feat: multipart-archives (#1222)

pkg/download/downloader.go

@@ -2,6 +2,7 @@ package download
 
 import (
 	"errors"
+	"fmt"
 	"math"
 	gohttp "net/http"
 	"net/url"
@@ -51,6 +52,8 @@ type ExtractStatus string
 const (
 	// ExtractStatusNone indicates extraction has not started
 	ExtractStatusNone ExtractStatus = ""
+	// ExtractStatusWaitingParts indicates waiting for other multi-part archive parts to complete
+	ExtractStatusWaitingParts ExtractStatus = "waitingParts"
 	// ExtractStatusExtracting indicates extraction is in progress
 	ExtractStatusExtracting ExtractStatus = "extracting"
 	// ExtractStatusDone indicates extraction completed successfully
@@ -74,6 +77,12 @@ type Progress struct {
 	ExtractStatus ExtractStatus `json:"extractStatus"`
 	// ExtractProgress is the percentage of extraction completed (0-100)
 	ExtractProgress int `json:"extractProgress"`
+	// MultiPartBaseName is set for multi-part archives to group related parts
+	MultiPartBaseName string `json:"multiPartBaseName,omitempty"`
+	// MultiPartNumber is the part number for multi-part archives (1-indexed)
+	MultiPartNumber int `json:"multiPartNumber,omitempty"`
+	// MultiPartIsFirst indicates if this is the first part of a multi-part archive
+	MultiPartIsFirst bool `json:"multiPartIsFirst,omitempty"`
 }
 
 type Downloader struct {
@@ -898,41 +907,7 @@ func (d *Downloader) watch(task *Task) {
 
 		// Auto-extract archive files
 		if e.AutoExtract && isArchiveFile(downloadFilePath) {
-			go func() {
-				// Set extraction status to extracting
-				task.Progress.ExtractStatus = ExtractStatusExtracting
-				task.Progress.ExtractProgress = 0
-				d.emit(EventKeyProgress, task)
-				d.storage.Put(bucketTask, task.ID, task.clone())
-
-				// Extract to the same directory as the downloaded file
-				destDir := task.Meta.Opts.Path
-				extractErr := extractArchive(downloadFilePath, destDir, e.ArchivePassword, func(extractedFiles int, totalFiles int, progress int) {
-					task.Progress.ExtractProgress = progress
-					d.emit(EventKeyProgress, task)
-				})
-				if extractErr != nil {
-					d.Logger.Error().Err(extractErr).Msgf("auto extract archive failed, task id: %s", task.ID)
-					task.Progress.ExtractStatus = ExtractStatusError
-					d.emit(EventKeyProgress, task)
-					d.storage.Put(bucketTask, task.ID, task.clone())
-				} else {
-					d.Logger.Info().Msgf("auto extract archive completed, task id: %s", task.ID)
-					task.Progress.ExtractStatus = ExtractStatusDone
-					task.Progress.ExtractProgress = 100
-					d.emit(EventKeyProgress, task)
-					d.storage.Put(bucketTask, task.ID, task.clone())
-					// Delete archive after successful extraction if enabled
-					if e.DeleteAfterExtract {
-						deleteErr := os.Remove(downloadFilePath)
-						if deleteErr != nil {
-							d.Logger.Error().Err(deleteErr).Msgf("delete archive after extraction failed, task id: %s", task.ID)
-						} else {
-							d.Logger.Info().Msgf("archive deleted after extraction, task id: %s", task.ID)
-						}
-					}
-				}
-			}()
+			go d.handleAutoExtract(task, downloadFilePath, e)
 		}
 	}
 }
@@ -1225,6 +1200,343 @@ func (d *Downloader) buildFetcher(url string) (fetcher.Fetcher, error) {
 	return fetcher, nil
 }
 
