Mirrors/chatmail-core
1
0
Fork 0
mirror of https://github.com/chatmail/core.git synced 2026-04-17 13:36:30 +03:00
Code Issues Packages Projects Releases Wiki Activity

feat: implement stale-while-revalidate for HTTP cache

Browse Source
This commit is contained in:
link2xt
2024-12-12 11:17:13 +00:00
committed by l
parent cb2157822a
commit 2f976d8050
2 changed files with 100 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

118
src/net/http.rs
View File

@@ -93,19 +93,28 @@ where
Ok(sender)
}
/// Converts the URL to expiration timestamp.
fn http_url_cache_expires(url: &str, mimetype: Option<&str>) -> i64 {
/// Converts the URL to expiration and stale timestamps.
fn http_url_cache_timestamps(url: &str, mimetype: Option<&str>) -> (i64, i64) {
let now = time();
if url.ends_with(".xdc") {
// WebXDCs expire in 5 weeks.
now + 3600 * 24 * 35
let expires = now + 3600 * 24 * 35;
let stale = if url.ends_with(".xdc") {
// WebXDCs are never stale, they just expire.
expires
} else if mimetype.is_some_and(|s| s.starts_with("image/")) {
// Cache images for 1 day.
//
// As of 2024-12-12 WebXDC icons at <https://webxdc.org/apps/>
// use the same path for all app versions,
// so may change, but it is not critical if outdated icon is displayed.
now + 3600 * 24
} else {
// Cache everything else for 1 hour.
// Revalidate everything else after 1 hour.
//
// This includes HTML, CSS and JS.
now + 3600
}
};
(expires, stale)
}
/// Places the binary into HTTP cache.
@@ -117,14 +126,16 @@ async fn http_cache_put(context: &Context, url: &str, response: &Response) -> Re
)
.await?;
let (expires, stale) = http_url_cache_timestamps(url, response.mimetype.as_deref());
context
.sql
.insert(
"INSERT OR REPLACE INTO http_cache (url, expires, blobname, mimetype, encoding)
VALUES (?, ?, ?, ?, ?)",
"INSERT OR REPLACE INTO http_cache (url, expires, stale, blobname, mimetype, encoding)
VALUES (?, ?, ?, ?, ?, ?)",
(
url,
http_url_cache_expires(url, response.mimetype.as_deref()),
expires,
stale,
blob.as_name(),
response.mimetype.as_deref().unwrap_or_default(),
response.encoding.as_deref().unwrap_or_default(),
@@ -136,18 +147,22 @@ async fn http_cache_put(context: &Context, url: &str, response: &Response) -> Re
}
/// Retrieves the binary from HTTP cache.
async fn http_cache_get(context: &Context, url: &str) -> Result<Option<Response>> {
let Some((blob_name, mimetype, encoding)) = context
///
/// Also returns if the response is stale and should be revalidated in the background.
async fn http_cache_get(context: &Context, url: &str) -> Result<Option<(Response, bool)>> {
let now = time();
let Some((blob_name, mimetype, encoding, is_stale)) = context
.sql
.query_row_optional(
"SELECT blobname, mimetype, encoding
"SELECT blobname, mimetype, encoding, stale
FROM http_cache WHERE url=? AND expires > ?",
(url, time()),
(url, now),
|row| {
let blob_name: String = row.get(0)?;
let mimetype: Option<String> = Some(row.get(1)?).filter(|s: &String| !s.is_empty());
let encoding: Option<String> = Some(row.get(2)?).filter(|s: &String| !s.is_empty());
Ok((blob_name, mimetype, encoding))
let stale_timestamp: i64 = row.get(3)?;
Ok((blob_name, mimetype, encoding, now > stale_timestamp))
},
)
.await?
@@ -170,14 +185,20 @@ async fn http_cache_get(context: &Context, url: &str) -> Result<Option<Response>
}
};
let expires = http_url_cache_expires(url, mimetype.as_deref());
let (expires, _stale) = http_url_cache_timestamps(url, mimetype.as_deref());
let response = Response {
blob,
mimetype,
encoding,
};
// Update expiration timestamp.
// Update expiration timestamp
// to prevent deletion of the file still in use.
//
// We do not update stale timestamp here
// as we have not revalidated the response.
// Stale timestamp is updated only
// when the URL is sucessfully fetched.
context
.sql
.execute(
@@ -186,7 +207,7 @@ async fn http_cache_get(context: &Context, url: &str) -> Result<Option<Response>
)
.await?;
Ok(Some(response))
Ok(Some((response, is_stale)))
}
/// Removes expired cache entries.
@@ -205,14 +226,10 @@ pub(crate) async fn http_cache_cleanup(context: &Context) -> Result<()> {
Ok(())
}
/// Retrieves the binary contents of URL using HTTP GET request.
pub async fn read_url_blob(context: &Context, original_url: &str) -> Result<Response> {
if let Some(response) = http_cache_get(context, original_url).await? {
