Init V4 community edition (#2265)

* Init V4 community edition

* Init V4 community edition

pkg/filemanager/driver/util.go

@@ -0,0 +1,37 @@
+package driver
+
+import (
+	"fmt"
+	"github.com/cloudreve/Cloudreve/v4/ent"
+	"net/url"
+	"path"
+	"strings"
+)
+
+func ApplyProxyIfNeeded(policy *ent.StoragePolicy, srcUrl *url.URL) (*url.URL, error) {
+	// For custom proxy, generate a new proxyed URL:
+	// [Proxy Scheme][Proxy Host][Proxy Port][ProxyPath + OriginSrcPath][OriginSrcQuery + ProxyQuery]
+	if policy.Settings.CustomProxy {
+		proxy, err := url.Parse(policy.Settings.ProxyServer)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse proxy URL: %w", err)
+		}
+		proxy.Path = path.Join(proxy.Path, strings.TrimPrefix(srcUrl.Path, "/"))
+		q := proxy.Query()
+		if len(q) == 0 {
+			proxy.RawQuery = srcUrl.RawQuery
+		} else {
+			// Merge query parameters
+			srcQ := srcUrl.Query()
+			for k, _ := range srcQ {
+				q.Set(k, srcQ.Get(k))
+			}
+
+			proxy.RawQuery = q.Encode()
+		}
+
+		srcUrl = proxy
+	}
+
+	return srcUrl, nil
+}