+// handleAutoExtract handles automatic extraction of archive files, including multi-part archives
+func (d *Downloader) handleAutoExtract(task *Task, downloadFilePath string, opts *http.OptsExtra) {
+	// Check if this is a multi-part archive
+	partInfo := getArchivePartInfo(downloadFilePath)
+
+	if partInfo.IsMultiPart {
+		// Set multi-part info on the task
+		task.Progress.MultiPartBaseName = partInfo.BaseName
+		task.Progress.MultiPartNumber = partInfo.PartNumber
+		task.Progress.MultiPartIsFirst = isFirstPart(downloadFilePath)
+		d.storage.Put(bucketTask, task.ID, task.clone())
+
+		// Check if all parts are downloaded
+		destDir := task.Meta.Opts.Path
+		allPartsReady, missingParts := d.checkMultiPartArchiveReady(downloadFilePath, destDir, partInfo)
+
+		if !allPartsReady {
+			// Not all parts are ready yet, set status to waiting
+			task.Progress.ExtractStatus = ExtractStatusWaitingParts
+			d.emit(EventKeyProgress, task)
+			d.storage.Put(bucketTask, task.ID, task.clone())
+			d.Logger.Info().Msgf("multi-part archive waiting for other parts, task id: %s, missing: %v", task.ID, missingParts)
+			return
+		}
+
+		// All parts are ready!
+		// Only one task should perform extraction - we'll use the one that completes last
+		// Check if extraction has already been started by another part
+		if d.isMultiPartExtractionInProgress(partInfo.BaseName) {
+			// Another part already started extraction, mark this as done
+			task.Progress.ExtractStatus = ExtractStatusDone
+			task.Progress.ExtractProgress = 100
+			d.emit(EventKeyProgress, task)
+			d.storage.Put(bucketTask, task.ID, task.clone())
+			d.Logger.Info().Msgf("multi-part archive part completed, extraction handled by another part, task id: %s", task.ID)
+			return
+		}
+
+		// This task will handle extraction - mark as extracting first to prevent others
+		task.Progress.ExtractStatus = ExtractStatusExtracting
+		d.emit(EventKeyProgress, task)
+		d.storage.Put(bucketTask, task.ID, task.clone())
+
+		// Extract the multi-part archive
+		d.performMultiPartExtraction(task, partInfo.FirstPartPath, destDir, opts)
+	} else {
+		// Regular (non-multi-part) archive
+		d.performExtraction(task, downloadFilePath, task.Meta.Opts.Path, opts)
+	}
+}
+
+// checkMultiPartArchiveReady checks if all parts of a multi-part archive are downloaded
+// by examining task status rather than file existence
+func (d *Downloader) checkMultiPartArchiveReady(filePath string, destDir string, partInfo ArchivePartInfo) (bool, []string) {
+	// Use task-based checking - find all tasks with the same MultiPartBaseName
+	// and verify they are all in Done status
+	baseName := GetMultiPartArchiveBaseName(filePath)
+	if baseName == "" {
+		return true, nil
+	}
+
+	return d.checkAllMultiPartTasksDone(baseName)
+}
+
+// checkAllMultiPartTasksDone checks if all tasks belonging to a multi-part archive are done
+func (d *Downloader) checkAllMultiPartTasksDone(baseName string) (bool, []string) {
+	var notDoneParts []string
+
+	d.lock.Lock()
+	defer d.lock.Unlock()
+
+	// Find all tasks that belong to this multi-part archive
+	var relatedTasks []*Task
+	for _, task := range d.tasks {
+		taskBaseName := ""
+		if task.Meta != nil && task.Meta.Res != nil && len(task.Meta.Res.Files) > 0 {
+			taskBaseName = GetMultiPartArchiveBaseName(task.Meta.SingleFilepath())
+		}
+		if taskBaseName == baseName {
+			relatedTasks = append(relatedTasks, task)
+		}
+	}
+
+	// If we found no related tasks, we can't determine readiness
+	if len(relatedTasks) == 0 {
+		return false, []string{"no related tasks found for " + baseName}
+	}
+
+	// Check if all related tasks are done
+	for _, task := range relatedTasks {
+		if task.Status != base.DownloadStatusDone {
+			notDoneParts = append(notDoneParts, task.Meta.SingleFilepath())
+		}
+	}
+
+	return len(notDoneParts) == 0, notDoneParts
+}
+
+// isMultiPartExtractionInProgress checks if any task for this multi-part archive
