support cache-control for static resources

README.md

@@ -66,6 +66,7 @@ This is the main configuration file. The file will be compiled statically into t
   "description": "<description>",
   "plugin_identifier": "com.example.change.this.to.whatever.you.like",
   "posts_per_page": 5,
+  "cache_maxage": 86400,
   "redirects": {
     "/foo": "/bar",
     ...
@@ -87,6 +88,8 @@ This is the main configuration file. The file will be compiled statically into t
 
 `redirects`: OPTIONAL. A map of URLs where the key will be mapped to the value by Paprika using 301 redirects. This is mainly useful for migration from another blogging platform.
 
+`cache_maxage`: OPTIONAL. A value in seconds determining how long the browser should cache static resources from the blog. If omitted, the default value is a week.
+
 `hljs`: An array of language support from `highlight.js` to be included in the final binary. The full `highlight.js` is notoriously huge and there's really no reason to include a bazillion languages you will never actually use in your blog posts. This will be read by `build.rs` to generate a JS shim that will load all languages in the array to the final binary via `webpack` support for `require`.
 
 Configuration: theme_config.json

src/lib.rs

@@ -43,6 +43,10 @@ lazy_static! {
     pub static ref CONFIG: utils::Config = {
         serde_json::from_str(std::include_str!("../config.json")).unwrap()
     };
+
+    pub static ref CACHE_CONTROL_STATIC_FILE: String = {
+        format!("max-age={}", CONFIG.cache_maxage)
+    };
 }
 
 fn build_routes() -> router::Router {
@@ -97,7 +101,8 @@ async fn proxy_remote_image(req: Request, url: Url) -> MyResult<Response> {
         ResponseInit::new()
             .status(remote_resp.status())
             .headers(headers!{
-                "Content-Type" => &get_header!(remote_headers, "content-type")
+                "Content-Type" => &get_header!(remote_headers, "content-type"),
+                "Cache-Control" => &CACHE_CONTROL_STATIC_FILE
             }.as_ref())
     ).internal_err()
 }

src/render.rs

@@ -29,7 +29,8 @@ async fn serve_static(_req: Request, url: Url) -> MyResult<Response> {
             ResponseInit::new()
                 .status(200)
                 .headers(headers!{
-                    "Content-Type" => mime_guess::from_path(path).first().unwrap().essence_str()
+                    "Content-Type" => mime_guess::from_path(path).first().unwrap().essence_str(),
+                    "Cache-Control" => &crate::CACHE_CONTROL_STATIC_FILE
                 }.as_ref())
         ).internal_err()
     } else {

src/utils.rs

@@ -156,10 +156,17 @@ pub struct Config {
     pub plugin_identifier: String,
     // How many posts to show in one page
     pub posts_per_page: usize,
+    // The browser cache timeout for static resources in seconds
+    #[serde(default = "default_maxage")]
+    pub cache_maxage: u64,
     // Hard-coded redirects (for migrating old articles and such)
     // Paths here MUST include the starting "/"
     // UNLIKE in article headers
     pub redirects: Option<HashMap<String, String>>
 }
 
+fn default_maxage() -> u64 {
+    60 * 60 * 24 * 7 // default to a week
+}
+
 include!(concat!(env!("OUT_DIR"), "/build_timestamp.rs"));