info!(context, "Returning {original_url:?} from cache.");
return Ok(response);
}
info!(context, "Not found {original_url:?} in cache.");
/// Fetches URL and updates the cache.
///
/// URL is fetched regardless of whether there is an existing result in the cache.
async fn fetch_url(context: &Context, original_url: &str) -> Result<Response> {
let mut url = original_url.to_string();
// Follow up to 10 http-redirects
@@ -273,6 +290,31 @@ pub async fn read_url_blob(context: &Context, original_url: &str) -> Result<Resp
Err(anyhow!("Followed 10 redirections"))
}
/// Retrieves the binary contents of URL using HTTP GET request.
pub async fn read_url_blob(context: &Context, url: &str) -> Result<Response> {
if let Some((response, is_stale)) = http_cache_get(context, url).await? {
info!(context, "Returning {url:?} from cache.");
if is_stale {
let context = context.clone();
let url = url.to_string();
tokio::spawn(async move {
// Fetch URL in background to update the cache.
info!(context, "Fetching stale {url:?} in background.");
if let Err(err) = fetch_url(&context, &url).await {
warn!(context, "Failed to revalidate {url:?}: {err:#}.");
}
});
}
// Return stale result.
return Ok(response);
}
info!(context, "Not found {url:?} in cache, fetching.");
let response = fetch_url(context, url).await?;
Ok(response)
}
/// Sends an empty POST request to the URL.
///
/// Returns response text and whether request was successful or not.
@@ -401,43 +443,47 @@ mod tests {
assert_eq!(http_cache_get(t, xdc_pixel_url).await?, None);
assert_eq!(
http_cache_get(t, "https://webxdc.org/").await?,
Some(html_response.clone())
Some((html_response.clone(), false))
);
http_cache_put(t, xdc_editor_url, &xdc_response).await?;
http_cache_put(t, xdc_pixel_url, &xdc_response).await?;
assert_eq!(
http_cache_get(t, xdc_editor_url).await?,
Some(xdc_response.clone())
Some((xdc_response.clone(), false))
);
assert_eq!(
http_cache_get(t, xdc_pixel_url).await?,
Some(xdc_response.clone())
Some((xdc_response.clone(), false))
);
assert_eq!(
http_cache_get(t, "https://webxdc.org/").await?,
Some(html_response.clone())
Some((html_response.clone(), false))
);
// HTML expires after 1 hour, but .xdc does not.
// HTML is stale after 1 hour, but .xdc is not.
SystemTime::shift(Duration::from_secs(3600 + 100));
assert_eq!(http_cache_get(t, "https://webxdc.org/").await?, None);
assert_eq!(
http_cache_get(t, "https://webxdc.org/").await?,
Some((html_response.clone(), true))
);
assert_eq!(
http_cache_get(t, xdc_editor_url).await?,
Some(xdc_response.clone())
Some((xdc_response.clone(), false))
);
// Expired cache entry can be renewed
// Stale cache entry can be renewed
// even before housekeeping removes old one.
http_cache_put(t, "https://webxdc.org/", &html_response).await?;
assert_eq!(
http_cache_get(t, "https://webxdc.org/").await?,
Some(html_response.clone())
Some((html_response.clone(), false))
);
// 35 days later pixel .xdc expires because we did not request it for 35 days and 1 hour.
// But editor is still there because we did not request it for just 35 days.
// We have not renewed the editor however, so it becomes stale.
SystemTime::shift(Duration::from_secs(3600 * 24 * 35 - 100));
// Run housekeeping to test that it does not delete the blob too early.
@@ -445,7 +491,7 @@ mod tests {
assert_eq!(
http_cache_get(t, xdc_editor_url).await?,
Some(xdc_response.clone())
Some((xdc_response.clone(), true))
);
assert_eq!(http_cache_get(t, xdc_pixel_url).await?, None);

18
src/sql/migrations.rs
View File

@@ -1103,6 +1103,24 @@ CREATE INDEX msgs_status_updates_index2 ON msgs_status_updates (uid);
.await?;
}
inc_and_check(&mut migration_version, 126)?;
if dbversion < migration_version {
// Recreate http_cache table with new `stale` column.
sql.execute_migration(
"DROP TABLE http_cache;
CREATE TABLE http_cache (
url TEXT PRIMARY KEY,
expires INTEGER NOT NULL, -- When the cache entry is considered expired, timestamp in seconds.
stale INTEGER NOT NULL, -- When the cache entry is considered stale, timestamp in seconds.
blobname TEXT NOT NULL,
mimetype TEXT NOT NULL DEFAULT '', -- MIME type extracted from Content-Type header.
encoding TEXT NOT NULL DEFAULT '' -- Encoding from Content-Type header.
) STRICT",
migration_version,
)
.await?;
}
let new_version = sql
.get_raw_config_int(VERSION_CFG)
.await?