Middle Proxy is so real

src/transport/middle_proxy/secret.rs

@@ -0,0 +1,76 @@
+use std::time::Duration;
+
+use tracing::{debug, info, warn};
+
+use crate::error::{ProxyError, Result};
+
+/// Fetch Telegram proxy-secret binary.
+pub async fn fetch_proxy_secret(cache_path: Option<&str>) -> Result<Vec<u8>> {
+    let cache = cache_path.unwrap_or("proxy-secret");
+
+    if let Ok(metadata) = tokio::fs::metadata(cache).await {
+        if let Ok(modified) = metadata.modified() {
+            let age = std::time::SystemTime::now()
+                .duration_since(modified)
+                .unwrap_or(Duration::from_secs(u64::MAX));
+            if age < Duration::from_secs(86_400) {
+                if let Ok(data) = tokio::fs::read(cache).await {
+                    if data.len() >= 32 {
+                        info!(
+                            path = cache,
+                            len = data.len(),
+                            age_hours = age.as_secs() / 3600,
+                            "Loaded proxy-secret from cache"
+                        );
+                        return Ok(data);
+                    }
+                    warn!(
+                        path = cache,
+                        len = data.len(),
+                        "Cached proxy-secret too short"
+                    );
+                }
+            }
+        }
+    }
+
+    info!("Downloading proxy-secret from core.telegram.org...");
+    let data = download_proxy_secret().await?;
+
+    if let Err(e) = tokio::fs::write(cache, &data).await {
+        warn!(error = %e, "Failed to cache proxy-secret (non-fatal)");
+    } else {
+        debug!(path = cache, len = data.len(), "Cached proxy-secret");
+    }
+
+    Ok(data)
+}
+
+async fn download_proxy_secret() -> Result<Vec<u8>> {
+    let resp = reqwest::get("https://core.telegram.org/getProxySecret")
+        .await
+        .map_err(|e| ProxyError::Proxy(format!("Failed to download proxy-secret: {e}")))?;
+
+    if !resp.status().is_success() {
+        return Err(ProxyError::Proxy(format!(
+            "proxy-secret download HTTP {}",
+            resp.status()
+        )));
+    }
+
+    let data = resp
+        .bytes()
+        .await
+        .map_err(|e| ProxyError::Proxy(format!("Read proxy-secret body: {e}")))?
+        .to_vec();
+
+    if data.len() < 32 {
+        return Err(ProxyError::Proxy(format!(
+            "proxy-secret too short: {} bytes (need >= 32)",
+            data.len()
+        )));
+    }
+
+    info!(len = data.len(), "Downloaded proxy-secret OK");
+    Ok(data)
+}