Proxy support

client/proxy.go

@@ -0,0 +1,47 @@
+package client
+
+import (
+	"context"
+	"github.com/geziyor/geziyor/internal"
+	"net/http"
+	"net/url"
+	"sync/atomic"
+)
+
+const ProxyURLKey = 0
+
+type roundRobinProxy struct {
+	proxyURLs []*url.URL
+	index     uint32
+}
+
+func (r *roundRobinProxy) GetProxy(pr *http.Request) (*url.URL, error) {
+	index := atomic.AddUint32(&r.index, 1) - 1
+	u := r.proxyURLs[index%uint32(len(r.proxyURLs))]
+
+	// Set proxy url to context
+	ctx := context.WithValue(pr.Context(), ProxyURLKey, u.String())
+	*pr = *pr.WithContext(ctx)
+	return u, nil
+}
+
+// RoundRobinProxy creates a proxy switcher function which rotates
+// ProxyURLs on every request.
+// The proxy type is determined by the URL scheme. "http", "https"
+// and "socks5" are supported. If the scheme is empty,
+// "http" is assumed.
+func RoundRobinProxy(proxyURLs ...string) func(*http.Request) (*url.URL, error) {
+	if len(proxyURLs) < 1 {
+		return http.ProxyFromEnvironment
+	}
+	parsedProxyURLs := make([]*url.URL, len(proxyURLs))
+	for i, u := range proxyURLs {
+		parsedURL, err := url.Parse(u)
+		if err != nil {
+			internal.Logger.Printf("proxy url parse: %v", err)
+			return nil
+		}
+		parsedProxyURLs[i] = parsedURL
+	}
+	return (&roundRobinProxy{parsedProxyURLs, 0}).GetProxy
+}