rspamd support

[MHillyer]

No description provided.

[djc]

@wez here's my super minimal rspamd client:

pub struct RspamdClient {
    client: reqwest::Client,
    url: String,
}

impl RspamdClient {
    pub fn new(rspamd_origin: &str) -> anyhow::Result<Self> {
        Ok(Self {
            client: reqwest::Client::new(),
            url: format!("{}/checkv2", rspamd_origin),
        })
    }

    pub async fn check(
        &self,
        from: &str,
        ip: IpAddr,
        helo: Option<&str>,
        message: Bytes,
    ) -> Result<Response, reqwest::Error> {
        let mut request = self
            .client
            .get(&self.url)
            .header("From", from)
            .header("IP", ip.to_string());
        if let Some(helo) = helo {
            request = request.header("Helo", helo);
        }

        request
            .body(message)
            .send()
            .await?
            .error_for_status()?
            .json::<Response>()
            .await
    }
}

#[derive(Deserialize)]
pub struct Response {
    pub score: f32,
}

[wez]

Thanks! I think we could fairly trivially write a little lua script that lives in assets/policy-extras/rspamd.lua that uses https://docs.kumomta.com/reference/kumo.http/build_client/ (which is a wrapper around reqwest) under the covers. Just pass in a Message and it can extract the ip from the metadata and the from field from the message sender. https://docs.kumomta.com/reference/connectionmeta/

We don't currently capture the ehlo string in the connection metadata, but we probably should and then we could use that here as well.