WeKnora deployment source with the reviewed wiki identity, summary and recovery fixes

cli/cmd/doc/download.go

@@ -0,0 +1,200 @@
+package doc
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+
+	"github.com/Tencent/WeKnora/cli/internal/cmdutil"
+	"github.com/Tencent/WeKnora/cli/internal/iostreams"
+)
+
+// downloadFields enumerates the fields surfaced for `--format json` discovery on
+// `doc download`. Matches the downloadResult struct.
+var downloadFields = []string{"path", "bytes", "filename"}
+
+// downloadResult is the typed payload emitted as the success envelope when
+// --format json is requested and output is going to a file (not stdout).
+type downloadResult struct {
+	Path     string `json:"path"`
+	Bytes    int64  `json:"bytes"`
+	Filename string `json:"filename"`
+}
+
+type DownloadOptions struct {
+	Output  string // --output / -O: target path, "-" for stdout, "" for server-suggested filename
+	Clobber bool   // --clobber: allow overwrite of an existing file
+}
+
+// DownloadService is the narrow SDK surface this command depends on. The
+// CLI calls OpenKnowledgeFile so it can inspect the server-suggested
+// filename and refuse-to-overwrite *before* streaming any bytes.
+type DownloadService interface {
+	OpenKnowledgeFile(ctx context.Context, knowledgeID string) (string, io.ReadCloser, error)
+}
+
+// NewCmdDownload builds `weknora doc download <id>`. Positional id, output
+// flag, `-` sentinel for stdout. Flags: `-O, --output <file>` for
+// destination, `--clobber` for overwrite control.
+func NewCmdDownload(f *cmdutil.Factory) *cobra.Command {
+	opts := &DownloadOptions{}
+	cmd := &cobra.Command{
+		Use:   "download <doc-id>",
+		Short: "Download a document by ID",
+		Long: `Streams the document bytes to disk (or stdout with --output -).
+
+Default behavior (no --output): writes to the cwd under the filename the
+server suggests via Content-Disposition. If the server doesn't suggest
+one, the command errors and asks for --output FILE explicitly.
+
+Existing files are NOT overwritten unless --clobber is passed.
+
+With --format json, on success emits a JSON envelope whose data has
+path, bytes, and filename fields. When output is stdout (--output -),
+the JSON envelope is suppressed because the raw bytes already occupy
+stdout.`,
+		Example: `  weknora doc download doc_abc                       # writes ./<server-name>
+  weknora doc download doc_abc -O report.pdf
+  weknora doc download doc_abc --output -            # stream to stdout (binary safe)
+  weknora doc download doc_abc -O report.pdf --clobber
+  weknora doc download doc_abc -O report.pdf --format json   # JSON envelope`,
+		Args: cobra.ExactArgs(1),
+		RunE: func(c *cobra.Command, args []string) error {
+			fopts, err := cmdutil.CheckFormatFlag(c)
+			if err != nil {
+				return err
+			}
+			fopts.ResolveDefault(iostreams.IO.IsStdoutTTY())
+			cli, err := f.Client()
+			if err != nil {
+				return err
+			}
+			return runDownload(c.Context(), opts, fopts, cli, args[0])
+		},
+	}
+	cmd.Flags().StringVarP(&opts.Output, "output", "O", "", `Output path; "-" for stdout. Defaults to the server-suggested filename.`)
+	cmd.Flags().BoolVar(&opts.Clobber, "clobber", false, "Overwrite the output file if it already exists")
+	cmdutil.AddIgnoredKBFlag(cmd)
+	cmdutil.AddFormatFlag(cmd, downloadFields...)
