/components/shared/file/file-card/file-card.component.ts

@@ -39,13 +39,13 @@ export class FileCardComponent implements OnInit, OnChanges, OnDestroy {
 
     async ngOnInit() {
         this.cachedId = this.entry.data.id;
-        this.setImageDelayed();
+        this.loading = true;
     }
 
     async ngOnChanges(changes: SimpleChanges) {
         if (changes["entry"] && (this.cachedId === undefined || this.entry.data.id !== this.cachedId)) {
             this.cachedId = this.entry.data.id;
-            this.setImageDelayed();
+            this.loading = true;
         }
         if (changes["fileChanged"]) {
             this.fileChanged.subscribe(() => this.changeDetector.markForCheck());

mediarepo-ui/src/app/components/shared/file/file-thumbnail/file-thumbnail.component.html

@@ -1,4 +1,7 @@
-<app-content-aware-image *ngIf="this.thumbnailSupported && this.thumbUrl" [imageSrc]="this.thumbUrl"
+<app-content-aware-image (appLoadEnd)="this.loadEnd.emit()" (appLoadError)="this.onImageLoadError()"
+                         *ngIf="this.thumbnailSupported && this.thumbUrl"
+                         [imageSrc]="this.thumbUrl"
+                         [maxRetry]="5" [retryDelay]="250"
                          borderRadius="0.25em"></app-content-aware-image>
 <div *ngIf="this.thumbnailSupported && this.thumbUrl" class="file-icon-overlay">
     <ng-icon *ngIf="fileType === 'video'" name="mat-movie"></ng-icon>

mediarepo-ui/src/app/components/shared/file/file-thumbnail/file-thumbnail.component.ts

@@ -4,8 +4,10 @@ import {
     ChangeDetectionStrategy,
     ChangeDetectorRef,
     Component,
+    EventEmitter,
     Input,
     OnChanges,
+    Output,
     SimpleChanges
 } from "@angular/core";
 import {File} from "../../../../../api/models/File";
@@ -24,10 +26,12 @@ export class FileThumbnailComponent implements OnChanges, AfterViewInit, AfterVi
 
     @Input() file!: File;
     @Input() public fileChanged: BehaviorSubject<void> = new BehaviorSubject<void>(undefined);
+    @Output() loadEnd = new EventEmitter<void>();
 
     public thumbUrl: SafeResourceUrl | undefined;
     public fileType!: string;
     public thumbnailSupported: boolean = false;
+    public displayError = false;
 
     private supportedThumbnailTypes = ["image", "video"];
     private previousStatus = "imported";
@@ -55,12 +59,18 @@ export class FileThumbnailComponent implements OnChanges, AfterViewInit, AfterVi
             );
             this.fileType = this.getFileType();
             this.thumbnailSupported = this.getThumbnailSupported();
+            this.displayError = false;
         }
         if (changes["fileChanged"]) {
             this.fileChanged.subscribe(() => this.changeDetector.markForCheck());
         }
     }
 
+    public onImageLoadError(): void {
+        this.loadEnd.emit();
+        this.displayError = true;
+    }
+
     private getThumbnailSupported(): boolean {
         const mimeParts = FileHelper.parseMime(this.file.mimeType);