+// has already started extraction (to prevent duplicate extractions)
+func (d *Downloader) isMultiPartExtractionInProgress(baseName string) bool {
+	d.lock.Lock()
+	defer d.lock.Unlock()
+
+	for _, task := range d.tasks {
+		taskBaseName := ""
+		if task.Meta != nil && task.Meta.Res != nil && len(task.Meta.Res.Files) > 0 {
+			taskBaseName = GetMultiPartArchiveBaseName(task.Meta.SingleFilepath())
+		}
+		if taskBaseName == baseName {
+			// Check if this task is already extracting or has completed extraction
+			if task.Progress.ExtractStatus == ExtractStatusExtracting ||
+				task.Progress.ExtractStatus == ExtractStatusDone ||
+				task.Progress.ExtractStatus == ExtractStatusError {
+				return true
+			}
+		}
+	}
+
+	return false
+}
+
+// performExtraction performs extraction for a regular (non-multi-part) archive
+func (d *Downloader) performExtraction(task *Task, archivePath string, destDir string, opts *http.OptsExtra) {
+	// Set extraction status to extracting
+	task.Progress.ExtractStatus = ExtractStatusExtracting
+	task.Progress.ExtractProgress = 0
+	d.emit(EventKeyProgress, task)
+	d.storage.Put(bucketTask, task.ID, task.clone())
+
+	// Extract the archive
+	extractErr := extractArchive(archivePath, destDir, opts.ArchivePassword, func(extractedFiles int, totalFiles int, progress int) {
+		task.Progress.ExtractProgress = progress
+		d.emit(EventKeyProgress, task)
+	})
+
+	d.handleExtractionResult(task, extractErr, []string{archivePath}, opts.DeleteAfterExtract)
+}
+
+// performMultiPartExtraction performs extraction for a multi-part archive
+func (d *Downloader) performMultiPartExtraction(task *Task, firstPartPath string, destDir string, opts *http.OptsExtra) {
+	// Set extraction status to extracting
+	task.Progress.ExtractStatus = ExtractStatusExtracting
+	task.Progress.ExtractProgress = 0
+	d.emit(EventKeyProgress, task)
+	d.storage.Put(bucketTask, task.ID, task.clone())
+
+	d.Logger.Info().Msgf("starting multi-part archive extraction, first part: %s, task id: %s", firstPartPath, task.ID)
+
+	// Extract the multi-part archive
+	extractErr := extractMultiPartArchive(firstPartPath, destDir, opts.ArchivePassword, func(extractedFiles int, totalFiles int, progress int) {
+		task.Progress.ExtractProgress = progress
+		d.emit(EventKeyProgress, task)
+	})
+
+	// Collect all part files for potential deletion
+	partFiles := d.collectMultiPartFiles(firstPartPath)
+
+	d.handleExtractionResult(task, extractErr, partFiles, opts.DeleteAfterExtract)
+
+	// Update status for all related multi-part tasks
+	d.updateMultiPartTasksStatus(task, extractErr)
+}
+
+// collectMultiPartFiles collects all files belonging to a multi-part archive
+func (d *Downloader) collectMultiPartFiles(firstPartPath string) []string {
+	var files []string
+	partInfo := getArchivePartInfo(firstPartPath)
+	dir := filepath.Dir(firstPartPath)
+
+	switch {
+	case strings.Contains(partInfo.Pattern, ".7z)"):
+		// 7z: .7z.001, .7z.002, etc.
+		files = d.collectSequentialFiles(dir, partInfo.BaseName, ".%03d")
+	case strings.Contains(partInfo.Pattern, ".part"):
+		// RAR new style
+		files = d.collectRarNewStyleFiles(dir, partInfo.BaseName)
+	case partInfo.Pattern == "rar-old-style" || strings.Contains(partInfo.Pattern, ".r("):
+		// RAR old style
+		files = d.collectRarOldStyleFiles(dir, partInfo.BaseName)
+	case strings.Contains(partInfo.Pattern, ".zip)"):
+		// ZIP multi-part
+		files = d.collectSequentialFiles(dir, partInfo.BaseName, ".%03d")
+	case strings.Contains(partInfo.Pattern, ".z("):
+		// ZIP split
+		files = d.collectZipSplitFiles(dir, partInfo.BaseName)
+	}
+
+	return files
+}
+
+// collectSequentialFiles collects sequential numbered files
+func (d *Downloader) collectSequentialFiles(dir, baseName, format string) []string {
+	var files []string
+	suffix := filepath.Ext(baseName)
+	nameWithoutExt := strings.TrimSuffix(baseName, suffix)
+	partNum := 1
+
+	for {
+		partPath := filepath.Join(dir, nameWithoutExt+suffix+fmt.Sprintf(format, partNum))
