Check if host works first before assigning random host

internal/universal/downloader.go

@@ -79,7 +79,7 @@ func (dl *Downloader) DownloadFile(directory, torrentName, fileName string, resp
 		}
 		if cfg.ShouldServeFromRclone() {
 			if cfg.ShouldVerifyDownloadLink() {
-				if !torMgr.Api.CanFetchFirstByte(unrestrict.Download) {
+				if !dl.client.CanFetchFirstByte(unrestrict.Download) {
 					log.Warnf("File %s is not available", fileName)
 					http.Error(resp, "File is not available", http.StatusNotFound)
 					return
@@ -123,7 +123,7 @@ func (dl *Downloader) DownloadLink(fileName, link string, resp http.ResponseWrit
 		}
 		if cfg.ShouldServeFromRclone() {
 			if cfg.ShouldVerifyDownloadLink() {
-				if !torMgr.Api.CanFetchFirstByte(unrestrict.Download) {
+				if !dl.client.CanFetchFirstByte(unrestrict.Download) {
 					log.Warnf("File %s is not available", fileName)
 					http.Error(resp, "File is not available", http.StatusNotFound)
 					return

pkg/http/client.go

@@ -198,11 +198,12 @@ func (r *HTTPClient) replaceHostIfNeeded(req *http.Request) {
 			break
 		}
 	}
-	if !found {
-		r.log.Debug("Not found, assigning random IPv6 host")
-		// random IPv6 host
+	if !found && !r.CanFetchFirstByte(req.URL.String()) {
 		req.Host = r.ipv6Hosts[rand.Intn(len(r.ipv6Hosts))]
 		req.URL.Host = req.Host
+		r.log.Debugf("Host is not a valid IPv6 host, assigning a random IPv6 host: %s", req.Host)
+	} else {
+		r.ipv6Hosts = append(r.ipv6Hosts, req.Host)
 	}
 }
 
@@ -267,3 +268,28 @@ func backoffFunc(attempt int) time.Duration {
 	}
 	return time.Duration(backoff) * time.Second
 }
+
+func (r *HTTPClient) CanFetchFirstByte(url string) bool {
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return false
+	}
+
+	req.Header.Set("Range", "bytes=0-0")
+
+	resp, err := r.client.Do(req)
+	if err != nil {
+		return false
+	}
+	defer resp.Body.Close()
+
+	// If server supports partial content
+	if resp.StatusCode/100 == 2 {
+		buffer := make([]byte, 1)
+		_, err = resp.Body.Read(buffer)
+		if err == nil {
+			return true
+		}
+	}
+	return false
+}

pkg/realdebrid/api.go

@@ -308,7 +308,7 @@ func (rd *RealDebrid) UnrestrictLink(link string, checkFirstByte bool) (*Downloa
 		return nil, fmt.Errorf("undecodable response: %v", err)
 	}
 
-	if checkFirstByte && !rd.CanFetchFirstByte(response.Download) {
+	if checkFirstByte && !rd.client.CanFetchFirstByte(response.Download) {
 		return nil, fmt.Errorf("can't fetch first byte")
 	}
 

pkg/realdebrid/unrestrict.go

@@ -1,30 +0,0 @@
-package realdebrid
-
-import (
-	"net/http"
-)
-
-func (rd *RealDebrid) CanFetchFirstByte(url string) bool {
-	req, err := http.NewRequest("GET", url, nil)
-	if err != nil {
-		return false
-	}
-
-	req.Header.Set("Range", "bytes=0-0")
-
-	resp, err := rd.client.Do(req)
-	if err != nil {
-		return false
-	}
-	defer resp.Body.Close()
-
-	// If server supports partial content
-	if resp.StatusCode/100 == 2 {
-		buffer := make([]byte, 1)
-		_, err = resp.Body.Read(buffer)
-		if err == nil {
-			return true
-		}
-	}
-	return false
-}