355 lines
12 KiB
Rust
355 lines
12 KiB
Rust
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/**
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* Thumbnail Generation Service
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*
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* Generates and manages image thumbnails for fast gallery previews.
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*
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* Features:
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* - Background thumbnail generation after upload
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* - Multiple sizes (icon 150x150, preview 800x600)
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* - WebP output for smaller file sizes
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* - LRU cache for hot thumbnails
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* - Lazy generation on first request if not pre-generated
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*/
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use std::path::{Path, PathBuf};
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use std::sync::Arc;
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use tokio::sync::RwLock;
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use tokio::fs;
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use image::{ImageFormat, imageops::FilterType};
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use lru::LruCache;
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use std::num::NonZeroUsize;
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use bytes::Bytes;
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/// Thumbnail sizes supported by the system
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#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
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pub enum ThumbnailSize {
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/// Small icon for file listings (150x150)
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Icon,
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/// Medium preview for gallery view (400x400)
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Preview,
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/// Large preview for detail view (800x800)
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Large,
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}
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impl ThumbnailSize {
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/// Get the maximum dimension for this size
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pub fn max_dimension(&self) -> u32 {
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match self {
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ThumbnailSize::Icon => 150,
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ThumbnailSize::Preview => 400,
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ThumbnailSize::Large => 800,
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}
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}
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/// Get the directory name for this size
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pub fn dir_name(&self) -> &'static str {
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match self {
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ThumbnailSize::Icon => "icon",
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ThumbnailSize::Preview => "preview",
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ThumbnailSize::Large => "large",
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}
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}
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/// Get all thumbnail sizes
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pub fn all() -> &'static [ThumbnailSize] {
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&[ThumbnailSize::Icon, ThumbnailSize::Preview, ThumbnailSize::Large]
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}
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}
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/// Cache key for thumbnails
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#[derive(Debug, Clone, PartialEq, Eq, Hash)]
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struct ThumbnailCacheKey {
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file_id: String,
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size: ThumbnailSize,
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}
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/// Thumbnail service for generating and caching image thumbnails
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pub struct ThumbnailService {
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/// Root path for thumbnail storage
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thumbnails_root: PathBuf,
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/// In-memory LRU cache for hot thumbnails
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cache: Arc<RwLock<LruCache<ThumbnailCacheKey, Bytes>>>,
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/// Maximum cache size in bytes
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max_cache_bytes: usize,
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/// Current cache size in bytes
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current_cache_bytes: Arc<RwLock<usize>>,
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}
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impl ThumbnailService {
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/// Create a new thumbnail service
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///
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/// # Arguments
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/// * `storage_root` - Root path of file storage
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/// * `max_cache_entries` - Maximum number of thumbnails to cache in memory
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/// * `max_cache_bytes` - Maximum total bytes to cache
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pub fn new(storage_root: &Path, max_cache_entries: usize, max_cache_bytes: usize) -> Self {
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let thumbnails_root = storage_root.join(".thumbnails");
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Self {
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thumbnails_root,
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cache: Arc::new(RwLock::new(LruCache::new(
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NonZeroUsize::new(max_cache_entries).unwrap_or(NonZeroUsize::new(1000).unwrap())
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))),
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max_cache_bytes,
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current_cache_bytes: Arc::new(RwLock::new(0)),
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}
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}
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/// Initialize the thumbnail directories
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pub async fn initialize(&self) -> std::io::Result<()> {
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for size in ThumbnailSize::all() {
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let dir = self.thumbnails_root.join(size.dir_name());
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fs::create_dir_all(&dir).await?;
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}
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tracing::info!("🖼️ Thumbnail service initialized at {:?}", self.thumbnails_root);
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Ok(())
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}
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/// Check if a file is an image that can have thumbnails
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pub fn is_supported_image(mime_type: &str) -> bool {
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matches!(
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mime_type,
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"image/jpeg" | "image/jpg" | "image/png" | "image/gif" | "image/webp"
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)
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}
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/// Get the path where a thumbnail would be stored