+		if _, err := os.Stat(partPath); os.IsNotExist(err) {
+			break
+		}
+		files = append(files, partPath)
+		partNum++
+	}
+
+	return files
+}
+
+// collectRarNewStyleFiles collects RAR new style part files
+func (d *Downloader) collectRarNewStyleFiles(dir, baseName string) []string {
+	var files []string
+	partNum := 1
+
+	for {
+		singleDigitPath := filepath.Join(dir, baseName+fmt.Sprintf(".part%d.rar", partNum))
+		doubleDigitPath := filepath.Join(dir, baseName+fmt.Sprintf(".part%02d.rar", partNum))
+
+		if _, err := os.Stat(singleDigitPath); err == nil {
+			files = append(files, singleDigitPath)
+		} else if _, err := os.Stat(doubleDigitPath); err == nil {
+			files = append(files, doubleDigitPath)
+		} else {
+			break
+		}
+		partNum++
+	}
+
+	return files
+}
+
+// collectRarOldStyleFiles collects RAR old style part files
+func (d *Downloader) collectRarOldStyleFiles(dir, baseName string) []string {
+	var files []string
+
+	// .rar file
+	rarPath := filepath.Join(dir, baseName+".rar")
+	if _, err := os.Stat(rarPath); err == nil {
+		files = append(files, rarPath)
+	}
+
+	// .r00, .r01, etc.
+	partNum := 0
+	for {
+		partPath := filepath.Join(dir, baseName+fmt.Sprintf(".r%02d", partNum))
+		if _, err := os.Stat(partPath); os.IsNotExist(err) {
+			break
+		}
+		files = append(files, partPath)
+		partNum++
+	}
+
+	return files
+}
+
+// collectZipSplitFiles collects ZIP split files
+func (d *Downloader) collectZipSplitFiles(dir, baseName string) []string {
+	var files []string
+
+	// .z01, .z02, etc.
+	partNum := 1
+	for {
+		partPath := filepath.Join(dir, baseName+fmt.Sprintf(".z%02d", partNum))
+		if _, err := os.Stat(partPath); os.IsNotExist(err) {
+			break
+		}
+		files = append(files, partPath)
+		partNum++
+	}
+
+	// .zip file
+	zipPath := filepath.Join(dir, baseName+".zip")
+	if _, err := os.Stat(zipPath); err == nil {
+		files = append(files, zipPath)
+	}
+
+	return files
+}
+
+// handleExtractionResult handles the result of an extraction operation
+func (d *Downloader) handleExtractionResult(task *Task, extractErr error, archiveFiles []string, deleteAfterExtract bool) {
+	if extractErr != nil {
+		d.Logger.Error().Err(extractErr).Msgf("auto extract archive failed, task id: %s", task.ID)
+		task.Progress.ExtractStatus = ExtractStatusError
+		d.emit(EventKeyProgress, task)
+		d.storage.Put(bucketTask, task.ID, task.clone())
+	} else {
+		d.Logger.Info().Msgf("auto extract archive completed, task id: %s", task.ID)
+		task.Progress.ExtractStatus = ExtractStatusDone
+		task.Progress.ExtractProgress = 100
+		d.emit(EventKeyProgress, task)
+		d.storage.Put(bucketTask, task.ID, task.clone())
+
+		// Delete archive files after successful extraction if enabled
+		if deleteAfterExtract {
+			for _, archiveFile := range archiveFiles {
+				deleteErr := os.Remove(archiveFile)
+				if deleteErr != nil {
+					d.Logger.Error().Err(deleteErr).Msgf("delete archive after extraction failed: %s", archiveFile)
+				} else {
+					d.Logger.Info().Msgf("archive deleted after extraction: %s", archiveFile)
+				}
+			}
+		}
+	}
+}
+
+// updateMultiPartTasksStatus updates the extraction status for all tasks that belong to the same multi-part archive
+func (d *Downloader) updateMultiPartTasksStatus(sourceTask *Task, extractErr error) {
+	if sourceTask.Progress.MultiPartBaseName == "" {
+		return
+	}
+
+	status := ExtractStatusDone
+	progress := 100
+	if extractErr != nil {
+		status = ExtractStatusError
+		progress = 0
+	}
+
+	d.lock.Lock()
+	defer d.lock.Unlock()
+
+	for _, task := range d.tasks {
+		if task.ID == sourceTask.ID {
+			continue
+		}
+		if task.Progress.MultiPartBaseName == sourceTask.Progress.MultiPartBaseName {
+			task.Progress.ExtractStatus = status
+			task.Progress.ExtractProgress = progress
+			d.emit(EventKeyProgress, task)
+			d.storage.Put(bucketTask, task.ID, task.clone())
+		}
+	}
+}
+
 func initTask(task *Task) {
 	task.timer = util.NewTimer(task.Progress.Used)
 

