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2026-07-13 13:39:12 +08:00

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TypeScript

/**
* proxyFallback.ts — Smart Proxy Fallback for Provider Validation
*
* When a direct fetch to a provider fails and no explicit proxy was configured,
* this module automatically gathers proxy candidates from all available sources,
* tests them in parallel against the provider URL, and returns the first working one.
* Results are cached per target URL to avoid repeated probing without letting
* a failed path poison a different endpoint on the same API host.
*/
import { fetch as undiciFetch } from "undici";
import { createProxyDispatcher, normalizeProxyUrl } from "./proxyDispatcher.ts";
import { resolveProxyForScopeFromRegistry, listProxies, listOneproxyProxies } from "@/lib/localDb";
import { isFeatureFlagEnabled } from "@/shared/utils/featureFlags";
// ---------------------------------------------------------------------------
// Types
// ---------------------------------------------------------------------------
interface CacheEntry {
proxyUrl: string;
expiresAt: number;
}
interface ProxyShape {
type: string;
host: string;
port: number;
username?: string;
password?: string;
}
// ---------------------------------------------------------------------------
// Cache
// ---------------------------------------------------------------------------
const PROXY_FALLBACK_CACHE = new Map<string, CacheEntry>();
const CACHE_TTL_MS = 5 * 60 * 1000; // 5 minutes
type ProxyFallbackTestHooks = {
getProxyCandidates?: (targetUrl?: string) => Promise<string[]>;
testSingleProxy?: (
proxyUrl: string,
targetUrl: string,
timeoutMs?: number
) => Promise<{ ok: boolean; latencyMs: number | null }>;
};
let proxyFallbackTestHooks: ProxyFallbackTestHooks | null = null;
/**
* Clear the in-memory proxy fallback cache.
* Useful for testing or admin operations.
*/
export function clearProxyFallbackCache(): void {
PROXY_FALLBACK_CACHE.clear();
}
export function __setProxyFallbackTestHooks(hooks: ProxyFallbackTestHooks | null): void {
proxyFallbackTestHooks = hooks;
}
// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------
/**
* Build a full proxy URL string from a proxy record's fields.
*/
function proxyRecordToUrl(proxy: ProxyShape): string {
const auth =
proxy.username
? `${encodeURIComponent(proxy.username)}:${encodeURIComponent(proxy.password || "")}@`
: "";
return `${proxy.type}://${auth}${proxy.host}:${proxy.port}`;
}
function cacheKeyForTarget(targetHostname: string, targetUrl: string): string {
try {
const url = new URL(targetUrl);
const normalizedPath = `${url.pathname || "/"}${url.search}`;
return `${url.protocol}//${url.host}${normalizedPath}`;
} catch {
return targetHostname.toLowerCase();
}
}
/**
* Resolve the environment proxy URL (HTTP_PROXY / HTTPS_PROXY / ALL_PROXY)
* for the given target URL. Returns null if no env proxy is configured or
* the target matches NO_PROXY.
*/
function resolveEnvProxyUrl(targetUrl: string): string | null {
// Honour NO_PROXY
const noProxy = process.env.NO_PROXY || process.env.no_proxy;
if (noProxy) {
let hostname: string | undefined;
try {
hostname = new URL(targetUrl).hostname.toLowerCase();
} catch {
return null;
}
const patterns = noProxy
.split(",")
.map((p) => p.trim().toLowerCase())
.filter(Boolean);
const match = patterns.some((pattern) => {
if (pattern === "*") return true;
if (pattern.includes("*")) {
const re = new RegExp(
"^" +
pattern
.split("*")
.map((s) => s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&"))
.join(".*") +
"$"
);
return re.test(hostname!);
}
return hostname === pattern || hostname!.endsWith(`.${pattern}`);
});
if (match) return null;
}
let protocol: string;
try {
protocol = new URL(targetUrl).protocol;
} catch {
return null;
}
const proxyUrl =
protocol === "https:"
? process.env.HTTPS_PROXY ||
process.env.https_proxy ||
process.env.ALL_PROXY ||
process.env.all_proxy
: process.env.HTTP_PROXY ||
process.env.http_proxy ||
process.env.ALL_PROXY ||
process.env.all_proxy;
if (!proxyUrl) return null;
try {
return normalizeProxyUrl(proxyUrl, "environment proxy");
} catch {
return null;
}
}
// ---------------------------------------------------------------------------
// Candidate collection
// ---------------------------------------------------------------------------
/**
* Collect all available proxy candidates from every source:
* 1. Global proxy from registry
* 2. All user-configured proxies from the proxy registry
* 3. Top 5 1proxy marketplace proxies
* 4. Environment proxy (HTTP_PROXY / HTTPS_PROXY / ALL_PROXY)
*
* @param targetUrl Optional. When provided, the env proxy is resolved for this URL.
