command: add presign command (#634)

command/app.go

@@ -209,6 +209,7 @@ func Commands() []*cli.Command {
 		NewSyncCommand(),
 		NewVersionCommand(),
 		NewBucketVersionCommand(),
+		NewPresignCommand(),
 	}
 }
 

command/presign.go

@@ -0,0 +1,134 @@
+package command
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/urfave/cli/v2"
+
+	"github.com/peak/s5cmd/v2/log/stat"
+	"github.com/peak/s5cmd/v2/storage"
+	"github.com/peak/s5cmd/v2/storage/url"
+)
+
+var presignHelpTemplate = `Name:
+	{{.HelpName}} - {{.Usage}}
+
+Usage:
+	{{.HelpName}} [options] source
+
+Options:
+	{{range .VisibleFlags}}{{.}}
+	{{end}}
+Examples:
+	1. Print a remote object url to stdout
+		 > s5cmd {{.HelpName}} s3://bucket/prefix/object
+
+	2. Print a remote object url with a specific expiration time to stdout
+		 > s5cmd {{.HelpName}} --expire 24h s3://bucket/prefix/object
+`
+
+func NewPresignCommand() *cli.Command {
+	cmd := &cli.Command{
+		Name:     "presign",
+		HelpName: "presign",
+		Usage:    "print remote object presign url",
+		Flags: []cli.Flag{
+			&cli.DurationFlag{
+				Name:  "expire",
+				Usage: "url valid duration",
+				Value: time.Hour * 3,
+			},
+			&cli.StringFlag{
+				Name:  "version-id",
+				Usage: "use the specified version of an object",
+			},
+		},
+		CustomHelpTemplate: presignHelpTemplate,
+		Before: func(c *cli.Context) error {
+			err := validatePresignCommand(c)
+			if err != nil {
+				printError(commandFromContext(c), c.Command.Name, err)
+			}
+			return err
+		},
+		Action: func(c *cli.Context) (err error) {
+			defer stat.Collect(c.Command.FullName(), &err)()
+
+			op := c.Command.Name
+			fullCommand := commandFromContext(c)
+
+			src, err := url.New(c.Args().Get(0), url.WithVersion(c.String("version-id")))
+			if err != nil {
+				printError(fullCommand, op, err)
+				return err
+			}
+
+			return Presign{
+				src:         src,
+				op:          op,
+				fullCommand: fullCommand,
+				expire:      c.Duration("expire"),
+				storageOpts: NewStorageOpts(c),
+			}.Run(c.Context)
+		},
+	}
+	return cmd
+}
+
+// Presign holds presign operation flags and states.
+type Presign struct {
+	src         *url.URL
+	op          string
+	fullCommand string
+	expire      time.Duration
+
+	storageOpts storage.Options
+}
+
+// Run prints content of given source to standard output.
+func (c Presign) Run(ctx context.Context) error {
+	client, err := storage.NewRemoteClient(ctx, c.src, c.storageOpts)
+	if err != nil {
+		printError(c.fullCommand, c.op, err)
+		return err
+	}
+
+	url, err := client.Presign(ctx, c.src, c.expire)
+	if err != nil {
+		printError(c.fullCommand, c.op, err)
+		return err
+	}
+	fmt.Println(url)
+	return nil
+}
+
+func validatePresignCommand(c *cli.Context) error {
+	if c.Args().Len() != 1 {
+		return fmt.Errorf("expected only one argument")
+	}
+
+	src, err := url.New(c.Args().Get(0), url.WithVersion(c.String("version-id")))
+	if err != nil {
+		return err
+	}
+
+	if !src.IsRemote() {
+		return fmt.Errorf("source must be a remote object")
+	}
+
+	if src.IsBucket() || src.IsPrefix() {
+		return fmt.Errorf("remote source must be an object")
+	}
+
+	if src.IsWildcard() {
+		return fmt.Errorf("remote source %q can not contain glob characters", src)
+	}
+
+	if err := checkVersioningWithGoogleEndpoint(c); err != nil {
+		return err
+	}
+
+	return nil
+}

storage/s3.go

@@ -558,6 +558,19 @@ func (s *S3) Read(ctx context.Context, src *url.URL) (io.ReadCloser, error) {
 	return resp.Body, nil
 }
 
+// Presign fetches the remote object url and returns its.
+func (s *S3) Presign(ctx context.Context, from *url.URL, expire time.Duration) (string, error) {
+	input := &s3.GetObjectInput{
+		Bucket:       aws.String(from.Bucket),
+		Key:          aws.String(from.Path),
+		RequestPayer: s.RequestPayer(),
+	}
+
+	req, _ := s.api.GetObjectRequest(input)
+	url, err := req.Presign(expire)
+	return url, err
+}
+
 // Get is a multipart download operation which downloads S3 objects into any
 // destination that implements io.WriterAt interface.
 // Makes a single 'GetObject' call if 'concurrency' is 1 and ignores 'partSize'.