pkg/download/extract.go

@@ -6,6 +6,7 @@ import (
 	"math"
 	"os"
 	"path/filepath"
+	"regexp"
 	"slices"
 	"strings"
 	"sync/atomic"
@@ -37,12 +38,45 @@ var supportedArchiveExtensions = []string{
 	".lz",
 }
 
+// multiPartArchivePatterns contains regex patterns for multi-part archive detection
+// Each pattern should have a capture group for the base name and part number
+var multiPartArchivePatterns = []*regexp.Regexp{
+	// 7z multi-part: file.7z.001, file.7z.002, etc.
+	regexp.MustCompile(`(?i)^(.+\.7z)\.(\d{3})$`),
+	// RAR multi-part (new style): file.part01.rar, file.part02.rar, etc.
+	regexp.MustCompile(`(?i)^(.+)\.part(\d+)\.rar$`),
+	// RAR multi-part (old style): file.rar, file.r00, file.r01, etc. (first file is .rar)
+	regexp.MustCompile(`(?i)^(.+)\.r(\d{2})$`),
+	// ZIP multi-part: file.zip.001, file.zip.002, etc.
+	regexp.MustCompile(`(?i)^(.+\.zip)\.(\d{3})$`),
+	// ZIP split: file.z01, file.z02, ... file.zip (last file is .zip)
+	regexp.MustCompile(`(?i)^(.+)\.z(\d{2})$`),
+}
+
+// ArchivePartInfo contains information about a multi-part archive
+type ArchivePartInfo struct {
+	// IsMultiPart indicates if this file is part of a multi-part archive
+	IsMultiPart bool
+	// BaseName is the common base name for all parts (without part number extension)
+	BaseName string
+	// PartNumber is the part number (1-indexed)
+	PartNumber int
+	// FirstPartPath is the path to the first part of the archive
+	FirstPartPath string
+	// Pattern indicates which pattern matched (for determining extraction method)
+	Pattern string
+}
+
 // ExtractProgressCallback is called to report extraction progress
 type ExtractProgressCallback func(extractedFiles int, totalFiles int, progress int)
 
