eporner: play through a redirect proxy; the signed CDN links expire after 2h

Expired eporner mp4 links are answered with a 302 to static.eporner.com/
na.mp4, a one-minute "watch it on eporner.com" clip. The links expire
exactly two hours after the /xhr/video call, so anything played from a
favourite, history entry or a list left open past that hit the decoy.

New /proxy/eporner/{alnum_id}/{height} re-resolves the hash/xhr chain at
play time and 302s to the matching (else best) quality. The eporner
provider and melonstube's eporner destinations now emit these proxy URLs;
verified app clients get the best quality as video.url via the existing
redirect-proxy rule. Verified live: proxy -> fresh CDN link -> 206 video/mp4
for app and non-app clients.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MUYdCh2nCVsQYgJAT7gwSi

src/proxies/eporner.rs

@@ -0,0 +1,65 @@
+use ntex::web;
+
+use crate::util::eporner_resolve::resolve_ranked;
+use crate::util::requester::Requester;
+
+#[derive(Debug, Clone)]
+pub struct EpornerProxy {}
+
+impl EpornerProxy {
+    pub fn new() -> Self {
+        EpornerProxy {}
+    }
+
+    /// `{alnum_id}[/{height}]`.
+    fn parse_endpoint(endpoint: &str) -> Option<(String, Option<u32>)> {
+        let mut parts = endpoint.trim_matches('/').split('/');
+        let alnum_id = parts.next().filter(|id| {
+            !id.is_empty() && id.chars().all(|c| c.is_ascii_alphanumeric())
+        })?;
+        let height = parts.next().and_then(|h| h.parse::<u32>().ok());
+        Some((alnum_id.to_string(), height))
+    }
+
+    /// Resolves a fresh signed mp4 at play time. The CDN URLs expire two hours
+    /// after the `/xhr/video` call, and an expired one is answered with a 302
+    /// to `static.eporner.com/na.mp4`, a one-minute "watch it on eporner.com"
+    /// clip; so a stale listing, favourite or history entry plays that clip.
+    pub async fn get_video_url(
+        &self,
+        endpoint: String,
+        requester: web::types::State<Requester>,
+    ) -> String {
+        let Some((alnum_id, height)) = Self::parse_endpoint(&endpoint) else {
+            return String::new();
+        };
+        let page_url = format!("https://www.eporner.com/video-{alnum_id}/");
+        let mut requester = requester.get_ref().clone();
+        let Some(ranked) = resolve_ranked(&mut requester, &alnum_id, &page_url).await else {
+            return String::new();
+        };
+        height
+            .and_then(|h| ranked.iter().find(|(height, _)| *height == h))
+            .or_else(|| ranked.first())
+            .map(|(_, format)| format.url.clone())
+            .unwrap_or_default()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::EpornerProxy;
+
+    #[test]
+    fn parses_id_and_optional_height() {
+        assert_eq!(
+            EpornerProxy::parse_endpoint("exfeTXHuL1x/720"),
+            Some(("exfeTXHuL1x".to_string(), Some(720)))
+        );
+        assert_eq!(
+            EpornerProxy::parse_endpoint("/exfeTXHuL1x/"),
+            Some(("exfeTXHuL1x".to_string(), None))
+        );
+        assert_eq!(EpornerProxy::parse_endpoint("../etc"), None);
+    }
+}