From c42aec785394b40645a283384838b856beace011 Mon Sep 17 00:00:00 2001
From: Ivan Goncharov <ivan.goncharov.ua@gmail.com>
Date: Thu, 24 Oct 2024 23:59:58 +0300
Subject: [PATCH] Add Http::http1_max_headers

---
 src/server/conn.rs | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/src/server/conn.rs b/src/server/conn.rs
index 951c9ee5cd..caaa6d2059 100644
--- a/src/server/conn.rs
+++ b/src/server/conn.rs
@@ -113,6 +113,7 @@ pub struct Http<E = Exec> {
     h1_keep_alive: bool,
     h1_title_case_headers: bool,
     h1_preserve_header_case: bool,
+    h1_max_headers: Option<usize>,
     #[cfg(all(feature = "http1", feature = "runtime"))]
     h1_header_read_timeout: Option<Duration>,
     h1_writev: Option<bool>,
@@ -260,6 +261,7 @@ impl Http {
             h1_title_case_headers: false,
             h1_preserve_header_case: false,
             #[cfg(all(feature = "http1", feature = "runtime"))]
+            h1_max_headers: None,
             h1_header_read_timeout: None,
             h1_writev: None,
             #[cfg(feature = "http2")]
@@ -349,6 +351,26 @@ impl<E> Http<E> {
         self
     }
 
+    /// Set the maximum number of headers.
+    ///
+    /// When a request is received, the parser will reserve a buffer to store headers for optimal
+    /// performance.
+    ///
+    /// If server receives more headers than the buffer size, it responds to the client with
+    /// "431 Request Header Fields Too Large".
+    ///
+    /// Note that headers is allocated on the stack by default, which has higher performance. After
+    /// setting this value, headers will be allocated in heap memory, that is, heap memory
+    /// allocation will occur for each request, and there will be a performance drop of about 5%.
+    ///
+    /// Default is 100.
+    #[cfg(feature = "http1")]
+    #[cfg_attr(docsrs, doc(cfg(feature = "http1")))]
+    pub fn http1_max_headers(&mut self, val: usize) -> &mut Self {
+        self.h1_max_headers = Some(val);
+        self
+    }
+
     /// Set a timeout for reading client request headers. If a client does not
     /// transmit the entire header within this time, the connection is closed.
     ///
@@ -623,6 +645,7 @@ impl<E> Http<E> {
             h1_keep_alive: self.h1_keep_alive,
             h1_title_case_headers: self.h1_title_case_headers,
             h1_preserve_header_case: self.h1_preserve_header_case,
+            h1_max_headers: self.h1_max_headers,
             #[cfg(all(feature = "http1", feature = "runtime"))]
             h1_header_read_timeout: self.h1_header_read_timeout,
             h1_writev: self.h1_writev,
@@ -687,6 +710,9 @@ impl<E> Http<E> {
                 if self.h1_preserve_header_case {
                     conn.set_preserve_header_case();
                 }
+                if let Some(max_headers) = self.h1_max_headers {
+                    conn.set_http1_max_headers(max_headers);
+                }
                 #[cfg(all(feature = "http1", feature = "runtime"))]
                 if let Some(header_read_timeout) = self.h1_header_read_timeout {
                     conn.set_http1_header_read_timeout(header_read_timeout);