 // isArchiveFile checks if a file is a supported archive format
 func isArchiveFile(filename string) bool {
 	lowerName := strings.ToLower(filename)
+	// Check for multi-part archive first
+	if isMultiPartArchive(filename) {
+		return true
+	}
 	return slices.ContainsFunc(supportedArchiveExtensions, func(ext string) bool {
 		return strings.HasSuffix(lowerName, ext)
 	})
@@ -273,3 +307,155 @@ func extractFile(ctx context.Context, fileInfo archives.FileInfo, destDir string
 	// Set file permissions
 	return os.Chmod(destPath, fileInfo.Mode())
 }
+
+// isMultiPartArchive checks if a file is part of a multi-part archive
+func isMultiPartArchive(filename string) bool {
+	info := getArchivePartInfo(filename)
+	return info.IsMultiPart
+}
+
+// getArchivePartInfo returns detailed information about a multi-part archive file
+func getArchivePartInfo(filename string) ArchivePartInfo {
+	baseName := filepath.Base(filename)
+
+	for _, pattern := range multiPartArchivePatterns {
+		matches := pattern.FindStringSubmatch(baseName)
+		if len(matches) >= 3 {
+			partNum := 0
+			_, err := parsePartNumber(matches[2], &partNum)
+			if err != nil {
+				continue
+			}
+
+			info := ArchivePartInfo{
+				IsMultiPart: true,
+				BaseName:    matches[1],
+				PartNumber:  partNum,
+				Pattern:     pattern.String(),
+			}
+
+			// Determine the first part path based on pattern
+			dir := filepath.Dir(filename)
+			info.FirstPartPath = determineFirstPartPath(dir, info.BaseName, pattern.String())
+
+			return info
+		}
+	}
+
+	// Check for .rar files that might be the first part of old-style multi-part RAR
+	if strings.HasSuffix(strings.ToLower(baseName), ".rar") && !strings.Contains(strings.ToLower(baseName), ".part") {
+		// Check if there are .r00, .r01 files in the same directory
+		dir := filepath.Dir(filename)
+		nameWithoutExt := strings.TrimSuffix(baseName, filepath.Ext(baseName))
+		r00Path := filepath.Join(dir, nameWithoutExt+".r00")
+		if _, err := os.Stat(r00Path); err == nil {
+			return ArchivePartInfo{
+				IsMultiPart:   true,
+				BaseName:      nameWithoutExt,
+				PartNumber:    1, // .rar is the first part in old-style
+				FirstPartPath: filename,
+				Pattern:       "rar-old-style",
+			}
+		}
+	}
+
+	return ArchivePartInfo{IsMultiPart: false}
+}
+
+// parsePartNumber parses a part number string and stores it in the provided pointer
+// Returns the parsed number and nil error on success
+func parsePartNumber(s string, partNum *int) (int, error) {
+	n := 0
+	for _, c := range s {
+		if c >= '0' && c <= '9' {
+			n = n*10 + int(c-'0')
+		}
+	}
+	// For .001, .002 style, part number is the value itself
+	// For .part01 style, part number is the value itself
+	// For .r00, .r01 style: r00=2 (since .rar is part 1), r01=3, etc.
+	// However, for consistency, we return the raw number and handle the offset elsewhere
+	*partNum = n
+	// Treat 00 as part 0, let callers handle the semantics
+	if n == 0 {
+		*partNum = 1 // For .001 format, 001 should be 1
+	}
+	return *partNum, nil
+}
+
+// determineFirstPartPath determines the path to the first part of a multi-part archive
+func determineFirstPartPath(dir, baseName, pattern string) string {
+	switch {
+	case strings.Contains(pattern, `.7z)`):
+		// 7z multi-part: first part is .7z.001
+		return filepath.Join(dir, baseName+".001")
+	case strings.Contains(pattern, `.part`):
+		// RAR new style: first part is .part01.rar or .part1.rar
+		// Try both single and double digit formats
+		if _, err := os.Stat(filepath.Join(dir, baseName+".part1.rar")); err == nil {
+			return filepath.Join(dir, baseName+".part1.rar")
+		}
+		return filepath.Join(dir, baseName+".part01.rar")
+	case strings.Contains(pattern, `.r(`):
+		// RAR old style: first part is .rar (not .r00)
+		return filepath.Join(dir, baseName+".rar")
+	case strings.Contains(pattern, `.zip)`):
+		// ZIP multi-part: first part is .zip.001
+		return filepath.Join(dir, baseName+".001")
+	case strings.Contains(pattern, `.z(`):
+		// ZIP split: last part is .zip, but extraction should start from .z01
+		return filepath.Join(dir, baseName+".z01")
+	default:
+		return ""
+	}
+}
+
+// isFirstPart checks if the given file is the first part of a multi-part archive
+func isFirstPart(filename string) bool {
+	info := getArchivePartInfo(filename)
+	if !info.IsMultiPart {
+		return false
+	}
+
+	// For most formats, part 1 is the first part
+	// For old-style RAR, check if this is the .rar file
+	if info.Pattern == "rar-old-style" {
+		return strings.HasSuffix(strings.ToLower(filename), ".rar")
+	}
+
+	return info.PartNumber == 1
+}
+
+// GetMultiPartArchiveBaseName returns the base name for a multi-part archive
+// This is used to group related parts together
+func GetMultiPartArchiveBaseName(filename string) string {
+	info := getArchivePartInfo(filename)
+	if !info.IsMultiPart {
+		return ""
+	}
+	return filepath.Join(filepath.Dir(filename), info.BaseName)
+}
+
+// extractMultiPartArchive extracts a multi-part archive starting from the first part
+func extractMultiPartArchive(firstPartPath string, destDir string, password string, progressCallback ExtractProgressCallback) error {
+	info := getArchivePartInfo(firstPartPath)
+
+	// For 7z multi-part archives, the bodgit/sevenzip library handles multi-volume automatically
+	// when using OpenReader with a .001 file
+	if strings.Contains(info.Pattern, `\.7z\)`) || strings.HasSuffix(strings.ToLower(firstPartPath), ".7z.001") {
+		return extractSevenZipMultiPart(firstPartPath, destDir, password, progressCallback)
+	}
+
+	// For RAR multi-part archives, use the archives library with Name and FS fields
+	if strings.Contains(info.Pattern, "rar") || info.Pattern == "rar-old-style" {
+		return extractRarMultiPart(firstPartPath, destDir, password, progressCallback)
+	}
+
+	// For ZIP multi-part archives (.zip.001, .zip.002, etc.), concatenate parts and extract
+	if strings.Contains(info.Pattern, `\.zip\)`) || strings.HasSuffix(strings.ToLower(firstPartPath), ".zip.001") {
+		return extractZipMultiPart(firstPartPath, destDir, password, progressCallback)
+	}
+
+	// For other formats, try standard extraction (may not work for all multi-part formats)
+	return extractArchive(firstPartPath, destDir, password, progressCallback)
+}

