fix(115): support null `UserAgent` (#5787)

drivers/115/driver.go

@@ -64,11 +64,7 @@ func (d *Pan115) Link(ctx context.Context, file model.Obj, args model.LinkArgs)
 		return nil, err
 	}
 	var userAgent = args.Header.Get("User-Agent")
-	if userAgent == "" {
-		userAgent = driver115.UA115Browser
-	}
-
-	downloadInfo, err := d.client.
+	downloadInfo, err := d.
 		DownloadWithUA(file.(*FileObj).PickCode, userAgent)
 	if err != nil {
 		return nil, err

drivers/115/util.go

@@ -5,12 +5,8 @@ import (
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
-	"github.com/alist-org/alist/v3/internal/model"
-	"github.com/alist-org/alist/v3/pkg/http_range"
-	"github.com/alist-org/alist/v3/pkg/utils"
-	"github.com/aliyun/aliyun-oss-go-sdk/oss"
-	"github.com/orzogc/fake115uploader/cipher"
 	"io"
+	"net/http"
 	"net/url"
 	"path/filepath"
 	"strconv"
@@ -18,8 +14,15 @@ import (
 	"sync"
 	"time"
 
-	driver115 "github.com/SheltonZhu/115driver/pkg/driver"
 	"github.com/alist-org/alist/v3/internal/conf"
+	"github.com/alist-org/alist/v3/internal/model"
+	"github.com/alist-org/alist/v3/pkg/http_range"
+	"github.com/alist-org/alist/v3/pkg/utils"
+	"github.com/aliyun/aliyun-oss-go-sdk/oss"
+
+	driver115 "github.com/SheltonZhu/115driver/pkg/driver"
+	crypto "github.com/gaoyb7/115drive-webdav/115"
+	"github.com/orzogc/fake115uploader/cipher"
 	"github.com/pkg/errors"
 )
 
@@ -74,6 +77,61 @@ const (
 	appVer = "2.0.3.6"
 )
 
+func (c *Pan115) DownloadWithUA(pickCode, ua string) (*driver115.DownloadInfo, error) {
+	key := crypto.GenerateKey()
+	result := driver115.DownloadResp{}
+	params, err := utils.Json.Marshal(map[string]string{"pickcode": pickCode})
+	if err != nil {
+		return nil, err
+	}
+
+	data := crypto.Encode(params, key)
+
+	bodyReader := strings.NewReader(url.Values{"data": []string{data}}.Encode())
+	reqUrl := fmt.Sprintf("%s?t=%s", driver115.ApiDownloadGetUrl, driver115.Now().String())
+	req, _ := http.NewRequest(http.MethodPost, reqUrl, bodyReader)
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	req.Header.Set("Cookie", c.Cookie)
+	req.Header.Set("User-Agent", ua)
+
+	resp, err := c.client.Client.GetClient().Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+	if err := utils.Json.Unmarshal(body, &result); err != nil {
+		return nil, err
+	}
+
+	if err = result.Err(string(body)); err != nil {
+		return nil, err
+	}
+
+	bytes, err := crypto.Decode(string(result.EncodedData), key)
+	if err != nil {
+		return nil, err
+	}
+
+	downloadInfo := driver115.DownloadData{}
+	if err := utils.Json.Unmarshal(bytes, &downloadInfo); err != nil {
+		return nil, err
+	}
+
+	for _, info := range downloadInfo {
+		if info.FileSize < 0 {
+			return nil, driver115.ErrDownloadEmpty
+		}
+		info.Header = resp.Request.Header
+		return info, nil
+	}
+	return nil, driver115.ErrUnexpected
+}
+
 func (d *Pan115) rapidUpload(fileSize int64, fileName, dirID, preID, fileID string, stream model.FileStreamer) (*driver115.UploadInitResp, error) {
 	var (
 		ecdhCipher   *cipher.EcdhCipher