* @returns Deduplicated array of normalized proxy URLs.
*/
export async function getProxyCandidates(targetUrl?: string): Promise<string[]> {
const candidates = new Set<string>();
// 1. Global proxy from registry
try {
const globalProxy = await resolveProxyForScopeFromRegistry("global");
if (globalProxy?.proxy) {
candidates.add(proxyRecordToUrl(globalProxy.proxy as ProxyShape));
}
} catch {
// Table may not exist yet
}
// 2. All user-configured proxies (include secrets for auth)
try {
const allProxies = await listProxies({ includeSecrets: true });
for (const p of allProxies) {
if (p.host && p.port) {
candidates.add(proxyRecordToUrl(p as unknown as ProxyShape));
}
}
} catch {
// Table may not exist yet
}
// 3. Top 5 1proxy marketplace proxies
try {
const oneproxyProxies = await listOneproxyProxies({ limit: 5 });
for (const p of oneproxyProxies) {
if (p.host && p.port) {
candidates.add(proxyRecordToUrl(p as unknown as ProxyShape));
}
}
} catch {
// Table may not exist yet
}
// 4. Environment proxy (needs targetUrl to determine protocol)
if (targetUrl) {
try {
const envProxy = resolveEnvProxyUrl(targetUrl);
if (envProxy) candidates.add(envProxy);
} catch {
// Ignore env proxy errors
}
}
return Array.from(candidates);
}
// ---------------------------------------------------------------------------
// Proxy testing
// ---------------------------------------------------------------------------
/**
* Test a single proxy against a target URL.
* Makes a lightweight HEAD request through the proxy with a short timeout.
*
* @param proxyUrl The proxy URL (e.g. "http://1.2.3.4:8080")
* @param targetUrl The provider URL to test reachability to
* @param timeoutMs Timeout in milliseconds (default 3000)
* @returns Object with success status and latency in ms
*/
export async function testSingleProxy(
proxyUrl: string,
targetUrl: string,
timeoutMs = 3000
): Promise<{ ok: boolean; latencyMs: number | null }> {
const start = Date.now();
try {
const controller = new AbortController();
const timeout = setTimeout(() => controller.abort(), timeoutMs);
const dispatcher = createProxyDispatcher(proxyUrl);
await undiciFetch(targetUrl, {
method: "HEAD",
signal: controller.signal,
dispatcher,
headers: {
"User-Agent": "OmniRoute/1.0",
},
});
clearTimeout(timeout);
const latencyMs = Date.now() - start;
// Any response (including 4xx) means the proxy can reach the target
return { ok: true, latencyMs };
} catch {
return { ok: false, latencyMs: null };
}
}
/**
* Bulk test multiple proxies against a target URL.
* Does NOT cache results (for manual API use).
*
* @param targetUrl The provider URL to test reachability to
* @param proxyUrls Array of proxy URLs to test
* @returns Array of results, one per proxy
*/
export async function testProxiesAgainstTarget(
targetUrl: string,
proxyUrls: string[]
): Promise<Array<{ proxyUrl: string; ok: boolean; latencyMs: number | null }>> {
if (proxyUrls.length === 0) return [];
const results = await Promise.allSettled(
proxyUrls.map(async (proxyUrl) => {
const result = await testSingleProxy(proxyUrl, targetUrl);
return { proxyUrl, ...result };
})
);
return results.map((r) =>
r.status === "fulfilled"
? r.value
: { proxyUrl: "unknown", ok: false, latencyMs: null }
);
}
// ---------------------------------------------------------------------------
// Find working proxy (with caching)
// ---------------------------------------------------------------------------
/**
* Find a working proxy for the given target hostname and URL.