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fn get_thumbnail_path(&self, file_id: &str, size: ThumbnailSize) -> PathBuf {
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self.thumbnails_root
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.join(size.dir_name())
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.join(format!("{}.webp", file_id))
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}
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/// Check if a thumbnail exists on disk
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pub async fn thumbnail_exists(&self, file_id: &str, size: ThumbnailSize) -> bool {
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let path = self.get_thumbnail_path(file_id, size);
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fs::metadata(&path).await.is_ok()
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}
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/// Get a thumbnail, generating it if needed
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///
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/// # Arguments
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/// * `file_id` - ID of the original file
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/// * `size` - Desired thumbnail size
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/// * `original_path` - Path to the original image file
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///
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/// # Returns
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/// Bytes of the thumbnail image (WebP format)
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pub async fn get_thumbnail(
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&self,
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file_id: &str,
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size: ThumbnailSize,
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original_path: &Path,
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) -> Result<Bytes, ThumbnailError> {
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let cache_key = ThumbnailCacheKey {
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file_id: file_id.to_string(),
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size,
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};
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// Check in-memory cache first
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{
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let cache = self.cache.read().await;
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if let Some(data) = cache.peek(&cache_key) {
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tracing::debug!("🔥 Thumbnail cache HIT: {} {:?}", file_id, size);
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return Ok(data.clone());
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}
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}
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// Check if thumbnail exists on disk
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let thumb_path = self.get_thumbnail_path(file_id, size);
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if fs::metadata(&thumb_path).await.is_ok() {
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// Load from disk
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let data = fs::read(&thumb_path).await
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.map_err(|e| ThumbnailError::IoError(e.to_string()))?;
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let bytes = Bytes::from(data);
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// Add to cache
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self.add_to_cache(cache_key, bytes.clone()).await;
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tracing::debug!("💾 Thumbnail loaded from disk: {} {:?}", file_id, size);
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return Ok(bytes);
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}
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// Generate thumbnail
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tracing::info!("🎨 Generating thumbnail: {} {:?}", file_id, size);
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let bytes = self.generate_thumbnail(original_path, size).await?;
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// Save to disk
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if let Some(parent) = thumb_path.parent() {
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fs::create_dir_all(parent).await
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.map_err(|e| ThumbnailError::IoError(e.to_string()))?;
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}
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fs::write(&thumb_path, &bytes).await
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.map_err(|e| ThumbnailError::IoError(e.to_string()))?;
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// Add to cache
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self.add_to_cache(cache_key, bytes.clone()).await;
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Ok(bytes)
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}
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/// Generate a thumbnail from an image file
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async fn generate_thumbnail(
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&self,
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original_path: &Path,
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size: ThumbnailSize,
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) -> Result<Bytes, ThumbnailError> {
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let path = original_path.to_path_buf();
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let max_dim = size.max_dimension();
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// Run image processing in blocking thread pool
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let result = tokio::task::spawn_blocking(move || -> Result<Vec<u8>, ThumbnailError> {
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// Load image
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let img = image::open(&path)
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.map_err(|e| ThumbnailError::ImageError(e.to_string()))?;
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// Calculate new dimensions preserving aspect ratio
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let (orig_width, orig_height) = (img.width(), img.height());
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let (new_width, new_height) = if orig_width > orig_height {
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let ratio = max_dim as f32 / orig_width as f32;
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(max_dim, (orig_height as f32 * ratio) as u32)
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} else {
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let ratio = max_dim as f32 / orig_height as f32;
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((orig_width as f32 * ratio) as u32, max_dim)
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};
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// Resize using high-quality Lanczos3 filter
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let thumbnail = img.resize(new_width, new_height, FilterType::Lanczos3);
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// Encode as WebP for smaller file size
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let mut buffer = Vec::new();
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thumbnail.write_to(
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&mut std::io::Cursor::new(&mut buffer),
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ImageFormat::WebP
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).map_err(|e| ThumbnailError::ImageError(e.to_string()))?;
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Ok(buffer)
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}).await
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.map_err(|e| ThumbnailError::TaskError(e.to_string()))?;
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result.map(Bytes::from)
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}
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/// Add a thumbnail to the in-memory cache
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async fn add_to_cache(&self, key: ThumbnailCacheKey, data: Bytes) {