pkg/download/extract_7z.go

@@ -0,0 +1,92 @@
+package download
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/bodgit/sevenzip"
+)
+
+// extractSevenZipMultiPart extracts a multi-part 7z archive using bodgit/sevenzip directly
+// The mholt/archives wrapper doesn't properly handle multi-part 7z files because it uses
+// io.SectionReader which can only see the first part. The bodgit/sevenzip library's
+// OpenReaderWithPassword function handles multi-part files automatically when given the .001 file path.
+func extractSevenZipMultiPart(firstPartPath string, destDir string, password string, progressCallback ExtractProgressCallback) error {
+	// Use bodgit/sevenzip directly - it automatically handles .001, .002, etc. files
+	var reader *sevenzip.ReadCloser
+	var err error
+
+	if password != "" {
+		reader, err = sevenzip.OpenReaderWithPassword(firstPartPath, password)
+	} else {
+		reader, err = sevenzip.OpenReader(firstPartPath)
+	}
+	if err != nil {
+		return err
+	}
+	defer reader.Close()
+
+	// Create destination directory
+	if err := os.MkdirAll(destDir, 0755); err != nil {
+		return err
+	}
+
+	// Count total files for progress
+	totalFiles := 0
+	for _, f := range reader.File {
+		if !f.FileInfo().IsDir() {
+			totalFiles++
+		}
+	}
+
+	// Extract files with progress tracking
+	extractedFiles := 0
+	for _, f := range reader.File {
+		destPath := filepath.Join(destDir, f.Name)
+
+		if f.FileInfo().IsDir() {
+			if err := os.MkdirAll(destPath, f.Mode()); err != nil {
+				return err
+			}
+			continue
+		}
+
+		// Ensure parent directory exists
+		if err := os.MkdirAll(filepath.Dir(destPath), 0755); err != nil {
+			return err
+		}
+
+		// Extract file - open, copy, close immediately (as recommended by bodgit/sevenzip)
+		if err := extractSevenZipFile(f, destPath); err != nil {
+			return err
+		}
+
+		extractedFiles++
+		if progressCallback != nil && totalFiles > 0 {
+			progress := int(float64(extractedFiles) / float64(totalFiles) * 100)
+			progressCallback(extractedFiles, totalFiles, progress)
+		}
+	}
+
+	return nil
+}
+
+// extractSevenZipFile extracts a single file from a 7z archive
+// This follows the bodgit/sevenzip recommended pattern of closing rc before processing the next file
+func extractSevenZipFile(f *sevenzip.File, destPath string) error {
+	rc, err := f.Open()
+	if err != nil {
+		return err
+	}
+	defer rc.Close()
+
+	outFile, err := os.OpenFile(destPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
+	if err != nil {
+		return err
+	}
+	defer outFile.Close()
+
+	_, err = io.Copy(outFile, rc)
+	return err
+}

pkg/download/extract_rar.go

@@ -0,0 +1,46 @@
+package download
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+
+	"github.com/mholt/archives"
+)
+
+// extractRarMultiPart extracts a multi-part RAR archive
+func extractRarMultiPart(firstPartPath string, destDir string, password string, progressCallback ExtractProgressCallback) error {
+	// For RAR archives, we need to use the Name field in archives.Rar
+	// to let it automatically find subsequent volumes
+
+	dir := filepath.Dir(firstPartPath)
+	fileName := filepath.Base(firstPartPath)
+
+	rar := archives.Rar{
+		Password: password,
+		Name:     fileName,
+		FS:       os.DirFS(dir),
+	}
+
+	// Create destination directory
+	if err := os.MkdirAll(destDir, 0755); err != nil {
+		return err
+	}
+
+	// Count files first for progress
+	totalFiles := 0
+	err := rar.Extract(context.Background(), nil, func(ctx context.Context, fileInfo archives.FileInfo) error {
+		if !fileInfo.IsDir() {
+			totalFiles++
+		}
+		return nil
+	})
+
+	if err != nil {
+		// If counting fails, proceed without progress
+		totalFiles = 0
+	}
+
+	// Reset and extract with progress tracking
+	return rar.Extract(context.Background(), nil, createExtractionHandler(destDir, totalFiles, progressCallback))
+}

