backend/Cargo.lock

@@ -2,6 +2,12 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "adler2"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "320119579fcad9c21884f5c4861d16174d0e06250625266f50fe6898340abefa"
+
 [[package]]
 name = "aho-corasick"
 version = "1.1.4"
@@ -11,6 +17,21 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "alloc-no-stdlib"
+version = "2.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc7bb162ec39d46ab1ca8c77bf72e890535becd1751bb45f64c597edb4c8c6b3"
+
+[[package]]
+name = "alloc-stdlib"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94fb8275041c72129eb51b7d0322c29b8387a0386127718b096429201a5d6ece"
+dependencies = [
+ "alloc-no-stdlib",
+]
+
 [[package]]
 name = "android_system_properties"
 version = "0.1.5"
@@ -20,6 +41,18 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "async-compression"
+version = "0.4.41"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d0f9ee0f6e02ffd7ad5816e9464499fba7b3effd01123b515c41d1697c43dad1"
+dependencies = [
+ "compression-codecs",
+ "compression-core",
+ "pin-project-lite",
+ "tokio",
+]
+
 [[package]]
 name = "atomic-waker"
 version = "1.1.2"
@@ -104,6 +137,7 @@ dependencies = [
  "axum",
  "chrono",
  "dotenvy",
+ "imagesize",
  "infer",
  "serde",
  "serde_json",
@@ -122,6 +156,27 @@ version = "2.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "843867be96c8daad0d758b57df9392b6d8d271134fce549de6ce169ff98a92af"
 
+[[package]]
+name = "brotli"
+version = "8.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4bd8b9603c7aa97359dbd97ecf258968c95f3adddd6db2f7e7a5bef101c84560"
+dependencies = [
+ "alloc-no-stdlib",
+ "alloc-stdlib",
+ "brotli-decompressor",
+]
+
+[[package]]
+name = "brotli-decompressor"
+version = "5.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "874bb8112abecc98cbd6d81ea4fa7e94fb9449648c93cc89aa40c81c24d7de03"
+dependencies = [
+ "alloc-no-stdlib",
+ "alloc-stdlib",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.20.2"
@@ -181,12 +236,39 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "compression-codecs"
+version = "0.4.37"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eb7b51a7d9c967fc26773061ba86150f19c50c0d65c887cb1fbe295fd16619b7"
+dependencies = [
+ "brotli",
+ "compression-core",
+ "flate2",
+ "memchr",
+]
+
+[[package]]
+name = "compression-core"
+version = "0.4.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "75984efb6ed102a0d42db99afb6c1948f0380d1d91808d5529916e6c08b49d8d"
+
 [[package]]
 name = "core-foundation-sys"
 version = "0.8.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "773648b94d0e5d620f64f280777445740e61fe701025087ec8b57f45c791888b"
 
+[[package]]
+name = "crc32fast"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9481c1c90cbf2ac953f07c8d4a58aa3945c425b7185c9154d67a65e4230da511"
+dependencies = [
+ "cfg-if",
+]
+
 [[package]]
 name = "deunicode"
 version = "1.6.2"
@@ -230,6 +312,16 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5baebc0774151f905a1a2cc41989300b1e6fbb29aff0ceffa1064fdd3088d582"
 
+[[package]]
+name = "flate2"
+version = "1.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "843fba2746e448b37e26a819579957415c8cef339bf08564fe8b7ddbd959573c"
+dependencies = [
+ "crc32fast",
+ "miniz_oxide",
+]
+
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -401,6 +493,12 @@ dependencies = [
  "cc",
 ]
 
+[[package]]
+name = "imagesize"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09e54e57b4c48b40f7aec75635392b12b3421fa26fe8b4332e63138ed278459c"
+
 [[package]]
 name = "indexmap"
 version = "2.14.0"
@@ -500,6 +598,16 @@ dependencies = [
  "unicase",
 ]
 