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let data_size = data.len();
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// Check if adding this would exceed max cache size
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let mut current_size = self.current_cache_bytes.write().await;
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// Evict items if needed to make room
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if *current_size + data_size > self.max_cache_bytes {
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let mut cache = self.cache.write().await;
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while *current_size + data_size > self.max_cache_bytes && !cache.is_empty() {
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if let Some((_, evicted)) = cache.pop_lru() {
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*current_size = current_size.saturating_sub(evicted.len());
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}
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}
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}
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// Add to cache
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let mut cache = self.cache.write().await;
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if let Some(old) = cache.put(key, data) {
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*current_size = current_size.saturating_sub(old.len());
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}
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*current_size += data_size;
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}
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/// Generate all thumbnail sizes for a file in the background
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///
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/// This is called after file upload to pre-generate thumbnails
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pub fn generate_all_sizes_background(
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self: Arc<Self>,
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file_id: String,
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original_path: PathBuf,
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) {
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tokio::spawn(async move {
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tracing::info!("🖼️ Background thumbnail generation starting: {}", file_id);
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for size in ThumbnailSize::all() {
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match self.generate_thumbnail(&original_path, *size).await {
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Ok(bytes) => {
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// Save to disk
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let thumb_path = self.get_thumbnail_path(&file_id, *size);
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if let Some(parent) = thumb_path.parent() {
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let _ = fs::create_dir_all(parent).await;
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}
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if let Err(e) = fs::write(&thumb_path, &bytes).await {
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tracing::warn!("Failed to save thumbnail {}: {}", file_id, e);
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} else {
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tracing::debug!("✅ Generated thumbnail: {} {:?}", file_id, size);
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}
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},
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Err(e) => {
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tracing::warn!("Failed to generate thumbnail {} {:?}: {}", file_id, size, e);
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}
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}
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}
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tracing::info!("✅ Background thumbnail generation complete: {}", file_id);
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});
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}
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/// Delete all thumbnails for a file
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pub async fn delete_thumbnails(&self, file_id: &str) -> Result<(), ThumbnailError> {
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for size in ThumbnailSize::all() {
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let path = self.get_thumbnail_path(file_id, *size);
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if fs::metadata(&path).await.is_ok() {
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fs::remove_file(&path).await
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.map_err(|e| ThumbnailError::IoError(e.to_string()))?;
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}
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// Remove from cache
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let cache_key = ThumbnailCacheKey {
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file_id: file_id.to_string(),
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size: *size,
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};
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let mut cache = self.cache.write().await;
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if let Some(removed) = cache.pop(&cache_key) {
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let mut current_size = self.current_cache_bytes.write().await;
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*current_size = current_size.saturating_sub(removed.len());
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}
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}
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tracing::debug!("🗑️ Deleted thumbnails for: {}", file_id);
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Ok(())
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}
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/// Get cache statistics
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pub async fn get_stats(&self) -> ThumbnailStats {
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let cache = self.cache.read().await;
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let current_size = *self.current_cache_bytes.read().await;
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ThumbnailStats {
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cached_thumbnails: cache.len(),
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cache_size_bytes: current_size,
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max_cache_bytes: self.max_cache_bytes,
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}
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}
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}
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/// Thumbnail service errors
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#[derive(Debug, thiserror::Error)]
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pub enum ThumbnailError {
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#[error("IO error: {0}")]
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IoError(String),
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#[error("Image processing error: {0}")]
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ImageError(String),
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#[error("Task error: {0}")]
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TaskError(String),
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#[error("Unsupported image format")]
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UnsupportedFormat,
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}
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/// Statistics about the thumbnail cache
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#[derive(Debug, Clone)]
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pub struct ThumbnailStats {
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pub cached_thumbnails: usize,
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pub cache_size_bytes: usize,
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pub max_cache_bytes: usize,
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}
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