예제 #1
0
// download starts or resumes and download. Always closes dlFile if non-nil
func (a *basicDownloadAdapter) download(t *Transfer, cb TransferProgressCallback, authOkFunc func(), dlFile *os.File, fromByte int64, hash hash.Hash) error {

	if dlFile != nil {
		// ensure we always close dlFile. Note that this does not conflict with the
		// early close below, as close is idempotent.
		defer dlFile.Close()
	}

	rel, ok := t.Object.Rel("download")
	if !ok {
		return errors.New("Object not found on the server.")
	}

	req, err := httputil.NewHttpRequest("GET", rel.Href, rel.Header)
	if err != nil {
		return err
	}

	if fromByte > 0 {
		if dlFile == nil || hash == nil {
			return fmt.Errorf("Cannot restart %v from %d without a file & hash", t.Object.Oid, fromByte)
		}
		// We could just use a start byte, but since we know the length be specific
		req.Header.Set("Range", fmt.Sprintf("bytes=%d-%d", fromByte, t.Object.Size-1))
	}

	res, err := httputil.DoHttpRequest(req, true)
	if err != nil {
		// Special-case status code 416 () - fall back
		if fromByte > 0 && dlFile != nil && res.StatusCode == 416 {
			tracerx.Printf("xfer: server rejected resume download request for %q from byte %d; re-downloading from start", t.Object.Oid, fromByte)
			dlFile.Close()
			os.Remove(dlFile.Name())
			return a.download(t, cb, authOkFunc, nil, 0, nil)
		}
		return errutil.NewRetriableError(err)
	}
	httputil.LogTransfer("lfs.data.download", res)
	defer res.Body.Close()

	// Range request must return 206 & content range to confirm
	if fromByte > 0 {
		rangeRequestOk := false
		var failReason string
		// check 206 and Content-Range, fall back if either not as expected
		if res.StatusCode == 206 {
			// Probably a successful range request, check Content-Range
			if rangeHdr := res.Header.Get("Content-Range"); rangeHdr != "" {
				regex := regexp.MustCompile(`bytes (\d+)\-.*`)
				match := regex.FindStringSubmatch(rangeHdr)
				if match != nil && len(match) > 1 {
					contentStart, _ := strconv.ParseInt(match[1], 10, 64)
					if contentStart == fromByte {
						rangeRequestOk = true
					} else {
						failReason = fmt.Sprintf("Content-Range start byte incorrect: %s expected %d", match[1], fromByte)
					}
				} else {
					failReason = fmt.Sprintf("badly formatted Content-Range header: %q", rangeHdr)
				}
			} else {
				failReason = "missing Content-Range header in response"
			}
		} else {
			failReason = fmt.Sprintf("expected status code 206, received %d", res.StatusCode)
		}
		if rangeRequestOk {
			tracerx.Printf("xfer: server accepted resume download request: %q from byte %d", t.Object.Oid, fromByte)
			// Advance progress callback; must split into max int sizes though
			if cb != nil {
				const maxInt = int(^uint(0) >> 1)
				for read := int64(0); read < fromByte; {
					remainder := fromByte - read
					if remainder > int64(maxInt) {
						read += int64(maxInt)
						cb(t.Name, t.Object.Size, read, maxInt)
					} else {
						read += remainder
						cb(t.Name, t.Object.Size, read, int(remainder))
					}

				}
			}
		} else {
			// Abort resume, perform regular download
			tracerx.Printf("xfer: failed to resume download for %q from byte %d: %s. Re-downloading from start", t.Object.Oid, fromByte, failReason)
			dlFile.Close()
			os.Remove(dlFile.Name())
			if res.StatusCode == 200 {
				// If status code was 200 then server just ignored Range header and
				// sent everything. Don't re-request, use this one from byte 0
				dlFile = nil
				fromByte = 0
				hash = nil
			} else {
				// re-request needed
				return a.download(t, cb, authOkFunc, nil, 0, nil)
			}
		}
	}