+[[package]]
+name = "miniz_oxide"
+version = "0.8.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1fa76a2c86f704bdb222d66965fb3d63269ce38518b83cb0575fca855ebb6316"
+dependencies = [
+ "adler2",
+ "simd-adler32",
+]
+
 [[package]]
 name = "mio"
 version = "1.1.1"
@@ -759,6 +867,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "simd-adler32"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "703d5c7ef118737c72f1af64ad2f6f8c5e1921f818cdcb97b8fe6fc69bf66214"
+
 [[package]]
 name = "slab"
 version = "0.4.12"
@@ -892,6 +1006,7 @@ version = "0.6.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d4e6559d53cc268e5031cd8429d05415bc4cb4aefc4aa5d6cc35fbf5b924a1f8"
 dependencies = [
+ "async-compression",
  "bitflags",
  "bytes",
  "futures-core",

backend/Cargo.toml

@@ -8,12 +8,13 @@ axum = { version = "0.8.8", features = ["multipart", "macros"] }
 chrono = { version = "0.4.44", features = ["serde"] }
 dotenvy = "0.15.7"
 infer = "0.19.0"
+imagesize = "0.14"
 serde = { version = "1.0.228", features = ["derive"] }
 serde_json = "1.0.149"
 serde_yaml = "0.9.34"
 slug = "0.1.6"
 subtle = "2.6.1"
 tokio = { version = "1.50.0", features = ["full"] }
-tower-http = { version = "0.6.8", features = ["cors", "fs"] }
+tower-http = { version = "0.6.8", features = ["cors", "fs", "compression-br", "compression-gzip"] }
 tracing = "0.1.44"
 tracing-subscriber = { version = "0.3.23", features = ["env-filter"] }

backend/src/handlers/posts.rs

@@ -4,15 +4,17 @@ use axum::{
     http::{HeaderMap, StatusCode},
 };
 use chrono::Utc;
-use std::sync::Arc;
+use std::{collections::HashMap, sync::Arc};
 use tokio::fs;
 use tracing::{error, info, warn};
 
 use crate::{
-    AppState,
+    AppState, CachedPost,
     auth::is_authed,
     error::AppError,
-    models::{CoverImage, CreatePostRequest, PostDetail, PostInfo, PostMeta, PostNeighbor},
+    models::{
+        CoverImage, CreatePostRequest, ImageDim, PostDetail, PostInfo, PostMeta, PostNeighbor,
+    },
 };
 
 const WORDS_PER_MINUTE: u32 = 200;
@@ -165,9 +167,87 @@ fn cover_from(images: &[(String, String)]) -> Option<CoverImage> {
     images.first().map(|(alt, url)| CoverImage {
         url: url.clone(),
         alt: alt.clone(),
+        w: None,
+        h: None,
     })
 }
 
