Feat: download file and get file downloading session

pkg/filesystem/file.go

@@ -8,6 +8,7 @@ import (
 	"github.com/HFO4/cloudreve/pkg/util"
 	"github.com/juju/ratelimit"
 	"io"
+	"strconv"
 )
 
 /* ============
@@ -105,8 +106,8 @@ func (fs *FileSystem) GetContent(ctx context.Context, path string) (io.ReadSeeke
 			return nil, ErrObjectNotExist
 		}
 		fs.FileTarget = []model.File{*file}
-		ctx = context.WithValue(ctx, fsctx.FileModelCtx, file)
 	}
+	ctx = context.WithValue(ctx, fsctx.FileModelCtx, fs.FileTarget[0])
 
 	// 将当前存储策略重设为文件使用的
 	fs.Policy = fs.FileTarget[0].GetPolicy()
@@ -173,6 +174,45 @@ func (fs *FileSystem) GroupFileByPolicy(ctx context.Context, files []model.File)
 	return policyGroup
 }
 
+// GetDownloadURL 创建文件下载链接
+func (fs *FileSystem) GetDownloadURL(ctx context.Context, path string) (string, error) {
+	// 找到文件
+	if len(fs.FileTarget) == 0 {
+		exist, file := fs.IsFileExist(path)
+		if !exist {
+			return "", ErrObjectNotExist
+		}
+		fs.FileTarget = []model.File{*file}
+	}
+
+	ctx = context.WithValue(ctx, fsctx.FileModelCtx, fs.FileTarget[0])
+
+	// 将当前存储策略重设为文件使用的
+	fs.Policy = fs.FileTarget[0].GetPolicy()
+	err := fs.dispatchHandler()
+	if err != nil {
+		return "", err
+	}
+
+	// 生成下載地址
+	siteURL := model.GetSiteURL()
+	ttl, err := strconv.ParseInt(model.GetSettingByName("download_timeout"), 10, 64)
+	if err != nil {
+		return "", serializer.NewError(serializer.CodeInternalSetting, "无法获取下载地址有效期", err)
+	}
+	source, err := fs.Handler.GetDownloadURL(
+		ctx,
+		fs.FileTarget[0].SourceName,
+		*siteURL,
+		ttl,
+	)
+	if err != nil {
+		return "", serializer.NewError(serializer.CodeNotSet, "无法获取下载地址", err)
+	}
+
+	return source, nil
+}
+
 // GetSource 获取可直接访问文件的外链地址
 func (fs *FileSystem) GetSource(ctx context.Context, fileID uint) (string, error) {
 	// 查找文件记录

pkg/filesystem/filesystem.go

@@ -32,6 +32,8 @@ type Handler interface {
 	Thumb(ctx context.Context, path string) (*response.ContentResponse, error)
 	// 获取外链地址，url
 	Source(ctx context.Context, path string, url url.URL, expires int64) (string, error)
+	//获取下载地址
+	GetDownloadURL(ctx context.Context, path string, url url.URL, expires int64) (string, error)
 }
 
 // FileSystem 管理文件的文件系统

pkg/filesystem/local/handler.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	model "github.com/HFO4/cloudreve/models"
 	"github.com/HFO4/cloudreve/pkg/auth"
+	"github.com/HFO4/cloudreve/pkg/cache"
 	"github.com/HFO4/cloudreve/pkg/conf"
 	"github.com/HFO4/cloudreve/pkg/filesystem/fsctx"
 	"github.com/HFO4/cloudreve/pkg/filesystem/response"
@@ -15,6 +16,7 @@ import (
 	"net/url"
 	"os"
 	"path/filepath"
+	"time"
 )
 
 // Handler 本地策略适配器
@@ -127,3 +129,29 @@ func (handler Handler) Source(ctx context.Context, path string, url url.URL, exp
 	finalURL := url.ResolveReference(signedURI).String()
 	return finalURL, nil
 }
+
+func (handler Handler) GetDownloadURL(ctx context.Context, path string, url url.URL, ttl int64) (string, error) {
+	file, ok := ctx.Value(fsctx.FileModelCtx).(model.File)
+	if !ok {
+		return "", errors.New("无法获取文件记录上下文")
+	}
+
+	// 创建下载会话，将文件信息写入缓存
+	downloadSessionID := util.RandStringRunes(16)
+	err := cache.Set("download_"+downloadSessionID, file, int(ttl))
+	if err != nil {
+		return "", serializer.NewError(serializer.CodeCacheOperation, "无法创建下載会话", err)
+	}
+
+	// 签名生成文件记录
+	signedURI, err := auth.SignURI(
+		fmt.Sprintf("/api/v3/file/download/%s", downloadSessionID),
+		time.Now().Unix()+ttl,
+	)
+	if err != nil {
+		return "", serializer.NewError(serializer.CodeEncryptError, "无法对URL进行签名", err)
+	}
+
+	finalURL := url.ResolveReference(signedURI).String()
+	return finalURL, nil
+}

pkg/filesystem/upload_test.go

@@ -46,6 +46,10 @@ func (m FileHeaderMock) Source(ctx context.Context, path string, url url.URL, ex
 	args := m.Called(ctx, path, url, expires)
 	return args.Get(0).(string), args.Error(1)
 }
+func (m FileHeaderMock) GetDownloadURL(ctx context.Context, path string, url url.URL, expires int64) (string, error) {
+	args := m.Called(ctx, path, url, expires)
+	return args.Get(0).(string), args.Error(1)
+}
 
 func TestFileSystem_Upload(t *testing.T) {
 	asserts := assert.New(t)

pkg/serializer/error.go

@@ -66,6 +66,10 @@ const (
 	CodeEncryptError = 50002
 	// CodeIOFailed IO操作失败
 	CodeIOFailed = 50004
+	// CodeInternalSetting 内部设置参数错误
+	CodeInternalSetting = 50005
+	// CodeCacheOperation 缓存操作失败
+	CodeCacheOperation = 50006
 	//CodeParamErr 各种奇奇怪怪的参数错误
 	CodeParamErr = 40001
 	// CodeNotSet 未定错误，后续尝试从error中获取