	// Signal auth OK on success response, before starting download to free up
	// other workers immediately
	if authOkFunc != nil {
		authOkFunc()
	}

	var hasher *tools.HashingReader
	if fromByte > 0 && hash != nil {
		// pre-load hashing reader with previous content
		hasher = tools.NewHashingReaderPreloadHash(res.Body, hash)
	} else {
		hasher = tools.NewHashingReader(res.Body)
	}

	if dlFile == nil {
		// New file start
		dlFile, err = os.OpenFile(a.downloadFilename(t), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
		if err != nil {
			return err
		}
		defer dlFile.Close()
	}
	dlfilename := dlFile.Name()
	// Wrap callback to give name context
	ccb := func(totalSize int64, readSoFar int64, readSinceLast int) error {
		if cb != nil {
			return cb(t.Name, totalSize, readSoFar+fromByte, readSinceLast)
		}
		return nil
	}
	written, err := tools.CopyWithCallback(dlFile, hasher, res.ContentLength, ccb)
	if err != nil {
		return fmt.Errorf("cannot write data to tempfile %q: %v", dlfilename, err)
	}
	if err := dlFile.Close(); err != nil {
		return fmt.Errorf("can't close tempfile %q: %v", dlfilename, err)
	}

	if actual := hasher.Hash(); actual != t.Object.Oid {
		return fmt.Errorf("Expected OID %s, got %s after %d bytes written", t.Object.Oid, actual, written)
	}

	return tools.RenameFileCopyPermissions(dlfilename, t.Path)

}
예제 #2
0
파일: custom.go 프로젝트: zhaohaiyi/git-lfs
func (a *customAdapter) DoTransfer(ctx interface{}, t *Transfer, cb TransferProgressCallback, authOkFunc func()) error {
	if ctx == nil {
		return fmt.Errorf("Custom transfer %q was not properly initialized, see previous errors", a.name)
	}

	customCtx, ok := ctx.(*customAdapterWorkerContext)
	if !ok {
		return fmt.Errorf("Context object for custom transfer %q was of the wrong type", a.name)
	}
	var authCalled bool

	rel, ok := t.Object.Rel(a.getOperationName())
	if !ok {
		return errors.New("Object not found on the server.")
	}
	var req *customAdapterTransferRequest
	if a.direction == Upload {
		req = NewCustomAdapterUploadRequest(t.Object.Oid, t.Object.Size, t.Path, rel)
	} else {
		req = NewCustomAdapterDownloadRequest(t.Object.Oid, t.Object.Size, rel)
	}
	err := a.sendMessage(customCtx, req)
	if err != nil {
		return err
	}

	// 1..N replies (including progress & one of download / upload)
	var complete bool
	for !complete {
		resp, err := a.readResponse(customCtx)
		if err != nil {
			return err
		}
		var wasAuthOk bool
		switch resp.Event {
		case "progress":
			// Progress
			if resp.Oid != t.Object.Oid {
				return fmt.Errorf("Unexpected oid %q in response, expecting %q", resp.Oid, t.Object.Oid)
			}
			if cb != nil {
				cb(t.Name, t.Object.Size, resp.BytesSoFar, resp.BytesSinceLast)
			}
			wasAuthOk = resp.BytesSoFar > 0
		case "complete":
			// Download/Upload complete
			if resp.Oid != t.Object.Oid {
				return fmt.Errorf("Unexpected oid %q in response, expecting %q", resp.Oid, t.Object.Oid)
			}
			if resp.Error != nil {
				return fmt.Errorf("Error transferring %q: %v", t.Object.Oid, resp.Error)
			}
			if a.direction == Download {
				// So we don't have to blindly trust external providers, check SHA
				if err = tools.VerifyFileHash(t.Object.Oid, resp.Path); err != nil {
					return fmt.Errorf("Downloaded file failed checks: %v", err)
				}
				// Move file to final location
				if err = tools.RenameFileCopyPermissions(resp.Path, t.Path); err != nil {
					return fmt.Errorf("Failed to copy downloaded file: %v", err)
				}
			} else if a.direction == Upload {
				if err = api.VerifyUpload(config.Config, t.Object); err != nil {
					return err
				}
			}
			wasAuthOk = true
			complete = true
		default:
			return fmt.Errorf("Invalid message %q from custom adapter %q", resp.Event, a.name)
		}
		// Fall through from both progress and completion messages
		// Call auth on first progress or success to free up other workers
		if wasAuthOk && authOkFunc != nil && !authCalled {
			authOkFunc()
			authCalled = true
		}
	}

	return nil
}