From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 15 Aug 2021 17:14:31 +0000 (+0100)
Subject: server: use Content-Length length hint
X-Git-Tag: hippotat/1.0.0~177
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=hippotat.git;a=commitdiff_plain;h=3ad612ad9f8c57d2b17235a619dedefbf157f857

server: use Content-Length length hint

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/src/bin/server.rs b/src/bin/server.rs
index b0bac2a..ceceddb 100644
--- a/src/bin/server.rs
+++ b/src/bin/server.rs
@@ -61,12 +61,17 @@ async fn handle(
 
   match async {
 
+    let get_header = |hn: &str| {
+      let mut values = req.headers().get_all(hn).iter();
+      let v = values.next().ok_or_else(|| anyhow!("missing {}", hn))?;
+      if values.next().is_some() { throw!(anyhow!("multiple {}!", hn)); }
+      let v = v.to_str().context(anyhow!("interpret {} as UTF-8", hn))?;
+      Ok::<_,AE>(v)
+    };
+
     let mkboundary = |b: &'_ _| format!("\n--{}", b).into_bytes();
     let boundary = match (||{
-      let mut ctypes = req.headers().get_all("Content-Type").iter();
-      let t = ctypes.next().ok_or_else(|| anyhow!("missing Content-Type"))?;
-      if ctypes.next().is_some() { throw!(anyhow!("several Content-Type")) }
-      let t = t.to_str().context("interpret Content-Type as utf-8")?;
+      let t = get_header("Content-Type")?;
       let t: mime::Mime = t.parse().context("parse Content-Type")?;
       if t.type_() != "multipart" { throw!(anyhow!("not multipart/")) }
       let b = mime::BOUNDARY;
@@ -84,9 +89,17 @@ async fn handle(
       },
     };
 
+    let length_hint: usize = (||{
+      let clength = get_header("Content-Length")?;
+      let clength = clength.parse().context("parse Content-Length")?;
+      Ok::<_,AE>(clength)
+    })().unwrap_or_else(
+      |e| { let _ = warnings.add(&e.wrap_err("parsing Content-Length")); 0 }
+    );
+
     let mut body = req.into_body();
     let initial = match read_limited_bytes(
-      METADATA_MAX_LEN, default(), default(), &mut body
+      METADATA_MAX_LEN, default(), length_hint, &mut body
     ).await {
       Ok(all) => all,
       Err(ReadLimitedError::Truncated { sofar,.. }) => sofar,