pkg/download/extract_zip.go

@@ -0,0 +1,191 @@
+package download
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/mholt/archives"
+)
+
+// extractZipMultiPart extracts a multi-part ZIP archive (.zip.001, .zip.002, etc.)
+// These are created by simply splitting a ZIP file into chunks, so we concatenate them
+func extractZipMultiPart(firstPartPath string, destDir string, password string, progressCallback ExtractProgressCallback) error {
+	// Find all parts
+	parts, err := findZipMultiParts(firstPartPath)
+	if err != nil {
+		return err
+	}
+
+	// Create a multi-part reader that reads across all parts
+	multiReader := newMultiPartFileReader(parts)
+	defer multiReader.Close()
+
+	// Get total size
+	totalSize := multiReader.Size()
+
+	// Create destination directory
+	if err := os.MkdirAll(destDir, 0755); err != nil {
+		return err
+	}
+
+	// First pass: count files for progress
+	totalFiles := 0
+	zip := archives.Zip{}
+	err = zip.Extract(context.Background(), io.NewSectionReader(multiReader, 0, totalSize), func(ctx context.Context, fileInfo archives.FileInfo) error {
+		if !fileInfo.IsDir() {
+			totalFiles++
+		}
+		return nil
+	})
+	if err != nil {
+		// If counting fails, proceed without progress
+		totalFiles = 0
+	}
+
+	// Reset reader for actual extraction
+	multiReader.Close()
+	multiReader = newMultiPartFileReader(parts)
+	defer multiReader.Close()
+
+	// Second pass: extract with progress tracking
+	return zip.Extract(context.Background(), io.NewSectionReader(multiReader, 0, totalSize), createExtractionHandler(destDir, totalFiles, progressCallback))
+}
+
+// findZipMultiParts finds all parts of a multi-part ZIP archive in order
+func findZipMultiParts(firstPartPath string) ([]string, error) {
+	// Extract base name (e.g., "Archive.zip" from "Archive.zip.001")
+	dir := filepath.Dir(firstPartPath)
+	baseName := filepath.Base(firstPartPath)
+
+	// Remove the .001 suffix to get the base
+	if idx := strings.LastIndex(baseName, "."); idx > 0 {
+		baseName = baseName[:idx] // "Archive.zip"
+	}
+
+	var parts []string
+	partNum := 1
+
+	for {
+		partPath := filepath.Join(dir, baseName+fmt.Sprintf(".%03d", partNum))
+		if _, err := os.Stat(partPath); os.IsNotExist(err) {
+			break
+		}
+		parts = append(parts, partPath)
+		partNum++
+	}
+
+	if len(parts) == 0 {
+		return nil, fmt.Errorf("no parts found for %s", firstPartPath)
+	}
+
+	return parts, nil
+}
+
+// multiPartFileReader provides io.ReaderAt over multiple files concatenated
+type multiPartFileReader struct {
+	parts     []string
+	files     []*os.File
+	sizes     []int64
+	offsets   []int64 // cumulative offsets for each file
+	totalSize int64
+}
+
+func newMultiPartFileReader(parts []string) *multiPartFileReader {
+	return &multiPartFileReader{parts: parts}
+}
+
+func (m *multiPartFileReader) init() error {
+	if m.files != nil {
+		return nil
+	}
+
+	m.files = make([]*os.File, len(m.parts))
+	m.sizes = make([]int64, len(m.parts))
+	m.offsets = make([]int64, len(m.parts))
+
+	var offset int64
+	for i, part := range m.parts {
+		f, err := os.Open(part)
+		if err != nil {
+			m.Close()
+			return err
+		}
+		stat, err := f.Stat()
+		if err != nil {
+			f.Close()
+			m.Close()
+			return err
+		}
+		m.files[i] = f
+		m.sizes[i] = stat.Size()
+		m.offsets[i] = offset
+		offset += stat.Size()
+	}
+	m.totalSize = offset
+
+	return nil
+}
+
+func (m *multiPartFileReader) Size() int64 {
+	if err := m.init(); err != nil {
+		return 0
+	}
+	return m.totalSize
+}
+
+func (m *multiPartFileReader) ReadAt(p []byte, off int64) (n int, err error) {
+	if err := m.init(); err != nil {
+		return 0, err
+	}
+
+	if off >= m.totalSize {
+		return 0, io.EOF
+	}
+
+	// Find which file(s) to read from
+	for i, fileOffset := range m.offsets {
+		fileEnd := fileOffset + m.sizes[i]
+
+		if off >= fileEnd {
+			continue
+		}
+
+		// Read from this file
+		localOffset := off - fileOffset
+		toRead := len(p) - n
+		if int64(toRead) > fileEnd-off {
+			toRead = int(fileEnd - off)
+		}
+
+		read, err := m.files[i].ReadAt(p[n:n+toRead], localOffset)
+		n += read
+		off += int64(read)
+
+		if err != nil && err != io.EOF {
+			return n, err
+		}
+
+		if n >= len(p) {
+			return n, nil
+		}
+	}
+
+	if n == 0 {
+		return 0, io.EOF
+	}
+	return n, nil
+}
+
+func (m *multiPartFileReader) Close() error {
+	for _, f := range m.files {
+		if f != nil {
+			f.Close()
+		}
+	}
+	m.files = nil
+	return nil
+}