+/// Probe an uploads-relative URL for image dimensions. Reads only header
+/// bytes via `imagesize::size`, off the runtime via `spawn_blocking`.
+async fn compute_dim_from_url(state: &AppState, url: &str) -> Option<ImageDim> {
+    let name = url.strip_prefix("/uploads/")?;
+    if name.is_empty()
+        || name.contains("..")
+        || name.contains('\\')
+        || name.starts_with('/')
+    {
+        return None;
+    }
+    let path = state.data_dir.join("uploads").join(name);
+    tokio::task::spawn_blocking(move || imagesize::size(&path).ok())
+        .await
+        .ok()
+        .flatten()
+        .map(|s| ImageDim {
+            w: s.width as u32,
+            h: s.height as u32,
+        })
+}
+
+/// Returns cached dim if present, else probes the file and caches the result.
+async fn dim_for_url(state: &AppState, url: &str) -> Option<ImageDim> {
+    {
+        let cache = state.image_dims_cache.read().await;
+        if let Some(d) = cache.get(url) {
+            return Some(*d);
+        }
+    }
+    let d = compute_dim_from_url(state, url).await?;
+    state
+        .image_dims_cache
+        .write()
+        .await
+        .insert(url.to_string(), d);
+    Some(d)
+}
+
+/// Returns a map of `url -> ImageDim` for the given URLs, using the cache
+/// and probing only the URLs that aren't cached yet.
+async fn dims_for_urls(state: &AppState, urls: &[String]) -> HashMap<String, ImageDim> {
+    let mut out: HashMap<String, ImageDim> = HashMap::new();
+    let mut missing: Vec<String> = Vec::new();
+    {
+        let cache = state.image_dims_cache.read().await;
+        for url in urls {
+            if out.contains_key(url) {
+                continue;
+            }
+            if let Some(d) = cache.get(url) {
+                out.insert(url.clone(), *d);
+            } else {
+                missing.push(url.clone());
+            }
+        }
+    }
+    if missing.is_empty() {
+        return out;
+    }
+    let mut newly: Vec<(String, ImageDim)> = Vec::new();
+    for url in &missing {
+        if let Some(d) = compute_dim_from_url(state, url).await {
+            newly.push((url.clone(), d));
+        }
+    }
+    if !newly.is_empty() {
+        let mut cache = state.image_dims_cache.write().await;
+        for (url, d) in &newly {
+            cache.insert(url.clone(), *d);
+            out.insert(url.clone(), *d);
+        }
+    }
+    out
+}
+
 fn excerpt_from(meta: &PostMeta, body: &str) -> String {
     if let Some(s) = meta.summary.as_ref() {
         if !s.trim().is_empty() {
@@ -204,7 +284,7 @@ fn build_post_info(slug: &str, meta: &PostMeta, body: &str) -> PostInfo {
 /// Called at startup and after any mutation (create/rename/delete).
 pub async fn rebuild_posts_cache(state: &AppState) {
     let posts_dir = state.data_dir.join("posts");
-    let mut posts: Vec<PostInfo> = Vec::new();
+    let mut posts: Vec<CachedPost> = Vec::new();
 
     let mut rd = match fs::read_dir(&posts_dir).await {
         Ok(rd) => rd,
@@ -234,7 +314,14 @@ pub async fn rebuild_posts_cache(state: &AppState) {
                     warn!("Skipping post with bad frontmatter: {}", slug);
                     continue;
                 };
-                posts.push(build_post_info(slug, &meta, &body));
+                let mut info = build_post_info(slug, &meta, &body);
+                if let Some(cover) = info.cover_image.as_mut() {
+                    if let Some(d) = dim_for_url(state, &cover.url).await {
+                        cover.w = Some(d.w);
+                        cover.h = Some(d.h);
+                    }
+                }
+                posts.push(CachedPost { info, body });
             }
             Ok(None) => break,
             Err(e) => {
@@ -244,7 +331,12 @@ pub async fn rebuild_posts_cache(state: &AppState) {
         }
     }
 
-    posts.sort_by(|a, b| b.date.cmp(&a.date).then_with(|| a.slug.cmp(&b.slug)));
+    posts.sort_by(|a, b| {
+        b.info
+            .date
+            .cmp(&a.info.date)
+            .then_with(|| a.info.slug.cmp(&b.info.slug))
+    });
     *state.posts_cache.write().await = posts;
 }
 
@@ -331,11 +423,20 @@ pub async fn create_post(
 
     info!("Post saved: {}", slug);
     let image_count = images.len() as u32;
-    let cover = cover_from(&images);
+    let mut cover = cover_from(&images);
 
     rebuild_posts_cache(&state).await;
     let (prev, next) = neighbors_from_cache(&state, &slug, true).await;
 
+    let image_urls: Vec<String> = images.iter().map(|(_, u)| u.clone()).collect();
+    let dimensions = dims_for_urls(&state, &image_urls).await;
+    if let Some(c) = cover.as_mut() {
+        if let Some(d) = dimensions.get(&c.url) {
+            c.w = Some(d.w);
+            c.h = Some(d.h);
+        }
+    }
+
     Ok(Json(PostDetail {
         slug,
         date: meta.date,
@@ -349,6 +450,7 @@ pub async fn create_post(
         image_count,
         prev,
         next,
+        dimensions,
     }))
 }
 
