feat(proxy): auto-fallback proxy selection when validation fails

open-sse/services/proxyAutoSelector.ts

@@ -0,0 +1,53 @@
+/**
+ * proxyAutoSelector.ts — Validation-layer proxy auto-selection service
+ *
+ * Wraps the low-level proxy fallback engine for use in the provider validation
+ * pipeline. When a direct validation request fails with a connectivity error,
+ * this service finds a working proxy and lets the caller retry with it.
+ *
+ * Proxies are discovered and returned for the current request only — they are
+ * NOT persisted to the proxy registry. Short-term caching (5-minute TTL) is
+ * handled by the in-memory cache in proxyFallback.ts.
+ */
+
+import { findWorkingProxy, clearProxyFallbackCache } from "@omniroute/open-sse/utils/proxyFallback.ts";
+
+// ---------------------------------------------------------------------------
+// Public API
+// ---------------------------------------------------------------------------
+
+/**
+ * Select a working proxy for the given target URL.
+ *
+ * Extracts the hostname, delegates to the underlying proxy fallback engine
+ * (candidate discovery + parallel testing + caching), and returns a working
+ * proxy URL or null if none can be found.
+ *
+ * The discovered proxy is NOT persisted to the registry — it is returned for
+ * the current request only. Short-term caching is handled in-memory within
+ * proxyFallback.ts (5-minute TTL).
+ *
+ * @param targetUrl The full URL to find a working proxy for.
+ * @returns A working proxy URL, or null if none was found.
+ */
+export async function selectProxyForValidation(targetUrl: string): Promise<string | null> {
+  if (!targetUrl) return null;
+
+  let hostname: string;
+  try {
+    hostname = new URL(targetUrl).hostname;
+    if (!hostname) return null;
+  } catch {
+    return null;
+  }
+
+  return findWorkingProxy(hostname, targetUrl);
+}
+
+/**
+ * Clear the in-memory proxy fallback cache.
+ * Useful after proxy config changes or in tests.
+ */
+export function clearProxySelectionCache(): void {
+  clearProxyFallbackCache();
+}

open-sse/utils/proxyDispatcher.ts

@@ -215,6 +215,9 @@ export function proxyConfigToUrl(
   }
 
   const config = proxyConfig as ProxyConfigObject;
+
+  // Partial / empty config object — treat as no proxy instead of crashing
+  if (!config.host) return null;
   const type = String(config.type || "http").toLowerCase();
 
   // Vercel Relay entries carry the relay URL in `host` — no dispatcher needed;
@@ -233,9 +236,6 @@ export function proxyConfigToUrl(
       "[ProxyDispatcher] SOCKS5 proxy is disabled (set ENABLE_SOCKS5_PROXY=true to enable)"
     );
   }
-  if (!config.host) {
-    throw new Error("[ProxyDispatcher] Context proxy host is required");
-  }
 
   const port = normalizePort(config.port, protocol);