+	cmdutil.SetAgentHelp(cmd, cmdutil.AgentHelp{
+		UsedFor:       "Download a document's bytes by id. Writes a file (or stdout with --output -).",
+		RequiredFlags: []string{"<doc-id> (positional)"},
+		Output:        "with --format json (file output): envelope.data has path, bytes, filename; suppressed with --output - (raw bytes to stdout)",
+		Examples: []string{
+			"weknora doc download doc_abc --output ./manual.pdf",
+			"weknora doc download doc_abc --output - > manual.pdf",
+		},
+	})
+	return cmd
+}
+
+func runDownload(ctx context.Context, opts *DownloadOptions, fopts *cmdutil.FormatOptions, svc DownloadService, id string) error {
+	suggested, body, err := svc.OpenKnowledgeFile(ctx, id)
+	if err != nil {
+		return cmdutil.WrapHTTP(err, "download %s", id)
+	}
+	defer body.Close()
+
+	dest, err := resolveDownloadDest(opts, suggested)
+	if err != nil {
+		return err
+	}
+	if dest == "-" {
+		// Raw bytes go to stdout — suppress any JSON envelope regardless of
+		// --format json because both can't occupy stdout simultaneously.
+		_, err := io.Copy(iostreams.IO.Out, body)
+		return err
+	}
+	if err := refuseIfExists(dest, opts.Clobber); err != nil {
+		return err
+	}
+	return streamToFile(body, dest, fopts)
+}
+
+// resolveDownloadDest returns the final destination ("-" for stdout, an
+// absolute or relative path otherwise) after applying the --output flag
+// and sanitizing the server-suggested name. A server that returns a path-
+// like filename (..\, /etc/foo) is rejected - only the basename is
+// accepted.
+func resolveDownloadDest(opts *DownloadOptions, suggested string) (string, error) {
+	if opts.Output == "-" {
+		return "-", nil
+	}
+	if opts.Output != "" {
+		return opts.Output, nil
+	}
+	if suggested == "" {
+		return "", &cmdutil.Error{
+			Code:    cmdutil.CodeInputMissingFlag,
+			Message: "server did not supply a filename and --output is unset",
+			Hint:    "pass --output FILE (or --output - for stdout)",
+		}
+	}
+	base := filepath.Base(suggested)
+	if base == "" || base == "." || base == ".." || base == string(filepath.Separator) {
+		return "", &cmdutil.Error{
+			Code:    cmdutil.CodeInputInvalidArgument,
+			Message: fmt.Sprintf("server returned an unusable filename %q", suggested),
+			Hint:    "pass --output FILE explicitly",
+		}
+	}
+	return base, nil
+}
+
+// refuseIfExists returns CodeInputInvalidArgument when path is present on
+// disk and clobber is false. Missing-file is success.
+func refuseIfExists(path string, clobber bool) error {
+	if clobber {
+		return nil
+	}
+	_, err := os.Stat(path)
+	if errors.Is(err, os.ErrNotExist) {
+		return nil
+	}
+	if err != nil {
+		return cmdutil.Wrapf(cmdutil.CodeLocalFileIO, err, "stat %s", path)
+	}
+	return &cmdutil.Error{
+		Code:    cmdutil.CodeInputInvalidArgument,
+		Message: fmt.Sprintf("%s already exists", path),
+		Hint:    "pass --clobber to overwrite",
+	}
+}
+
+// streamToFile copies body into a newly-created file at path. On any
+// streaming error the partial file is removed so callers don't see a
+// truncated artifact at the user-visible path.
+//
+// On success: if fopts.WantsJSON(), emits a downloadResult envelope to
+// stdout instead of the "✓ Saved" text.
+func streamToFile(body io.Reader, path string, fopts *cmdutil.FormatOptions) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return cmdutil.Wrapf(cmdutil.CodeLocalFileIO, err, "create %s", path)
+	}
+	n, copyErr := io.Copy(f, body)
+	if copyErr != nil {
+		_ = f.Close()
+		_ = os.Remove(path)
+		return cmdutil.Wrapf(cmdutil.CodeLocalFileIO, copyErr, "write %s", path)
+	}
+	if err := f.Close(); err != nil {
+		_ = os.Remove(path)
+		return cmdutil.Wrapf(cmdutil.CodeLocalFileIO, err, "close %s", path)
+	}
+
+	if fopts.WantsJSON() {
+		return fopts.Emit(iostreams.IO.Out, downloadResult{
+			Path:     path,
+			Bytes:    n,
+			Filename: filepath.Base(path),
+		}, nil)
+	}
+	fmt.Fprintf(iostreams.IO.Err, "✓ Saved %s\n", path)
+	return nil
+}