@@ -389,8 +491,8 @@ pub async fn list_posts(
     let cache = state.posts_cache.read().await;
     let posts: Vec<PostInfo> = cache
         .iter()
-        .filter(|p| admin || !p.draft)
+        .filter(|p| admin || !p.info.draft)
-        .cloned()
+        .map(|p| p.info.clone())
         .collect();
     Json(posts)
 }
@@ -403,7 +505,8 @@ async fn neighbors_from_cache(
     let cache = state.posts_cache.read().await;
     let visible: Vec<&PostInfo> = cache
         .iter()
-        .filter(|p| admin || !p.draft)
+        .filter(|p| admin || !p.info.draft)
+        .map(|p| &p.info)
         .collect();
     let Some(i) = visible.iter().position(|p| p.slug == slug) else {
         return (None, None);
@@ -424,30 +527,39 @@ pub async fn get_post(
 ) -> Result<Json<PostDetail>, AppError> {
     validate_slug(&slug)?;
     let admin = is_authed(&headers, &state.admin_token);
-    let file_path = state.data_dir.join("posts").join(format!("{}.md", slug));
 
-    let raw = fs::read_to_string(&file_path).await
+    let (info, body) = {
-        .map_err(|_| AppError::NotFound("Post not found".to_string()))?;
+        let cache = state.posts_cache.read().await;
-    let (meta, body) = parse_post(&raw)?;
+        let Some(p) = cache.iter().find(|p| p.info.slug == slug) else {
+            return Err(AppError::NotFound("Post not found".to_string()));
+        };
+        if p.info.draft && !admin {
+            return Err(AppError::NotFound("Post not found".to_string()));
+        }
+        (p.info.clone(), p.body.clone())
+    };
 
-    if meta.draft && !admin {
-        return Err(AppError::NotFound("Post not found".to_string()));
-    }
-
-    let images = extract_images(&body);
     let (prev, next) = neighbors_from_cache(&state, &slug, admin).await;
+
+    let image_urls: Vec<String> = extract_images(&body)
+        .into_iter()
+        .map(|(_, u)| u)
+        .collect();
+    let dimensions = dims_for_urls(&state, &image_urls).await;
+
     Ok(Json(PostDetail {
-        slug,
+        slug: info.slug,
-        date: meta.date,
+        date: info.date,
-        title: meta.title,
+        title: info.title,
-        summary: meta.summary,
+        summary: info.summary,
-        tags: meta.tags,
+        tags: info.tags,
-        draft: meta.draft,
+        draft: info.draft,
-        reading_time: reading_time(&body),
+        reading_time: info.reading_time,
         content: body,
-        cover_image: cover_from(&images),
+        cover_image: info.cover_image,
-        image_count: images.len() as u32,
+        image_count: info.image_count,
         prev,
         next,
+        dimensions,
     }))
 }

backend/src/handlers/upload.rs

@@ -89,6 +89,11 @@ pub async fn delete_upload(
             error!("Delete error for file {}: {}", filename, e);
             AppError::Internal("Delete error".to_string(), Some(e.to_string()))
         })?;
+        state
+            .image_dims_cache
+            .write()
+            .await
+            .remove(&format!("/uploads/{}", filename));
         info!("Deleted file: {}", filename);
         Ok(StatusCode::NO_CONTENT)
     } else {
@@ -227,10 +232,12 @@ pub async fn upload_file(
             AppError::Internal("Write error".to_string(), Some(e.to_string()))
         })?;
 
