[pve-devel] [PATCH proxmox 1/2] notify: webhook: gotify: set Content-Length header

[Lukas Wagner]

To quote from RFC 9110 [1]:

  A user agent SHOULD send Content-Length in a request when
  the method defines a meaning for enclosed content and it
  is not sending Transfer-Encoding. For example, a user agent
  normally sends Content-Length in a POST request even when
  the value is 0 (indicating empty content).
  A user agent SHOULD NOT send a Content-Length header field
  when the request message does not contain content and the
  method semantics do not anticipate such data.

It seemed like our HTTP client lib did not set the header
automatically, which is why we should do it manually.

While most services seemed to have worked fine without setting
the header, some Microsoft services seem to require it
to accept the webhook request [2].

[1] https://datatracker.ietf.org/doc/html/rfc9110#name-content-length
[2] https://forum.proxmox.com/threads/158827

Signed-off-by: Lukas Wagner <l.wagner at proxmox.com>
---
 proxmox-notify/src/endpoints/gotify.rs  |  4 ++++
 proxmox-notify/src/endpoints/webhook.rs | 19 ++++++++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/proxmox-notify/src/endpoints/gotify.rs b/proxmox-notify/src/endpoints/gotify.rs
index 3e977131..e154daab 100644
--- a/proxmox-notify/src/endpoints/gotify.rs
+++ b/proxmox-notify/src/endpoints/gotify.rs
@@ -136,6 +136,10 @@ impl Endpoint for GotifyEndpoint {
                 format!("Bearer {}", self.private_config.token),
             ),
             ("X-Gotify-Key".into(), self.private_config.token.clone()),
+            (
+                http::header::CONTENT_LENGTH.to_string(),
+                body.len().to_string(),
+            ),
         ]);
 
         let proxy_config = context()
diff --git a/proxmox-notify/src/endpoints/webhook.rs b/proxmox-notify/src/endpoints/webhook.rs
index 34dbac54..604777c7 100644
--- a/proxmox-notify/src/endpoints/webhook.rs
+++ b/proxmox-notify/src/endpoints/webhook.rs
@@ -35,7 +35,7 @@ pub(crate) const WEBHOOK_TYPENAME: &str = "webhook";
 const HTTP_TIMEOUT: Duration = Duration::from_secs(10);
 
 #[api]
-#[derive(Serialize, Deserialize, Clone, Copy, Default)]
+#[derive(Serialize, Deserialize, Clone, Copy, Default, PartialEq)]
 #[serde(rename_all = "kebab-case")]
 /// HTTP Method to use.
 pub enum HttpMethod {
@@ -347,6 +347,23 @@ impl WebhookEndpoint {
             builder = builder.header(header.name.clone(), value);
         }
 
+        // From https://datatracker.ietf.org/doc/html/rfc9110#name-content-length :
+        //
+        // A user agent SHOULD send Content-Length in a request when the method
+        // defines a meaning for enclosed content and it is not sending
+        // Transfer-Encoding. For example, a user agent normally sends
+        // Content-Length in a POST request even when the value is 0 (indicating
+        // empty content). A user agent SHOULD NOT send a Content-Length header
+        // field when the request message does not contain content and the
+        // method semantics do not anticipate such data.
+        //
+        // -> send the header always, unless we do a get with no body (which is the expected case
+        // for GET)
+        let content_length = body.as_bytes().len();
+        if !(self.config.method == HttpMethod::Get && content_length == 0) {
+            builder = builder.header(http::header::CONTENT_LENGTH, content_length);
+        }
+
         let request = builder
             .body(body)
             .map_err(|err| self.mask_secret_in_error(err))
-- 
2.39.5