feat(fasthttpproxy): add dual-stack connection support to enable IPv6 proxies for HTTP and SOCKS5 dialers (#1885)

* feat(fasthttpproxy): add dual-stack connection support to enable IPv6 proxies for HTTP and SOCKS5 dialers

- Added `FasthttpHTTPDialerDualStack` to support dual-stack (IPv4 and IPv6) connections for HTTP proxies, enabling IPv6 proxy usage.
- Added `FasthttpSocksDialerDualStack` to support dual-stack (IPv4 and IPv6) connections for SOCKS5 proxies, enabling IPv6 proxy usage.
- Improved dialer configuration to ensure compatibility with both IPv4 and IPv6 proxies.

* fix(lint): address linting issues in code

Author: lavish440

fasthttpproxy/http.go

@@ -33,3 +33,33 @@ func FasthttpHTTPDialerTimeout(proxy string, timeout time.Duration) fasthttp.Dia
 	dialFunc, _ := d.GetDialFunc(false)
 	return dialFunc
 }
+
+// FasthttpHTTPDialerDualStack returns a fasthttp.DialFunc that dials using
+// the provided HTTP proxy with support for both IPv4 and IPv6.
+//
+// Example usage:
+//
+//	c := &fasthttp.Client{
+//		Dial: fasthttpproxy.FasthttpHTTPDialerDualStack("username:password@localhost:9050"),
+//	}
+func FasthttpHTTPDialerDualStack(proxy string) fasthttp.DialFunc {
+	return FasthttpHTTPDialerDualStackTimeout(proxy, 0)
+}
+
+// FasthttpHTTPDialerDualStackTimeout returns a fasthttp.DialFunc that dials using
+// the provided HTTP proxy with support for both IPv4 and IPv6, using the given timeout.
+// The timeout parameter determines both the dial timeout and the CONNECT request timeout.
+//
+// Example usage:
+//
+//	c := &fasthttp.Client{
+//		Dial: fasthttpproxy.FasthttpHTTPDialerDualStackTimeout("username:password@localhost:9050", time.Second * 2),
+//	}
+func FasthttpHTTPDialerDualStackTimeout(proxy string, timeout time.Duration) fasthttp.DialFunc {
+	d := Dialer{
+		Config: httpproxy.Config{HTTPProxy: proxy, HTTPSProxy: proxy}, Timeout: timeout, ConnectTimeout: timeout,
+		DialDualStack: true,
+	}
+	dialFunc, _ := d.GetDialFunc(false)
+	return dialFunc
+}

fasthttpproxy/socks5.go

@@ -18,3 +18,17 @@ func FasthttpSocksDialer(proxyAddr string) fasthttp.DialFunc {
 	dialFunc, _ := d.GetDialFunc(false)
 	return dialFunc
 }
+
+// FasthttpSocksDialerDualStack returns a fasthttp.DialFunc that dials using
+// the provided SOCKS5 proxy with support for both IPv4 and IPv6.
+//
+// Example usage:
+//
+//	c := &fasthttp.Client{
+//		Dial: fasthttpproxy.FasthttpSocksDialerDualStack("socks5://localhost:9050"),
+//	}
+func FasthttpSocksDialerDualStack(proxyAddr string) fasthttp.DialFunc {
+	d := Dialer{Config: httpproxy.Config{HTTPProxy: proxyAddr, HTTPSProxy: proxyAddr}, DialDualStack: true}
+	dialFunc, _ := d.GetDialFunc(false)
+	return dialFunc
+}