Counting number of times an HTTPS endpoint has dropped connection

[nickguo]

Hello, I am sending POST requests every second to the same HTTPS endpoint via ureq::Agent. Is there a way to detect whether the request was sent on a resumed connection or a new connection?

Context:
Despite my frequent requests, I suspect the server is closing the connection. I can see from my debug logs a lot of

DEBUG ureq::unit] dropping stream from pool; closed by server: Stream(RustlsStream)
DEBUG ureq::stream] dropping stream: Stream(RustlsStream)
DEBUG ureq::stream] connecting to ...
...
DEBUG ureq::unit] dropping stream from pool; closed by server: Stream(RustlsStream)
DEBUG ureq::stream] dropping stream: Stream(RustlsStream)
DEBUG ureq::stream] connecting to ...

But I would like to detect these events programmatically.

Code:
I have asked the web service's team if I should send HTTP KeepAlive header, and they said they do not support it.

struct MyStruct {
    ureq_agent: Agent,
}

impl MyStruct {
    fn new() -> Self {
        Self {
            ureq_agent: Agent::new(),
        }
    } 

    fn send_post() {
        let response = self
            .ureq_agent
            .post(&"https://problematic_url.com)
            .set("Content-Type", "application/json")
            .send_string(&"Some Data")
            .unwrap();
        // get connection new or resumed status from response subfield?
    }
}

[algesten]

Currently there isn't a way to know whether a connection was reused from the pool or not. We could probably provide an API for this quite easily. We would add it as a new function in ResponseExt. Something like reused_connection(&self) -> bool

[nickguo]

Appreciate your fast reply 🙏

I poked around the codebase and found:

• reconnect attempt is decided here

  ureq/src/pool.rs

  Line 42 in 7ff0e8a

  return Ok(conn);

• we could change the signature to return Result<(Connection, bool), Error>
• we bubble up the bool to the eventual run caller

  ureq/src/run.rs

  Line 130 in 7ff0e8a

  let mut connection = connect(agent, config, &uri, timings)?;

  and assign the new ResponseExt bool field struct into extensions_mut as you suggested.
• if the reused connection fails for whatever reason, I assume somewhere inside flow_run will return an Error and the request is retried according to policy. Upon retry, the bool should now return false for new connection.

Would you be open to me contributing a PR to add this functionality? Open to all your advice and feedback 🙂

[algesten]

I poked around the codebase and found:

* reconnect attempt is decided here https://github.com/algesten/ureq/blob/7ff0e8a8b6b22a2ed3016db152a7b07fdb8c876c/src/pool.rs#L42
* we could change the signature to return `Result<(Connection, bool), Error>`

Sounds good!

* we bubble up the bool to the eventual `run` caller https://github.com/algesten/ureq/blob/7ff0e8a8b6b22a2ed3016db152a7b07fdb8c876c/src/run.rs#L130
   and assign the new ResponseExt bool field struct into `extensions_mut` as you suggested.

Yep. You need a new wrapper struct to put into the extensions_mut.

* if the reused connection fails for whatever reason, I assume somewhere inside `flow_run` will return an Error and the request is retried according to policy.  Upon retry, the bool should now return false for new connection.

ureq 3 doesn't have any built-in retry logic, but yes. The result would be exactly what you describe for the caller.

Would you be open to me contributing a PR to add this functionality? Open to all your advice and feedback 🙂

Go for it! :D

[nickguo]

awesome thank you!! working on it 🫡