+        let url = format!("/uploads/{}", final_name_str);
+        // Invalidate any stale dim cache entry (matters when replacing an existing file).
+        state.image_dims_cache.write().await.remove(&url);
+
         info!("File uploaded successfully to {:?}", final_path);
-        return Ok(Json(UploadResponse {
+        return Ok(Json(UploadResponse { url }));
-            url: format!("/uploads/{}", final_name_str),
-        }));
     }
 
     warn!("Upload failed: no file found in multipart stream");

backend/src/main.rs

@@ -12,20 +12,27 @@ use axum::{
 use std::{collections::HashMap, env, path::PathBuf, sync::Arc, time::Duration};
 use tokio::sync::{Mutex, RwLock};
 use tower_http::{
+    compression::CompressionLayer,
     cors::{AllowOrigin, CorsLayer},
     services::ServeDir,
 };
 use tracing::{error, info, warn};
 
 use crate::handlers::contact::RATE_LIMIT_WINDOW_MS;
-use crate::models::PostInfo;
+use crate::models::{ImageDim, PostInfo};
+
+pub struct CachedPost {
+    pub info: PostInfo,
+    pub body: String,
+}
 
 pub struct AppState {
     pub admin_token: String,
     pub data_dir: PathBuf,
     pub cookie_secure: bool,
     pub post_lock: Mutex<()>,
-    pub posts_cache: RwLock<Vec<PostInfo>>,
+    pub posts_cache: RwLock<Vec<CachedPost>>,
+    pub image_dims_cache: RwLock<HashMap<String, ImageDim>>,
     pub contact_rate_limit: Mutex<HashMap<String, Vec<i64>>>,
 }
 
@@ -67,6 +74,7 @@ async fn main() {
         cookie_secure,
         post_lock: Mutex::new(()),
         posts_cache: RwLock::new(Vec::new()),
+        image_dims_cache: RwLock::new(HashMap::new()),
         contact_rate_limit: Mutex::new(HashMap::new()),
     });
 
@@ -97,6 +105,10 @@ async fn main() {
         None => CorsLayer::new(),
     };
 
+    // JSON routes get a tight 1 MB cap; the upload route keeps 50 MB.
+    const JSON_BODY_LIMIT: usize = 1024 * 1024;
+    const UPLOAD_BODY_LIMIT: usize = 50 * 1024 * 1024;
+
     let app = Router::new()
         .route("/api/auth/login", post(handlers::auth::login))
         .route("/api/auth/logout", post(handlers::auth::logout))
@@ -118,7 +130,11 @@ async fn main() {
             "/api/uploads/{filename}",
             delete(handlers::upload::delete_upload),
         )
-        .route("/api/upload", post(handlers::upload::upload_file))
+        .route(
+            "/api/upload",
+            post(handlers::upload::upload_file)
+                .layer(DefaultBodyLimit::max(UPLOAD_BODY_LIMIT)),
+        )
         .route("/api/contact", post(handlers::contact::submit_contact))
         .route("/api/messages", get(handlers::contact::list_messages))
         .route(
@@ -127,7 +143,8 @@ async fn main() {
         )
         .route("/healthz", get(|| async { "ok" }))
         .nest_service("/uploads", ServeDir::new(uploads_dir))
-        .layer(DefaultBodyLimit::max(50 * 1024 * 1024))
+        .layer(DefaultBodyLimit::max(JSON_BODY_LIMIT))
+        .layer(CompressionLayer::new().br(true).gzip(true))
         .layer(cors)
         .with_state(state);
 

backend/src/models.rs

@@ -1,5 +1,6 @@
 use chrono::NaiveDate;
 use serde::{Deserialize, Serialize};
+use std::collections::HashMap;
 
 #[derive(Serialize, Deserialize, Clone)]
 pub struct ContactLink {
@@ -80,10 +81,20 @@ pub struct PostMeta {
     pub draft: bool,
 }
 
+#[derive(Serialize, Clone, Copy)]
+pub struct ImageDim {
+    pub w: u32,
+    pub h: u32,
+}
+
 #[derive(Serialize, Clone)]
 pub struct CoverImage {
     pub url: String,
     pub alt: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub w: Option<u32>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub h: Option<u32>,
 }
 
 #[derive(Serialize, Clone)]
@@ -129,6 +140,8 @@ pub struct PostDetail {
     pub prev: Option<PostNeighbor>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub next: Option<PostNeighbor>,
+    #[serde(skip_serializing_if = "HashMap::is_empty")]
+    pub dimensions: HashMap<String, ImageDim>,
 }
 
 #[derive(Deserialize)]