*
* Collects all proxy candidates, tests them in parallel against the provider
* URL, and returns the first one that responds. Results are cached per target
* URL for 5 minutes to avoid repeated probing while keeping different
* endpoints on a shared host independent.
*
* @param targetHostname The provider hostname (used as cache key)
* @param targetUrl The full provider URL to test against
* @returns A working proxy URL, or null if none found
*/
export async function findWorkingProxy(
targetHostname: string,
targetUrl: string
): Promise<string | null> {
if (!targetHostname) return null;
const cacheKey = cacheKeyForTarget(targetHostname, targetUrl);
// Check cache first
const cached = PROXY_FALLBACK_CACHE.get(cacheKey);
if (cached) {
if (cached.expiresAt > Date.now()) {
// Cached hit — return the proxy (or null if previously all failed)
return cached.proxyUrl || null;
}
// Expired entry — remove it and re-probe
PROXY_FALLBACK_CACHE.delete(cacheKey);
}
// Collect candidates
const candidates = await (proxyFallbackTestHooks?.getProxyCandidates ?? getProxyCandidates)(
targetUrl
);
if (candidates.length === 0) {
return null;
}
// Test all in parallel, return first that works
const results = await Promise.allSettled(
candidates.map(async (proxyUrl) => {
const { ok } = await (proxyFallbackTestHooks?.testSingleProxy ?? testSingleProxy)(
proxyUrl,
targetUrl
);
return { proxyUrl, ok };
})
);
const working = results.find(
(r) => r.status === "fulfilled" && r.value.ok
);
if (working && working.status === "fulfilled") {
const proxyUrl = working.value.proxyUrl;
// Cache the working proxy
PROXY_FALLBACK_CACHE.set(cacheKey, {
proxyUrl,
expiresAt: Date.now() + CACHE_TTL_MS,
});
return proxyUrl;
}
// All failed — cache the negative result to avoid re-probing too often
PROXY_FALLBACK_CACHE.set(cacheKey, {
proxyUrl: "",
expiresAt: Date.now() + CACHE_TTL_MS,
});
return null;
}
// ---------------------------------------------------------------------------
// Auto-selection fallback (used by resolveProxyForConnection as step 11)
// ---------------------------------------------------------------------------
/**
* Try to auto-select a working proxy as a last-resort fallback when no
* explicit proxy was configured. This wraps getProxyCandidates() and
* findWorkingProxy() into a single call that returns a result compatible
* with resolveProxyForConnection()'s return type.
*
* @param _connectionId Optional connection ID (reserved for future use).
* @returns A proxy resolution result with level "autoSelect", or null.
*/
export async function selectWorkingProxyFallback(
_connectionId?: string
): Promise<{
proxy: { type: string; host: string; port: number; username: string; password: string } | null;
level: string;
levelId: string | null;
source: string;
} | null> {
// #3332: auto-selection is opt-in. Without this gate, any single proxy in the
// registry silently becomes a global fallback for ALL connections (ignoring
// assignments / per-connection proxy_enabled). Default OFF — only run when the
// operator explicitly enables PROXY_AUTO_SELECT_ENABLED.
if (!isFeatureFlagEnabled("PROXY_AUTO_SELECT_ENABLED")) return null;
const candidates = await getProxyCandidates();
if (candidates.length === 0) return null;
// Use a well-known AI API endpoint as the test target. If a proxy can
// reach this, it is likely suitable for routing AI traffic.
const targetUrl = "https://api.openai.com/v1/models";
const targetHostname = "api.openai.com";
const workingUrl = await findWorkingProxy(targetHostname, targetUrl);
if (!workingUrl) return null;
try {
const url = new URL(workingUrl);
return {
proxy: {
type: url.protocol.replace(":", "") || "http",
host: url.hostname,
port: parseInt(url.port, 10) || (url.protocol === "https:" ? 443 : 80),
username: url.username ? decodeURIComponent(url.username) : "",
password: url.password ? decodeURIComponent(url.password) : "",
},
level: "autoSelect",
levelId: null,
source: "automatic",
};
} catch {
return null;
}
}